June, 2005

Transcription

June, 2005

The Shell Petroleum Development Company of Nigeria Limited Operator for
the NNPC/Shell/Agip/Elf Joint Venture
ENVIRONMENTAL IMPACT ASSESSMENT (EIA)
(FINAL REPORT)
OF
THE OPUGBENE-WEST (TOLOGBENE) PROSPECT
EXPLORATION DRILLING
Report: SPDC 2002-465
June, 2005
Final EIA of Opugbene-West (Tologbene) Prospect Exploration Drilling
Title:
ENVIRONMENTAL IMPACT ASSESSMENT (EIA)
(FINAL REPORT) OF THE OPUGBENE-WEST (TOLOGBENE)
PROSPECT EXPLORATION DRILLING
Originator:
Corporate Environmental Department,
The Shell Petroleum Development Company of Nigeria Limited
Author:
EPG-PN-CFHEV
Approved by:
EPX-G-XNEO
Document Number: SPDC 2002-465
Date:
June 2005
Version:
02
Security:
Change History:
Version
Date
Pages
Reason
01
October 2002
Whole Document
Complete Revision
02
June 2005
Whole Document
Complete Revision
Chapter Three
June 2005
Page 2 of 14
TABLE OF CONTENTS
TITLE
Status Page
Tables of Contents
List of Tables
List of Figures
List of Plates
Abbreviations and Acronyms
List of Preparers
Acknowledgement
Executive Summary
PAGE
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iv of xiv
v of xiv
viii of xiv
vix of xiv
xiii of xiv
xiv of xiv
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CHAPTER ONE
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
10.0
INTRODUCTION
Background
Terms of Reference
Nigeria
The Applicant
The EIA Premises
Administrative and Legal Framework
Objectives of EIA
Benefits of the EIA
EIA Methodology
Structure of the Report
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CHAPTER TWO
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.6.1
2.6.2
2.7
2.8
2.8.1
2.9
PROJECT SETTING
Declaration
The Project Site/Area description
Project Justification
Value of the Project
Envisaged sustainability
Project Alternatives
No Drilling Option
Exploratory Drilling Option
HSE Management Strategy
The SHELL Policy
The Strategy
Safety Evaluation
CHAPTER THREE
3.0
3.1
3.2
3.3
3.4
3.4.1
Chapter Three
PROJECT AND PROCESS DESCRIPTION
The Proposed Project
Project Scope
Project Site/Area
Design of Facilities
Basis for Design
June 2005
Page 3 of 14
3.5
3.5.1
3.5.2
3.5.3
3.6
3.6.1
3.6.2
3.7
3.7.1
3.7.2
3.8
3.9
The Project Activities
Pre-Construction/Construction Activities
Drilling Programme
Waste Management Strategy
Operation and Maintenance Activities
General
Operation
Decommissioning/Abandonment
General
Demolition and Site Clean-up
Oil Spill Contingency Plan
Project Schedule
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CHAPTER FOUR
4.0
4.1
4.2
4.3
4.4
4.5
4.6
STAKEHOLDER CONSULTATIONS
Introduction
Objectives of Stakeholder Consultation
Principal Stakeholders
Regulators
Issues of Concern
Future Stakeholder Consultations
1
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CHAPTER FIVE
5.0
DESCRIPTION OF THE ENVIRONMENT
5.1
Baseline Data Acquisition Methods
5.2
Study Approach
5.3
Geographical Location
5.4
Field Data
5.4.1 Climatic Conditions
5.4.2 Air Quality Assessments
5.4.3 Noise Level Assessment
5.4.4 Soil and Land Use Pattern
5.4.4.1
Soil
5.4.4.2
Land Use Pattern
5.4.5 Terrestrial Ecology
5.4.5.1
Vegetation
5.4.5.2
Ecologically Sensitive Areas
5.4.5.3
Wild Life and Forestry
5.4.6 Geology, Hydrogeology and Geophysical Survey
5.4.6.1
Geology
5.4.6.2
Hydrogeology
5.4.6.3
Geophysical Survey
5.4.6 Water Quality
5.4.61 Surface Hydrology
5.4.6.2
Ground Water Quality
5.4.7 Sediment Quality
5.4.8 Microbiological Studies
5.4.9 Aquatic Ecological
5.4.10 Socio-economic Status
5.4.10.1
The Social Environment
5.4.10.3
Population
Chapter Three
June 2005
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Page 4 of 14
5.4.10.4
5.4.10.5
5.4.10.6
5.4.10.7
Economic Environment
Quality of Life
Archaeological Studies
Health Status
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CHAPTER SIX
•
6.0
6.1
6.2
6.3
6.4
6.5
Hemp
ASSOCIATED AND POTENTIAL ENVIRONMENTAL IMPACTS
1
Introduction
1
Impacts Identification Methodology
1
Potential Impact Evaluation
4
Characterisation of Associated and Potential Impacts
8
Environmental Risk Assessment
9
Process
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CHAPTER SEVEN
7.0
7.1
7.2
MITIGATION MEASURES
General
Best Available Technology
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CHAPTER EIGHT
8.0
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
ENVIRONMENTAL MANAGEMENT PLAN
Introduction
The Shell Approach
Audit Programme
Waste Management
Resource Requirement
Monitoring Programmed
Responsibilities and Training
Oil Spillage and Contingency Plans
Consultation
Emergency Response Plan
Remediation Plans after Decommissioning/
Abandonment/Closure
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CHAPTER NINE
9.0
CONCLUSIONS AND RECOMMENDATIONS
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REFERENCES
GLOSSARY OF TERMS
APPENDICES
Chapter Three
June 2005
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LIST OF TABLES
Table 3.1:
Waste Generation & Management Strategy
Table 5.1:
Ambient Concentrations of Air Pollutants at some
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Locations during the Wet and Dry Seasons Field Sampling 6 of 68
Table 5.2
Nigerian Ambient Air Quality Standards (FEPA, 1991)
Table 5.3:
World Health Organisation (WHO) Guidelines for Maximum
6 of 68
Exposure to the Major Pollutants and Possible Effects if
Exceeded.
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Table 5.4:
Tolerance Limits (µg/m3) for some Ambient Air Pollutants
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Table 5.5:
Mean and Range of Noise Levels in the Study Area
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Table 5.6:
Noise Exposure Limits for Nigeria
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Table 5.7
Description of Soil pH
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Table 5.8:
Economic Uses of the Key Plant Species
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Table 5.9:
Checklist of Reptilian and Amphibian Species
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Table 5.10:
Checklist of Bird Species
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Table 5.11:
Checklist of Mammalian Species
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Table 5.12:
Stratigraphic Sequence of the Niger Delta Basin with Aquifer
Prospectivity
Table 5.13:
Table 5.14:
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Representative Boreholes/ VES Stations and their
Individual Depths of Penetration
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Guidelines of Water Quality for Different Purposes
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Table 5.15a: Wet Season Physico-Chemical Characteristics of Sediment 44 of 68
Table 5.15b: Dry Season Physico-Chemical Characteristics of Sediment
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Table 5.16a: The Levels of Cadmium, Chromium, Copper, Lead & Zinc
in Unpolluted Soils (Concentration in ppm)
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Table 5.16b: Range in Micro-Nutrient Content Commonly Found in Soils 46 of 68
Table 5.17:
Microbial Densities of Surface Water Samples for Wet and
Dry Seasons
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Table5.18:
Microbial Densities of Ground Water Samples
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Table 5.19:
Microbial Densities of Sediment Samples
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Table 5.20a: Microbiology of Soil in the Wet Season
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Table 5.20b: Microbiology of Soil in the Dry Season
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Table 5.21:
Species Abundance and Condition Factor of the Fin
and Shellfishes in the Waters
Chapter Three
June 2005
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Page 6 of 14
Table 5.22:
Gonado-somatic Ratio for Major Species
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Table 5.23:
Summary of Stomach Content Analyses
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Table 5.24: Common Fish Species and Landing Estimates Per Gear
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Table 5.25:
Estimated Population of the Study Area by Settlements
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Table 5.26:
Distribution of Ages in the Study Area
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Table 5.27:
Estimated Annual Income of Households
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Table 6.1:
Environmental Components and Potential Impact
Indicators
Table 6.2:
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Project Phases and Description of Potential and
Associated Impacts
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Table 6.3:
Associated and Potential Impacts Evaluation
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Table 6.4:
Characterisation of Associated and Potential
Impacts of the Proposed Exploratory Drilling Project
Table 6.5:
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Environmental Risk Assessment of the Exploratron
Drilling Project
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Table 7.1:
Mitigation Measures for Identified Potential Impacts
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Table 8.1
Monitoring Program for the Prospect Exploration
Drilling Project
Table 8.2:
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Environmental Monitoring Programme for the
Exploration Drilling Project
Chapter Three
June 2005
5 of 7
Page 7 of 14
LIST OF FIGURES
Figure 2.0:
Location Map of Opugbene (Tologbene)
Figure 3.0
Proposed Prospect Exploration Well Location in
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Opugbene (Tologbene)
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Figure 3.1:
Opugbene-Tebidaba E5000 Top Reservoir Depth Map
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Figure 3.2:
Chosen Design: Tologbene-1X Exploration Well
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Figure 3.3:
Political Map of Bayelsa State Showing of Opugbene
(Tologbene)
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Figure 3.4:
Full Preparation Survey of Tologbene Exploration Location 12 of 14
Figure 3.6:
Full Preparation Survey of Tologbene Exploration Location
(Creek extension)
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Figure 3.7:
Project Schedule
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Figure 5.0
Sample Location Map of Opugbene (Tologbene)
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Figure 5.1:
Wind Distribution Pattern (Rose) for Opugbene
(Tologbene) Field
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Figure 5.2:
Landuse/Cover Map of Opugbene (Tologbene)
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Figure 5.3:
Borehole lithological profile for BOREHOLE-1 located
at Ikebiri primary school.
Figure 5.4:
at Ikebiri (by Agip Line)
Figure 5.5:
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at Mammy Water Creek opposite Ikebiri market
Figure 5.9:
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at Mammy Water Creek near Ikebiri market
Figure 5.8:
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at Bolokubu- Ikebiri
Figure 5.7:
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at Ikebiri market (by Agip Line).
Figure 5.6:
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at Ikebiri Creek near Okumutorupa village
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Figure 5.10: Borehole lithological profile for BOREHOLE-8
located near Well-13 (along Agip Line)
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Figure 5.11: Wet Season Graphical Trend of pH, TSS and
Turbidity of Surface Waters
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Figure 5.12: Dry Season Graphical Trend of pH, TSS and
Turbidity of Surface Waters
Chapter Three
June 2005
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Page 8 of 14
Figure 5.13: Wet Season Trend Graph of Conductivity, Total Dissolved
Solids and Salinity of Surface Waters
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Figure 5.14: Dry Season Trend Graph of Conductivity, Total Dissolved
Solids and Salinity of Surface Waters
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Figure 5.15: Wet Season Graphical Relationship of pH, Dissolved
Oxygen and Biochemical Oxygen Demand of
Surface Waters
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Figure 5.16: Dry Season Graphical Relationship of pH,
Dissolved Oxygen and Biochemical Oxygen Demand
of Surface Waters
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Figure 5.17: Wet Season Graphical Relationship of Exchangeable
Cations of Surface Waters
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Figure 5.18: Dry Season Graphical Relationship of Exchangeable
Cations of Surface Waters
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Figure 5.19: Wet Season Graphical Trend of pH, Turbidity and
TSS of Ground Water
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Figure 5.20: Dry Season Graphical Trend of pH, Turbidity and TSS
of Ground Water
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Figure 5.21: Wet Season Graphical Relationship of
Conductivity, Total Dissolved Solids and Salinity of
Ground Water
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Figure 5.22: Dry Season Graphical Relationship of Conductivity,
Total Dissolved Solids and Salinity of Ground Water
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Figure 5.23: Wet Season Percentage Composition of the major
Divisions of Phytoplankton
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Figure 5.24: Dry Season Percentage Composition of the major
Divisions of Phytoplankton
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Figure 5.25: Wet Season Percentage Composition of the major Order
of Zooplankton
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Figure 5.26: Dry Season Percentage Composition of the major Order
of Zooplankton
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Figure 5.27: Wet Season Percentage Composition of the major
Order of Benthic macrofauna
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Figure 5.28: Dry Season Percentage Composition of the major Order
of Benthic macrofauna
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Figure 5.29: Distribution of Deaths by Age Group in Niger Delta Region 66 of 68
Figure 6.1: Assessment of Potential and Associated Impacts
Chapter Three
June 2005
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Page 9 of 14
Figure 6.2:
Approach to Impact Assessment Using
ISO 14001 Guideline
Chapter Three
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June 2005
Page 10 of 14
LIST OF PLATES
Plate 4.1:
Consultation Session with Ikebiri Community
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Plate 4.2:
Consultation Session with Ikebiri Community
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Plate 5.1:
Logging Activities in the Study Area
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Plate 5.2:
Mix Forest in the Study Area
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Plate 5.3:
Ikebiri I Community
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Plate 5.4:
Ikebiri II Community
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Plate 5.5:
Fish Caught in the Area on Display for Sale
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Plate 5.6:
Fish Caught in the Area being Dried
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Chapter Three
June 2005
Page 11 of 14
LIST OF ABBREVIATIONS AND ACRONYMS
AAS
AG
Al
ALSCON
AMU
APHA
B&K
bbls/d
BH
BOD
C
Ca
CaCO3
CBA
Cc
CCl4
Cd
cfu
CITES
Cl
CLO
cm
Co
COD
COMAC
CCP
CPP
Cu
Cv
D
d
dB
DEG
DO
DOF
DPR
DS
EBH
E
EA
EC
ECEC
EDTA
ESD
Fe
FEPA
FGIIP
FLKO
FMENV
FS
GP
Chapter Three
-
Atomic absorption spectrophotometer
Associated gas
Aluminium
Aluminium Smelting Company of Nigeria
Atomic mass units
America Public Health Association
Bruel and Kjaer
barrels per day
Borehole
Biochemical Oxygen Demand
Carbon
Calcium
Calcium Carbonate
Cost Benefit Analysis
Cost of conservation
Carbon tetrachloride (Tetrachloromethane)
Cadmium
Colony forming unit
Convention on International Trade in Endangered Species
Chloride
Community Liaison Officer
centimetre
Cobalt
Chemical Oxygen Demand
Computer Aided Maintenance Management System
Consolidated Contromatic Pump
Consolidated Pneumatic Pump
Copper
contingent value
hydrodynamic dispersion coefficient
Margalef's index
Decibel
Diethylene Glycol
Dissolved oxygen
Daniels Orifice Fitting
Department of Petroleum Resources
Dissolved solids
Borehole Sample Station
Evenness
Exchangeable acidity
Electrical conductivity
Effective Cation Exchange capacity
Ethylenediaminotetra-acetic acid
Emergency Shut Down
Iron
Federal Environmental Protection Agency
Free Gas In Place
Free Liquid Knock Out
Federal Ministry of Environment
Flowstation
Gas Plant
June 2005
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g
g
h
h
H
H
HAC
HCO3
Hg
HP
h1
Chapter Three
-
H20
H 2S
IA
kg
LC50
-
LLWSL
log
LP
Ls
LTS
m
M
MEDEVAC
meq
METS
Mg
mg
MJR
ml
mm
mmb
mmstb
mmscfd
Mn
MOU
mS
MSDV
my
n
N
Na
NAFCON
Na2PO4
NAOC
NaOH
NBc
NGC
NH3
NH4+
Ni
ni
-
acceleration due to gravity
gramme
average stream depth
hour
Shannon-Wienner index of diversity
Hydrogen
Hazardous Area Classification
Bicarbonate
Mercury
High Pressure
level at time t1, (m)
water
Hydrogen sulphide
Industrial Area
kilogramme
Lethal concentration which kills 50% of a population in a
specified period e.g. 48 or 96 hours, etc.
Lowest Expected Water Level
logarithm
Low Pressure
lower scale
Low Temperature Separator
metre
Molar
Emergency Medical Evacuation
milli equivalent
Macgill Engineering & Technical Services
Magnesium
milligramme
Maintenance Job Routine
millilitre
millimetre; million
million barrels
million stock tank barrel
million standard cubic feet per day
Manganese
Memorandum of Understanding
milli-siemen
Master Shut Down Valves
million years
Neuman's constant
Nitrogen
Sodium
National Fertiliser Company of Nigeria
Sodium phosphate
Nigerian Agip Oil Company
Sodium hydroxide
net benefits of conservation
Nigerian Gas Company
Ammonia
Ammonium ion
Nickel
frequency with which each meter reading occurs
June 2005
Page 13 of 14
Chapter Three
NIOSH
-
nm
No
NO2NO3NOx
NPSHr
%
‰
O2
O3
OML
OMPADEC
OPL
p
P
Pb
PD
POE-CEM
PFS
pH
PHC
PIE-ITS
PO4
ppb
PPE
ppm
PtCo
PTW
RH
RGL
RMS
ROW
RPI
RPM
RS
RV
sec
SHOC
SiO2
SIPM
SO2
SO4-2
SPDC
SS
ss
STOIIP
SV
Ta
TA
TAO
TDS
TEV
-
National Institute for Occupational Safety and Health
(America)
nanometre
Number
nitrite ion
nitrate ion
Nitrogen oxides
Net Positive Suction Head
Percentage
Parts per thousand
Oxygen
Ozone
Oil Mining Licence/Lease
Oil Mineral Producing Area Development Commission
Oil Prospecting Licence/Lease
density of fluid
Phosphorus
Lead
Positive Displacement
Production Chemistry Department
Process Flow Scheme
Hydrogen ion concentration
Petroleum hydrocarbon
Production Information Centre
Phosphate
parts per billion
Personnel Protection Equipment
parts per million
Platinum Cobalt
Permit to Work
Relative humidity
Relative Gut Length Index
Root mean square
Right of Way
Research Planning Institute
Rotation per minute
Random Sample
Relief Valve
second
Safe Handling Of Chemicals
Silica
Shell International Petroleum Maatschappij B.V.
Sulphur dioxide
Sulphate ion
Shell Petroleum Development Company of Nigeria Ltd.
Soil Sample Station
Suspended solids
Stock Tank Oil Initially in Place
Surge Vessel
ambient air temperature
Total Alkalinity
Telemetric Assisted Operations
Total dissolved solids
total economic value
June 2005
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THC
oC
TS
TS
TSS
µ
UV
V
VES
VOC
WHO
WS
WTP
µS
µg
µm
2D
3D
Chapter Three
-
Total hydrocarbon
-
Temperature in degrees Celsius
Transect Sample
Total Solids
Total Suspended Solids
micron
Ultraviolet
Vanadium
Vertical Electrical Sounding
Volatile organic compounds
World Health Organisation
Water Sampling Station
Water Treatment Plant
micro Siemen
microgramme
micrometre
Two dimensional
Three dimensional.
June 2005
Page 15 of 14
EIA REPORT PREPARERS
The following represents the EIA Report Preparers and their roles:
Baseline Data Collection Team Members (API Consultant)
Dr. Abah, S. O.
Dipo Onikede
Dr. Clement Edikpai
Dr. Edosonwan Larry
Ude Godwin
Onwudiwe Chris
Wagbasoma Mc Donald
Dr. Amah, J. I.
Nanaopiri Benson
Samuel Okoronkwo
-
Team Leader
Air Quality
Wildlife Ecology
Soil/Landuse/Agriculture
Vegetation
Water Chemistry
Geology/Hydrogeology
Socio-Economic/Noise/HIA
Hydrobiology
Safety Officer
EIA Report–Written in-house By HSW-ENVE Team
Dr Ibanga, A. J.
(HSW-ENVE)
Dr. Yammama, A. (HSW-ENVE)
Mr. Adesanya, W. (HSW-ENVE)
Mr. Sarwuan, T.
(HSW-ENVE)
EIA Reviewers
Mrs. Moore Obiageli
Ms. Samuel Sophia
Dr. Seye Babatunde
Dr. Mrs. Aguabobo Hart
Chapter Three
June 2005
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ACKNOWLEDGEMENT
The Shell Petroleum Development Company of Nigeria Limited (SPDC) wishes to
acknowledge the opportunity granted by the Government of the Federal Republic of
Nigeria through its Agencies, to conduct this Environmental Impact Assessment
(EIA) in support of Opugbene West (Tologbene) Prospect Exploratory drilling,
recognising the national regulatory requirements and standards, the Shell Group
and international specifications. We have enjoyed cordial working relationship with
the National Petroleum Investment Management Services (NAPIMS) the Joint
Venture Partners, the Federal Ministry of Environment (FMENV), Department of
Petroleum Resources (DPR), Bayelsa State Government and Southern Ijaw Local
Government Area.
The contributions of Ambah Projects International commissioned to collate the
baseline data for the EIA study cannot be overemphasised.
The efforts of the EIA Team comprising representatives from various SPDC-West
Departments, viz:- Environment, Engineering, Public and Government Affairs,
Geomatics, and Legal are also recognised.
Chapter Three
June 2005
Page 17 of 14
1
2 EXECUTIVE SUMMARY
The Applicant
Shell Nigeria operates four companies under the names of the Shell Petroleum
Development Company of Nigeria Limited (SPDC), Shell Nigeria Exploration and
Production Company (SNEPCO), Shell Nigeria Oil Products (SNOP) and Shell
Nigeria Gas (SNG). SNEPCO a Shell company was set up in 1991 to explore for and
produce oil and gas in deep offshore and in the Northern Benue Basin of the
country while SNG was incorporated in 1998 to distribute natural gas to
customers. SNOP was incorporated in 2000 to market oil products.
The Shell Petroleum Development Company of Nigeria Limited (SPDC) is the largest
oil and gas Exploration and Production Company in Nigeria and the operator of a
joint venture on behalf of Nigerian National Petroleum Corporation (NNPC, 55%),
Shell (30%), Total (10%), and Agip (5%). SPDC’s Exploration and Production (E &
P) activities are centred within the delicate ecology of the Niger Delta.
SPDC, Western Division is stepping up its exploration/production activities and an
Environmental Impact Assessment (EIA) of all new major activities/developments
as required by law.
EIA Premises
The key premises that affect EIA process were established from the initial stages of
the project and has provided the general guidance, framework, and commitment to
standards acceptable nationally and internationally.
The premises shall be
retained and variations allowed only in certain circumstances with supporting
evidence.
3 Administrative and Legal Framework
In line with the National regulatory requirements of Acts 86 of 1992, and other
relevant regulations of the then Federal Environmental Protection Agency (FEPA),
now Federal Ministry of Environment (FMENV) and the Department of Petroleum
Resources (DPR), and SPDC environmental policy, SPDC West commissioned an
EIA of Opugbene-West (Tologbene) Prospect Exploration Drilling.
EIA Methodology
The methodology adopted in conducting this EIA were: desktop research to
establish an environmental information database; gap analysis, field research to
verify and complement information gathered from desktop research; and
consultation with stakeholders, experts in relevant fields, and leaders of thought in
environmental matters. The identification of environmental aspects and evaluation
of the potential impacts of the proposed project was done using ISO 14001
approach.
The EMP was developed in accordance with the World Bank
environmental assessment guidelines.
Objectives of EIA
The objectives of the EIA are:
•
Establishment of the existing ecological and socio-economic conditions of the
area;
•
Establishment of the environmental and socio-economic sensitivities of the
area to project development;
Chapter Three
June 2005
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•
•
•
Identification, evaluation and prediction of the impact of the project on the
environment including socio-economic aspects with interfacing and project
interaction;
Development of control strategies with a view to mitigating and ameliorating
significant impacts the project would have on the totality of measurable
environmental characteristics;
Development of plans and procedures for effective proactive environmental
management of the area.
The Project Site
The proposed development is located to the south - eastern part of OML-36 and lies
roughly between longitudes 58000 - 73000N and latitudes 370000 - 388000E).
Opugbene (Tologbene) is located in Southern Ijaw Local Government Area of
Bayelsa State, approximately 100km Southeast of Warri.
Exploratory drilling will identify more crude reserve for the area and subsequently
enhance Nigeria’s crude oil capacity. This will enlarge the country’s resource base
and lead to a sustained economy.
The justification for this project is therefore embedded in the need to increase the
strategic oil reserves of the country, given its importance in the economy.
Basically 2 major alternatives have been considered for this project viz:
• The no drilling option that was rejected in view of its incompatibility with the
national and company policy to increase potential hydrocarbon reserves.
• Drilling explorations well; this option was favoured because it will provide an
opportunity to increase oil and gas production.
•
•
•
•
•
•
•
The specific project activities to be carried out include:
Site preparation
Pre-drilling activities;
Movement and transport of equipment, personnel and supply;
Rig movement and positioning;
Drilling sequence;
Well completion;
Oil production (operation)
•
Demobilisation and rehabilitation
Consultation
Consultations were held with both primary and secondary stakeholders, which
include host communities and regulatory authorities at national and state levels.
Description of Environment
Climate
Annual rainfall in the area ranges from 2500 – 3000mm, temperature ranged from
24.6°C - 32.0°C with a mean of over 30.5oC. Monthly relative humidity values are
from 67% to 90%. Wind speed values ranged from 2.0m/s to 4.5m/s.
Air Quality Studies
NOx and SOx levels were generally below detection limit of 5.0µg/m3 in all the
sampling locations spanning stations 1, 4, 5, except for sampling station 3 which
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recorded 23.7 and 32.4µg/m3 respectively (wet season) as well as 28.5 and
12.5µg/m3 respectively (dry season). Some diffuse contribution to the NOx and
SOx levels in this location may have been derived from emissions from the
flowstation. FEPA specifies an upper limit of 75-113µg/m3 of NOx. The present
condition of the study area is thus safe with respect to the concentrations of NOx.
Similarly, the levels of sulphur dioxide found at these locations are all far less than
the upper regulatory limit of 260µg/m3 set by FEPA. In all, the levels of
atmospheric pollution in the study area is relatively low with most of the pollutants
being either below detectable levels or at levels which are within the safe limits.
Soil and Landuse Pattern
The soils in the area are classified as “acid sands” and are terrace sands with
mottled loamy sand over fine sand texture. They were classified as Aquic
Udipsamments and Eutric Regosols respectively. At the local level, they are known
as chikoko series
From the top (0-15cm) and sub-surface (15-30cm) of the soil and analysed. None
of them had chromium (0.05 to 0.62ppm) or lead level (0.19 – 11.56ppm) and other
toxic metals significantly outside normal ranges for unpolluted soil. However iron
appeared the dominant metal and elevated with a two-season range of 160535ppm. A study of nine-(9) sediment samples yielded similar observation, even
though heavy metals appeared concentrated in the sediment, values recorded were
well within national and international ranges quoted for unpolluted soil and
sediment. Hydrocarbon contamination was restricted to sediments from the
vicinity of Agip area.
The major land use types in the area are forestry, subsistence farming and
settlement.
Vegetation and Wildlife
There are three distinct vegetation patterns viz: rainforest; transition and mangrove
forest. The vegetation is essentially thick rainforest vegetation from Ikebiri I
through Ikebiri II to Okoluba-Ikebiri creek junction. There is intensive subsistence
crop farming and extensive commercial lumbering activities in the rainforest zone.
The pristine forest in the area has been removed by various human activities other
than petroleum exploration and production, while the secondary forest is still
useful for agricultural purposes. Logs of various sizes and of different plant
species particularly Alstonia were noticed at strategic locations by the sides of the
Ikebiri creek.
The project area is not rich in wild life. Four main classes of Vertebrates are
represented namely: Reptiles, Amphibians, Mammals and Birds. The bird’s fauna
are the richest.
Geology/Hydrogeology
The Field lies within the Niger delta basin early Tertiary sediment build up. Two
stratigraphic units from the aquifer system; the Alluvial and the Benin formation
(Oligocene – Recent).
The area and environs is drained mainly by the Ikebiri River, which runs in an
almost North – South direction and fed by other smaller creeklets and tributaries,
which flow in the southward direction. All the rivers within the study area are
tidally influenced and are inundated twice daily by the flood and ebb tides, while
their water volumes are greatly reduced in the dry season.
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Water Quality
The values obtained for the various parameters were well within DPR limits. The
studies revealed no unusual characteristics in the chemistry of surface and
groundwater samples, the physico-chemical characteristics of the surface water
were normal for class 1 river in terms of quality ranking, except for the high
Turbidity and TSS above the WHO’s and DPR limits, which is inherent
characteristics of the waters of the area. There is no indication of anthropogenic
elevation of chromium and other toxic metals in the surface or ground water.
Microbiology
Microbiologically, values (<0.10) of ratios of total hydrocarbon utilises count (HYD)
to heterotrophic (HET) count in the various sites is a reflection of the ability of
autothrophic microbes in the locations to respond favourably to hydrocarbon
contamination. The underground waters did not contain significant levels of
hydrocarbon utilises, indicating insignificant level of hydrocarbon.
Bacteria
encountered are: Pseudomonas fluorescens, Micrococcus sp and Flavobacterium sp
with Penicillium sp. Escherichia coli, Kbebsiella sp,and Proteus sp.
Aquatic Ecology
Fishes: Fishing is carried out in most cases from permanent camp and temporary
shelters. Fishing gears used include basket traps, cast nets, silk nets, traps, long
lines and hooks. Fishes caught are represented by Periophthalmus (Gobiidae),
Chrysichthy’s Spp, Clarias anguillaries, Tilapia Macroephala, Ethmalosa fimbriata,
and shellfishes.
Plankton: The ecological species encountered are essentially a mixture of
freshwater and brackish forms of phytoplankton, zooplankton and benthic
organisms. Thirty (30) and twenty four (24) phytoplankton species were recorded
in this location for wet and dry seasons respectively; there was basically no
difference in composition except for the new species added in the wet season. The
wet season species belong to the following taxonomic groups namely divisions
Bacillariophyta (14), Chlorophyta (10), Cyanophyta (3), Dyanophyta (1) and
Euglenophyta (2), while for the dry season three taxonomic group recorded
changes; they are Bacillariophyta (13), Chlorophyta (9) and Cyanophyta (2).
Bacillariophyta (diatoms) is the dominant phytoplankton species in terms of taxa
richness in the study area. Followed by Chlorophyta (green algae), Cyanophyta
(blue-green), Euglenophyta (Euglenoids) and Dyanophyta (the lowest in species
composition and richness). These are Rotifera, Copepoda and Cladocera out of
which thirty species of zooplankton were identified in the study location; they
belong to the following taxonomic groups Rotifera (16), Copepoda (6) and Cladocera
(8). A total of 14 benthic macrofaunal species were recorded in the study area.
The fauna observed for both seasons can be categorised into Diptera (5),
Ephemeroptra (4) and Annelida (5) with almost equal representation except for
Ephemetoptra, which had 4 species. Generally, the benthic macrofauna were
poorly represented in the study stations. Diversity indices indicate that the waters
of the area are fairly stable in species composition and structure, while phyto and
zooplankton were of various classes; the creek is oligotrophic (Nutrient Poor) in
nature.
Socio-Economics Studies
The main communities – Ikebiri I & II and Lobia form the host communities in the
study area. The seat of leadership for the communities is in Ikebiri I, which has a
larger population. The setting is basically rural. The major economic activities of
the people are fishing, lumbering and haulage. Basic amenities such as roads,
electricity and pipe borne water are generally lacking.
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No health facilities are available in either of the communities. Several traditional
worshipping shrines were noticed. In addition, a portion of the rainforest is
reserved as sacred and entry is prohibited.
Associated
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
•
and Potential Impacts
Loss of vegetation
Loss of ecological habitat for fauna
Interruption of drainage pattern
Surface erosion
Employment opportunities of the unskilled labour
Complaints by local communities for employment and payment for land
acquired.
•
Improved level of income
Interference with other public and private water transport activities
Pollution of water bodies by improper disposal of drill cuttings and effluents from
drilling operations
Physical disturbance of water bodies by the rig
Localised increase in ambient concentrations of air pollutants
Alteration of the physico-chemical parameters of the ecosystem
Noise and vibration on site for drilling activities
Increase in biological and chemical toxicity of water from discharges oily wastewater,
spent muds and chippings, produced water, sewage, cooling water and additives etc.
Mitigation Measures
•
SPDC shall minimise size of site and re-vegetate cleared area with
indigenous plants
•
SPDC shall maintain noise levels at site boundary within regulatory limit,
also the use of earmuff shall be enforced.
•
SPDC shall limit dredging activities to only areas that are absolutely
necessary and use narrow gauge bargers
•
SPDC shall create awareness before commencement of project activities
•
Adequate consultation shall be carried out and sustained. Signed
Memorandum of Understanding (MOU) shall be observed by SPDC
•
The rig and associated facilities shall be clearly marked and illuminated
during poor weather conditions to warn other river users. Consult with local
communities regarding preferred routings/plan movement to minimise
interference
•
Non-polluting and environment friendly anti-fouling chemicals shall be used
for coating the submerged surfaces of the rig and other structures
•
Existing emergency / spill response actions/contingencies shall be activated
for prompt clean-up operations at the incidence of any spill in the area
•
SPDC shall maintain all fuel combustion engines at optimal operating
conditions to reduce emission of exhaust gases
SPDC shall develop and implement waste management plans for all wastes
generated in accordance with regulatory requirements and standard practice. All
industrial wastes such as plastics, metals, rubber etc will be segregated on site and
collected in designated containers for final disposal in accordance with the
standard waste management guideline.
Environmental Management Plan
The EMP for the exploratory drilling project in Opugbene (Tologbene) shall form the
basis for the actual project implementation.
Decommissioning Plan
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A decommissioning team shall be set up to plan and implement the guidelines for
decommissioning to ensure that the best and practicable methods are adopted.
The following activities shall be carried out during decommissioning:
♦ Subsurface abandonment-the objective here is to isolate formations and prevent
fluid migration. The casing shall be removed and plugged with cement.
♦ Surface facilities abandonment - all associated surface facilities (well heads,
Christmas trees) and cellar (concrete) shall be removed. Surface facilities shall
be taken to SPDC Industrial Area waste re-cycling depot for re-use or onward
delivery to SPDC approved re-cycling vendors.
♦ Areas cleared shall be re-vegetated with indigenous plant species.
Conclusion
The Environmental Impact Assessment indicates that during the exploratory
drilling activities the major environmental components that would be adversely
impacted include vegetation, soil, water quality and aquatic life. These impacts
are associated with site preparation, rig movement, drilling and
decommissioning/abandonment exercise. Although these impacts are adverse,
they are short-term and reversible.
Mitigation measures that will eliminate or reduce the potential adverse impact
have been identified and put in place. An Environmental Management Plan has
been developed. It incorporates mitigation plan and monitoring schedule.
All the identified potential adverse impacts of the proposed drilling activities
shall be eliminated or reduced through the application of the mitigation
measures contained in this EIA.
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CHAPTER ONE
•
1.1
INTRODUCTION
Background
This report represents the final Environmental Impact Assessment (EIA) of the
Opugbene-West (Tologbene) Prospect Exploration Drilling located west of Agip’s
Tebidaba Field. The project shall involve the drilling of one exploratory well in the
onshore concession OML-36 (Opugbene-West (Tologbene) Prospect) possibly to be
followed by three additional exploratory/appraisal wells.
The exploitation of this undeveloped reserve is in line with SPDC’s policy of
continuous development.
1.2
Terms of Reference
This report represents the Environmental Impact Assessment (EIA) for the
exploratory drilling of one well in OML 36 proposed by The Shell Petroleum
Development Company of Nigeria Limited (SPDC), Warri. In accordance with the
FEPA EIA Procedural Guidelines of 1995, the Project Proposal was submitted to the
Regulatory Authorities in 1998 and the Terms of Reference (TOR) on which the EIA
was
based
was
approved
by
FEPA
(now
FMENV),
referenced
FEPA/CONF/EIA/123.163/Vol.1/10 of 08/03/98. Draft copies of the EIA were
submitted to FMENV in October 2002. FMENV has conducted a panel review
session and Provisional EIA Approval has been issued for the commencement of the
project through a letter referenced FMENV/CONF/EIA/123.129/Vol.1/145 dated
6th October 2004.
The use of EIA as a management tool in this project would ensure that SPDC
complies with its own policy, national, regional, and international environmental
laws, standard design codes, promote consultation, and reduce future liabilities, so
helping to protect the environment. This EIA has been undertaken to:
•
•
•
•
1.3
provide a comprehensive environmental baseline data of the proposed project
area by updating existing information,
identify and assess the environmental sensitivities of the project area and
activities, and evaluate the associated and potential impacts of the project on
the environment,
confirm the environmental acceptability of the selected project site;
develop Environmental Management Plan that shall translate potential impact
prevention and mitigative measures into control measures through contracts,
workshops, supervision, training, field briefing, monitoring and auditing.
Nigeria
Nigeria is the largest and most populous country in West Africa. It lies between
latitudes 4o and 14o North of the Equator and longitudes 3o and 14o East of the
Greenwich Meridian. It has a geographical area of 923,768km2 and a population of
approximately 88.5 million by the November, 1991 Census. It is bordered by Chad
and Niger Republics to the north, Cameroon to the East; Republics of Benin and
Togo to the west and the Atlantic Ocean to the south. It is made up of several
ethnic groups, the major ones being Hausa, Fulani, Igbo, Yoruba, Edo, Efik Ijaw
and Kanuri. The oil industry, which is the mainstay of the economy, controls over
70% of Nigeria’s total revenue and is concentrated within the Niger Delta
ecosystem. The sub-sector of the economy employs a significant proportion of the
population. Other socio-economic activities in the country include commerce, and
agriculture (farming/fishing).
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1.4
The Applicant
Shell Nigeria operates four companies under the names of the Shell Petroleum
Development Company of Nigeria Limited (SPDC), Shell Nigeria Exploration and
Production Company (SNEPCO), Shell Nigeria Oil Products (SNOP) and Shell
Nigeria Gas (SNG). SNEPCO a Shell company was set up in 1991 to explore for and
produce oil and gas in deep offshore and in the Northern Benue Basin of the
country while SNG was incorporated in 1998 to distribute natural gas to
customers. SNOP was incorporated in 2000 to market oil products.
The Shell Petroleum Development Company of Nigeria Limited (SPDC) is the largest
oil and gas Exploration and Production Company in Nigeria and the operator of a
joint venture on behalf of Nigerian National Petroleum Corporation (NNPC, 55%),
Shell (30%), Total (10%), and Agip (5%). SPDC’s Exploration and Production (E &
P) activities are centred within the delicate ecology of the Niger Delta.
The Shell Petroleum Development Company Limited (SPDC), Western Division is
stepping up its exploration/production activities and an Environmental Impact
Assessment (EIA) of all new major activities/developments as required by law.
1.5
The EIA Premises
The key premises that affect EIA process were established from the initial stages of
the project and has provided the general guidance, framework, and commitment to
standards acceptable nationally and internationally.
The premises shall be
retained and variations allowed only in certain circumstances with supporting
evidence to do so. The premises include that:
•
•
•
•
•
•
1.6
•
the area is within the exclusive jurisdiction of the Federal Government of
Nigeria. Therefore, federal laws, including the environmental laws apply,
the project recognises the laws and regulations of the Federal Republic of
Nigeria as represented by the Federal Ministry of Environment, the
Department of Petroleum Resources (DPR), the State and the Local
Government Environmental Agencies, and insist that best options will be
adopted for the project execution;
the project will be designed and operated to comply with local and national
laws, together with all the international protocols, agreements and conventions
entered into by Nigeria,
the agreements and understanding reached with government officials during
the course of the EIA process will be respected and honoured,
extensive consultations have and will continue to be held with Federal, State,
and Local Governments together with the host communities and concerned
Non Governmental Organisations (NGOs),
an Environmental Management Plan (EMP) will be developed as part of the EIA
process. The implementation of this plan will be the responsibility of SPDC
and
the SPDC policy on Community Affairs, Safety, Health, Environment and
Security (CASHES) will provide the preliminary guidelines that will be adhered
to by all parties involved in the project. Regular briefing on this policy will be
given to all personnel.
ADMINISTRATIVE AND LEGAL FRAMEWORK
The scope for this project involves drilling of a single exploratory well in Opugbene
(Tologbene). Several Nigerian statutes, guidelines and standards regulate the
activities of the drilling project.
Most of the environmental legislation and
regulations laid out by agencies of the Federal Government of Nigeria and other
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international agencies, SPDC and SIEP corporate policies have relevance to crude
oil and gas E & P operations in general and to the drilling process in particular.
The two primary agencies with mandatory statutory legislation are the Federal
Environment Protection Agency (FEPA) now Federal Ministry of Environment
(FMENV) and the Department of Petroleum Resources (DPR). Some of these laws
are summarised below.
The Mineral Oil (Safety) Regulations 1963
Section 37 states that no person at any well or installations where petroleum is
being handled shall:
•
•
•
Sleep when in charge of boiler or machinery or
Consume any alcoholic liquor during the period he is duty, or
Report for duty while under the influence of alcoholic liquor
Section 40 requires that a competent person shall be responsible for the observance of all
safety measures at any drilling site or installations handling petroleum where work is in
progress. Provisions of 40 (1) is that failure on the part of the holder of a licence or lease to
which this schedule applies to fulfil any of the terms or conditions of the licence or lease
shall not (except it may be otherwise provided for in or in relation to the licence or lease) give
the minister any claim against the licensee or the lessee or be deemed a breach of the
licence or lease, if the failure arises from causes beyond the control of the licensee or lessee.
40 (2): If from any such cause the fulfilment by any such licensee or lessee of any term or
condition of his licence or lease or of any provision of this Act is delayed, the period of delay
shall be added to the period fixed for the fulfilment of the term or condition.
The regulations in section 3 require every licensee or lessee to provide sufficient safety belts
for the derrickman and hard hat and safety boots for persons working in every drilling and
work over crew; the provision of adequate fire fighting and first aid equipment in accordance
with good operating practices and to the satisfaction of the head of the Petroleum
Inspectorate at every well being drilled or work over, block station, pump station or
installation/handling of crude oil, natural gas or petroleum
Section 5 requires the licensee or lessee to appoint a person to be the manager who
shall have continual charge of all operations. It shall be duty of every manager to
ensure that the provisions of the regulation are fully complied with. Section 6
requires the manager to appoint competent person for the purposes of supervising
all drillings, production, transmission and loading operations and shall at once
report each appointment and change in appointment to the Head of the Petroleum
Inspectorate. Section 7 applies to drilling and production operation and requires
that all drilling, production and other operations necessary for the production and
subsequent handling of crude oil and natural gas shall conform with the good oil
field practice adequately covered by Institute of Petroleum Safety Codes, the
American Petroleum Institute Codes or the American Society of Mechanical
Engineers Codes.
Oil Pipeline Ordinance CAP 145, 1996 and Oil Pipelines Act 1965.
The Oil Pipeline Ordinance CAP 145, 1956, as amended by the Oil Pipelines Act
provides under Section 4 (2) for a permit to survey (PTS) the pipeline route to be
issued to the applicant by the Minister of Petroleum Resources, for the purpose of
transporting mineral oil, natural gas or any product of such oil or gas to any point
of destination to which such a person requires such oil, gas product thereof for any
purpose connected with petroleum trade or operations. Such a survey should
include the approximate route or alternative routes proposed in order to determine
the suitability of the land for laying and construction of the pipeline and ancillary
installations.
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Section 15 (1) of the Oil pipeline Ordinance (CAP) 145 prohibits the holder of an
OPL to Licence (OPL) enter upon, take possession of, or use any of the following
lands unless the occupiers or persons in charge thereof have given their assent.
•
•
•
any land occupied in a burial ground or cemetery,
any land containing grave, grotto, and trees or things held to be sacred or
the object of veneration,
any land under actual cultivation.
Petroleum (Drilling and Production) Regulations, 1969
The Petroleum (Drilling and Production) Regulations 1969 (CAP 350) empowers the
holder of an OPL to be cautions and shall be held responsible for all the actions of
his agents and contractors that pollute the environment or interfere with protected
and productive tree, venerated objects, fishing rights and safety of navigation.
Section 21-24 address the issues of licensee interfering with protected and productive trees, venerated
objects, fishing right and safety of navigation, while Section 25 requires the licensee to “adapt all
practicable precautions, including provision of up-to-date technology approved by Director of
Petroleum Resources, to prevent the pollution of inland waters, rivers, creeks, the territorial waters of
Nigeria or the high seas by oil, mud or other fluids or substances which might
cause harm or destruction to freshwater/marine life, and where such pollution
occurs or has occurred, shall take control and if possible end it”
Where the licensee is not able, for whatever reason, to comply with the provisions
of sections 21-24 of these regulations, he shall pay adequate compensation for the
contravention to those concerned. Section 36 concerns the maintenance of
apparatus and conduct of operations. Among other the licensee or leasee shall
carry out all his operations in a proper and workman like manner in accordance
with the directives of the Head of the Petroleum Inspectorate as good oil field
practice, and without prejudice to the generality of the foregoing, he shall, in
accordance with these practices, take all steps practicable:
To control the flow and to prevent the escape of avoidable waste of petroleum
discovered in or obtained from the relevant areas.
To prevent damage to adjoining petroleum bearing strata, to prevent the escape of
petroleum into any water, well, spring stream, river, lake, reservoir, estuary or
harbour, and
To cause as little damage as possible to the surfaces of the relevant areas
Section 39 deals with confinement of Petroleum. “The licensee or leasee shall use
approved method and practices acceptable to the Head of Petroleum Inspectorate
for confining the petroleum obtained from the relevant areas in tanks, gas holders,
pipes, pipelines or other receptacles constructed for the purpose”
Section 40 regulates drainage of waste oil “The licensee or leasee hall drain all
waste oil, brine and sludge or refuse from all storage vessel, boreholes and wells
into proper receptacles constructed in compliance with safety regulations made
under the act or any other applicable regulation and shall dispose thereof in a
manner approved by the Head of the Petroleum Inspectorate or as provided by
other applicable regulation”
Federal Environmental Protection Agency Acts No 58, 1988
This Acts, which was issued in 1989, provides National Interim
Guidelines and Standards for industrial effluents, gaseous
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emissions, noise, air quality and hazardous wastes management for
Nigeria. The Federal Environmental Protection Agency (FEPA), which
is now under the Federal Ministry of Environment, was set up by
Acts 58 of 1988. The Ministry enforces the EIA Acts No. 86 of 1992,
which also gives specific powers to the ministry to facilitate
Environmental Impact Assessment (EIA) of projects. The
specifications and requirements of an EIA have been outlined in the
EIA guidelines for the Oil and Gas industries in Nigeria.
The mandatory guidelines and regulations on oil/gas exploration
and production activities are highlighted in various provisions
namely:
•
FEPA National Interim Guidelines and Standards for
Industrial Effluents, Gaseous Emissions and Hazardous
Waste Management in Nigeria (FEPA, 1991)
•
FEPA S.1.8 of 1991: National Effluent Limitation, Official
Gazette, Federal republic of Nigeria No. 42, Vol. 78, August
1991; makes it mandatory for industries to install antipollution and pollution abatement equipment.
•
FEPA S.1.9 of 1991: Pollution Abatement in Industries
Generating Waste, Official Gazette, Federal Republic of
Nigeria No. 42, Vol. 78, 20th August, 1991; spells out the
restriction on the release of toxic substances, requirement for
pollution monitoring unit, machinery for combating pollution
and contingency plan by industries, submission of lists and
details of chemicals used by industries to FEPA, strategies for
waste reduction, permissible limits of discharge into public
drains, requirements for environmental audit and penalty for
contravention.
•
FEPA S.I. 15-National Environmental Protection (Management
of Solid and hazardous Wastes) Regulations (FEPA, 1991)
•
FEPA EIA Procedural Guideline (FEPA, 1995),
stipulates projects/activities that require EIA studies.
•
FEPA (1995) Sectoral Guidelines for oil/gas industry projects
which specifies the procedures and methods for EIA.
•
EIA Acts 86 of 1992.
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The Environmental Impact Assessment (EIA) Acts No. 86, 1992,
among other things, sets out the procedures and methods to enable
the prior consideration of environmental impact assessment on
certain public or private projects. The Acts also gives specific powers
to the Federal Ministry of Environment to facilitate environmental
assessment of projects in Nigeria.
The objectives of the EIA Acts are:
•
To take into account, before embarking on any project or
activity, the likely impacts and the extent of these impacts on
the environment;
•
To promote the implementation of appropriate policy in all
Federal lands consistent with all laws and decision making
processes through which the goal of the Acts many be
realized; and
•
To encourage the development of procedure for information
exchange notification and consultation between organizations
and persons on which the proposed activities are likely to
have significant environmental effects on.
The Acts also specifically requires an Environmental Impact
Assessment (EIA) for any project that involves:
•
Drilling operations (exploratory, appraised, and development
wells) onshore and near-shore areas;
•
Construction of crude oil production, tank farm and terminal
facilities;
•
Laying of crude oil and gas delivery line, flowline and pipeline
in excess of 50km in length; and
•
Hydrocarbon processing facilities such as natural gas plants.
In September 1994, FEPA published Sectoral EIA guidelines for onshore-offshore
oil and gas pipeline projects. The guidelines are intended to assist in the proper
and detailed execution of EIA of oil and gas projects in consonance with EIA Acts of
1992.
National Environmental Guidelines and Standards for the Petroleum Industry in Nigeria, 1992
In the oil and gas industry in Nigeria, the Petroleum Act 1969
section 8 (i) b (ii) confers on the Minister of Petroleum Resources the
power to promulgate legislation to prevent environmental pollution.
The NNPC Acts 1979 section 191 set up the Department of
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Petroleum Resources and empowered them to ensure that petroleum
industry operators prevent environment pollution. The key
document identifying relevant requirements is the Environmental
Guidelines and Standards for the Petroleum Industry in Nigeria,
Published in 1991.
The DPR Environmental Guidelines and Standards for the Petroleum Industries in
Nigeria (EGASPIN) 2002 stipulate in Part VIII (A), the manner of preparing EIA.
Section 3.1.1 and 6 provide guidelines for preliminary EIA report, while the content
of detailed EIA report is outlined in section 5 of part VIII (A).
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Endangered Species Acts No 11 of 1985
Endangered Species (Control of International Trade and Traffic) Acts No 11, 1985
lists those animal species under absolute prohibition from international trade and
those allowed for trade.
National Inland Waterways (NIWA) Acts No 13 of 1997
The national Inland Waterways (NIWA) Acts is concerned with the standards and
regulation of non-routine activities within navigable inland waterways within the
territorial boundaries of Nigeria e.g., dredging of new canals/slots, river crossings,
sand winning from marine borrow pits, etc.
Bayelsa State Environmental Protection Agency Edict (1994)-Now Bayelsa
State Ministry of Environment
The Bayelsa State Environmental Protection Agency has the responsibility of
environmental protection within Bayelsa State. The Bayelsa State Environmental
Protection Agency Edict (1994) contains the functions of the Agency which include:
•
•
•
•
•
Liaise routinely and ensure effective harmonisation within FEPA (now
FMENV) in order to achieve the National policy on the Environment;
Co-operate with FMENV and other relevant National Directorates/Agencies
in the promotion of environmental education in the citizenry;
Be responsible for monitoring compliance with waste management
standards;
Be responsible for general environmental matters in the state including the
negative effects of soil degradation due to flooding and erosion, mineral and
oil exploitation and exploration, deforestation, physical planning including
amusement parts, gardens and beautification programmers, sewerage
matters, water quality and pollution control; and
Monitor the implementation of EIA and Environmental Audit Report (EAR)
guideline and procedures on all development policies and project within the
state.
World Bank Guidelines on Environmental Assessment (EA)
To be able to obtain financial assistance in the form of loans of some projects, the
World Bank requires an EA report as a condition from the borrower before granting
such loans. The EA report normally forms part of the feasibility study of the project.
Projects are categorized based on their EA requirements ad is very much similar to
that of FEPA.
Checklists of potential issues for EA, which apply to upstream oil and gas projects,
include: biological diversity, coastal and marine resources management, cultural
properties, hazardous and toxic materials, and international waterways. Volume III
(1991) of the World Bank EA source book states, “EA for oil and gas pipelines
should include an analysis of reasonable alternatives to meet the ultimate project
objective”. This analysis may lead to improvement in designs from socio-economic
point of view to insure that the project options under consideration are
environmentally sound and sustainable.
International Union for Conservation of Nature and Natural Resources (IUCN)
Guidelines
The IUCN (The World Conservation Union) in conjunction with the oil Industry
International Exploration and Production forum (E & P Forum) have guidelines,
which contain internationally acceptable practices and standards for oil and gas
exploration and production. These guidelines present practical measures to
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conserve wetlands and enhance protection of aquatic ecosystem during oil and gas
E & P activities.
The general discussions are on Environmental Profile activity, preliminary
Environment Impact Assessment, Environmental Impact Assessment (EIA),
Environmental Management, Environmental Monitoring, and Environmental Audit.
Form the guidelines, it is recommended that a Preliminary EIA report be prepared
before any activity commences at the project site; and it is to build on the findings
of the environmental profile and examine sensitive issue in details.
Other international environmental conventions which Nigeria is signatory to and
national environmental laws and legislations are presented in Appendix 1.1.
SPDC Policies
For SPDC, the following policies and guidelines also apply:
•
•
•
Shell Policy on Environment, which requires all Shell companies to take full
responsibility for the protection of the environment with respect to new
developments;
Shell Group Guidelines on Environmental Impact Assessment (EP 95-0370);
Shell Group Guidelines on Social Impact Assessment (EP 95-0371).
It is in compliance with the above national regulations and the SPDC CASHES
policy and guidelines that this EIA study on the proposed exploratory drilling
project is to be undertaken.
In this regard, SPDC “intends to and is obligated to” ensure that effective
monitoring of the various impact indicators is undertaken during the site
preparation, construction and operational phases of the project.
HSE Policies - General
It is SPDC’s Policy that all activities shall be planned and executed in a manner
that:
(i)
(ii)
(iii)
(iv)
•
preserves the health, safety and security of all company and contractor
personnel and members of the public;
preserves the integrity and security of company assets;
minimises the impact of operations on the environment, and
is sensitive to the needs and concerns of the host communities.
Implications of implementing this policy are that;
(i)
all activities shall be analysed to systematically identify related hazards,
risks and sensitivities,
(ii)
arrangements shall be put in place to control the hazards, risks and
sensitivities and to deal with consequences should they arise,
(iii)
any activity which is unhealthy, unsafe, environmentally unsound or may
adversely impact relations with the community, shall be suspended until an
acceptable solution is found,
(iv)
all personnel, including those of contractors, shall be trained and made fully
aware of the hazards, risks, sensitivities and controls in place,
(v)
plans and procedures shall be in place to respond to any emergency or loss
of control.
every SPDC employee and contractor’s employee must plan and perform his work
in accordance with this policy. Each employee is required to report, and where
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necessary, suspend any activity which he considers is a contravention of this
policy.
1.7
Objectives of EIA
The purpose of this EIA is to establish the environmental sensitivities, impact and mitigation
measures with respect to the Opugbene-West (Tologbene) Prospect Exploratory Drilling
project. This will enable effective and adequate:
•
•
•
•
•
1.8
1.9
Establishment of the existing ecological and socio-economic conditions of the
area;
Establishment of the environmental and socio-economic sensitivities of the
area to project development;
Identification, evaluation and prediction of the impact of the project on the
environment including socio-economic aspects with interfacing and project
interaction;
Development of control strategies with a view to mitigating and ameliorating
significant impacts the project would have on the totality of measurable
environmental characteristics;
Development of plans and procedures for effective proactive environmental
management of the area.
Benefits of the EIA
The benefits of the EIA include:
♦
Obtaining authorisation; this is required by regulatory authorities before the
commencement of any major development.
♦
Providing a forward planning tool; when environmental implications are
taken into account with other design considerations at the conceptual design
stage. It allows for important decisions to be built into the project while
avoiding undue damage to the environment.
♦
Providing a design tool that will allow a systematic evaluation of potential
environmental problems from the proposed development and identification of
key issues that require special consideration for effective environmental
management and controls.
♦
Involving all stakeholders through consultation so as to address common
problems, impacts and mitigating measures that might be proposed.
♦
Informing management with a view to achieving long-term management
objectives and plans associated with specific activities, in order to minimise
associated financial and environmental risks.
EIA Methodology
The methodologies adopted for conducting this EIA are as follows:
Desktop Research
Desktop research was used to establish an environmental
information database for the EIA. Consulted materials include
textbooks, articles, reports, maps, internet, photographs and a
baseline mapping and change (1960s-1990s) analysis report that
covered Opugbene (Tologbene) where the project is located.
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Consultation with Stakeholders
Experts in relevant fields, leaders of thought in environmental matters, Non Governmental
Organisations and regulators, local communities have been consulted for their opinions on issues
relating to the potential ecological and socio-economic impacts of the proposed project.
Field Research
Two seasoned fieldwork activities have been carried to verify and
complement information gathered from desktop studies. The fieldwork
covered all relevant components of ecological and socio-economic
environments.
Laboratory Analysis
Samples collected during the two-season field sampling were analysed in an
established and accredited laboratory.
Impact Assessment and Evaluation
The assessment of all associated and potential impacts of the proposed project were carried out using
checklist method. Impacts evaluation was carried out using ISO 14001 approach.
10.0 Structure of the Report
This report is presented in Nine Chapters. Chapter One is an introduction with the
EIA Terms of Reference (TOR), relevant background information about SPDC (the
Applicant), and the Legal and Administrative Framework for EIA in Nigeria.
The second chapter discusses the project justification and presents the need/value
of the project and project development options.
The third chapter describes the proposed project, namely, location, project activities, drilling rig
specification, drilling discharges, emergency/contingency plan, commissioning/abandonment.
The fourth chapter is the documentation of the various consultation activities with
Government Agencies, the public and the communities within the project areas.
The chapter five describes the baseline data acquisition methods and the existing
environmental status of the study area. Information on socio-economic studies is
also contained in this chapter.
Chapter six discusses the Associated and Potential Environmental Impacts of the
proposed exploratory drilling project.
Chapter seven discusses the Mitigation Measures and Alternatives.
Chapter eight recommends a cost-effective environmental management plan that would be adopted
throughout the project cycle. It also recommends an environmental monitoring and wastes
management programmes and outlines the plans for site restoration and remediation after
closure/abandonment.
Chapter Nine gives the conclusion and offers advice on project implementation.
References, Glossary of Terms and Appendices are also included in this report.
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CHAPTER TWO
•
PROJECT SETTING
2.1
Declaration
The SPDC, in her capacity as the operator of the joint venture, and on behalf of
herself and the other partners, hereby declares her intention to abide to its HSE
policies and relevant environmental laws at all phases of Exploratory Drilling at
Opugbene (Tologbene) in OML 36, West of Agip’s Tebidaba Field.
2.2
The Project Site/Area Description
The proposed exploratory activity is located to the south - eastern part of OML-36
and lies roughly between longitudes 58000 - 73000N and latitudes 370000 388000E (Fig. 2.0). Opugbene (Tologbene) is located in Southern Ijaw Local
Government Area of Bayelsa State, approximately 100 km Southeast of Warri.
There are SPDC wells located close to the area. These are the oil discovery
Opugbene-1 drilled in 1990 (10 km Southeast) and the unsuccessful Bassan-1 well
drilled in 1961 (15 km Northwest).
Existing development of oil and gas facilities in the area is limited to the NAOC
flowstation and oil well Tebidaba-01 to 13. In addition, a network of NAOC
pipelines cross the field.
The settlements around the area include the Ikebiri I and Ikebiri II communities,
several fishing camps and squatter settlements exist throughout the course of the
Ikebiri creeks. The inhabitants are Ijaws, mostly Christians, with no social
amenities. The main sources of sustenance for the people come from fishing and
lumbering (saw milling). Farming is rarely practised.
The main method of
transportation in the area is by river or sea in speedboats or transport and fishing
vessels/boats.
The area is a swamp location, and is water logged all year round.
It is
characterised by a network of creeks in a depressed plain. The soils are grey
coloured, contain extensive layers of peat, have low pH and high salinity. The
vegetation is a mixture of fresh water trees and mangrove, while the surface water
is generally fresh. The area has high ecological diversity and low levels of
hydrocarbon degrading bacteria.
2.3
The Federal Government of Nigeria through its joint venture participation is making
conscious efforts with various multi-national oil companies operating in the
country, to increase its oil and gas reserves by adding to the current oil and gas
production. This is expected to significantly improve the economic base of the
country and be a catalyst to the further infusion of foreign participation in the
country’s industrialisation efforts. Furthermore, the drilling activities are expected
to offer job opportunities in various categories to a number of Nigerian
professionals, skilled and semi-skilled craftsmen.
Exploratory drilling will identify more crude reserve for the area and subsequently
enhance Nigeria’s crude oil capacity. This will enlarge the country’s resource base
and lead to a sustained economy.
The justification for this project is therefore embedded in the need to increase the
strategic oil reserves of the country, given its importance in the economy.
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Location Map of Opugbene (Tologbene): Fig. 2.0
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2.4
Value of the Project
The project when successfully completed will provide justification for further
development of the expected reserves. This development will entail the drilling of
more wells and it will boost the potentials of SPDC as a major player in the oil
industry in Nigeria. It would enhance SPDC’s policy of continuous development
and prevent production stagnation. The successful outcome of this well will
significantly increase SPDC’s hydrocarbon reserves and gross production level. It
will also contribute towards achieving Nigeria’s 2010 40 Billion Barrels Reserves
Base aspiration.
2.5
Envisaged Sustainability
Data acquired by SPDC through 3-D seismic investigations and the existence of the
Tebidaba field from which NAOC has been producing indicate that significant
quantities of oil and gas are contained within the Opugbene (Tologbene) area. It is
expected that the crude oil reserves in the area can be sustained for longer than 20
years. This project is therefore expected to ensure continuous availability of oil and
gas for the company’s numerous customers.
2.6
The project alternatives were considered on the basis of their technical feasibility,
economic and environmental considerations.
2.6.1 No Drilling Option
The no drilling option consists of no drilling, in which the exploration well will not
be drilled. This option is rejected in view of the following reasons:
It would lead to production stagnation, which would contravene the
provision of the Petroleum Decree of 1969, Petroleum Profit Tax Laws and
contractual arrangements;
It would lead to continued decline in oil production leading to low capacity
production;
To total loss of investment already made in the area in data acquisition and
analysis; and
It is not in consonance with the policies of the Federal government and
SPDC to continually replenish the hydrocarbon reserve base through
exploration.
2.6.2 Exploratory Drilling Option
This option was favoured because it will provide an opportunity to increase
oil and gas production. This is the only means to sustain the business of oil
and gas production.
Furthermore, this option is in line with the
Government policy on oil and Gas Industry sector.
The technical information for the wells is in line with the national laws and
international protocol agreements and conventions governing the design and
drilling of these wells.
2.7
HSE Management Strategy
The development of an effective HSE Management Strategy is intended to ensure that
throughout the life of the project, from pre-drilling activities, site preparation, drilling,
decommissioning and abandonment. Shell’s HSE policy is constantly kept in focus.
Responsibility for the implementation of developed HSE Strategy rests on the Contractor as
implied in the SHELL HSE policy. Within SPDC, policies, guidelines and procedures are
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available to guarantee Health, Safety and Environment as chemicals are used. All these are
embedded in the concept of safe Handling of chemicals (SHOC). The SHOC process
encompasses the following: Procurement, Handling Hazards and disposal. The SHOC
manual gives information on the properties and handling procedures for all chemicals in
SPDC operations. The SHOC manual consists of numerous SHOC cards and the card lists
the threats and hazards inherent in the properties of a particular chemical and the precautions
that must be taken in using the chemical. The shock card is laminated and made available in
SHOC racks at all SPDC facilities. Every chemical has a SHOC card and must be referred to
when one is not sure before using any chemical. Every worker has a duty to himself to stay
alive and healthy while on the job and to preserve the integrity of the environment. Safe
handling of chemicals is therefore an essential part of the daily activities within SPDC.
2.8
•
The SHELL Policy
SPDC’s Exploration and Production activities will be planned and executed in such
a way as to:
Avoid injury to and preserve the health and safety of its own employees, those of its
contractors and any member of the public that may be affected;
•
Minimise the impact on the environment in which SPDC operates.
Every SPDC employee must plan and perform his or her day’s work in accordance
with the HSE Plan. An activity must be suspended when the employee believes that
it cannot be carried out in accordance with the policy and he or she must report
this immediately to the supervisor.
2.8.1 The Strategy
Compliance with applicable legislation
In keeping with its environmental management policy, SPDC is committed to complying
with relevant legislation covering various potential environmental effects arising from the
proposed project, including noise, emissions, effluents, spoils and wastes. In particular, the
DPR guidelines and standards as well as other national and international conventions (such as
the African Convention on the Conservation of Nature and Natural Resources, 1969), are
relevant. In this various impact indicators are undertaken during construction and operational
phases of the project.
2.9
Safety Evaluation
SPDC will undertake quantitative evaluation of likely sources of accident in all the phases of
the project implementation. Drilling processes are undertaken in strict compliance with
SPDC HSE guideline.
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CHAPTER THREE
3.0
PROJECT AND PROCESS DESCRIPTION
3.1
The Proposed Project
The proposed project is for drilling an exploration well. If the exploration well is
successful, three additional appraisal wells could be drilled within Opugbene
(Tologbene) area (Fig. 3.0).
Tologbene-1X is an Exploration well proposed to test and prove hydrocarbon in the
Tologbene collapsed crest structure. The objective sequence comprises the E5000
to E9000 sands. The structure straddles the Opugbene/Tebidaba field to the East,
where the equivalent intervals are known to be hydrocarbon bearing (Fig. 3.1).
Fig. 3.1:
Opugbene-Tebidaba E5000 Top Reservoir Depth Map
The sequence lies between 10,300 ft ss and 11,300 ft ss. The Prospect has Mean
Success Oil Volume (MSVO) of 191 MMbbls and Mean Success Gas Volume (MSVG)
of 258 BScf.
The Tologbene main exploration-appraisal prospect is a linear elongated NW-SE
faulted rollover anticline. The Tologbene structure lies in the same structural trend
as Opugbene/Tebidaba field and is defined essentially by the same structure
building growth fault (The Kifori macro-structural building fault). An echelon of
synthetic and antithetic faults dissects the structure. The prospect is thought to be
the western extension of Opugbene/Tebidaba field from which it is separated by a
saddle at the E5000 and E6000 levels. At the E7000 and E9000 reservoirs, the
prospect is one elongated NW-SE trending anticlinal structure with a series of
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echelon anthithetic faults. The area of closure is about 17.8 sq km with a relief of
about 300 feet.
Proposed Prospect Exploration Well Location in Opugbene
(Tologbene): Fig. 3.0
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3.2
Project Scope
The project scope includes drilling one vertical well to a total depth (TD) of about
11700 ft ss with a deviated pilot hole into adjoining block to the North of Tologbene
main block (Fig. 3.2). Sidewall coring, wireline logging, pressure and fluid
sampling would appraise the prospective reservoirs. Three additional wells will be
drilled when the prospect is successful.
20” S/P
Plug back pilot hole
KOP @
5500ftah
12-1/4” hole 9- 5/8”
csg 5450ftah
E5/E6
10364ft Loss
Zone E5/E6
E7, E9 sands
8-1/2” hole
7” liner
10750ftah
6” OH
11700ftah TD conting.
Loss Zones
11960 12165ftah
7” liner conting.
12200ftah
6” OH
- Need to build in
scenario for severe
depleted sands
(cased off)
- Dual completion
feasible
12370ftah TD
Fig. 3.2: Chosen Design: Tologbene-1X Exploration Well
3.3
Project Site/Area
The proposed drilling location lies in the south-eastern part of OML-36 and falls
roughly within longitudes 58000 - 73000N and latitudes 370000 - 388000E. The
area is located in the Southern Ijaw Local Government Area of Bayelsa State,
approximately 100 km Southeast of Warri (Fig. 3.3). The inhabitants are Ijaws,
mostly Christians, with no social amenities. The main sources of sustenance for
the people come from fishing and lumbering (saw milling). Farming is rarely
practised. The main method of transportation in the area is by river or sea in
speedboats or transport and fishing vessels/boats.
It is
coloured, contain extensive layers of peat, have low pH and high salinity. The
vegetation is a mixture of mangrove, transition and rainforest. The surface water is
generally brackish and fresh. The area has high ecological diversity
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3.4
Design of Facilities
3.4.1 Basis for Design
Quality Assurance of Design
In a surface and sub-surface development with large spatial structural variability,
such as in this project, it is imperative that certain basic parameters must be
reasonably and accurately defined in the overall project specification to ensure that
the full objectives of the project are realised. SPDC has therefore specified the
following quality objectives for the design:
•
Compliance with statutory requirements;
•
The system must meet performance requirements;
•
Production availability;
•
Environmental and safety;
•
Operationality and maintainability;
•
Life expectancy;
•
Extendibility; and
•
Use of innovative technology.
To ensure that the above quality objectives are met, SPDC intends to adopt timetested Standard Well Designs, employing new technology where safety and
economics dictate.
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Map of Bayelsa Showing Opugbene (Tologbene): (Fig.
3.3)
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Applicable Standards and Codes
•
•
•
•
•
•
The engineering design, procurement and installation will be in accordance with:
Statutory codes and standards;
Shell Design and Engineering Practice (DEPs);
SPDC standard facility design manuals;
Specific design features of the development;
SPDC HSE Policy; and
Applicable National and International Standards
3.5
•
•
•
•
•
•
•
•
The specific project activities to be carried out include:
Pre-drilling activities;
Site preparation
Movement and transport of equipment, personnel and supply;
Rig movement and positioning;
Drilling sequence;
Well completion;
Oil production (operation);
Demobilisation and rehabilitation.
3.5.1 Pre-Construction/Construction Activities
Pre-Drilling Phase
The activities in this phase are essentially desktop works involving feasibility,
technical and financial investigations/considerations. These investigations are
aimed at ensuring the viability and sustainability of the project. The results of
these investigations culminated in the preparation of a detailed drilling, casing and
mud programme. The operating environment was taken into consideration in
deciding the type of drilling mud most suited for this activity.
Consultations and meetings with regulatory bodies, host communities and
contractors are also prominent features of this phase. These consultations will
ensure that all stakeholders are notified and carried along, pathways and
schedules clearly defined. The benefits of these meetings/consultations are to
ensure that the exploratory drilling is carried out within regulatory compliance and
to ensure crisis-free project execution.
Site preparation
Site preparation activities consist essentially of preparing access route, wellhead
area, rig position. SPDC intends to acquire a total land area of 10.029ha for the
project, while a total of 1.42ha of land area will be dredged within the project area.
Movement and Transport of Equipment, Personnel and Supplies
•
•
•
•
•
The technical requirements of the exploratory drilling operation such as the drilling
rig and all its associated equipment having been established, the next phase of
action is to proceed with the mobilisation of required personnel, equipment and
materials. Materials that shall be transported include:
The rig;
Pipes and casing;
Drilling chemicals;
Generators; and
Diesel oil;
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Supply boats shall be used to transport equipment & materials.
creeks/creeklets and river shall be used.
Existing
Rig Movement and Positioning
The rig is the jack-up type, supported by well-positioned legs. Generators running
on diesel oil, as fuel, will supply power to the rig. The fuel oil (diesel) will be brought
into the field by supply boats.
•
•
•
•
3.5.2
The drilling rig has all necessary facilities on board for the drilling programme.
Consequently land shall not be cleared for campsite or storage of equipment.
The entire route (APO 1 Creek–Gbaran canal–Lobia junction- Azuzuma junction
and Tologbene) as shown in (Figs. 3.4) and (Fig. 3.5) for rig movement to the
drilling location as follows:
The Gbaran Canal (from APO1 creek junction), the manual sounding indicates that
a stretch of about 1500 m requires additional deepening of 0.60 m by dredging. The
existing creek width is adequate for rig move activities.
The stretch along the APO1 creek around the AGIP pipeline crossing measuring
1000 m (500 m on either side of the pipeline crossing) also requires additional
deepening of 0.06 m by dredging.
The entire stretch between the LOBIA junction to AZUZUAMA junction requires
major creek movement. The stretch is measuring 3000 m long x 24 m wide x 1.8 m
deep. This area requires creek widening by 0.6 m to give minimum overall width of
3.0 m +/- 150 mm below LLWS. The area for the creek improvement will require
temporary land acquisition to accommodate the dredged spoil.
The stretch from Azuzuama junction to the Tologbene location equally requires
deepening by about 0.60 m.
Drilling Programme
Drilling
Water based mud (bentonite) will be used for the top-hole sections. At the
intermediate and deeper-sections, pseudo oil based mud will be used. Oil based
mud shall not be used for drilling. Blow-out prevention liquid will be circulated in
a closed system. The wastes expected include drill cuttings, chemicals and spent
mud.
The drilling and completion operations shall be managed at Opugbene (Tologbene).
In the event that large quantities of hydrocarbon are produced during an optional
production test, it will be evacuated in barges to Agip flowstation. The supplies
shall come from SPDC’s Industrial Area (IA) Ogunu, Warri in Delta State.
Well Type
A vertical well, with a deviated pilot hole would be drilled.
Drilling/Mud System
Drilling operation requires the use of special drilling fluid (mud). The mud is
continuously pumped down the “drill string” to the ‘drill bit’ and returns to the
surface through the space between the drilling string and borehole. Drilling mud
performs the following functions:
· Exerts hydrostatic pressure on the down hole and prevents formation fluids from
entering the well bore;
· Removes drill cuttings from the bottom of the hole and carries them to the surface and
when circulation is interrupted, it suspends drill cuttings in the hole;
· Lubricates and cools the drill bit and drill string; and
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·
·
·
·
·
Deposits an impermeable cake on the wall of the “well bore” effectively sealing and
stabilising the formations being drilled.
Types of mud in use are:
Bentonite spud mud (circa 8000 bbls/well)
Material: Bentonite, Caustic, PACR, CMC, drilling detergent, barite, lost circulation
materials;
Pseudo oil based mud composition
Well Completion
The well shall be completed with the same rig that drilled them and flushed with
brine based fluids. Drilling fluid is often not a serious concern here, and in most
cases, only the casing content of the drilling fluid (about 800 – 1000 bbls) need to
be managed. The main concerns during completion are salinity or chloride
contents of the fluids.
Materials are: salt (NaCl), NaOH, XC polymer. Total volume is about 2500 bbls,
mainly low-density fluids. Special materials used for sand consolidation are diesel,
iso-propyl alcohol, Shell SOL “K”.
Drainage Discharges
Drainage discharges upon the drilling rig will occur from a number of sources
including:
· Clean area floor drains;
· Deluge drains;
· Machine area floor drains;
· Bunded areas beneath fuel or chemical storage areas;
· Overflow drains on diesel fuel tank system.
The first two sources contain non-oily water and are therefore discharged overboard
without any treatment. The other discharges may contain oil or chemicals and
would be routed to the oily water drainage and treatment system.
3.5.3 Waste Management Strategy
The expected waste from the drilling activities and other activities shall be managed
in line with regulatory requirements stated below as tabulated in Appendices 3.1ac and Table 3.1.
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Table 3.1: Waste Generation & Management Strategy
Waste
Mud
Cuttings
Cement
Brine (NaCl)
Discharge
Acids
Sand
Consolidation
Fluid
Sewage
Control Measure/Management Strategies
· Excess and used WBM will be re-used/re-injected or diluted to
meet DPR discharge standard before disposal.
· Used POBM will be re-used in the drilling of other wells.
· Spent POBM would be incinerated at the Forcados Thermal
Desorption Unit (TDU) or re-injected in dedicated approved
disposal wells (Opukushi-19 or Kokori-33 Cutting Re-injection
Well (CRI)).
· Top-hole cuttings drilled with WBM will be fluidised and reinjected in dedicated approved re-injection well.
· Bottom hole cuttings drilled with POBM and contaminated with
POBM will be incinerated at the Forcados TDU or re-injected in
dedicated approved re-injection well.
· POBM cuttings can be also processed by separating the
cutting into solid and liquid phases using shaker. The liquid
shall be passed through active carbon and filters (carbon &
silica) to remove contaminants. The resultant clean water is
discharge or re-use. The resultant cuttings shall be reinjected.
· The percentage mud on cuttings shall be kept below 10% before
incineration through the use of installed high gravity
shakers/dryers.
· Total expected volume of drill cuttings from WBM & POBM drilled
sections are 200m3 and 270m3 per well respectively.
· Cement residues and returns (spud mud and cement –
contaminated water) generated during the top-hole cementation
stage will be collected and re-injected.
· Solids free, lightweight, non-toxic completion brine will be used.
· Excess brines shall be re-injected.
· Used or spent acids will be diluted and neutralised through the
addition of dilute caustic soda. Thereafter it will be disposed off
through re-injection.
· Used sand consolidation fluids (well fix etc.) will be collected in
drums and sent for incineration at the TDU or re-injected.
·
Industrial and
domestic wastes
·
Rig bilge
·
·
·
Chapter Three
It is envisage that the maximum number of personnel at drilling
site at any one time will be about 150 persons. Sanitary sewage
produced at site will be treated on the rig sewage treatment plant
as per DPR standard. The water can be re-used for flushing the
system or disposed in rivers. Regular monitoring will be carried
out.
Industrial and domestic wastes will be segregated according to the
currently operated segregation scheme which distinguishes
between food waste, paper waste, scrap metals, chemical waste,
medical waste etc. These will be sent to SPDC respective waste
disposal facilities, e.g. the food waste will be taken to the decomposting plant at Jeddo.
Oily water discharges shall be controlled to less than 20ppm
through treatment oil in water by the rig oil/water separation
system.
The rig bilge cockpit has a hollow bridge deck with a secure lid
across the forward end, this decrease its size and is used as grab
bag for any spilled oil.
The rig bilge is also fitted with storm shutters to cover all the
windows to prevent oil spill into water bodies.
June 2005
Page 47 of 14
3.6
Operation and Maintenance Activities
3.6.1 General
The wellhead shall be operated in accordance with operational procedures
developed through SPDC extensive experience. The project will be managed by
fully trained and qualified personnel who are conversant with SPDC’s HSE policy
guidelines.
3.6.2 Operation
Facilities Safeguarding Philosophy
Wellhead
The wellhead will be maintained and safeguarded in accordance with SPDC’s HSE
policy and guidelines.
Maintenance Philosophy
Upkeep of Structures
Maintenance and inspection activities will be based on periodic inspection to
determine the condition of structures and performance of their protection systems.
Refurbishment activity to restore the integrity of structures will be based on their
condition. Coating systems applied to structures will be replaced on a time based
maintenance schedule.
Containment of Hydrocarbons
Maintenance and inspection activity will be based on periodic inspections to
determine the condition of all elements of the process fluid containment envelope.
Inspection will be related not only to the containment envelope, but also to any
protective coatings applied thereon. Inspection programmes for certifiable pressure
vessels, pressure / vacuum relieving devices will be inspected to meet the
requirements of the Minerals Oils (Safety) regulations of Nigeria. Refurbishment
activity to restore the integrity to the envelope will be based on their condition.
Where appropriate, economic systems to mitigate the effects of corrosion shall be
put in place and their effectiveness routinely monitored.
Control and Protection
Control and protection systems will be based on periodic inspections / calibration /
testing both their input and output functions as detailed in the Maintenance Job
Routes (MJR).
Hazard Detection Systems
Maintenance of hazard detection systems will be based on periodic inspection /
calibrations / testing of both their input and output functions. Non-availability of
hydrocarbon production caused by such inspections / calibrations / test will be
accounted for in the production plan.
3.7
Decommissioning/Abandonment
3.7.1 General
The wellhead and their ancillary installations have a life expectancy of about 25
years. The operation and maintenance procedure shall provide for monitoring the
performance and the integrity of the system components. When the performance of
the system scales to diminishing returns, SPDC standard procedures for
decommissioning shall be invoked. A decommissioning team shall be set up to
Chapter Three
June 2005
Page 48 of 14
plan and implement laid down guidelines on decommissioning.
activities are involved in decommissioning/abandonment:
•
Demolition and site clean-up;
•
Disposal of wastes;
•
Rehabilitation of site.
The following
3.7.2 Demolition and Site Clean-up
The demolition exercise shall be carried out with skill and diligence to avoid spill of
hazardous liquids and damage to the environment. At the end of demolition, solid
wastes shall be segregated according to their types and then disposed of according
to SPDC waste disposal guidelines (Appendices 3.0a-c).
3.8
Oil Spill Contingency Plan
SPDC’s oil spill contingency plan shall be applied to the proposed drilling project.
The spill contingency plan shall be based upon the location and volume of potential
spill and shall address the possibilities of well blowouts in the drilling emergency
plan.
The spill contingency plan clearly identifies the actions necessary in the event of an
oil spill including communication network, the individual responsibilities of key
personnel and the procedures for reporting to the authorities and arranging the
logistics of extra labour need for clean-up work. Finally, the plan shall address the
disposal of contaminated waste generated by a spill.
3.9
Project Schedule
The project schedule is shown in Fig 3.6 below. The duration for the drilling of the
well is specified in the project schedule.
Chapter Three
June 2005
Page 49 of 14
Full Preparation Survey of Tologbene Exploration
Location Fig. 3.4.
Chapter Three
June 2005
Page 50 of 14
Full Preparation Survey of Tologbene Exploration
Location (Creek Extension) Fig. 3.5
Chapter Three
June 2005
Page 51 of 14
Fig 3.6: Project Schedule
Chapter Six
June 2005Page 1 of 12
CHAPTER FOUR
4.0
4.1
STAKEHOLDER CONSULTATIONS
Introduction
SPDC recognises the need to engage all stakeholders including primary and
secondary in its activities. Stakeholders are individuals or groups who have
interest that may influence or affect the activities of the company. For this project,
consultation with principal stakeholders and regulators shall be a continuous
process all through the drilling, development and operational phases of the
development. The strategy is in line with SPDC's commitment of openness and
transparency with stakeholders and in compliance to regulatory requirements for
Environmental Impact Assessment (EIA).
Lee and Wood (1995) have defined consultation as the process of seeking information
about the environmental implications of a development project. It is therefore apparent
that the consultation programme has a wide scope in different communities and
cultures and is greatly influenced by the educational level and the political
consciousness and attitudinal disposition.
Within the Niger Delta area of Nigeria, where most of the Exploration and
Production activities associated with the oil industry take place, environmental
consciousness is beginning to change positively. It is worthy to note that this
consciousness is rapidly increasing especially among the youths of this zone.
The major stakeholders for this project are the project proponent (SPDC), The
Federal Government through the regulatory agencies (DPR, FMENV), the state and
Local Governments within the project area, the local communities and nonGovernmental organisations.
SPDC has established and will maintain close relationship with the key
stakeholders in this project.
Detailed consultations with host communities
commenced during fieldwork activities (Plates 4.1 & 4.2) and shall be sustained
throughout the project life cycle.
4.2
Objectives of Stakeholder Consultation
The objectives of the consultation are to identify and address and maintain effective as well
as factual communication with its stakeholders, so as to keep them constantly abreast of all
the activities relating to the Opugbene-West (Tologbene) Exploration Drilling Project.
The overall objectives of the stakeholder consultation are to:
•
Inform and educate to avoid misunderstandings about the drilling
project/development;
•
Establish areas of co-operation and development;
•
Identify problems, concerns and needs;
•
Obtain feedback;
•
Learn through local knowledge and understanding, particularly for
environmental and social baseline feedback;
•
Dissemination of information on the Opugbene-West (Tologbene) Exploratory
Drilling project;
•
Promote ownership and enhance social acceptability;
•
Build trust amongst the various stakeholders;
•
Evaluate alternatives and seek solutions; and
Chapter Six
•
4.3
Resolve and avoid conflicts.
Principal Stakeholders
The primary stakeholders to the Opugbene West (Tologbene) Exploration Well project have
been identified as the Ikebiri I & II and Lobia communities in the Southern Ijaw Local
Government Area of Bayelsa State. Consultation with the primary stakeholders is intended to
show how these immediate communities within the project area would be affected directly or
indirectly by the project.
An initial stakeholder consultation with the host communities was carried out
during pre-entry and fieldwork activities conducted between January 20-25th and
September 13-14th 2000 (Plates 4.1-4.2). During these visits, the team had useful
discussions with the host community executives, elders and women groups as well
as youths leaders.
4.4
Regulators
Institutional consultations are intended to show how the regulatory authorities such as the
Federal Ministry of Environment (FMENV) (formally FEPA), DPR, and the Bayelsa State
Environmental Protection Agency that constitute the secondary stakeholders participate in the
assessment of the proposed project.
SPDC’s intention to carry out the exploratory drilling project and the EIA have been
sent to both the FMENV and DPR in form of a project proposal and terms of
reference (TOR), comments have been received. Copies of this draft EIA report shall
be sent to the FMENV for review and comments, copies shall also be sent to DPR
for their review. Comments from the review activities shall be addressed and
incorporated into the final EIA report.
4.5
Issues of Concern
The major concern of the community is neglect by previous government in terms of
providing infrastructure and social amenities. This led to the absence of electricity and
portable water in the area. The host communities requested SPDC to assist them in the
provision of educational facilities as well as portable water. They sought explanations on the
scope of work for the EIA and subsequent work, which would take place within the field and
express concern for payment of compensation for fishing grounds and fish ponds which
would be affected by the project.
The host communities took pains to explain that the surrounding swampy
conditions provide breeding grounds for fishes and that efforts should be made by
SPDC to protect them because the majority of them depended on fishing for their
livelihood.
4.6
Future Stakeholder Consultations
SPDC shall sustain and continue to consult with key stakeholders-the host
communities, NGOs, Southern Ijaw LGA, Bayelsa State Government through
BSEDPA, FMENV and DPR who are stakeholders to be affected by the exploratory
drilling project.
Consultation is ongoing with the following communities Lobia, Azuzuama, Ukubie
who are also considered as stakeholders to the proposed project (Appendix 4.1).
Chapter Six
Plate 4.1: Consultation Session with Ikebiri Community
Plate 4.2: Consultation Session with Ikebiri Community
Chapter Six
Chapter Six
CHAPTER FIVE
5.0
5.1
DECSRIPTION OF THE ENVIRONMENT
Baseline Data Acquisition Methods
An important step in Environmental Impact Assessment (EIA) is the acquisition of
baseline data on the environmental components of the area in question. Baseline
data provide information on the current quality of the environment in which a new
development is being proposed. The environmental characteristics of proposed
drilling location in OML 36 were established by extensive literature review, twoseason sampling conducted in the dry and wet season of 2000 (January 20-25th
and September 13-14th 2000).
Routine and Standard methods were employed for baseline data acquisition and
analysis, details of the field and laboratory procedures are provided in Appendix
5.1. Basically, samples were analysed using methods specified by DPR guidelines
and standards along with other international Analytical Standards such as APHA
for water. Trace metals were analysed using Atomic Absorption Spectrophotometer
while other physiochemical parameters were determined using DREL 2000 HACH
Spectrophotometer and a flame photometer.
5.2
Study Approach
The field-sampling programme was designed to cover biophysical parameters
on land and water. Where ever possible measurements were made in situ.
Control stations were established away from the project zone while socioeconomic studies were carried out in communities within the project
location. Sampled points were co-ordinated and mapped up (Fig. 5.0).
Quality Assurance
The quality assurance programme covers all aspects of the study, including sample
collection, handling, laboratory analysis, data coding and manipulation, statistical
analysis, presenting and communicating results.
Sample Collection and Handling
This was carried out as far as possible in accordance with DPR Guidelines
Standards (Part (VIII) D (2) (Sampling & Handling of Samples)). Where logistic
safety considerations precluded strict compliance with the above guidelines
standards, other proven, scientifically acceptable methods of sample collection
handling were used.
and
and
and
and
Data coding
EIA studies in most developing countries where reliable data banks are nonexistent invariably involve acquisition of large amounts of baseline data. To ensure
preservation of the integrity of data collected, data coding forms for use in the field
were designed in such a way that field data could be directly entered into computer
data sheets.
Since the results of data analysis may be required in legal
proceedings, it is essential to establish sample authenticity. Samples must be
properly sealed and labelled. All data collected were labelled and the following
information provided among others:
· Identification code or sample number,
· Date and time of sampling,
· Description of sample,
· Methods of sampling,
· Particulars of any photographs taken.
Chapter Six
Sample Location Map of Opugbene (Tologbene):
Fig 5.0
Chapter Six
Where samples were sent to another laboratory for analysis, a duplicate copy of
this information was sent along with the sample to the laboratory, independent of
the sample. All movements of the samples were included on the sample record.
Basic information was recorded together with results of analysis, in a sample
register.
Statistical Analysis
Errors in field data include those resulting from the instrument and those
introduced by the observer. With proper, sustained calibration of the instrument
and the use of standardised observational procedures, equipment errors were
brought to acceptable minimum. However, other errors arise from the method of
sampling. Errors often arise from two-stage sampling or sub sampling, or even
from the fact that the samples collected are not representative samples of the
medium. Thus, it is necessary to determine the true mean and the estimated
variance among the number of samples taken, so as to establish a reasonable level
of confidence in the results obtained. A good result is obtained when the variance is
within 5% of the mean.
5.3
Geographical Location
The proposed drilling location lies in the South-Eastern part of OML-36 and falls
roughly within longitudes 58000 - 73000N and latitudes 370000 - 388000E. The
area is located in Southern Ijaw Local Government Area of Bayelsa State,
approximately 100 km Southeast of Warri.
It is
coloured, contain extensive layers of peat. The vegetation is a mixture of fresh
water trees and mangrove, while the surface water is generally fresh.
5.4
Field Data
The detailed description of the environmental field data for the study area as
established during this study is presented in the following sections:
5.4.1 Climatic Conditions
Rainfall
The area is influenced by two seasonal periods, namely the wet and dry seasons.
The wet season is the dominant season, and it lasts from April through November.
It is characterised by the South-West trade winds laden with moisture from the
Atlantic Ocean. Abundant rainfall marks the wet season with annual rainfall in the
range from 2500 – 3000mm.
The dry season lasts from November to March and is characterised by North-East
trade winds, which brings in harmattan between December and January.
Temperatures
Temperatures within the Opugbene (Tologbene) area in the wet season ranged from
24.6°C - 30.0°C, dry season temperature ranged from 25.0°C - 32.0°C. The mean
temperature was over 30.5oC.
Relative Humidity
The monthly relative humidity values of the study area for dry season ranged from
67% and 85% while that for wet season ranged from 72% and 90%. The afternoons
are generally hot and humid.
Chapter Six
Wind Speed and Direction
The wind speed in the study area during the wet season averaged at 2.0m/s, while
4.0m/s was the maximum speed recorded during the fieldwork these values
increased slightly to 2.2 m/s and 4.5m/s respectively during the dry season. The
frequency of wind direction indicates that the prevailing direction ranges from
southerly (10.0%), south-westerly (67.5%), westerly (14.0%) and easterly (8.5% of
the time). The percentage of calm was 20.0% (Fig. 5.1).
N
20.0%
Percentage of Calm = 20.0%
Wind Speed
2
Fig.5.1:
Chapter Six
5
3
1
4
Wind Distribution Pattern (Rose) for Opugbene (Tologbene) Field
5.4.2 Air Quality Assessments
The mean concentrations of the gaseous pollutants and suspended particulate
matter are given in Table 5.1. Details of Nigeria and WHO ambient air quality
standards are given in Tables 5.2 & 5.3.
The Total Suspended Particulate (TSP) concentrations were measured based on
average exposure rate of 8-hour daily.
Based on limited 1-hour average
observations, the air quality parameters such as SO2, NOx, and Volatile Organic
Compound (VOC) in the project areas were determined. Also, due to possible future
impact of Exploration and Production activities the communities nearby were
subjected to air quality monitoring in order to establish the ambient baseline values
of the monitored parameters. The coefficient of variation was generally of the order
of 25-35% for the determinations at each location, for both seasons.
NOx levels ranged from <5.0 µg/m3 -23.7 µg/m3 (wet season) at stations 1, 4, 5 and
the control station, while level 28.5 µg/m3 (dry season) was recorded at station 3.
Values above the detection limit were only obtained during the wet and dry seasons at
a location near Agip flowstation which was either urban or semi-urban, and where
fossil fuel was in significant use for powering electricity generators in the flowstation
in the area. High NOx level is known to be associated with combustion of fuels in
stationary sources (Manahan, 1984). Relatively lower levels of NOx which were below
detection limit <5.0 µg/m3 were obtained at the non-industrialised and less built-up
area of stations, 1, 4, 5 and the control station. Thus there was no diffuse
contribution to the NOx levels in these locations that may have been derived from
emissions from automobiles and burning of fossil fuel from a near by location.
The general pattern of the distribution of NOx in the study area thus appears to be
average levels of <5.0 µg/m3 in the very remote areas, on which is superimposed
higher levels of about 23.7 µg/m3 (wet season) and 28.5 µg/m3 (dry season), which
occur at the Agip flowstation area in the entire study area. The general NOx levels of
<5.0-28.5 µg/m3 obtained in the study area during the entire study period are within
the safe limits specified by FEPA for ambient air quality in Nigeria. FEPA specifies an
upper limit of 75-113 µg/m3 of NOx. The present condition of the study area is thus
safe with respect to the concentrations of NOx, which is one of the pollutants whose
atmospheric concentrations could be elevated as a result of increased levels of
industrial activities, which may be derived from the implementation of the gas
pipeline project.
Chapter Six
Table 5.1:
Ambient Concentrations of Air Pollutants at some Locations
during the Wet and Dry Seasons Field Sampling
Air Sampling Point
Station 1 (Ikebiri 1)
Station 3 (Close to Agip
NOx
SO2
NH3
O3
SPM
VOC
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(mg/m3)
(mg/m3)
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Wet
Dry
Wet
Dry
<5.0
<5.0
11.
<5
n.d.
n.d.
n.d
n.d
n.d.
n.d.
n.d
.n.d
n.d.
n.d.
n.d
n.d.
n.d.
23.7
32.
12.
n.d
n.d
3.3
2.6
5
<5.
n.d
n.d
2.3
2.0
<5
n.d.
n.d.
2.0
1.2
n.d
n.d
n.d.
n.d.
n.d.
2.0
1.5
n.d
n.d
n.d.
n.d.
Station 4 (Ikebiri II)
<5.0
<5.0
4
12
Station 5 (Proposed F/S)
<5.0
<5.0
10.
<5.0
1.6
28.5
(F/S)
Control Station
2.1
Dry
<5.0
(Okuromukpa)
12.
<5
.
n.d.
n.d
8
FEPA Limit (Ambient)
75-113
26-260
200
100
0.25-0.6
0.16
* n.d. = not detected, detection limits are 2.0 µg/m3 for ammonia and ozone, 0.02 mg/m3 for SPM, and
0.1 mg/m3 for VOC.
Table 5.2
Nigerian Ambient Air Quality Standards (FEPA, 1991)
Pollutant
Particulates
Sulphur oxides
(Sulphur dioxide)
Non-methane
hydrocarbon
Carbon monoxide
Nitrogen oxides
(Nitrogen dioxide)
Photochemical
oxidant
Time of Average
Daily average of 1hr values
Daily average of
values, 8hr average
Daily average of
values (range)
Hourly values
Limit
260µg/m3 - *600µg/m3
0.01 ppm (26g/m3) 0.1 ppm (260µg/m3)
160 µg /m3
hourly 10 ppm (11.4 µg/m3)
20 ppm (22.8 µg/m3)
hourly
• ppm - 0.06 ppm
(75.0 µg/m3 – 113 µg/m3)
0.06 ppm
*Concentrations not to be exceeded for more than once a year.
Chapter Six
Table 5.3:
World Health Organisation (WHO) Guidelines for Maximum
Exposure to the Major Pollutants and Possible Effects if Exceeded
Pollutant
Sulphur dioxide
(SO2)
Suspended
Particulate
Matter (SPM)
Possible Effects
Worsening respiratory illness from
short term exposure, increased
respiratory symptoms, including
chronic bronchitis, from long-term
exposures
Pulmonary effects are associated
with the combined exposure to
SPM and SO2
WHO Guidelines
40-60 µg/m3 (annual mean);
100-150 µg/m3 (Daily
average)
Black:
40-60 µg/m3 (Annual mean).
average)
Total SPM:
60-150 µg/m3 (Annual
mean);
average)
Nitrogen dioxide Effects on lung function in persons 150 µg/m3 for 24 hr mean;
(NO2)
suffering from asthma from short400 µg/m3: Not to be
term exposures
exceeded
Carbon
Reduced oxygen - carrying capacity 10 mg/m3 (for 8 hr), not to
Monoxide (CO)
of blood
be exceeded.
Source: WHO Air Quality Guidelines for Europe, 1984.
The pattern of variation of sulphur dioxide levels in the study area is somewhat
similar to that of NOx. This may be due to the fact that, as is the case with NOx,
sulphur dioxide emission is also associated with fossil fuel combustion in power
generators, automobile emissions and to a less extent on release of aerosol mist
from near by ocean during the wet season. Thus, higher level of sulphur dioxide
(32.4 µg/m3) was obtained at station 3, as was the pattern for NOx (Table 5.1).
The other four locations however had comparable low levels of <5.0-12.8 µg/m3 for
both the wet and dry seasons. The highest level of 30.6 µg/m3 at station is
significantly different from those of the other non-industrialised locations.
The distribution pattern which is discernible for sulphur dioxide in the study area
is thus one of a general background level of <15 µg/m3 on which is superimposed
the 30.6 µg/m3 level in station 3. The levels of sulphur dioxide found at these
locations were all far less than the upper regulatory limit of 260 µg/m3 set by FEPA
and WHO Guidelines for emission (Tables 5.2 & 5.3). The baseline condition for
atmospheric sulphur dioxide concentrations in the study area is thus one of very
low level, which is within safety limits. The ambient levels of tropospheric ozone
during the wet and dry season were very low in the project area (1.2-3.3 µg/m3),
and these were far below the critical FEPA limit of 100 µg/m3. High levels of ozone
are implicated in the incidence of smog and damages to plants, rubber materials
and other items (Manahan, 1984).
The concentrations of ammonia, suspended particulate matter and volatile organic
compounds (VOC) during the entire study period were very low and below the
detection limit of the sampling/analytical method. These detection limits were 2.0
µg/m3, 0.02 µg/m3 and 0.1 µg/m3 for ammonia, particulate matter and VOC
respectively below the critical limits set by FEPA for these materials.
Chapter Six
The values obtained for the measured parameters pointed to the fact that the air
around the project site still maintains its natural quality. However, emissions from
the Agip flowstation as reflected in the results of analysis carried out at station 3
are implicated in the natural air quality of the study area.
In all, the levels of atmospheric pollution in the study are relatively low with most
of the pollutants being either below detectable levels or at levels, which are within
the safe range and within FEPA/DPR and WHO guidelines (Tables 5.2, 5.3 & 5.4).
Table 5.4:
FEPA (FMENV) Tolerance Limits (µg/m3) for some Ambient Air
Pollutants
Pollutant
Long Term*
Short Term*
Particulate
150
500
Nitrogen oxides
4.0
100
Sulphur dioxide
50
500
Ozone
100
200
Ammonia
200
200
Hydrocarbon (Total)
2.0
5.0
* Long-term = 24 hr; short-term = 30 min
5.4.3 Noise Level Assessment
Noise had long been recognised as a health hazard, but not until very recent times,
had research delved into the phenomenon to uncover the extent of its potential for
health hazard.
The psychological and physiological effects of working in a noisy environment for
prolonged periods have been amply documented (Passcluer-Vermeer, 1971; Starck
et al 1987; Willingham 1976). All researchers in the field now agree that noise
may:
• Damage hearing if consistently of high level or of an impulsive nature;
• Impair safety by making warnings difficult to hear;
• Hinder communication between employees who work as a team and where
efforts are interactive, such as telephone communication between wellhead,
flowstation and base;
• Interfere with efficiency, either as a direct result of communication loss, as
above, or by causing fatigue and loss of concentration; and
• Be annoying.
The mean and range of noise levels measured during the sampling periods are as
shown in Table 5.5. There were no sources of noise other than the intermittent
noise of birds and passing boats. The noise level average recorded at station 3 was
86.0 dB(A) which was slightly below the FEPA limit of 90 dB(A) with range of 68.0 –
120 dB(A). The upper limit was higher than the regulatory limit of FEPA indicated
in Table 5.6. The result obtained is applicable to both dry and wet seasons.
Chapter Six
Table 5.5:
Mean and Range of Noise Levels in the Study Area
Locations
Mean Noise Level
Range of Noise Levels
(dB(A))
(dB(A))
Station 1
35
27.0-45.0
Station 3
86
68.0-120.0
Station 4
36
29.4-40
Station 5
26
24.0-36.0
Station 6
50
47.0-64.0
Table 5.6:
Noise Exposure Limits for Nigeria
Duration per Day, Hour
8
6
4
3
2
1.5
1
0.5
0.25 or less
Permissible Exposure Limit (dB(A))
90
92
95
97
100
102
105
110
115
Source: FEPA National Standards and Guidelines (1991).
Note:
Exposure to impulsive or impact noise should not exceed 140 dB (A) peak sound
pressure level. WHO Criteria for Community/Residential Areas Daytime Noise Limit
is 55 dB (A) while, Night-time Sleep Limit is 45 dB (A).
5.4.4 Soil and Land Use Pattern
5.4.4.1 Soil
The topography of the area consists of low-lying and relatively flat terrain. The
vegetation consists of mangrove, transitional and rain forest. The soils under the
tall mangroves consist of saturated organic material, black to dark grey in colour,
containing silt and clay bands where tall mangroves give way to short, stunted
mangrove, thus soft mud is replaced by peaty clayey soils locally called chikoko.
Texture
The texture of the soils in the project area range from loam, silty clay to sandy clay.
The soils have mean clay content of about 2.94%, silt of about 5.63%, and
predominantly sand of about 91.4%.
pH
The degree of acidity and alkalinity in soils is characterised by soil pH and is also
known as soil reaction. This is determined by the hydrogen ion (H+) concentration
in the soil solution. Based on soil pH values, soil in the area can be described as
shown in Table 5.7 as suggested by Brady (1974) and Moss (1975).
The soils during the wet season are extremely acidic to medium acidic pH 4.21-5.67
at surface and 3.21-5.11 at subsurface. This was also the case during the dry season
with soils being strongly acidic except for very few like those from stations 8, 10 and
13 with concentrations of hydrogen ion in water of (5.57, 5.56), (5.25, 5.32), (5.49,
3.05) respectively that were moderately acidic. However, soil from point 13
Chapter Six
recorded a concentration of 3.05 and therefore very strongly acidic. This conforms
to the findings of earlier workers, who classified the soils of similar hydrogen ion
concentrations as "acid sands" (SSSN, 1981).
Table 5.7
pH Value
< 4.5
4.5-5.0
5.1-5.5
5.6-6.0
6.1-6.5
6.6-7.3
7.4-7.8
7.9-8.4
8.5-9.0
> 9.1
Description of Soil pH
Description
Extremely acidic
Very Strongly acidic
Strongly acid
Medium acid
Slightly acid
Neutral
Mildly alkaline
Moderately alkaline
Strongly alkaline
Very strongly acid
Generally, the subsoil has lower pH values of 3.21-5.11 (wet season) and 4.18-5.57
(dry season) indicative of higher acidity than the surface soils with pH range of
4.21-5.67 and 3.05-5.68 for wet and dry season respectively.
However, soil from point 13 recorded a concentration of 3.21 and therefore very
strongly acidic. In Nigeria, Oguntoyinbo et al (1994) mainly attributed the relative
lack of crop intensification in the high rainfall areas like the study area to soil
acidity. The most conspicuous effects of high acidity normally occur at pH values
below 5.5. Under this pH value, soluble aluminium (A13+) and Manganese (Mn2+)
tend to be highest. Phosphorus tends to convert into insoluble aluminium and iron
phosphates through fixation by sesquioxides, while calcium becomes unavailable
for crop uptake especially when the Ca/Al ratio in the soil is quite low i.e. high
acidity.
The low pH values could be due to over-flooding of the forest areas resulting in
organic acids and the presence of pyrite materials in the mangrove swamps which
oxidise on exposure to Sulphuric acid (Dent, 1986). Similar values have been
recorded for the Niger Delta area.
Soil Organic Carbon
The soil organic carbon includes the living organisms partly decomposed and
decomposed plant and animal residue. Upon decomposition, the organic matter
increases the water-holding capacity of soils and promotes the development of
stable and soil structures. Chemically, it is a source of plant nutrients. A survey
in Western Nigeria shows that organic matter range from 0.5 to 7.0% in the soils
(Agboola and Corey, 1973).
The organic carbon content of soils in the study area is shown in Appendices 5.2 a
& b. The total organic carbon contents is low (<2.5), ranged from 0.23% around
point 2 to 0.83% at point 10 (wet season) and 0.26% around point 2 to 0.86% in
point 10 (dry season). The result shows that the nutrient contents (ECEC) of the
area is also low since most of the soil nutrients are held on the exchange complex
of organic matter (Agboola and Corey, 1973). All the values recorded for organic
content were well below the 1.5% critical level reported by Adepetu (1986) thus the
organic carbon content level is not high enough to maintain optimum yield of
continuous cropping of the land.
Chapter Six
Nitrate Nitrogen
Nitrogen is the most important nutrient of plants and like the organic carbon, the
values in the field are generally low (0.002-0.43%), this could be due to low organic
carbon contents (Agboola and Corey, 1973). From extensive soil analysis, the
nitrate nitrogen in Western Nigeria soils has been classified as low (< 20ppm),
medium (20 – 40 ppm) and high (> 40 ppm) (Agboola, A.A. and Sobulo, 1981).
The nitrate nitrogen in study area ranged from 0.002ppm at point 1 to 0.43 ppm at
point 12 and from a non-detectable value of <0.1ppm at point 1 to 53.53 ppm at
point 12 with an overall average of 15.35 ppm for wet and dry season respectively.
Generally, the concentration in most points sampled; 1,2,3,4,5,6,7, 9 and 13 were
low while points 10 and 13 (15-30cm) were moderate; point’s 12a and b recorded
high values. The total nitrogen contents showed a very high positive correlation
with organic carbon indicating that the reserve of this element is mainly from
organic matter.
The generally low nitrate nitrogen concentrations could be attributed to leaching
losses and denitrification. The susceptibility of nitrate anion to leaching becomes
prominent under condition of heavy rainfall as in the study area.
Available Phosphorus
Phosphorus (phosphate) is an essential plants nutrient and is taken up by plants
in the form of inorganic ions; H2PO42- and HPO4-. It is needed for root development,
seed formation and for controlling plant maturity. It is also an essential component
of Adenosine diphosphate (ADP) and Adenosine triphosphate (ATP), which play a
vital role in photosynthesis and ion uptake and transport in plants. For soils
throughout Nigeria a phosphorus range of 17 to 72 %, has been established and
quoted.
The concentrations of phosphate in soils of the study area are shown in
Appendices 5.2 a & b. The phosphate values is very low and not up to 1.0 ppm in
most sampling points. Like most other major nutrients in the area, the available
phosphorus is generally low in the samples; they are less than 8.0ppm critical level
for maize (Agboola and Obigbesan, 1974). With the exception of one point, namely
point 12 (8.15 ppm-10.46 ppm in the sub-surface soil as per wet and dry seasons).
The values range from 0.05 – 3.2ppm in the 0-15cm layers and 0.2 – 8.1ppm in the
subsoil (wet season) and the dry season values ranged from <0.5 ppm in point 5 (015cm) to 10.46 ppm in point 12 with an average of 1.64 ppm. The sulphate levels
are also low 0.13-0.44% (0-15cm) and 0.13-0.82 (15-30cm) for the wet season and
0.15-4.44% from subsurface to surface (dry season). The low available phosphorus
contents could be attributed to the fixation of available phosphorus by free oxides
of iron and aluminium, which become very soluble at low soil. The mean available
phosphorus of the surface soils unlike in organic carbon and total nitrogen was
higher than that of the sub-soils. The very low values of phosphate in area could
be attributed also to the high acidity of the soils. Under such condition, iron and
aluminium becomes very soluble and form insoluble complexes with phosphorus
thereby making the element unavailable to plants.
Exchangeable Cations
The Exchangeable cations in the soil are calcium (Ca), Magnesium (Mg), Sodium
(Na) and Potassium (K). Calcium is believed to have beneficial effect in development
of soil structure and plant growth. The primary source of calcium is dolomite. A
calcium concentration between 0.1 to 1.0 mm at the root surface is considered
adequate for plant growth.
Chapter Six
Calcium was the most abundant cation in the soil exchange complex. This finding
corroborates the observation that calcium is the predominant cation in the soil
complex because of its strong adsorption by the soil (Beckeh, 1965). In order of
abundance, Calcium was followed closely by Magnesium, sodium and potassium.
The calcium concentration is shown in (Appendices 5.2 a & b). The wet season
concentrations at the surface ranged from 0.64 meq/100g at point 3 (0-15cm) to
3.5 meq/100g at points 4 and 13. The values are very low irrespective of the
season in some points below 2.0 meq/100g that is considered critical for plant
growth especially at points 3 and 5, while the sub-surface concentration is in the
range 0.58-3.1 meq/100g the dry season value indicated similar pattern with the
concentration ranging from 0.55 meq/100g at point 3 (0-15cm) to 3.72 meq/100g
in point 13 with an average of 2.09 meq/100g. Magnesium is an essential
constituent of chlorophyll and vital in photosynthesis. The average magnesium
content in the soil is approximately 1.35 meq/100g and 1.38 meq/100g for both
wet and dry season respectively. The Magnesium content in some soils in the area
is low. With reference to both seasons Points 4, 6,7, 8,9 and 13 that had values
below 1.0 meq/100g and can be judged to be low while points 1,2,3 and 5 are
moderate and 10, 12 high. The overall values range from 0.32-3.16 meq/100g soil
in the 0-15cm and 0.27-3.18meq/100g soil for the lower 15-30cm depths. The low
concentrations of calcium and Magnesium could be attributed to high acidity.
Under such low soil pH as in the area, these elements become unavailable for crop
uptake especially when the Ca/Al ratio in the soil is quite low. Sodium is the next
in abundance with a mean value of <1.0meq/100g soil at the surface and the
subsurface, the overall values fall in the range 0.45-1.73 meq/100g (wet season)
and 0.37-2.29. meq/100g (dry season).
Potassium is present in all rocks and its contents in mineral soils are
approximately 0.83% (Tan, 1994). On the average, the potassium concentration in
the soil solution is <0.5 meq/l00. Generally, the concentration of Potassium in in
the area is low in most of the points sampled. These points 1,3,4,5,7,9,12,13a and
13b recorded values below 0.3 meq/100g. Only points 10 and 11 recorded
concentrations up to 0.7 meq/100g respectively, that can be ranked as high.
Generally the range of values recorded for both top and sub-soil is 0.030.78meq/100g. These low values could be attributed to leaching which is common
in high rainfall areas like in the study area.
The contents of these cations were in most cases higher in the sub- soils than in
the surface soils and showed a high positive correlation with organic carbon.
Generally, the exchangeable bases, like the other nutrients, were high in some few
cases and above the 2.0 meq/100g soil of Ca and Mg required of a good soil in
Nigeria and 0.2 meq/100g soil for K and therefore will require straight Mg and K
fertilisation for optimum crop production.
Effective Cation Exchange Capacity (ECEC)
The values of ECEC in shown Appendices 5.2 a & b. The cation exchange
capacity which is a reflection of the levels of exchangeable bases (K+, Na+, Ca2+ and
Mg2+) the ECEC of all the soils in the study area is very high in most cases and
above 4meq/100g critical limit for good yield (FAO, 1979). Like the total nitrogen
and exchangeable cations, the ECEC showed a positive correlation with organic
carbon with the values in the subsoil higher than those of the surface in most
cases. The mean CEC value of the 0-15cm soil (65.77 meq/100g soil) was higher
than the 15-30cm subsurface value (61.13 meq/100g soil) as a result of higher
organic carbon in the surface soils (Agboola and Corey, 1973).
A greater
percentage of the CEC was contributed by the exchangeable bases, thereby
resulting in high base saturation. The CEC values range from 3.01-8.13 meq/100g
Chapter Six
soils at the 0-15cm layers and 3.04 –7.28 meq/100g soil at the 15-30cm depths for
the wet season and 2.94-8.08 meq/100g meq/100g soils at both depth for the dry
season. Low values below the critical limit of 4.0 meq/100g soil (FAO, 1979) were
recorded at points 3, 5 (0-15cm), 6 (0-15cm), 7, 8 and 9. These low values could be
attributed to high acidity and leaching resulting from high rainfall intensity.
The contribution of aluminium ions (Al3+) to the total acidity in the soil was higher
than that of hydrogen ions (H+) which showed that the soils were strongly acidity.
However, the mean values of the exchangeable acidity did not follow any definite
pattern with depth.
Base Saturation
This is a good measure of how much of the ECEC is being utilised to store plant
nutrients. The base saturation in the area is quite high, the value ranged from
82.72-99.49% at the surface and 74.89-99.35% at the subsurface, wet season and
80.68% in point 6 to 99.69% in point 13 for dry season. . The average for the area
is 90.45% and 92.71% for wet and dry season respectively. . This values shows that
most of the exchangeable complex was occupied by bases Ca Mg, Na and K.
Total Hydrocarbon:
The total hydrocarbon content of soil in the study area is shown in Appendices 5.2
a & b. The values are low and less than 50 ppm which is the limit for biogenic level
of hydrocarbon (Concawe, 1972) and also far below the critical level of 100 ppm
(NCC, 1991). In the absence of any crude oil spill and crude oil production
activities in the area, values of total hydrocarbon recorded could be attributed to
contributions from the mangrove vegetation. Soils normally contain from about 1015ppm of biogenic hydrocarbon (Concawe, 1972). In areas with abundant leaf fall
as in the forest patches, biogenic hydrocarbons are expected to be much higher,
because higher molecular weight hydrocarbons are major components of the
surface wax of plant leaves (Eglinton et al, 1962). The surfaces of leaves are
covered with waxes, which were reported to contain high molecular weight
hydrocarbons (Higgins and Burns, 1975).
Heavy Metals
The heavy metals concentration in the study area is shown in (Appendices 5.2 a &
b). According to the international standard, (Nature Conservancy Council NCC,
1991) and FEPA (1991) guidelines, the heavy metals contents of the soils are
generally below the critical levels to constitute hazard. Results indicate relatively
low values of these metals in the soil except iron.
The dominant heavy metal in the soils is iron. Iron is important as a trace element
in plant nutrition and any concentration up to 230 ppm has been reported to be
toxic to rice plants (Ponnamperuma, 1974).
The concentration of iron in the area is high and ranged from 164 - 522 ppm at the
surface and 162- 535 ppm at the subsurface (wet season) and 162 ppm in point 9 534 ppm in point 12, with an average of 356 ppm (dry season). These high iron
concentrations can be attributed to high acidity especially in wet soils (Brady,
1974). FAO (1972) reported that high value of Iron is peculiar to poorly drained
soils and a concentration of 20 ppm has been reported to be toxic to rice plants
(Kyuma et al, 1986). Extremely high values, more than 1 x 104 ppm will be very
toxic to crop plants.
Zinc is a micro-nutrient required by plants and acts as catalyst in several plant
enzymes. Zinc has been implicated in root-to-shoot translocation. The average zinc
Chapter Six
content in normal agricultural soil is 50meq/g (Brady, 1974). High soluble zinc
occurs in acid soils. The concentrations of this metal in Opugbene (Tologbene) soils
were mostly higher than the critical limit of 1.5 ppm and ranged from 2.40 - 7.1
ppm at the 0-15 depth and 1.20 - 14.95 ppm at the 15-30 depths for the wet
season and also ranged from 1.12 ppm in point 6 - 15.16 ppm in point 12 for the
dry season. Zinc concentrations greater than 400meq/g of leaf dry matter are
considered excessive and may induce zinc toxicity. Soils in the mangrove areas are
known to record high value of zinc. Ponnamperuma (1974) reports a 1.5-ppm
critical level of zinc and most values exceeded this limit.
Copper is required for chlorophyll formation and hence photosynthesis. Copper is
also needed in reproductive stages, protein and carbohydrate metabolism and
nitrogen fixation. Copper concentration in leaf tissue greater than 20mg/g will
result in copper toxicity. The copper concentrations in The area was low and
ranged from 1.5 to 6.5 ppm at the surface and 1.7 - 6.63 ppm at the subsurface
and from 1.41 ppm in Point 7 - 7.63 ppm in Point 12 with an average of 3.30 ppm
for both wet and dry season respectively. The other heavy metals recorded were
lead (0.27-11.56ppm), nickel (0.21-5.13ppm), cadmium (0.08-0.72 ppm), chromium
(0.06-0.9ppm) and mercury (<0.02). The abundance level in the soil shows a
decreasing order as Fe >>>Zn>Cu >Pb>Ni >Cd > Hg.
Chapter Six
5.4.4.2 Land Use Pattern
The major land use types in the Opugbene (Tologbene) area are forestry and
settlement. The area consists of Mangrove vegetation (tall ones near the banks of
Ikebiri creek and stunted ones at the plains), Raffia palm & mixed rainforest (Fig.
5.2). Only few settlements (Ikebiri 1 & II and fishing camps) exist in the Field.
5.4.5 Terrestrial Ecology
5.4.5.1 Vegetation
There is no significant change with respect to seasonal variation in the vegetation of
study area in terms of composition, structure and diversity. What is however
evident is that there is speedy regeneration of plants that were burnt and affected
by the dry season following the entry of the rainy season Overall, the area
considered as an ecologically rich diverse genetic base of plant species. There are
three distinct thick vegetation patterns viz: rainforest; transition and mangrove
forest (Fig. 5.2 and Plates 5.1 & 5.2).
Rainforest
The vegetation is essentially thick rainforest vegetation from Ikebiri I through
Ikebiri II to Okoluba-Ikebiri creek junction. There is intensive subsistence crop
farming activities and extensive commercial lumbering activities in the rainforest
zone resulting in loss of vegetation over an extensive area. Logs of various girth
sizes of different plant species particularly Alstonia were noticed at strategic
locations by the sides of the Ikebiri creek. Main identified dominant plant species
in this rainforest zone are:- Adansonia digitata, Musa sp, Manihot sp, Dioscorea sp,
Chromolaena odorata, Azadirachta indica, Anthostema aubryaum, Elaeis guineensis
Cocos nucifera, Alstonia boonei, Mangifera indica, Irvingia gabonensis.
Chapter Six
Land use/Cover Map of Opugbene (Tologbene):
Fig 5.2
Chapter Six
Transition Forest
The vegetation from Okoluba creek junction to about 5km upstream along the
Okoluba creek down to Ikebiri market square is a transition forest from rainforest
to swamp forest densely populated with Raphia africana and Rhizophora species on
both sides of the creek.
The thick transition forest along the Okoluba creek is regarded as forbidden
forest and special permission must be sought from the community, for
necessary consultation before carrying out any work in the forest. The main
dominant plant species in this transition forest are Raphia africana (both tall
and dwarf), Rhizophora species (Red mangrove) and few Acrostichum aureum.
Raphia africana are densely populated and Rhizophora species has a device
network of stilt roots and branches that make accessibility extremely
difficult. These features are of ecological important of protecting the bark
against erosion. The vegetational resources of this area are of importance as
source of genetic materials and firewood used for smoking fish catches.
Identified plant species in this ecology are: Avicennia sp (White Mangrove);
Acrostichum aureum, Terminalia superba, Raphia africana (dwarf), Raphia africana
(tall), Alchornea laxiflora, Rhizophora racemosa (Red mangrove) and Rhizophora
mangle.
Mangrove Forest
The vegetation down stream (southeast and southwest) from Ikebiri market
junction and to Agip flow station is a mangrove forest. Plant species found in this
swamp ecology are Rhizophora racemosa, Rhizophora mangle, Avicennia sp. Nauclea
latifolia, Avicennia geminanans, Crotolaria retusa, Urena lobata, Cyperus esculentus,
Cassia obstusifolia, and Bracheria deflexa.
The vegetation types of the study area enhance the ecological balance. The
transition and rainforest wetlands serve as natural flood control system by storing
water during rainy season and subsequently releasing it slowly into the rivers and
streams when flood and high tides recede. In addition, the mangrove protects the
banks from erosion.
The economic uses of the key plant species in the study area are presented in
Table 5.8. The mangroves are important source of tannin while edible oil is
obtained from palm tree. Nypa fructicans is an important source of wine and
alcohol. Halea ciliata, Nauclea diderrichii and Rhizophora racemosa are good source
of timber while erosion can be controlled by Dalbergia ecastaphylum and Paspalum
vaginatum.
Chapter Six
Plate 5.1: Logging Activities in the Study Area
Plate 5.2: Mix Forest in the Study Area
Chapter Six
Table 5.8:
Economic Uses of the Key Plant Species
Taxa
1
Acrostichum aureum
2
3
10
11
12
Anthocleista nebilis
Calapogorium
mucunoides
Calamus decratus
Dalbergia ecastaphyllum
Elaeis guineensis
Halea ciliata
Hibiscus tiliaceous
Harungana
madagascariensis
Nauclea diderrichii
Nypa fructicans
Phoenix reclinata
13
14
15
16
17
Mangifera indica
Musa paradisiaca
Paspalum vaginatuim
Ipomoe pes capre
Rhizophora racemosa
18
Avicennia germinans
19
20
Crotalaria retusa
Aframomum sceptrum
21
Laguncularia racemosa
4
5
6
7
8
9
Common
Name
Mangrove
fern
Cabbage tree
Calapo
1
2
3
4
5
6
7
8
9
O
Ratta palm
10
11
C
O
12
13
C
C
C
Oil palm
Abura
Hibiscus
C
C
C
C
Opepe
Nipa palm
Wild date
palm
Mango
Plantain
Couch grass
Tall red
mangrove
White
mangrove
C
C
C
C
C
C
C
C
C
C
C
C
C
C
O
C
Grain of
paradise
Black
mangrove
C
C
C
Key to Category:
1: Tannin, 2: Salt, 3: Timber, 4: Fibre, 5: Medicine, 6: Fruit, 7: Structure Material, 8: Wined Alcohol,
9: Charcoal, 10: Erosion Control, 11: Ornamental, 12: Edible Oil, 13: Spice, 14: Furniture.
C: Common & O: Occasional.
5.4.5.2 Ecologically Sensitive Areas
The project area is composed of swamp rain forests and mangrove vegetation which
are widely recognised as environmentally sensitive settings. For example, the
ground water table is very shallow. Making it easily liable to contamination from
drilling wastes if not carefully handled. Furthermore, the geomorphology of the
area is sensitive to development on account of its flat terrain which pre-disposes it
to erosion if artificial trees are created through the deposition of spoils.
5.4.5.3 Wildlife and Forestry
Wildlife is defined as mammals, aves, amphibians and reptiles encountered in the
wild. In the Opugbene (Tologbene), based on the number of sightings, faecal
droppings and footprints per square kilometre and literature, it was found that
birds were most dominant group of wildlife. The number of individuals belonging
to each species and their conservation status are presented in Tables 5.9 –5.11.
Chapter Six
14
Table 5.9:
Checklist of Reptilian and Amphibian Species
Reptiles
1. Lizard (Agama agama)
2. Green snake
3. Alligator
4. Carpet snake
5. Crocodile
6. Free snake (Boiga blandingii)
Amphibian
Free frogs (Hyperolius fusciventris)
Brooks gecko
Birds encountered included strict arboreal and aquatic forms, mostly waders and
divers. The species encountered are presented in Table 5.10.
Table 5.10: Checklist of Bird Species
Birds
1. Herons (family Ardedae)
2. Kingfishers (Halegon senegalensis)
3. Mangrove Robin
4. Large billed warbler
5. Egret (family Ardedae)
6. White headed vulture (Neophron monethus)
7. Fish Eagle (Haliacetier vocifera)
8. Kite (Milus nigrans)
9. Harrier hawk (family Falconidae)
10. Swallow – tailed kite
11. Yellow-bellied parrot (Psittacidae)
12. African grey parrot (Psittacida erithacus)
13. River Eagles
14. Palm swift
15. Curlew sandpiper
16. Common sandpiper (Actitis hypoleucos)
17. Mash sandpiper
18. Dove
19. Red eyed dove
20. Yellow fronted canary
21. Brown-backed woodpecker
22. Red-headed weaver
Table 5.11: Checklist of Mammalian Species
•
•
•
•
•
•
•
•
•
•
Chapter Six
Maxwell’s Duiker Cephalopus maxwelli
Bushbuck Tragelaphus scriptus
Bush mice
Ground squirrel (Epixerus sp) –“Kekro”
Giant rat Cricetomys gambianus – "Igbikprieke”
Cane rat Thryonomys swinerianus –“ Ikpupele”
Fruit bat
African civet (Viverra civetta) – “Olorkorlo” (Endangered-IUCN)
Red Patas monkey (Endangered)
Mona monkey (Cercopitheaus petaurista) – “Aka-Ogbukor” (EndangeredJune 2005Page 25 of 12
IUCN).
It was further observed that over 80% of the mammalian species encountered in
the field were resident in high forest areas with none occurring in the freshwater
and mangrove swamps.
The vegetation in the project is predominantly made up of mangrove swamp
species. Some of the typical species of economic importance include: Rhizophora
racemosa and R mangle which are used as timber and building materials.
5.4.6 Geology, Hydrogeology and Geophysical Survey
5.4.6.1 Geology
The study area and environs lie within the Niger Delta Basin early Tertiary
sediment build-up. This sedimentary succession comprises of chronostratigraphic
units; The Benin Formation (Oligocene- Recent), the Agbada Formation (OligoceneRecent) and the Akata Formation (Eocene- Recent).
Overlying these sequence, in most parts of the Delta Basin (the study area
inclusive) are Quaternary Deposits. Four (4) geomorphologic units characterise
these deposits, these are:
(a)
The Deltaic Plain Belts (Sombreiro-Warri):- This is an extensive low lying area
dominated by fluvial systems some with branded characteristic, although some few
member belts are developed. The two plant species predominant in this area are
the raffia and oil palms.
(b)
The Fresh- Water Swamps and Meander Belts:- This belts is represented and
dominated by abandoned meander loops (ox-bow lakes) and extensive point bars.
It is capped by natural levees with the crevasse splay deposits typifying the flood
plains. The registration is mainly mangrove.
(c)
The Saltwater Mangrove Swamp Belts:- This area surround the estuaries, creeks
and lagoons, and are dominated by a system of inter- connecting fairly rectangular
meandering tidal creeks, out-off meander loops surrounded by centrally depressed
tidal flats in places. Its vegetation is characterised by thick undergrowth and rich
mangrove trees.
(d)
Coastal Islands and Beach Ridges:- This belt includes both active and abandoned
ridges facing the sea, separated laterally by the various river mouths which direct
them into small islands of 5-45km long and approximately 12km wide.
Quaternary
Table 5.12: Stratigraphic Sequence of the Niger Delta Basin with Aquifer
Prospectivity
Geologic
Stratigraphic Units
Lithologic Description
Aquifer
Age
Prospect
Alluvium
Gravely sands, sands silt
Good
and clays.
Chapter Six
Meander Belt Deposit
Wooded Back
Swamps & Fresh- Water
Swamps Deposits
Gravely sands, sands with
thin clays units.
Mainly silt and silty clays
with clayey intercalations.
Good
Poor
Magrove Swamps Deposit
Miocene
to
Recent
Sombreiro-Deltaic
Plain Sediments
Benin Formation
Fine sands to silt and silty
clays, and clays with
organic matter.
Coarse to fine grained
sands, silts and clays
Mainly coarse-medium
grained sands, lenticular
with clay and shale lens.
Poor
(Saline
water)
Medium
Prolific
Aquifer
5.4.6.2 Hydrogeology
Two (2) Stratigraphic units form the main aquifer systems in the Delta region
(see Table 5.12). These are:
(i)
The Alluvial:- Aquifer systems within this stratigraphic unit, especially the shallow
beds close to the shore are often saline bearing. However, the lateral extent of
these shallow aquifers is very erratic and occurs as lenses of sands within less
permeable beds of silt and clays. This group of aquifer is susceptible to pollution
since they are very shallow and have direct contact with surface runoffs and river
waters. The likelihood of saline intrusion into the aquifer systems is a function of
the distance of the site to the shoreline.
(ii)
The Benin Formation: - This chronostratigraphic unit in most parts of the Niger
Delta Basin form the main aquifer systems, having a total thickness of 1829m
(600ft) around Warri. Its lithologic composition is 90% sand and sandstone while
the remaining 10% is made up of clays and lignitic beds that are hardly continuous
over any substantial distance. The Benin formation is one large continuous aquifer
system with enormous storage capacity. Water within this aquifer system is
generally fresh water. Recharge to this system is mainly from rainfall. However, in
the area, long effects of tidal influence could favour saline intrusion into the aquifer
system at depths much shallower than 1600m.
Borehole Records
Eight (8) boreholes were drilled for this study after the initial surface mapping and
VES (Vertical Electrical Sounding) investigation. Figs. 5.2-5.9 are lithological
records of all the boreholes. Basically all the lithology records show a common
topsoil configuration, followed by a sequence of clays (occasionally silty), which acts
a barrier or cap rock to the phreatic zone, which is composed of silty sands to
sands. The dark colour nature of the topsoil and underlying clays including the
sands is an indication of the high organic matter of the surrounding environment.
Chapter Six
BOREHOLE-1
0 (ft)
POSITION: E 005° 59.871′
N 04° 42.163′
Top soil: Loamy soil
5
Silty clay: light grey, plastic, with abundant pyritic material
10
Clay: as above
15
Sand: Greyish white to grey, very fine to fine grains, well sorted,
clayey,
20
25
Clay: as above
30
Total depth is 28.2ft
35
Fig. 5.3:
Chapter Six
Borehole lithological profile for BOREHOLE-1 located at Ikebiri
primary school.
BOREHOLE-2
POSITION: E 005° 55.200′
N 04° 39.567′
0 (ft)
Top soil: Loamy soil with
5
Clay: Greyish to light brown, plastic, slightly silty, with abundant
pyritic material
10
Clay: Grey, plastic, blocky, soft, with blackish iron stains
15
Clay: Grey, plastic, soft, slightly sandy, with wood debris
20
Sand: Grey, very fine to medium grain, occasionally coarse grain,
loose, clayey, poorly sorted
25
30
35
Fig. 5.4:
Chapter Six
Borehole lithological profile for BOREHOLE-2 located at
Ikebiri (by Agip Line)
BOREHOLE-3
POSITION: E 005° 52.642′
N 04° 35.106′
0 (ft)
Top soil: Loamy soil, with plant remains
5
Clay: Grey, plastic, slightly silty, with abundant pyritic material
10
Sand: Off white, fine to medium grain, clayey, poorly sorted
15
20
Fig. 5.5:
Ikebiri market (by Agip Line).
BOREHOLE-4
POSITION: E 005° 53.737′
0 (ft)
5
10
15
20
Top soil: L
N 04° 36.401′
Top Soil: Loamy soil with plant rootlets
Peat: Black, slightly hard, with dead/ decaying organic material, and
abundant plant roots
Clay: Light brown to greyish brown, plastic, with abundant organic
matter and plant remains
Sand: Off white to grey, fine to medium grain, loose, slightly
clayey, moderately sorted
25
Fig. 5.6:
Chapter Six
Bolokubu- Ikebiri
BOREHOLE-5
0 (ft)
POSITION: E 005° 52.154′
Top soil:
N 04° 34.310′
Top Soil: Loamy soil
Clay: Brown, occasionally greyish, plastic, slightly hard, with
abundant plant rootlets
5
10
Clay: Grey, plastic, with blackish iron noodles
15
20
Clay: Grey to brown, with abundant dead/ decaying organic
matter
25
30
Sand: Off white to grey, fine to medium grains, occasional
coarse grains in place, loose with well-rounded quartz
grains, moderately sorted
35
40
Fig. 5.7:
Chapter Six
Mammy Water Creek near Ikebiri market
BOREHOLE-6
0 (ft)
POSITION: E 005° 51.581′
N 04° 33.911′
Top soil: Loamy soil
5
Clay: Light grey to grey, occasionally dark grey, plastic, slightly
silty,
With rootlets
10
15
20
25
Fig. 5.8:
Chapter Six
Peat: Black, slightly hard, with abundant dead/ decaying plant
remains
Sand: Off white to grey, fine to medium grains, loose, slightly
silty, moderately
Mammy Water Creek opposite Ikebiri market
BOREHOLE-7
0Top
(ft) soil:
5
POSITION: E 005° 52.723′
N 04° 32.544′
Top Soil: Loamy soil, light brown, slightly hard, with plant rootlets
Clay: Grey to dark grey, plastic, soft, slightly silty, with
abundant plant Remains.
10
Clay: Dar
15
Sand: Off white to grey, fine to medium grains, loose, silty,
moderately sorted
Grey, plastic, soft and sticky, with blackish iron noddles
20
25
Fig. 5.9:
Ikebiri Creek near Okumutorupa village
BOREHOLE-8
POSITION: E 005° 54.644′
0 (ft)
5
Top soil:
N 04° 33.071′
Top Soil: Loamy soil, with plant rootlets
Clay: Brown, occasionally greyish, plastic, slightly silty, with
abundant pyritic material
Peat: Black, slightly hard, with abundant dead/ decaying plant
remains
10
15
Sand: White to translucent, medium grains, occasionally very coarse
grains in place, loose with well-rounded quartz grains, moderately
sorted
20
Fig. 5.10:
Chapter Six
Borehole lithological profile for BOREHOLE-8 located near
Well-13 (along Agip Line)
5.4.6.3 Geophysical Survey
Field position of VES and borehole positions are shown in Table 5.13, while the
Field Data for geophysical investigation is shown in Appendices 5.3 (a-e).
Table 5.13:
VES
STATION
VES 1
VES 2
VES 3
VES 4
Representative boreholes/ VES
individual depths of penetration
DEPTH PENETRATED m
(ft)
>10.6 (~34.8)
>11.80 (~38.7)
>15.0 (~49.21)
>22.5 (~73.8)
BORHOLE #
BH-1
BH-2, BH-3
BH-4, BH-5, BH6
BH-7
stations
and
their
DEPTH PENETARTED
(ft)
28.2
27.4 & 17.8
24.0, 36.0 & 22.0
18.0
VES – 1
tion 1 are presented in Appendix 5.3 a. The profile is shown as a minor bowl shaped curve at the left
segment, and a rising bell shaped at right segment.
Automatic computer
interpretation of the field curve gives a four (4) layer strata model. Geoelectric layers
GL- 1, 2 and 4 are believed to be clay bodies, while the geoelectric layer 3 (GL-3)
could be interpreted as the first aquifer (sand) encountered at a depth of 2.7m (≈9ft)
from the surface.
Appendix 5.3 b is the response data for the VES station 2. The initial field
data show some scatter, especially at the right segment. Automatic iterative
computer data correction gave the resulting curve, which is bowl shaped at
the left end and gradually rising to bell shaped at the right end. Thus,
computer interpretation gives a best-fit model for a four (4) layer strata
model. The geoelectric layer 1 (GL-1) indicates a conductive surface about
0.2m thick with resistivity value corresponding to a silty clay topsoil.
Underlying the GL-1 is a more conductive geoelectric layer 2 (GL-2) with
thickness of about 2.1m. This can be interpreted as a possible clay horizon.
The GL-3 is a more resistive geoelectric layer with thickness of about 9.5m,
and can be interpreted as a wet sand (or first aquifer). This clearly indicates
that an impermeable material (clay body) overlies the aquifer in the
immediate subsurface. The last geoelectric layer the GL-4 corresponds to a
possible clay body as indicated by its resistivity value.
VES-3
The response data and characteristic response curve for VES station 3 is as
presented in Appendix 5.3 c. The curve displays a descending curve at the left
segment terminating as a bowl, followed by flat bell middle portion, and a
descending curve, which terminates into a minor bowl shape at the right
segment. Computer interpretation of the field curve gives another four (4)
layer model. The geoelectric layer 1 (GL- 1), which is 0.2m thick and referred
to as the topsoil, corresponds to a highly resistive surface composed of sandy
clay material. Underlying this resistive layer 1 (GL-1), are a less resistive
geoelectric layers 2 and 3 (GL-2 and GL-3) which could be interpreted as
possible clay bodies whose thickness are 3.7m and 31.7m respectively.
Geoelectric layers 4 (GL-4) could correspond to clayey sand, because it
exhibits a relatively high resistivity value. The first aquifer in this station is
relatively deep in excess of 36m from surface.
VES-4
Chapter Six
The response data and characteristic response curve for VES station 4 is as
presented in Appendix 5.3 d. The curve shows a descending curve at the left
segment terminating as a bowl, followed by a fairly flat middle portion, and a
descending curve, which terminates into a minor bowl shape at the right
segment. Computer interpretation of the field curve gives another four (4)
layer model. The geoelectric layer 1 (GL- 1) which is 0.1m thick is a highly
resistive surface composed of sandy clay material. While the underlying layers
2 and 3 (GL-2 and GL-3) are very conductive horizons interpreted as possible
clay bodies whose thickness are 4.1m and 21.6m respectively. Geoelectric
layers 4 (GL-4) could correspond to a possible clayey sand stratum, because it
exhibits a relatively high resistivity value. Again, the first aquifer in this
station is fairly deep in excess of 26m from surface.
The data interpreted from the four (4) VES stations are correlated as shown in Figs.
5.3-5.10. Seven (7) shallow boreholes were drilled in the area. The maximum
depth penetrated is 36.0ft (approximately 10.97m), in BH-5. Some of the boreholes
were drilled close to the VES stations and Table 5.13 shows boreholes/ VES
stations and their individual depths of penetration.
The conductive layer(s) determined in the above VES interpretations are mostly
extensive near surface clays and silts, while the remaining materials interpreted are
sandy. It should be noted that the study area, are dominated by clays/ silts up to
some deeper horizons, which agrees with the general interpretation of the geology of
the area. Four (4) distinct layers can be recognisd from the borehole profiles versus
VES inferred section correlation. They are GL – 1, GL - 2, GL –3, GL – 4. The
topmost soil dump layer (which is not definitive) is a very thin resistive layer
(resistivity values of 118.04Ωm and 534.14Ωm of sand, presumably a product of
the soil dumping exercise and site preparation as mapped around VES-3 and VES4 respectively. Its thickness does not appear to exceed 0.3m, observed generally
around VES-3 and VES-4, thinning out completely in the vicinity of VES-2. This
layer is underlain by a sequence of conductive material having a resistivity range of
4.84Ωm to 9.59Ωm. The GL-3 is less resistive layer (1.08Ωm to 4.16Ωm).
Correlating the interpretation obtained in all 4 VES occupied stations for this
horizon GL-2, which shows a wide variation in its thickness from 2.4m in VES-1,
2.1m in VES-2, 3.7m in VES-3 to 4.1m in VES-4. Layer 4 (GL-4), which constitutes
the substratum in VES-1 is a fairly resistive one; (ranging from 11.10Ωm in VES-1,
14.15Ωm in VES-2, 44.56Ωm in VES-3 to 39.64Ωm in VES-4).
From the geological history of the study area, while layer 1 (GL-1) should represent
the dredged sand spread, layer 2 (GL-2) is composed of mainly clays, silts and
possibly mud waste and sludge matter (dumped material). But Layer 2 (GL-2) has
the characteristics of the originally deposited clay body as part of the sedimentary
fill in the area. The high resistivity value of 217Ωm obtained for this layer in VES2, which might have been caused by shallow anomalies, is considered irregular,
judging from the high 'root mean square' (RMS) error obtained from SUPER VES
apparent resistivity calculations.
The presence of a considerably thick clay sequence seen in VES-1 (2.4m), VES-2
(2.1m), VES-3 (31.7m) and VES-4 (21.6m) provides an adequate seal to vertical
movement of groundwater (seepage) or even liquid contaminants into the
underlying aquifer (layer 4). This is at a depth in excess of 2.3m, in VES-2 and
35.5m in VES-3.
Aquifer Systems
Chapter Six
Fresh water aquifers within the deltaic terrain are much deeper, usually in
excess of the estimated total thickness of the alluvial deposits.
The
likelihood of saline intrusion to near surface aquifers is a function of the
distance of the site to the shoreline. But areas affected by tidal influence
between the direct contact relationships of the near surface aquifers to
surface flows can also experience saline intrusion. This poses a saline
pollution effect on near surface group of aquifer systems.
The Phreatic Zone: The sediments, which constitute this system, are generally
coloured dark grey to off white and occasionally dark brown due to the presence of
varying amounts of organic matter. They are predominantly characterised by
medium to coarse grain sands with small to medium percentage of silt/ clay.
Majorities of the grains are sub-angular to sub-rounded, poorly to moderately
sorted and having sand to shale ratio range of between 60:40 to 80:20. Table 3.20
is a summary of the textural parameters of all potential aquifer sediments
penetrated by the boreholes drilled in the study area.
The water contained in this zone and those in the swamp areas behind the
mangrove are fresh. Those contained in the highly compacted clayey/ silty bodies
are in continuity with the water in the creeks and rivers, which are tidally
influenced and therefore are brackish.
The First Aquifer: This hydrogeological system occurs at depths ranging from
2.5m at VES-1 to between 16m to 20m from VES-3 to VES-5. The water at this
depth is considered to be brackish.
Water Table Data
The static water level in the eight (8) boreholes drilled for this study was measured
using a simple hand held water level indicator before flushing. The boreholes were
restricted in depths to examine the phreatic zone. The static water level measured
at equilibrium for each borehole for the two seasons ranged 2.0-5.0m (dry season)
and 2.7-5.8m (wet season).
The water table ranged between 0.6m (approximately 2.0ft) to 1.54m
(approximately 5ft) during the dry season, while in the rainy season it was between
0.3m (approximately 1.0ft) to 1.2m (approximately 4ft).
5.4.6 Water Quality
5.4.61 Surface Hydrology
Physical and chemical characteristics
The results of the physico-chemical analysis of the surface water samples are given
in the (Appendices 5.4 a & b). Table 5.14 lists the various guidelines or water
quality criteria, which may be used to assess the suitability of the water samples
for drinking, recreational and support for aquatic life.
Ikebiri creek provides the main system of creeks that drain the study area. Water
and sediment samples were collected at 20 study sites (WS1 – WS20). Generally,
the 20 surface water samples obtained from the study area appear not too different
significantly in their physico-chemical characteristics in their values for the two
seasons, except that following the influence of rain there was dilution in the
increased the particulate matter (TSS) and turbidity.
Temperature
Aquatic temperatures in the wet season and dry season displayed a narrow range
between 25.8 and 28.1°C and between 28.4 and 30.1°C respectively, showing less
Chapter Six
fluctuation from station to station and were minimally lower than atmospheric
temperatures in both cases. The aquatic temperature for both seasons was well
within the DPR limit of 40°C.
Turbidity and Total Suspended solids (TSS)
Generally, the qualities of the water samples appear normal for clean aquatic
environment except for the elevated Turbidity and TSS, which was further
influenced by runoff from rain during the wet season sampling. Turbidity values
for both seasons were high as shown in Appendices 5.4 a & b and Figs. 5.11 &
5.12. The values were above the DPR limit of 15NTU, the lowest values being 36
NTU (station WS7-wet season) and 20 NTU (dry season), highest values of 80 NTU
(station WS10-wet season) and 50 NTU (dry season) was also recorded. The
corresponding TSS values were expectedly high. Thus, the waters within the
vicinity of study area are poorly illuminated.
All the 20 samples were of moderate to high turbidity of 36-80 NTU (wet season)
and 20-51 NTU (dry season) with correspondingly high values of TSS 48-100mg/l
(wet season) and 27-60mg/l (dry season). Estuarine waters are typically turbid
especially in the rainy season months but display higher clarity in the dry season
months when much of the suspended particles settle to the bottom of the water
body. It will suffice to note that the quality of the surface water in a place like
Opugbene (Tologbene) is of great concern, since the local inhabitants depend on the
river water for domestic use.
Total Dissolved Solids and Conductivity
A slight variation in the Total dissolved solids (DS) content of the waters was
observed (Appendices 5.4 a & b) the values obtained are typical of fresh water
environment indicating absence of occasional intrusion of salt water. The TDS
values are between 63-82mg/l (wet season) and 48-68 mg/l (dry season) with a
corresponding electrical conductivity of 125-162 µs/cm and 94-142 µs/cm for the
wet season and dry season respectively, (Figs. 5.13 & 5.14). These values may
also have been influenced by tidal regime.
Conductivity values reflect the associated salinity trend. Conductivity measures
the total ionic composition of water and it is a good indicator of the overall chemical
richness of water body. The moderate levels of conductivity observed in this study
could be related to the leaching of nutrients and minerals from surrounding
vegetation and farmlands (Odum, 1971).
This is the trend in the Niger Delta where high precipitation and runoff from
drainage contribute and shift the freshwater/brackish water boundary downstream
(Opute, 1991).
Chapter Six
pH
WS20
WS19
WS18
WS17
WS16
WS15
WS14
6.6
WS13
0
WS12
6.8
WS11
20
WS10
7
WS9
40
WS8
7.2
WS7
60
WS6
7.4
WS5
80
WS4
7.6
WS3
100
WS2
7.8
pH
TSS, mg/l
120
WS1
Turbidity (NTU) TSS (mg/l)
Turbidity, NTU
Sampling Stations
Fig. 5.11: Wet Season Graphical Trend of pH, TSS and Turbidity of Surface Waters
Turbidity, NTU
TSS, mg/l
pH
7.8
80
7.6
70
60
7.4
50
7.2
40
30
pH
Turbidty (NTU) & TSS (mg/l)
90
7
20
6.8
10
WS20
WS19
WS18
WS17
WS16
WS15
WS14
WS13
WS12
WS11
WS10
WS9
WS8
WS7
WS6
WS5
WS4
WS3
WS2
6.6
WS1
0
Sampling Stations
Fig. 5.12: Dry Season Graphical Trend of pH, TSS and Turbidity of Surface Waters
Chapter Six
Salinity
The study area which, is near the sea and is typically estuarine, is expected to
display high values of salinity. For the same reasons explained above, salinity
values were low paralleling those of conductivity and dissolved solids (Figs. 5.13 &
5.14 and Appendices 5.4 a & b). The range recorded varied from 23 to 40mg/l
and 21 to 30mg/l for both the wet and dry season respectively.
Chemical Oxygen Demand (COD)
The chemical oxygen demand (COD) is used as a measure of the oxygen equivalent
of the organic matter content of water that is susceptible to oxidation by a strong
chemical oxidant. COD, which, is related empirically to BOD, organic carbon or
organic material, is a useful tool for monitoring and control of waters either in
industry or from polluted sources. COD values of over 50 mg/L indicate levels of
pollution. The study area water bodies recorded relatively low levels of COD in the
range of 8.0-14.5 mg/l for wet season and 2.7-9.9 mg/l for the dry season
(Appendices 5.4 a & b, Figs. 5.15 & 5.16) indicating low level of organic pollution.
Thus hydrocarbon, oil and grease were not implicated in the values recorded.
Overall the wet season values were slightly higher than that of the dry season
owing to influx of organic matter following the rain.
Biochemical Oxygen Demand (BOD)
The biochemical oxygen demand (BOD) which, is an empirical measurement of the
relative oxygen requirement of waste waters, effluents and polluted waters,
measures the amount of oxygen utilised during a specific incubation period,
usually 5 days, for the biochemical degradation of organic material as well as the
amount of oxygen used to oxidise inorganic material. BOD values of over 6 in
natural waters indicate some level of pollution. The gross organic pollution loads of
the samples were low during both season sampling, as indicated by the generally
low-moderate values ranging from 6.5 to 8.4 mg/l (wet season) and 1.6-4.8 mg/l
(dry season) this show moderate BOD values for most waters analysed, indicates
low levels of organic pollution in the water bodies (Appendices 5.4 a & b, Figs.
5.15 & 5.16).
BOD limitation guideline for water bodies in Nigeria as
recommended by FEPA is 50 mgL-1. The highest BOD of 8.44 mg/l recorded at
WS15 during the wet season sampling may be due to pollution from domestic
activities of villagers.
Dissolved Oxygen
Dissolved oxygen (DO) measurements, which ranged from 4.0 to 6.7 mgL-1 (average
of 5.04 mg/L) and 4.8 to 8.0 mgL-1 for wet and dry season sampling respectively
(Appendices 5.4 a & b, Figs. 5.15 & 5.16) showed that some waters are not
properly aerated, however majority are well oxygenated despite the shallow photic
zone (low transparency). This level of oxygenation can be accounted for by the
thorough mixing of the water due to turbulence occasioned by wave action and
tidal force. The dissolved oxygen of the waters were generally higher than those
reported for most polluted inland waters in Nigeria (Edokpayi, 1988; Victor and
Ogbeibu, 1986).
Chapter Six
SALINITY (mg/l)
WS20
0
WS19
0
WS18
5
WS17
20
WS16
10
WS15
40
WS14
15
WS13
60
WS12
20
WS11
80
WS10
25
WS9
100
WS8
30
WS7
120
WS6
35
WS5
140
WS4
40
WS3
160
WS2
45
Salinity (mg/l)
CND (µS/cm)
180
WS1
TDS (mg/l) & CND (uS/cm)
TDS (mg/l)
Sampling Stations
Fig. 5.13: Wet Season Trend Graph of Conductivity, Total Dissolved Solids and
Salinity of Surface Waters
SALINITY (mg/l)
35
140
30
120
25
100
20
80
15
60
Salinity (mg/l)
CND (µS/cm)
160
10
40
WS20
WS19
WS18
WS17
WS16
WS15
WS14
WS13
WS12
WS11
WS10
WS9
WS8
WS7
WS6
WS5
0
WS4
0
WS3
5
WS2
20
WS1
TDS (mg/l) & CND (uS/cm)
TDS (mg/l)
Sampling Stations
Fig. 5.14: Dry Season Trend Graph of Conductivity, Total Dissolved Solids and
Salinity of Surface Waters
Hydrogen ion Concentration (pH)
The waters of the area appeared well-buffered and displayed fairly uniform pH
(Appendices 5.4 a & b, Figs. 5.15 & 5.16). The values were within the 6.5 – 8.5
range stipulated by DPR. The pH values of the surface water ranged between 6.98
and 7.67 (wet season) and 7.00-7.87 (dry season), which is normal for most
purposes. The near neutral to neutral pH values of the water falls within the DPR
Chapter Six
limits (DPR, 1991) and were similar to those reported for most water bodies in the
Niger-Delta (RPI, 1985; Courant et al., 1987; Edokpayi, 1989).
Alkalinity
The alkalinity of water is its acid neutralising capacity and it is the sum of all
titrable bases. The trends in bicarbonate ion concentrations are generally similar
to those observed for salinity. The bicarbonate alkalinity values are in the range
10.4-21.56 mg/l for wet season and 8.8 -16.5 mg/l for dry season measurements,
reflecting the neutral pH and estuarine nature of the waters, and indicate also that
the waters are well buffered. High alkalinity values have been recorded for this
estuarine region in previous studies (Opute, 1990; Macgill, 1995).
•
Soluble Anions:
Sulphates (SO42-)
Sulphates are widely distributed in nature and may be present in natural waters in
concentrations ranging from a few to several thousand milligrammes per litre.
Sulphate, which is normally low in fresh waters increases in values as the river
makes its course downstream to the coast. The study area is situated on the coast
and the concentrations of sulphates in all the stations are characteristic of
brackish waters at this time of the year. The results indicated a range of between
4.5 and 9.46 mg/l for the wet season as against the dry season values ranging from
2.15-6.66 mg/l (Appendices 5.3 a & b). In virtually all cases, the values are within
FEPA's acceptable upper limit of 600 mg L-1 that relates to freshwater for domestic
needs and waters for all categories of industries.
(ii) Nitrate (NO3)
Nitrate which represents the most completely oxidised state of nitrogen commonly
found in water occurred in relatively low values 0.01- 0.09 mg/l (wet season) and
0.06-0.72 mg/l (dry season) in the waters of the area, the dry season value
appeared elevated as against the dry season value, this might be due to the effect of
concentration of the water. Comparatively nitrate is present at levels, which are
normal for unpolluted freshwater bodies.
(iii) Nitrite (NO2)
Nitrite is a nitrogen source of great interest not only because it is next to nitrate in
the oxidation state, but also because it is biochemically interconvertible and is a
component of the nitrogen cycle. Nitrite can enter water in the environment
through its use as a corrosion inhibitor in the oil industry. Observed values for
both wet and dry season were below the detection limit of <0.02 mg/l and compare
favourably with values recorded in the Niger Delta by Imevbore and Ekundayo
(1987).
(iv) Ammonia (NH4+)
Ammonia is present naturally in surface waters where it is produced largely by deammination of organic nitrogen-containing compounds. Ammonia concentrations
encountered in water vary from less than 10 µgL-1 ammonia nitrogen in natural
surface waters and ground waters to more than 30 mgL-1 in some wastewater. The
ammonia concentrations as ammonium in the waters are typically low varying
between 0.01 to 0.10 mg/l in the wet season and 0.02-0.27 mg/l in the dry season
sampling, again the dry season values appeared higher, this may be due to
concentration of some of the constituents of the water.
Chapter Six
BOD
pH
COD
9
16
8
14
7
12
6
10
8
4
pH
5
6
3
4
2
WS20
WS19
WS18
WS17
WS16
WS15
WS14
WS13
WS12
WS11
WS10
WS9
WS8
WS7
WS6
WS5
0
WS4
0
WS3
2
WS2
1
WS1
DO, BOD & COD (mg/l)
DO
Sampling Stations
Fig 5.15: Wet Season Graphical relationship of pH, Dissolved Oxygen and
Biochemical Oxygen Demand of Surface Waters
DO
BOD
pH
COD
12
9
8
6
8
5
6
4
3
pH
DO, BOD & COD (mg/l)
10
7
4
2
2
1
WS20
WS19
WS18
WS17
WS16
WS15
WS14
WS13
WS12
WS11
WS10
WS9
WS8
WS7
WS6
WS5
WS4
WS3
WS2
0
WS1
0
Sampling Stations
Fig. 5.16:Dry Season Graphical relationship of pH, Dissolved Oxygen and
Biochemical Oxygen Demand of Surface Waters
Chapter Six
(v) Available Phosphate (PO43--)
A certain amount of phosphates is essential to organisms in natural waters and often
is the limiting nutrient for growth. Phosphate can as well enter the environment
through the use of phosphate containing detergents. However too much phosphates,
can produce eutrophication or over-fertilisation of receiving waters especially if large
amounts of nitrates are present. The result for fairly dilute waters is rapid growth of
aquatic vegetation in nuisance quantities and the eventual lowering of dissolved
oxygen content of the water due to death and decay of the vegetation.
The phosphate contents of the waters of the area were generally low ranging from
0.002 to 0.007 mg/l during the wet season sampling as against the dry season result
of 0.01- 0.023 mg/l (Appendices 5.4 a & b). These values are low and they compare
favourably with values of between 25 and 303 µgL-1 obtained for similar locations
within the Niger Delta (RPI, 1985). Phosphates concentration in all cases were by far
below FEPA standards of 5 000 µgL-1.
Exchangeable Cations
Generally the background chemistry of water in the area was rather constant with
little or no variation. Sodium, Potassium, Calcium and Magnesium, the alkaline earth
metals, in solution constitute the exchangeable cations. The levels of the major
cations, Na, K, Ca and Mg were low and this is indicative of low levels of dissolved
solutes, as corroborated by the TDS values which is in the range 63 to 82mg/l (wet
season) and 48-68 mg/l (dry season) with corresponding Conductivity of 125-162
µs/cm (wet season) and 94-142 µs/cm (dry season). The order of dominance in
waterways was Na > Ca>K> Mg (Appendices 5.4 a & b, Figs. 5.17 & 5.18).
The ratio of sodium to total cations is important in agriculture and human pathology.
Soil permeability can be harmed by a high sodium ratio. Persons afflicted with certain
diseases require water with low sodium concentration. Small concentrations of
calcium carbonate combat corrosion of metal pipes by laying down a protective
coating. Appreciable calcium and magnesium salts, on the other hand, precipitate on
heating to form harmful scales in boilers, pipes and cooking utensils. Calcium and
magnesium also contribute to the total hardness of water.
The dominant cations are between sodium and calcium, followed by potassium then
magnesium. The calcium content of the waters was similar to those of most Nigerian
rivers (Holden and Green, 1960; Egborge, 1971; Imevbore, 1975; Edokpayi, 1988,
1989). The peaty clays and soft mud common in the Niger-Delta contain relatively
higher calcium than other types of soil in Nigeria (Edokpayi, 1989). The high calcium
content may be due to contribution from drainage of the terrain through surface runoff in addition to erosion of calcareous materials of biogenic origin (Wetzel, 1975).
However the average Ca and Mg load is also indicative of absence of hardness in the
waters.
(l) Heavy Metals (Trace Elements)
The results for the analysis of the heavy metals of the study area waterways are shown
in Appendices 5.4 a & b.
Natural waters are extremely dilute chemical solutions with very small quantities of
several essential metals including Fe, Mn, Zn, Cu, Cr, Cd, Pb, Hg, and V. Animals
require these elements and plants in minute quantities and for this reason are referred
to as trace elements or micronutrients. Their main role in the cell is at the active
centre of enzymes or as cofactors in enzyme reactions. In short supply they can limit
Chapter Six
the growth of micro-organisms such as algae, the primary producers.
plants and animals can result from high concentration of trace elements.
Toxicity to
The levels of heavy metals Pb, Cd, Zn, Cu, Cr, and V were generally low and below
detection limits in some cases except for Iron which indicate value above WHO limit
(0.3mg/l) overall the values of iron range between 0.13-1.36/mg/l (wet season) and
0.32-1.48 mg/l (dry season), while zinc was in the range 0.02-0.13mg/l (wet season)
and <0.01 and 0.16 (dry season). Thus Iron was the only heavy metal recorded above
the allowable limits. Generally, the usual trend is a decrease in the Fe content of
surface waters in transitional zone depending on the conductivity of the water. When
the conductivity is low as in the study area waters, the small colloidal iron particles
are kept from coagulation to larger particles but the negative surface charge on the
colloidal particles (RPI, 1985). This encourages the iron particles to remain in the
water column rather than settle to the bottom sediment. This perhaps accounted for
the peak levels of iron in the water column of the waters.
The other metals recorded values within the regulatory limit for drinking water,
support of freshwater aquatic life and recreation, Table 5.14. Overall, in terms of only
the physico-chemical characteristics the study area surface water samples as obtained
from this study appear to be relatively clean and unpolluted. The river would easily
rank as a class 1 river in terms of quality ranking which makes it suitable for
municipal water supply and almost all other uses.
Table 5.14: Guidelines of Water Quality for Different Purposes
Characteristics
PH
Temperature, oC
Turbidity, NTU
TDS, mg/l
TSS, mg/l
DO, mg/l
BOD5, mg/l
COD, mg/l
Oil & Grease Content, mg/l
Conductivity, µs/cm
Total Hydrocarbon, mg/l
-
Nitrate (NO3 ), mg/l
2-
Sulphate (SO4 ), mg/l
Salinity (CI-), mg/l
Carbonate (CO32-), mg/l
Bicarbonate (HCO -), mg/l
Drinking Water (WHO,
1984)
6.5-8.5
-
Freshwater Aquatic
Life Support
-
Recreational (Water
Contact)
6.0-10.0
50
Groundwater Protection
(FEPA, 1991)
-
5
1000
45
-
50
100
20
-
-
400
-
-
-
250
-
-
-
-
-
-
-
-
-
-
-
200
-
-
-
-
-
-
-
-
-
-
-
0.05
0.1
-
0.05
3
-
Nitrite (NO2 ), mg/l
Phosphate (PO4-3), mg/l
Sodium (Na+), mg/l
Potassium (K+), mg/l
Calcium (Ca2+, mg/l
Magnesium (Mg2+), mg/l
Lead (Pb2+), mg/l
Cadmium (Cd2+), mg/l
0.005
0.01
-
0.01
Zinc (Zn2+), mg/l
Copper (Cu2+), mg/l
5.0
0.1
-
-
1.0
-
-
-
Chromium (Cr6+), mg/l
Manganese (Mn), mg/l
Total Iron (Fe2+, Fe3+), mg/l mg/l
0.05
0.05
-
0.05
0.10
0.3
0.3
-
-
-
-
-
-
mg/l mg/l mg/l mg/l
Nickel (Ni), mg/l
Vanadium (V), mg/l
Chapter Six
Na
Mg
Ca
K
7
Milligramme Per Litre
6
5
4
3
2
1
WS20
WS19
WS18
WS17
WS16
WS15
WS14
WS13
WS12
WS11
WS10
WS9
WS8
WS7
WS6
WS5
WS4
WS3
WS2
WS1
0
Sampling Stations
Fig. 5.17: Wet Season Graphical relationship of Exchangeable Cations of
Surface Waters
Na
Mg
Ca
K
8
Milligramme Per Litre
7
6
5
4
3
2
1
WS20
WS19
WS18
WS17
WS16
WS15
WS14
WS13
WS12
WS11
WS10
WS9
WS8
WS7
WS6
WS5
WS4
WS3
WS2
WS1
0
Sampling Stations
Fig. 5.18: Dry Season Graphical relationship of Exchangeable Cations of Surface
Waters
Chapter Six
5.4.6.2 Ground Water Quality
The results of the physico-chemical analysis of the underground water samples for
both wet and dry season are given in Appendix 5.5. Table 5.14 lists the various
guidelines or water quality criteria, which may be used to assess the suitability of
the water samples for drinking, recreation and support of aquatic life. The physicochemical characteristics of the ground water samples from the monitoring
boreholes were typical of fresh groundwater environment.
The water samples were obtained from the monitoring boreholes, which were dug
during the dry season, in the cause of the study. The general trend of physicochemical characteristics of the samples are discussed below:
pH values of the borehole water ranged between 6.35 and 6.91 (wet season ) and
6.7-7.6 (dry season), that is very weakly acidic to neutral, no value was greater
than WHO upper limit of 9.2, in compliance with WHO range of 6.5-9.2. The wet
season temperature was about the normal ambient range usually observed in the
rainy season the values was in the range 25.2-26.7oC, typical of wet season.
The percentages of major ions in the borehole waters indicate that the background
chemistry is rather constant. Sodium appears to be the dominant cation, calcium,
magnesium, and potassium closely followed this pattern. Chloride is the dominant
anion, followed by bicarbonate then sulphate in the wet season while dry season
results indicated that bicarbonate is the dominant anion, followed by Chloride then
sulphate. Phosphate is practically nil in the wet season values recorded is in the
0.003-0.048mg/l, dry season values were higher in the range 0.1-0.24 mg/l with
carbonate being less than 0.05mg/l. Nitrate on the other hand is in the range 0.030.052mg/l (wet season) and 0.1-0.27 mg/l (wet season). The results of analysis
indicate that the area covered by the study is a non-saline zone and values were
well within WHO specified limits for potability; from the result of wet and dry
season analysis conductivity covered a narrow range of 150-194 µs/cm and 188345 µs/cm respectively and values obtained are within normal range. Though
reflecting slight intrusion of salt water on normal fresh water, such values are
common with many creeks in the area. These low values were adequately
accounted for by low salinity ranging between 36-48mg/l (wet season) and 2849mg/l (dry season), thus there is no indication of significant salt-water intrusion.
However the water samples appeared to be stressed with respect to particulate
matter (though not necessarily from petroleum activities) with a correspondingly
high Turbidity above WHO limits of 5NTU. The ranges of values for Turbidity is
24.8- 57NTU and TSS is 34-80mg/l for the wet season, while the result of dry
season indicated Turbidity of 17- 34 NTU and TSS is 31-53mg/l, this
characteristics appeared to be inherent one for the waters of the study area (Figs.
5.19 & 5.20).
The total dissolved solid (TDS) values ranged from 76-97mg/l (wet season) and 96176mg/l (dry season) indicate 1ow cations and anions values (Figs. 5.21 & 5.22).
The average calcium and magnesium load is also indicative of absence of hardness
in the water. The gross organic pollution loads of the samples were moderate;
hence COD of the samples from the 8-boreholes were in the order 14.8-18.6mg/l
and 8-25.0 for wet and dry seasons respectively. The water bodies did not show
evidence of adequate aeration, based on the DO values of 4.0 -4.9mg/l (wet season)
and 1.16-2.62 mg/l (dry season). The BOD value is a reflection of the COD and DO
values, values recorded are in the range 6.1-6.8mg/l and 3.5-12.0 mg/l for wet and
dry seasons respectively this is reminiscent of minimal pollution probably
influenced by the presence of particulate matters of organic and inorganic origin.
Chapter Six
There was complete absence of oil & grease or hydrocarbon based pollutant base on
the non-detection of oil & grease as well as THC, thus values were below detection
limit of <0.05, for the wet season however trace oil and grease (0.11- -0.24 mg/l)
was recorded in all the boreholes during the dry season, this may have been
influenced by drilling actions this was corroborated by the no- detection of
hydrocarbon and wet season result.
Heavy metals concentrations were generally low (except for slight elevation of iron)
and this observation is an inherent characteristic of underground water found in
the Niger-Delta region. Wet season results indicated that iron values were in the
range 0.09-3.64mg/l, while copper (0.002-0.009mg/l), zinc (0.046-0.134mg/l),
cadmium (<0.002mg/l), lead (0.01-0.03mg/l), nickel (<0.05) and chromium
(<0.005mg/l). The dry season result indicated similar pattern but were generally,
slightly higher values observed were in the range iron (0.87-1.42mg/l), while copper
(0.002-0.008mg/l), zinc (0.346-0.1.73mg/l), cadmium (0.003-0.006mg/l), lead
(0.014-0.05mg/l), nickel (0.05-0.08mg/l) and chromium (<0.005mg/l).
TSS, mg/l
pH
90
7
80
6.9
70
6.8
6.7
60
6.6
50
6.5
40
pH
Turbidity (NTU) & TSS (mg/l)
Turbidity, NTU
6.4
30
6.3
20
6.2
10
6.1
0
6
BH-1
BH-2
BH-3
BH-4
BH-5
BH-6
BH-7
BH-8
Sampling Stations
Fig. 5.19: Wet Season Graphical Trend of pH, Turbidity and TSS of Ground
Water
Chapter Six
Turbidity, NTU
TSS, mg/l
pH
7.8
7.6
50
7.4
40
7.2
30
7
pH
Turbidity (NTU) & TSS (mg/l)
60
6.8
20
6.6
10
6.4
0
6.2
BH-1
BH-2
BH-3
BH-4
BH-5
BH-6
BH-7
BH-8
Sampling Stations
Fig. 5.20: Dry Season Graphical Trend of pH, Turbidity and TSS of Ground
Water
TDS (mg/l)
CND (µS/cm)
SALINITY (mg/l)
60
50
200
40
150
30
100
20
50
Salinity (mg/l)
TDS (mg/l), CND (uS/cm)
250
10
0
0
BH-1
BH-2
BH-3
BH-4
BH-5
BH-6
BH-7
BH-8
Sampling Stations
Fig. 5.21 Wet Season Graphical Relationship of Conductivity, Total Dissolved
Solids and Salinity of Ground Water
Chapter Six
TDS (mg/l)
CND (µS/cm)
SALINITY (mg/l)
60
400
50
300
40
250
200
30
150
20
Salinity (mg/l)
TDS (mg/l), CND (uS/cm)
350
100
10
50
0
0
BH-1
BH-2
BH-3
BH-4
BH-5
BH-6
BH-7
BH-8
Sampling Stations
Fig. 5.22: Dry Season Graphical Relationship of Conductivity, Total Dissolved
Solids and Salinity of Ground Water
5.4.7 Sediment Quality
The physico–chemical properties of sediment from the Opugbene (Tologbene) area
are summarised in Tables 5.15 a & b. A total of 9 sediment samples were collected
each for both wet and dry seasons and investigated for the parameters. The
characteristics of the sediment samples are discussed as follows:
Table 5.15a: Wet Season Physico-Chemical Characteristics of Sediment
SAMPLE CODES
CHARACTERISTICS
pH
THC, mg/kg
Pb, mg/kg
Cd, mg/kg
Zn, mg/kg
Cr, mg/kg
Cu, mg/kg
Fe, mg/kg
Ni, mg/kg
Mn, mg/kg
Hg, , mg/kg
SD1
4.45
<50
4.28
2.2
54.9
1.24
5.98
4450
12.4
544
<0.05
SD2
3.25
<50
3.83
4.01
72.3
3.43
9.44
7367
13.43
891
<0.05
SD3
4.12
<50
10.7
2.6
69.1
2.80
6.78
1622
9.80
204
<0.05
SD4
4.32
<50
8.02
2.0
66.8
2.36
7.20
3284
10.6
224
<0.05
SD5
3.86
<50
2.06
4.8
75.9
5.55
8.24
8300
22.5
875
<0.05
SD6
4.58
<50
5.2
3.2
65.2
4.80
5.39
2446
9.80
576
<0.05
SD7
5.12
<50
6.04
1.2
47.2
3.5
4.69
2934
6.5
184
<0.05
SD8
5.35
185
8.40
1.43
42.7
3.4
4.22
2726
7.2
178
<0.05
SD9
4.62
256
12.4
2.93
48.9
5.5
10.3
4748
8.7
294
<0.05
Table 5.15b: Dry season Physico-Chemical Characteristics of Sediment
CHARACTERISTICS
pH
THC, mg/kg
Pb, mg/kg
Cd, mg/kg
Zn, mg/kg
Cr, mg/kg
Cu, mg/kg
Fe, mg/kg
Ni, mg/kg
Mn, mg/kg
Hg, , mg/kg
Chapter Six
SD1
5.45
<50
3.38
4.6
65.1
2.2
2.9
4772
10.2
644
<0.05
SD2
4.84
<50
6.45
3.5
90.2
1.2
5.66
5191
11.13
718
<0.05
SD3
5.59
<50
7.54
3.6
95.7
1.8
5.61
5371
8.9
185
<0.05
SAMPLE CODES
SD4
SD5
SD6
6.81
5.05
6.80
<50
<50
<50
6.36
7.22
4.24
6.0
4.8
2.7
95.7
51.7
71.2
1.9
4.0
4.0
6.53
6.78
7.2
5514
5153
5153
12.3
26.0
11.0
236
778
613
<0.05
<0.05
<0.05
SD7
7.11
<50
5.7
2.6
33
1.2
7.5
2039
5.9
232
<0.05
SD8
5.30
50
5.42
2.0
33
2.2
3.56
1368
7.8
167
<0.05
SD9
4.89
153
2.7
2.5
39
3.4
4.7
5008
8.68
256
<0.05
pH
The pH of the sediments was acidic ranging within the lower end of 3.25-5.35 (wet
season) and strongly acidic to neutral (pH 4.84 – 7.11) during the dry season.
Similar low pH was recorded for bottom sediment of Benin River at Koko (Edokpayi,
1989). The low pH levels is related to biodegradation of nutrient by bacteria leading
to H2S production commonly carried out in peaty soils characteristic of the bottom
sediment of the rivers in the study area (Odum, 1971).
Total Hydrocarbon
The total petroleum hydrocabon in the sediment samples were generally less than
the biogenic level of <50ppm. However, elevated levels of total hydrocarbon were
found to be accumulated in the sediments around the Agip flowstation. However,
the values recorded for all the sampling stations ranged from <50 - 256 ppm (wet
season) and <50-153 ppm (dry season). Levels in sediments are higher than the
associated surface water this is because sediments generally accumulate and
concentrate contaminants such as hydrocarbon oils.
Heavy Metals
The Heavy metal contents of the bottom sediment were high. Heavy metals have
been reported to coalesce in to larger particles and settle to river bottom in rivers
with high conductivity especially close to their mouth (RPI, 1985). The total iron in
the sediment samples was high and these high values are probably due to the
settling of the ions in the sediment from the water column. Levels of the metals in
the sediments were generally much higher than in the overlying surface water
columns, but are within the range normally found in sediments. Iron level in the
nine (9) sediment samples from the study site in the wet season ranged from 2446 8300 ppm. Similarly ranges for the other heavy metal concentrations were Pb
(2.06-12.4 mg/kg), Cd (1.2-4.8 mg/kg), Zn (42.7-75.9 mg/kg), Cr (1.24-5.55
mg/kg), Cu (4.22-10.3 mg/kg), Ni (6.5-22.5 mg/kg) and Mn (178-891 mg/kg).
Levels of mercury were below detection limit of <0.05 ppm in all the sediments.
Dry season analytical result indicated that iron in the nine sediment samples
ranged from 1368 – 5514 mg/kg. However, copper levels (2.9-7.5mg/kg), Zinc
levels (33 – 95.7 mg/kg), Nickel levels (5.9 –26.0mg/kg), Mercury with less than
detection limits of < 0.02mg/kg, Cadmium levels (2.0 – 6.0mg/kg), Chromium
levels (1.2 –4.0mg/kg) and Lead levels (2.7- 7.54mg/kg).
The flocculation’s of the metallic ions and subsequent settling of the ions in the
sediment as earlier explained is responsible for this trend. In general, reactions of
transition metals tend to form immobilisation of the metal and the transition
metals usually are known to be concentrated in sediment than in the associated
water, the concentration of the metals in the sediments may not be as critical as
their corresponding level in the water.
Generally the levels of heavy metals found in sediments of the area are comparable
to those in southwestern Nigeria and World-wide (Tables 5.16 a & b).
Chapter Six
Table 5.16a: The Levels of Cadmium, Chromium, Copper, Lead & Zinc
in Unpolluted Soils (Concentration in ppm)
HEAVY METALS
Cadmium
Chromium
Copper
Lead
Zinc
*
b
+
c
LITERATURE VALUES
South Western
World Wide +
Nigeria
<1 - 2
0.9 - 1.7c *
13.1 - 30c
1.6 - 36b
15 -300
18 - 101 *c
6.0 - 60 b
10 - 15
2 - 60
25 - 200
Sediment
Fagbami, A. Ajayi S. O. and Ali E. M. (1985)
Thorton, (1991)
Ajayi S. O. and Mombeshera C. (1989).
Table 5.16b: Range in Micro-Nutrient Content Commonly Found in Soils
Normal Range
Nutrient
Iron
Manganese
Copper
Percent
0.500 - 5.000
0.02 - 1,000
0.0005 - 0.015
ppm *
5,000 - 50,000
200 - 10,000
5 - 150
*ppm - Part per million, mg/kg. These estimates are based on data from a number of sources
especially Mitchel (1955)
5.4.8 Microbiological Studies
Microbiology of Surface Water
The results of water analysis for bacteria represented higher heterotrophic density
in the surface. This is mostly as a result of organic matter and direct sunshine at
the surface, which promote microbial growth, especially during the drying season,
see Table 5.17.
For surface water samples, heterotrophic bacterial densities ranged from 74x102
cfu/ml to 308x102 cfu/ml (wet season) and 8-124x102 cfu/ml (dry season), while
the hydrocarbon utilising bacteria ranged from non-detectable to 8.0x102 cfu/ml
and 1.6-9.6 x102 cfu/ml, during the wet season and dry season study. Total
heterotrophic fungal densities (surface water) varied between 6.5x102 cfu/ml and
23x102 cfu/ml (wet season) as against dry season value of the order 2-37x102
cfu/ml. While hydrocarbon utilising fungi indicated range between non-detectable
and 2.0x102cfu/ml for both wet and dry season. The percentage hydrocarbon
utilising fungi were lower than 0.1% as shown in Table 5.17. On the whole the
percentage hydrocarbon utilizers were less than 0.1%, indicating low level of
hydrocarbon contamination in the aquatic environment.
Chapter Six
Table 5.17: Microbial Densities of Surface Water Samples for Wet and Dry
Seasons
Bacterial Densities
Surface
Fungi Densities
Total Het. Total Hyd. Percentage
Bact. X104
Bact.
Hyd-utiliser
cfu/ml
x102cfu/ml
Wet
Dry
Wet
Dry
Wet
WS-1
WS -2
WS -3
WS -4
WS -5
WS -6
WS -7
WS -8
WS -9
WS -10
WS -11
WS -12
WS -13
WS -14
WS -15
WS -16
2.1
1.2
1.8
2.0
1.44
2.33
2.6
2.41
0.85
0.74
3.08
1.90
0.90
1.50
3.00
2.70
81
102
97
132
96
124
77
72
81
71
64
72
24
15
17
9
8.0
Nil
1.0
1.0
Nil
Nil
4.0
2.0
Nil
Nil
6.0
2.0
1.0
1.0
3
4.5
1.8
1.7
3.2
4.9
1.8
5.2
1.4
9.6
3.2
9.4
4.2
2.4
1.2
9.2
4.2
3.2
0.04
0.006
0.005
0.015
0.008
0.02
0.01
0.011
0.007
0.01
0.017
WS -17
1.87
32
2.0
1.9
0.011 0.006
WS -18
0.89
12
1.0
2.7
0.011 0.002
WS -19
1.44
21
1.0
4.2
0.007 0.002 20.0
WS -20
3.00
8
3.0
1.6
Water Code
Dry
Total Het
Fungi
x102
cfu/ml
Wet Dry
Wet
Dry
Wet
Dry
9
5
12
5
14
10
17
9
19
32
26
9
6
16
37
5
1.0
Nil
1.0
Nil
1.0
Nil
Nil
Nil
Nil
Nil
2.0
Nil
Nil
1.0
-
Nil
Nil
2.0
Nil
1.0
Nil
Nil
1.0
Nil
1.0
1.0
Nil
1.0
2.0
1.0
Nil
0.09
0.06
0.01
0.09
0.05
-
0.2
19
11
Nil
Nil
-
-
4.0
2
Nil
1.0
-
0.5
15
1.0
2.0
0.05
0.1
20
1.0
Nil
0.043
-
0.002 11
0.002
7
0.003 18
0.004 6.5
0.002 10
0.004 14
0.002 18
0.001 17
0.004 22
0.003 17
0.007 23
0.003 11
0.005 4.0
0.006 20.0
0.002 44
0.004
9
0.01 0.002
Total Hyd. Percentage
Fungi. x102
Hyd.
cfu/ml
Utilizers
23
0.07
0.1
0.03
0.04
0.2
0.1
0.03
-
Groundwater
The underground water during the wet season recorded heterotrophic bacterial
densities ranging from 3.0 x102cfu/ml in borehole 6 (BH6) to 20.0 x102cfu/ml in
borehole water 3 (BH3) dry season values was however slightly reduced ranging
from 2.0 x102cfu/ml in borehole 8 (BH8) to 17.0 x102cfu/ml in borehole water 4
2
(BH4). Similarly, fungi population counts were in the order 1.0 x 10 cfu/ml (BH-6)
to 10.0x102cfu/ml in BH-4 (wet season) and 2.0 x102cfu/ml in borehole 6 (BH6) to
150.0-x102cfu/ml in borehole water 4 (Dry season) see Table 5.18. Hydrocarbon
utilizers were not detected at all for bacteria and fungi for both seasons. This
showed that the underground water was free from hydrocarbon contamination.
This result is in conformity with the chemical analysis results.
The coliform count during the dry season ranges from 8 – 120/100ml, which was
expected since they are indicators to check the presence of contamination from
human source. Through their presence is an indication of contamination from
human origin, (e.g. faeces) but naturally occurring organism of the
Enterobacteriacea family can cause an increase in their number. Surprisingly,
coliforms were not detected in the borehole water samples during the rainfall (wet
season), indicating non-contamination of underground water with faecal matter. A
situation, which indicate that the waters show compliance with the recommended
Chapter Six
1cfu/100ml acceptable limit of coliform (APHA, 1989). This suggests that the water
was microbiologically fit for drinking purposes during the raining season.
Table 5.18: Microbial Densities of Ground Water Samples
Borehole
Bacterial Density
Total Het.
Total Hyd.
Bact. x102
Bact.
cfu/ml
x102cfu/ml
Percentage
Hyd-utiliser
Fungal Densities
Total Het
Total Hyd. Percentage
Fungi
Fungi.
Hyd.
x102 cfu/ml
x102
Utilizers
cfu/ml
Code
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
BH-1
10
13
Nil
Nil
-
-
7
5
Nil
Nil
-
-
BH-2
12
15
Nil
Nil
-
-
7
8
Nil
Nil
-
-
BH-3
8
10
Nil
Nil
-
-
6
2
Nil
Nil
-
-
BH-4
20
17
Nil
Nil
-
-
10
15
Nil
Nil
-
-
BH-5
4
6
Nil
Nil
-
-
3
4
Nil
Nil
-
-
BH-6
3
3
Nil
Nil
-
-
1
2
Nil
Nil
-
-
BH-7
6
10
Nil
Nil
-
-
8
9
Nil
Nil
-
-
BH-8
4
2
Nil
Nil
-
-
4
6
Nil
Nil
-
-
Sediment
The two season microbial data on sediment is given in Table 5.19, the result show
that the heterotrophic bacteria counts ranged between 42x104cfu/g at SD7 and
75x104cfu/g at SD8 while total heterotrophic fungi ranged from 2.0x104cfu/g at the
SD9 to 14 x104cfu/g at SD6 during the wet season. The situation was not too
different during the dry season as the values recorded were comparable to that of
the wet season values obtained being 41x104cfu/g at SD6 and 70x104cfu/g at SD9
4
while total heterotrophic fungi ranged from 3.0x10 cfu/g at the SD9 to 14.0
4
x10 cfu/g at SD5. Total hydrocarbon utilising bacteria ranged between nondetected to 6.5 x 104cfu/g for both season.
The absence of hydrocarbon
contamination in most sampling stations was also indicated by the low percentage
hydrocarbon utilizers (<0.1%).
Generally, the presence of the hydrocarbon utilizers in the environment even in
such low densities dictates the possibility of self-purification in case of oil spill
incident. Most of the microorganisms encountered do not differ from those isolated
in the dry season of the study. The dominant bacteria included: Bacillus sp,
Micrococcus sp, Pseudomonas sp and Flavobacteria sp. The most prominent fungi
are Aspergillum sp, Penicillium sp, Penicillium notatum and Mucor sp.
Chapter Six
Table 5.19: Microbial Densities of Sediment Samples
Bacterial Density
Code
Sediment
Samples
SD 1
Total Het.
Bact.
x104
cfu/gm
Wet
Dry
Total Hyd.
Bact. x104
cfu/gm
Wet
Dry
Fungal Densities
Percentage
Hyd-utiliser
Wet
Dry
Total Het
Fungi
x104 cfu/gm
Wet
Dry
Total Hyd.
Fungi.
x104
cfu/gm
Wet
Dry
Percentage
Hyd.
Utilizers
Wet
Dry
-
Nil
45
60
2.0
4.0
0.044 0.067
6
5
Nil
Nil
SD2
47
45
3.0
4.0
0.064 0.089
10
12
1.0
1
SD3
48
53
1.0
2.0
0.021 0.038
11
9
Nil
1
SD4
48
49
3.0
2.0
0.063 0.041
13
12
1.0
1
0.040 0.08
SD5
46
48
6.5
5.0
0.14
0.1
12
14
5.0
4
0.227 0.29
SD6
50
41
Nil
1
-
0.02
14
10
Nil
Nil
-
Nil
SD7
42
47
3.00
3.0
0.07
0.06
4.00
5
1.00
1
0.25
0.2
SD8
75
68
2.00
3.0
0.03 0.044 3.00
4
1.00
1
0.33
0.25
SD9
66
70
4.00
3.0
0.06 0.043 2.00
3
1.00
Nil
0.50
0.33
0.105 0.08
-
0.11
Soil Microbiology
The results of heterotrophic and hydrocarbon utilisers counts for bacteria and
fungi around the study is shown in Tables 5.20 a & b. Levels of hydrocarbon
utilizers in all stations were less than 1.0%. Coonney (1984) has shown that sites
chronically contaminated with hydrocarbons contain greater than 1% hydrocarbon
utilizers. Therefore, the study site has low level of hydrocarbon contamination. The
soil samples, which were collected at, designated points within and around the
study showed variations in the microbial population as shown in the tables below.
The wet season result indicated that the total heterotrophic bacterial densities
represented range of 50x103cfu/g to 290x103cfu/g while heterotrophic fungal
densities ranged between 10x103cfu/g and 44x103cfu/g. The hydrocarbon utilizing
bacteria ranged from 1.0x103cfu/g to 36.0x103cfu/g and the percentage
hydrocarbon utilizer ranged between 0.003% (points 1, 2, 4 & 5) and 0.212% (point
13). Similarly, the dry season result shows that the total heterotrophic bacterial
densities represented range of 50x103cfu/g to 208x103cfu/g while heterotrophic
fungal densities ranged between 10x103cfu/g and 35x103cfu/g. The hydrocarbon
3
utilizing bacteria also ranged from 0-to 24.0x10 cfu/g and hydrocarbon utilizing
3
fungi recorded 0-5.0x10 cfu/g. In the course of study, the following bacteria were
mostly encountered: Pseudomonas fluorescens, Micrococcus sp and Flavobacterium
sp while Penicillium sp, Aspergillum sp, Penicillium sp, Penicillium notatum and
Mucor sp were the main fungal species identified.
Chapter Six
Table 5.20a:
Microbiology of Soil in the Wet Season
Bacteria
SAMPLING
POINT CODE
Fungal Flora
Total HET x
103 cfu/g
HYD Utiliser
101+ cfu/g
Percent HYD
Utiliser
Total HET
Fungal
x 103 cfu/g
HYD Utiliser
101+ cfu/g
Percent HYD
Utiliser
1K1-SS1A
132
2
0.015
35
5
0.14
1K1-SS1B
152
4
0.03
10
2
0.2
1K1-SS2A
114
1
0.008
33
2
0.06
1K1-SS2B
104
1
0.009
36
3
0.08
1K1-SS3A
140
4
0.029
23
2
0.09
1K1-SS3B
222
2
0.009
19
2
0.11
1K1-SS4A
78
1
0.013
18
2
0.11
1K1-SS4B
125
2
0.016
10
2
0.11
1K1-SS5A
135
2
0.02
15
3
0.2
1K1-SS5B
90
1
0.01
18
3
0.17
1K-JT-SS6A
80
2
0.03
15
3
0.2
1K-JT-SS6B
80
2
0.03
25
5
0.2
1K-JTU-SS7A
90
4
0.04
20
5
0.25
1K-JTU-SS7 B
50
1
0.02
16
3
0.19
1K-MKDS-SS8A
73
2
0.03
21
4
0.19
1K-MKDS-SS8B
55
2
0.04
16
4
0.25
1K-MKT-JT-SS9A
93
6
0.06
44
6
0.14
1K-MKT-JT-SS9B
100
7
0.07
21
5
0.24
1K1-MKT-EDSSS10A
100
4
0.04
20
2
0.1
1K1-MKT-EDSSS10B
116
5
0.04
10
2
0.2
1K-AGSS-11A
143
4
0.03
27
3
0.11
1K-AGSS-11B
114
2
0.02
20
3
0.10
1K-AGSS-12A
60
4
0.08
15
2
0.15
1K-AGSS-12B
80
5
0.07
15
2
0.15
1K-AGSS-13A
290
36
0.12
34
8
0.24
1K-AGSS-13B
176
10
0.06
18
2
0.11
Chapter Six
Table 5.20b:
Microbiology of Soil in the Dry
Season
Bacteria
SAMPLING
POINT CODE
Fungal Flora
Total HET
x 103 cfu/g
HYD
Utiliser 103
cfu/g
Percent
HYD
Utiliser
Total HET
Fungal
x 103 cfu/g
HYD
Utiliser 103
cfu/g
Percent
HYD
Utiliser
1K1-SS1A
144
2
0.014
37
4
0.011
1K1-SS1B
208
6
0.029
11
3
0.3
1K1-SS2A
130
2
0.015
30
2
0.07
1K1-SS2B
124
2
0.016
35
1
0.03
1K1-SS3A
115
4
0.026
22
1
0.05
1K1-SS3B
192
2
0.010
20
NIL
0.
1K1-SS4A
98
NIL
-
12
NIL
-
1K1-SS4B
115
1
0.008
11
NIL
-
1K1-SS5A
130
ND
-
10
2
0.2
1K1-SS5B
98
ND
-
26
4
0.15
1K-JT-SS6A
86
2
0.02
27
3
0.11
1K-JT-SS6B
67
1
0.015
19
4
0.21
1K-JTU-SS7A
86
3
0.03
11
3
0.27
1K-JTU-SS7 B
50
2
0.04
17
1
0.06
1K-MKDSSS8A
70
2
0.03
18
3
0.17
56
3
0.05
15
4
0.27
102
5
0.05
24
4
0.12
98
8
0.08
20
4
0.2
94
3
0.03
14
2
0.14
115
6
0.05
10
2
0.2
150
4
0.03
25
2
0.08
110
2
0.02
22
2
0.09
56
4
0.08
10
2
0.2
65
4
0.06
11
2
0.2
1K-AGSS-13A
208
24
0.12
28
5
0.18
1K-AGSS-13B
180
8
0.04
11
1
0.1
1K-MKDSSS8B
1K-MKT-JTSS9A
1K-MKT-JTSS9B
1K1-MKT-EDSSS10A
1K1-MKT-EDSSS10B
1K-AGSS-11A
1K-AGSS-11B
1K-AGSS-12A
1K-AGSS-12B
5.4.9 Aquatic Ecological
Fisheries
The study area is fresh/brackish water ecological zone. Fishing is carried out in
most cases from permanent camp and temporary shelters set up on the banks of
Ikebiri creek and along man made- dredge slots. Fishes caught are represented by
Chapter Six
Periophthalmus (Gobiidae), the common mudskipper is found at almost all the
stations outside the sandy beach. They are more abundant at the random stations
of the mudflat.
The catches by local fishermen within the study area and fishing camps include:
Finfish
Chrysichthys sp
Clarias anguillaries
Tilapia macroephala
Ethmalosa fimbriata
Shell Fish
Shrimps: Macrobrachium vollenhovenii
Tivela triple (water snail)
Natica sp
Periwinkle (Tympanotonus fuscatus) is of economic value. The species abundance
and condition factor of the fin and shellfishes in the waters of the study field area is
shown in Table 5.21 below.
Table 5.22 shows Gonado-Somatic Index ratios of the female fish specimens
collected. Generally, the ratios were below 1 except for Tilapia macrocephala (4.06),
Umbrina ronchus (3.02) and Pseudotolithus senegalensis (1.29). The low G.S.I may
be due to seasonal effect, as sampling was during the dry season (January 2000) as
against the wet season of September, when fishes with gravid and ripe gonads are
found.
Results obtained for the stomach analyses are summarised in Table 5.23. All the
fish species did not exhibit any physical evidence of parasitic infection. There was
also no observation of disease infestation, abnormalities or physical stress
indicating fish palatability.
Table 5.21: Species Abundance and Condition Factor of the Fin and
Shellfishes in the Waters
ABUNDANCE
MEAN STANDARD
LENGHT (CM)
CONDITION
FACTOR
FINFISH
Gymnarchidae
Gymnarchus niloticus
2
60.00
3.24
12
25.2
3.6
30
6
3
2
2
3
10.2
12.3
11.1
18.9
9.48
5.8
5.55
6.3
5.85
7.8
5.7
9.15
5
19.8
5.1
Citharinidae
Citharinus citharus
Cichlidae
Tilapia zilli
Hemichromis bimaculatus
Hemichromis fasciatus
Sarotherodon galilaeus
Tilapia mariae
Oreochromis niloticus
Notopteridae
Xenomystus nigri
Pantodontidae
Chapter Six
Pantodon buchholzi
Polypteridae
Erptoichthys
(=Calmoichthys)
calabaricus
Osteoglossidae
Heterotis niloticus
Tetraodontidae
Tetraodon fahaka
Clariidae
Clarias gariepinus
Characidae
Alestes baremose
Alestes nurse
SHELLFISH
Palaemonidae
Macrobrachium
vollenhovenii
Macrobrachium dux
Atyidae
Caridina africana
Bivalvia
Egeria paradoxa
Tovela tripla
2
42.6
3.3
2
22.6
0.36
3
72.0
2.25
6
12.15
3.75
3
25.8
5.1
5
3
9.75
8.7
3.3
3.6
30
5.1
6.3
15
2.75
4.65
12
3.3
5.1
15
3
10.8
8.7
6.3
5.23
Source: SPDC Environmental Baseline Report of Tebidaba/Opugbene Field (2000)
Gonado-somatic Ratio for Major Species
Species
Chrysichthys nigrodigitatus
Hemichromis fasciatus
Liza falcipinnis
Plectorhynchus macrolepis
P. brachygnathus
Pseudotolithus elongatus
Pseudotolithus moori
Pseudotolithus senegalensis
Tilapia macrocephala
Trichiurus lepturus
Umbrina ronchus
Number of
fish
Examined
1
1
14
2
9
2
7
2
1
5
3
Size Range
S.L. (cm)
25
12.5
10.5 - 20.5
13 - 18.5
8.5 - 20.5
22 and 26
16.5-26
21.8 and 31.5
15
28-53
18-22.5
GonadoSomatic
Ratio
0.03
0.08
0.05
0.09
0.21
0.46
0.64
1.29
4.06
0.28
3.02
Source: SPDC Environmental Baseline Report of Tebidaba/Opugbene Field (2000)
Chapter Six
Summary of Stomach Content Analyses
PLANKTON FEEDERS
HERBIVORES
CARNIVORES
OMNIVORES
Sardinella maderensis, S. rouxi, Tilapia mariae,
T. macrocephala
Liza falcipinnis
Ilisha africana, Sphyraena sp., Pseudotolithus
elongatus,
Caranx senegallus, Pseudotolithus epipercus, Sarda
sarda
Hemichromis fasciatus, Lutjanus goreensis, Psettias
sebae
Pomadasys peroteti, Plectorhynchus macrolepis,
Galeoides decadactylus, Polydactylus longifilis
Umbrina ronchus, Chrysichthys sp. Pseudotolithus
moori
Sources: SPDC Environmental Baseline Report of Tebidaba/Opugbene Field (2000)
The fisher-folks in the fishing camps and communities of the area use a variety of
fishing gears which include basket traps, cast nets, silk nets, traps, long lines and
hooks. The common fish species and landing estimates per gear are presented in
Table 5.24.
Table 5.24: Common Fish Species and Landing Estimates Per Gear
S/No.
1.
2.
3.
4.
5.
Fishing
Gears
Large Mesh
Gillnet
Small Mesh
Gillnet
Long Line Hooks
6.
7.
Beach Seine
Basket Trap
(Funnel)
Fences
Castnet
8.
Pond Bailing
Common Fish
Species
Croakers, Bonga, ShinyNose
Mullet, Cichlids, Catfish
Weight (kg)
Income* (N)
2 – 15
300 – 3,000
2–5
200 – 800
Catfish, Snapper,
Croakers
Cichlids, Alestes, Mullets
Goby, Tilapia, Shrimps,
5 – 12
1,000 – 4,000
1–5
0.5 – 1.5
100 – 600
100 – 300
Mixed Finfish
Young of common species
of the season
Clarias sp., Channa sp.,
Xenomystus
3 – 10
1-6
500 – 1,500
100 – 800
Up to 15kg
Up to 5,000
Phytoplankton
Phytoplankton constitute the autotrophic microscopic plant organisms in water
bodies. These fix solar energy by the process of photosynthesis using carbon
dioxide and water to produce organic matter and oxygen. Phytoplankton organisms
are of great ecological significance because they comprise the major portion of
primary producers in the aquatic ecosystem. They are, like the plants on land, the
basic food in the water for all consumers such as zooplankton and fish. They are
not only the first stage in the food chain but also the main producers of oxygen; the
two (i.e. food and oxygen) together form the life support system or the basic
requirements for the maintenance of aquatic life forms.
Appendices 5.6 a & b shows the phytoplankton community in the waters from the
study area in both seasons, highlighting the species composition, density, and
Chapter Six
distribution of phytoplankton in the study location. Thirty (30) and twenty four
(24) phytoplankton species were recorded in this location for wet and dry seasons
respectively; there was basically no difference in composition except for the new
species added in the wet season. The wet season species belong to the following
taxonomic groups namely divisions Bacillariophyta (14), Chlorophyta (10),
Cyanophyta (3), Dyanophyta (1) and Euglenophyta (2), while for the dry season
three taxonomic group recorded changes; they are Bacillariophyta (13),
Chlorophyta (9) and Cyanophyta (2). Bacillariophyta (diatoms) is the dominant
phytoplankton species in terms of taxa richness in the study area. Followed by
Chlorophyta (green algae), Cyanophyta (blue-green), Euglenophyta (Euglenoids) and
Dyanophyta (the lowest in species composition and richness). The contribution of
Dyanophyta and Euglenophyta were not significant. The percentage composition of
the major divisions of phytoplankton in the study area for wet and dry season
respectively are represented in Figs. 5.23 and 5.24. Wet season compositions are
in the order Bacillariophyta (46.67%), Chlorophyta (33.33%), Cyanophyta (10.00%),
Euglenophyta (6.67%) and Dyanophyta (3.33%) while dry season recorded
Bacillariophyta
(50.00%),
Chlorophyta
(34.62%),
Cyanophyta
(7.69%),
Euglenophyta (3.85%) and Dyanophyta (3.85%) Euglenophyta and Dyanophyta
were poorly represented and their contribution was therefore insignificant. The
species were mixture of fresh water and brackish assemblages.
Bacillariophyta were represented by some species like Aulocosira sp, Coscinodiscas
radiatus, Gomphonema sp, Fragillaria sp, Leptocylindrus danicus, and Nitzschia
obtusa.
While Chlorophyta were represented by Closterium sp, Desmidium
quadrutum, Spirogyra sp, Oedogonium sp, Coeastrum microporum, Volvox sp.
Cyanophyta was represented by Oscillatoria sp and Microcystis sp. The Dyanophyta
and Euglenophyta, which had 1 and 2 species respectively, recorded Peridium
cinctum, Euglena sp and Phacus sp. The bulk of phytoplankton species belonged to
the Bacillariophyta division and is of both marine and brackish forms.
Phytoplankton have long been used as indicators of water quality because of their
short life cycles. They respond quickly to environmental changes, and hence their
standing crop (biomass) and species composition indicate the quality of the water
mass in which they are found. They strongly influence certain non-biological
aspects of water quality.
Species distribution from station to station within the field was sparse and typical
of phytoplankton patchiness. The low biomass (cells/litre) in most of the (stations
5 to 8) in minor drainage channels is probably due to the level of turbidity and
transparency, as a result of their small volumes and stagnant nature (Appendices
5.6 a & b). The much higher biomass per unit area recorded for sampling stations
1 to 4 may not be unrelated with the high transparency and low turbidity of these
major waters during the study.
Chapter Six
7%
3%
10%
Bacillariophyta
47%
Chlorophyta
Cyanophyta
Euglenophyta
Dyanophyta
33%
Fig. 5.23: Wet Season Percentage Composition of the major Divisions of
Phytoplankton
4%
4%
8%
Bacillariophyta
Chlorophyta
49%
Cyanophyta
Euglenophyta
Dyanophyta
35%
Fig. 5.24: Dry Season Percentage Composition of the major Divisions of
Phytoplankton
These are minute free-floating or weakly swimming animals within the pelagic zone
of the water column (Ross, 1970; Davis, 1972). They consist of the Rotifera,
Copepoda, Cladocera, and sometimes occur in larval forms. The zooplankton
community is subdivided according to its-history patterns as follows:
·
Holoplankton: These are organisms whose entire life cycle is as zooplankton,
e.g., calanoid copepods.
Chapter Six
·
Meroplankton: Those organisms that spend only part of their life cycle as
plankton, e.g., eggs and larvae of fish, shrimp, crabs, molluscs and
polychaete worms.
Appendix 5.6 c shows the glossary of zooplankton community of the sampling
stations at the study area for wet and dry seasons respectively. A total of 3
zooplankton types were recorded in the area for both seasons. These are Rotifera,
Copepoda and Cladocera out of which thirty species of zooplankton were identified
in the study location; they belong to the following taxonomic groups Rotifera (16),
Copepoda (6) and Cladocera (8). Thirteen zooplankton groups were further isolated
and identified from the 3 taxonomic groups.
They are Brachionidae,
Asplanchinidae,
Collurellidae,
Epiphenidae,
Euchlanidae,
Filinidae,
Testudinellidae, Cyclopidae, Diaptronidae, Sididae, Daphinidae, Moinidae and
Bosminidae, these zooplankton family were further classified under Rotifera (7),
Copepoda (2) and Cladocera (4).
Wet season results indicated that at sampling point 6 the lowest zooplankton
counts (density) was recorded with a count of 242 organisms 0.1m-3, followed by
sampling point 5 with 350 organism 0.1m-3, while the highest density (count) of
1578 organisms 0.1m-3 was recorded at sampling station 1, this was also closely
followed by sampling point 7 (1194 organisms 0.1m3) similar observation made in
the dry season show that sampling point 5 the recorded the lowest zooplankton
counts (density) of 187 organisms 0.1m-3, followed by sampling point 6 with 296
organism 0.1m-3, while the highest density (count) of 1571 organisms 0.1m-3 was
recorded at sampling station 1, this was also closely followed by sampling point 7
(1184 organisms 0.1m3). The mean Zooplankton count was 630 organisms. The
total number of zooplankton species (taxa) in the waters of the area field fluctuated
between 9 taxa at sampling point 5 and 25 taxa at sampling point 7, with a mean
of 16.5 species.
The most dominant group in the wet season was Cladocera (55%) followed by
Rotifera (23.5%), and Copepoda (21.5%) this was repeated in the dry season as
follows dominant group was Cladocera (56.46%) followed by Rotifera (25.36%), and
Copepoda (18.17%). The percentage composition of major order of zooplankton in
the study area is shown as Figs. 5.25 & 5.26. Zooplankton diversity was highest
(0.8563) at station 4 and lowest (0.4607) at station 5. Generally, the barge slots
station and the Agip creek canal stations were higher in diversity than the minor
drainage channels. The very low diversity at station 5 may be due to the time of
year and temporary nature of the water body that derives mainly from the storm
water. Surprisingly, this did not affect the abundance of cyclopoids, Arcata and
copepod naupli. These groups are known to dominate widely polluted waters,
reducing the overall faunal diversity (RPI, 1985).
Chapter Six
24%
Rotifera
Copepoda
22%
54%
Cladocera
25.36%
Fig. 5.25: Wet Season Percentage Composition of the major Order of
Zooplankton
Rotifera
Copepoda
18.17%
56.46%
Cladocera
Fig. 5.26: Dry Season Percentage Composition of the major Order of
Zooplankton
Macrofauna
This component of the aquatic biota represents those animals, which are over 1.0
mm in size, living on or in the substrate or bottom sediment. They may be found
living wholly or partially buried in soft or hard substrates as Infauna (e.g. bottom
dwelling annelids, chironomids and bivalve molluscs). They may also live on the
surface, either crawling as mobile benthic inhabitants or attached to different types
of substrates as Epifauna (e.g. crabs, littorinid gastropods, barnacles and oysters
on the stilt roots of mangroves). Several groups of macrobenthic fauna are of
special interest to fisheries, parasitology and pollution monitoring studies.
Many molluscs are economically important (e.g. the edible periwinkles,
Tympanotonus and Pachymelania and some bivalves like Egeria, Anadara, Pecten,
Crassostrea, etc.) as good source of protein, and the empty shells of periwinkles
Chapter Six
now have additional values in decorating buildings and in the making of cement
concrete and solid foundation floors for houses. The decapods crustaceans are
more important economically as the shrimps and crabs are harvested for both
subsistence and commercial purposes. The annelid polychaetes and oligochaetes
though not edible play an important ecological role in bioturbation, helping through
their burrowing activities, in the release of nutrients from sediment into the water
column for use by the phytoplankton.
The structure and function of benthic communities reflect the condition of the
biotic and abiotic environments. They delimit water types and indicate shifts in
water quality. Because of their fairly long life span and environmental sensitivity,
macrobenthic fauna are now widely used as reliable bioindicators in pollution and
impact assessment study (Colwel, 1971; Weber, 1973; Lee et al; 1978; Tsui &
McCart, 1981; Ogbeibu & Victor, 1989).
In order to effectively manage an ecosystem, and be able to evaluate possible
anthropogenic impact, it is imperative that basic information be obtained on the
fauna under relatively undisturbed conditions.
Taxonomic Composition, Abundance and Distribution of Fauna
Appendices 5.6 d & e summarises the faunal composition and distribution
at the supra-generic level in the hierarchy of zoological classification
encountered in Opugbene (Tologbene) area.
A total of 14 benthic
macrofaunal species were recorded in the study area. The fauna observed
for both seasons can be categorised into Diptera (5), Ephemeroptra (4) and
Annelida (5) with almost equal representation except for Ephemetoptra,
which had 4 species. Generally, the benthic macrofauna were poorly
represented in the study stations. The natures of the substratum and
physico-chemical parameters are major factors that control the occurrence
and distribution of benthic fauna. The movement of vessels makes the
bottom sediment unstable and this reduces the density and diversity of
benthos.
The number of organisms in the wet season ranged from 15 organisms 0.1m-3
(WS15) to 36 organisms 0.1m-3 at sampling stations WS16. While the total number
of species range from 7-10 species, as for dry season the number of organisms
ranged from 7 organisms 0.1m-3 (WS6) to 28 organisms 0.1m-3 at sampling stations
WS7 and WS16. While the total number of species range from 2 – 9 species. The
percentage composition of the major order of benthic fauna in the study area is in
the order Diptera (46.8%), Ephemeroptra (24.7%) and Annelida (28.5%) and Diptera
(44.84%), Ephemeroptra (24.2%) and Annelida (30.96%) for wet and dry seasons
respectively. The most dominant group was Diptera followed by Annelida and then
Ephemeroptra.
The percentage composition of the major order of benthic
macrofauna in the study area is shown in Figs. 5.27 & 5.28. Sampling station
WS3, WS6 and WS14 did not record any species of fauna in the family
Ephemeroptoera. A situation, which contributed to the low flora and fauna counts.
Generally, the density and diversity of the macrobenthic fauna in the study
area is low compared to other studies in similar biogeographic environment
(Ogbeibu, 1994; 1996 a & b) where between 54–135 macro-invertebrates
taxa were recorded. This observation may be due to the habitat area of the
present study area.
Chapter Six
Malacostracan crustaceans were represented by Mysis sp. (Mysidacea), Apseudes
sp. (Tanaidacea), Sphaeroma terebrans (Isopoda) and several decapods. Mysis had
the highest abundance at station 8 were over 1000 individuals were caught in the
grab samples. Sphaeroma was confined to stations 14 and 15. The decapods were
the most widespread. The diogenid Clibanarius (hermit crab) occurred in large
numbers at the random stations (1, 2 and 3), inhabiting the empty shells of
periwinkles. The grapsids were represented by sesarmid crabs living in burrows
among mangrove roots.
Relative Abundance of Fauna
Figs. 5.27 & 5.28 shows the relative abundance of the major faunal groups at the
study stations for wet and dry seasons respectively. The contributions of different
groups to the total faunal abundance in each station showed distinct variations.
There was a general trend in which some groups dominated the total collection in
most of the stations. In general, the crustaceans were most dominant, ranking
highest in almost all the stations. Crustacean dominance was most remarkable
stations 12 - 15 (beach stations) were the other groups were virtually absent. The
next dominant group was the Mollusca, represented mainly by the periwinkles,
which were very prominent at the creek and mudflat stations, but became
insignificant at the beach stations.
29%
Annelids were not prominent; they however gained dominance at station 5 due to
the absence of most of the other groups. The Pisces, controlled mainly by
Periophthalmus, were more represented at the creek stations than along the canal.
They disappeared at the sandy beach stations. The minor groups Coelenterata,
and Insecta were not important components in all the stations. At station 8 the
Arrow worm, Sagitta sp (Chaetognatha) was collected in high numbers.
Diptera
Annelida
25%
46%
Ephemeroptera
Fig. 5.27: Wet Season Percentage Composition of the major Order of Benthic
macrofauna
Chapter Six
31%
Ephemeroptera
Annelida
24%
45%
Diptera
Fig. 5.28: Dry Season Percentage Composition of the major Order of Benthic
macrofauna
The faunal taxa number and density calculated for each station are presented in
Appendices 5.6 d & f. The number of taxa and density of macrobenthic fauna
varied considerably among the stations. The number of taxa varied between 0
(Station 5) and 9 (Station 2). The pattern of fluctuation was closely related to
ecotype classification (major creeks and minor drainage channels. The creek
stations (1 to 4) were richer than those of the drainage channels. The three
diversity indices, Margalef (d), Shannon-Wiener (H) and Evenness (e) followed
almost similar fluctuation trend. Of these three, the Shannon index gave the most
accurate picture of faunal diversity. The major creek stations had high diversities,
with station 2 scoring the highest, while the lowest diversities were recorded at the
drainage channels; Station 5 had the lowest diversity in the study area.
Chapter Six
5.4.10.1 The Social and Health Environments
There are two major settlements in the project area namely Ikebiri I and II (Plates
5.3 & 5.4) (which is the largest and oldest of the settlements) with many other
minor settlements and fishing camps, including a new one near the Agip Flow
Station, consisting mainly of migrant fishermen from neighbouring towns and
villages who have decided to settle down in this area. The houses in the
settlements are built with simple materials. Thatches made from raffia palm leaves
were use for roofing, while plywood was mostly used for wall and room partitioning.
5.4.10.2 Social Organisation and Institution
The people in the settlement belong to the Ijaw ethnic group. A Chief in
conjunction with the village executive council administers the communities from
Ikebiri I. The village executive council is made up of a President, Secretary,
Treasurer, Public relation officer (spokesmen).
5.4.10.3 Demography
National Population Commission (NPC) Census figures projected for 1996 are
presented in Table 5.25. The estimates for the study period were calculated using
an annual growth rate of 2.8% - these are also shown in the Table. It was observed
that the communities were small settlements.
However, during field study, total enumeration of the population in the
communities revealed a de facto population presented in Table 5.25.
The age distribution (Structure) of the population based on field survey is presented
in Table 5.26. The table shows that the communities are typical of settlements in
developing countries and mirror the age distribution pattern reported in the 1991
NPC Census Report (NPC, 1996). The NPC Census data for the old Rivers State,
which includes present day Bayelsa State, indicated that Children under the age
of 15 years account for 44.1%, while those from 15-64 years are 53.8%, and the
rest, over 65 years, 2.1%.
Table 5.25: Estimated Population of the Study Area by Settlements
Settlement
1996 (NPC
Projections, 1991)
Ikebiri I
Ikebiri II
Lobia
Azuzuama
Ukubie
Total
2673
548
1585
2626
2305
9737
Population Estimate
2000
2000 (Field Survey)
(Estimates at
2.8% GR)
2972
1350
609
1050
1763
1300
2920
1000
2563
934
10827
5634
Table 5.26: Distribution of Ages in the Study Area
Years
0 – 14
15 – 44
45 – 59
60 +
Total
Chapter Six
Number
1,994
1,707
1,251
682
5,634
Percentage (%)
35.4
30.3
22.2
12.1
100
Sex Distribution
The 1991 NPC Census Report (1996) indicated a male to female ratio of 3:2 for
Rivers/Bayelsa States. This implies a sex distribution of 58% males and 42%
females for the project area.
Household Size
The probability cross-sectional survey of households using structured
questionnaires required a minimum sample of 116 heads of households.
Interviews revealed an average household size of five (5) persons. This compares
well with figures stated for Rivers/Bayelsa States (5.2) and the National Average of
4.9 persons reported in the 1991 NPC Census Report (1996).
Occupation
The household survey also provided information on the occupational structure of
the heads of households. Approximately 35% of the household heads had definite
employment, which is lower than the national labour force participation rate of
39.6% for individuals aged 15 to 64 (World Bank EDSTATS). Fishing was the
dominant occupation accounting for over 45% while crop farming accounted for
12%. Trading/commerce and artisanal services accounted for 15%; casual E & P
labour (at the nearby Agip facilities) constitute over 15%; while other occupational
are over 13%.
Education
There are no educational institutions or facilities in the entire area. The literacy
level in the communities is generally low. Indigenes of the area who are currently
in school are all living outside the locality. Illiteracy rate for Rivers/Bayelsa States
was reported as 21.9% in the 1991 NPC Reports.
Religion
People in the study area practice both the Christian and the African traditional
religion. There is no distinction between the traditional worshippers and the
Christians as some persons combine both.
Settlement
The study area exhibits linear settlement patterns. The settlements are basically
nodal with creeks and rivers providing the modes for communication and
transportation while the elevated lands (islands) provided settlements grounds
5.4.10.4 Economic Environment
The local economy base is primarily dependent on the exploitation of the resources
of the immediate environment of the project area. Fishing is the main occupation
engaging the people all the year round (Plates 5.5 & 5.6). Their income status is
mainly dependent on the productivity of the fishing sector. Other occupations are
logging and haulage.
Fishing is conducted mainly along the creeks and river within the project area.
Simple fishing instruments, such as nets, traps and hooks are employed. The
quantity of fish caught and the income generated will partly depend on the level of
technology employed and other environmental constraints. Men earn higher from
these activities compared to women.
Chapter Six
Table 5.27: Estimated Annual Income of Households
Income (N)
No of Households
0 – 25,000
2
25,001 – 50,000
8
50,001 – 75,000
80
75,001 – 100,000
20
100,001 – 125,000
4
125,001 – 150,000
2
Total
116
Percentage (%)
1.7
6.9
69.0
17.2
3.5
1.7
100
5.4.10.5 Quality of Life
Quality of life is a measure of the amount and distribution of socio-economic
variables. The socio-economic indices used in measuring quality of life in rural
areas include electricity, pipe borne water supply system, access road, and a
market for the exchange of farm and other products (Omofonmwan, 1992).
There are no portable water supply facilities. Water for domestic use is obtained
from hand-dug wells, rainwater and surrounding creeks. There is currently no
electricity supply. The 1995 Progress of Nigerian Children (PONC) Report indicated
that 49% of households in Rivers/Bayelsa States obtain their source of drinking
water from ponds and streams.
Electricity
No electricity supply exists in the communities; people rely on lantern for lighting.
Individuals also own small generators. The 1995 Progress of Nigerian Children
(PONC) report1indicated that 59% have no access to electricity in Rivers/Bayelsa
State.
Transport and Communication
Transportation is by hand-propelled canoe. A few commercial transport boats ply
the creek at regular intervals although transportation fares are reported to be very
exorbitant.
Sanitation and Waste Disposal
Sanitation or waste disposal system is lacking. Domestic wastes are disposed
arbitrarily behind or beside houses or even directly into the river. Human waste is
discharged directly into the rivers or creeks since the existing houses lack toilet
system. The 1995 Progress of Nigeria Children (PONC) report showed that 21% and
90% of households in Rivers/Bayelsa States use “unconventional” toilets and
unsatisfactory refuse disposal methods.
Housing
Houses in the area are built of ephemeral materials such reeds and thatch. Along
the shoreline, the houses are built on stilts, which although fairly durable, are
physically very fragile and aesthetically unattractive.
Over crowding and poor ventilation are obvious problems in the area. An average
of eight (8) persons share one hut (house) of one or two small rooms. This pattern
of living also has its social implications, as it does not allow privacy for adults and
the provision of a suitable setting for the upbringing of children.
Household Energy
Chapter Six
The people cook their meals and process fish (smoking) with firewood.
Life Style/Habit
The life style /habit of a community or an individual plays an important role
in the health status of the people. The alcohol consumption rate in the
communities is high as most of the respondents admitted either daily
consumption of the locally made gin. The average number of cigarette
smoked daily ranges 3 – 4 mainly within the age bracket of 18 - 30 years.
Physical exercise like jogging, running, jumping are not practiced.
5.4.10.6 Archaeological Studies
The study identified a shrine at Ikebiri I located close to an overhead water-tank
within built up area. The forest and burial grounds are also held sacred in
Opugbene (Tologbene).
5.4.10.7 Health Status
Health Facilities
There are no health facilities people depend on traditional medicine. In
extreme case, sick people are taken to Twon Brass for medical attention.
The prevalent sicknesses include malaria, cholera, diarrhea, measles and
"belly ache."
Nutrition
The people of the study area depend mainly on marine resources such as
fish oysters, lobsters, periwinkles, snails, etc. for food. Other food items like
garri, yam and plantain are purchased elsewhere. However, no significant
health problem associated with the nutritional habit was observed amongst
the people.
Overall, the average child amongst the sample population recorded nutritional
indices (Standard Deviation-scores or Z-scores) within normal limits, that is, when
compared to the NCHS/WHO/CDC reference population.6 As shown in table 4.6,
the average (mean) standard deviation scores of our study population, for the 3
nutritional indices, are not less than minus 2 SD.
Regional data for the Niger Delta were reported as 6.9% for Acute
Malnutrition (Wasting), 24.9% for Under-nutrition, and 30.0% for Chronic
Malnutrition (Stunting) (ENVHRA, 2000).
Birth and Death Rates
No official information on birth and death rates exist in the communities. A
number of respondents interviewed during our survey, claimed that most women
still patronize the services of traditional birth attendants. Records from these
sources are not normally recorded. In general, respondents were less willing to
discuss death, hence the lack of concrete figures.
Review of existing literature revealed that these sparse indices had also being
reported in a rare regional study conducted between 1998 and 1999 by the
Environmental & Human Health Research Association (ENVHRA) as part of the
integrated studies of the Niger Delta Environmental Survey (NDES). The study
reported a Crude Birth Rate of 31 per 1000 and a Crude Death Rate of 26 per
Chapter Six
1000. Over a third (36.9%) of the deaths was reported in children under 5 years
(Fig. 5.29).
Existing information about the pattern of deaths in the region are mostly from
hospital studies, and they present a wider array of causes of death of patients seen
at the health institutions.
25
20
15
%
10
5
0
<6mo 6-11mo
1-4
5-9
10-14
15-19
20-24
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65-69
70-74
75+
Age
Fig 5.29: Distribution of Deaths by Age Group in Niger Delta Region
Source: Environmental and Human Health Research Association (ENVHRA). 2000. Survey of the Health
Status and Health Infrastructure in the Niger Delta Region. NDES Reports, Vol. 43. Port Harcourt: Niger
Delta Environmental Survey.
Chapter Six
Plate 5.3: Ikebiri I Community
Plate 5.4: Ikebiri II Community
Chapter Six
Plate 5.5: Fish Caught in the Area on Display for Sale
Plate 5.6: Fish Caught in the area being dried
Chapter Six
CHAPTER SIX
6.0
ASSOCIATED AND POTENTIAL ENVIRONMENTAL IMPACTS
6.1
Introduction
The objectives of this chapter are to:
•
•
identify associated and potential impacts of the proposed project;
predict magnitude of the impacts and evaluate the importance of affected
environmental components;
The potential and associated impact assessment covers all stages of the project,
from site preparation through rig movement / installation, drilling,
operation/maintenance to decommissioning.
The general approach to the
assessment is shown in Fig. 6.1. The approach acknowledges that there can be
uncertainties over a number of issues arising from:
•
•
•
natural variability of the environment, particularly the occurrence of rare events
such as floods;
inadequate understanding of the behaviour of the environment;
socio-economic uncertainties.
Identify Associated and Potential Impacts
(Checklist Method)
Predict Impact Magnitude and Importance
(‘ISO 14001)
Evaluate Significance of Impacts
(ISO 14001/Regulatory Approach)
Fig. 6.1:
6.2
Assessment of Potential and Associated Impacts
Impacts Identification Methodology
The FEPA EIA Sectoral Guidelines for Oil and Gas Industry Projects was used in identifying
the total project impacts on the environmental components. The guidelines were used in
conjunction with the following:
• knowledge of the project activities and operational procedures;
• past experience on similar projects;
• the results of field investigations and understanding of the environmental
characteristics (ecological, socio-economic and health variables) of the project
area;
• FMENV, DPR, UNEP, and WHO Guidelines and Standards; and
• project specific risks and hazards identified using professional judgement.
Chapter Six
Impact indicators for the various environmental components are presented in
Table 6.1. The impact assessment process was borne on the premise that these
indicators will register any changes in the environment occurring as a result of
exploration drilling activities.
Table 6.1:
Environmental Components and Potential Impact Indicators
Impactable
Components of the
Environment
Climate
Air
Surface Water
Hydrology
Groundwater
Soil/Land Use
Ecology
Fisheries
Archaeological
Sites
Noise & Vibration
Socioeconomic/Health
Vegetation,
Wildlife & Forestry
Impact Indicators
Humidity, temperature, rainfall, wind
speed and direction
Particulates, NOx, SOx, CO, H2S
Salinity, pH, Temperature, TDS, TSS, DO,
BOD, Oil and Grease, Conductivity,
Anions, Heavy Metals, Microbial Load.
Drainage/Discharge, Hydrologic Balance,
Sedimentation, Shoreline erosion,
Flooding.
Water table and Quality, salt water
intrusion
pH, Organic Carbon, Available
Phosphorus, Nitrate-Nitrogen, Sulphate,
Chloride, Oil and Grease, Microbial Load,
Erosion, Fertility.
Diversity and abundance of aquatic and
terrestrial flora & fauna, habitats quality
Productivity, Reduced diversity &
abundance, Catch/Yield,
Cultural relics, Cultural Sites.
Daytime disturbance, Hearing loss,
Communication Interference, Night-time
disturbance.
Demography, Social Structure, Income,
Settlement pattern, Employment,
Agriculture, Health, Safety and Security,
Marital status (population of married
persons).
Biodiversity, Species abundance,
Environmental sensitivities,
Wetland/Swamp.
A checklist of project activities and a description of potential and associated
impacts are presented in Tables 6.2 overleaf.
Chapter Six
Chapter Six
Table 6.2: Project Phases and Description of Potential and Associated
Impacts
Project
Phase/Activities
Site Preparation
♦ Bush
clearing/stumping,
Stripping
♦ Equipment transport
♦ Dredging
♦ Spoils, domestic and
industrial wastes
disposal
Environmental
Aspect
Biodiversity
(vegetation/wildlife)
Soil & landuse
Noise/vibration
Aquatic life
Social and health
status
Air quality (SOx, NOx,
COx)
Description of Potential Impacts
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Rig Movement and
Positioning
Socio-economic and
health status
♦
♦
Biodiversity
Noise/vibration
Aquatic life
COx)
Drilling
•
Exhaust
emission
•
Waste disposal
•
Hydrocarbon
and
chemical
spill
•
Blowouts
•
Fire out break
Biodiversity
♦
♦
♦
♦
♦
♦
♦
♦
Soil & landuse
♦
♦
♦
♦
Noise/vibration
Aquatic life
Social
status
and
health
COx)
♦
♦
♦
♦
Chapter Six
Loss of vegetation
Loss of ecological habitat for fauna
Loss of biodiversity
Surface erosion
Alteration of soil overburden
Disturbance and interference in communication and
hearing loss
Dredging activities will result in the disturbance of
fish spawning areas and their associated food chain
within the creeks.
Land use conflict
Drainage and soil contamination
Aesthetic visual intrusion
Vibration and emission of pollutants from dredgers
Employment opportunities for local labour
Introduction of alien diseases
Complaints by local communities for employment and
payment for land acquired.
Increased social vices (crime, drug abuse, alcoholism,
promiscuity, broken homes etc)
Increased STIs, abortion, unwanted pregnancies,
HIV/AIDS
Interference with other public and private water
transport activities
Economic losses due to suspension of fishing
activities
High noise level
Increased shoreline erosion due to increased water
traffic
Contamination of water and loss of aquatic life
Water pollution from increased turbidity of water
bodies
Air pollution
Localised increase in ambient concentrations of air
pollutants
Alteration of the physico-chemical parameters of the
ecosystem
Obstruction of the water way
Noise and vibration on site for drilling activities
Disturbance of habitat
Employment opportunities for the skilled and
unskilled local labour
payment for land acquired
Increase in biological and chemical toxicity of water
from discharged chemicals, wastes and materials
including spent muds and chippings, produced water,
oily wastewater, sewage, cooling water and additives
etc.
Pollution of water bodies by improper disposal of drill
cuttings and effluents from drilling operations
Decommissioning
Abandonment
and
Biodiversity
•
•
•
Soil & landuse
Loss of recreational and aesthetic value of site
because of abandoned structure.
Hydrocarbon leak from abandoned wellhead.
Lifting of access restriction and availability of site
for alternative uses.
Noise/vibration
Aquatic life
Social
status
6.3
and
health
Potential Impact Evaluation
The associated and potential impact evaluation of this project was based on the
International Organisation for Standardisation ISO 14001–Environmental
Management System approaches. The approach is illustrated in Fig. 6.2.
The criteria used in evaluating identified impacts significance were
legal/regulatory requirement (L), risk factor (R), frequency of occurrence of impact
(F), importance of impact on affected environmental component (I) and public
perception/interest (P). The quantification scale of 1-5 was used (Fig. 6.2).
•
•
•
•
•
•
This approach was adopted considering its interactive and descriptive analysis of
the relationship between the proposed drilling activities and the ecosystem
components. The approach combines the following factors in assessing the overall
impact rating of the project on the environment:
The sensitivity / vulnerability of the ecosystem component;
The productivity evaluation / rating of the ecosystem components;
Knowledge of the possible interactions between the drilling and the environment;
Envisaged sustainability of the project environment;
The economic value of the drilling; and
Projected duration of the impact of each project activity on various environmental
components.
To reduce elements of subjectivity inherent in the ranking process, a team of six
experts (multi-disciplinary) was co-opted to independently rank / quantify the
impacts based on the five criteria.
The four independent results obtained from the ranking process were pooled or
combined by calculating simple averages for each of the three criteria to determine
significance of impacts thus:
4
(L+R+F+I+P) > 15
(F + I) > 6
P=5
By considering individual drilling activities in the light of their effects on the
environmental impact indicators, a qualitative and quantitative impact
prediction/evaluation/description is indicated in Table 6.3.
Chapter Six
1
2 Identification of
Impacts using
·
·
·
·
·
Associated
and
Potential
knowledge of the project activities and operational procedures;
past experience on similar projects;
the results of field investigations and understanding of the
environmental characteristics (ecological, socio-economic and health
variables) of the project area;
FMENV, DPR, UNEP, and WHO Guidelines and Standards; and
project specific risks and hazards identified using professional
judgement.
3 Impact Evaluation Criteria
Legal/Regulatory
Requirements (L)
0 = There is no legal /
regulatory requirement
3 = There is
a
legal
/
regulatory
requirement
Impact
Frequency (F)
Risk (R)
Importance (I)
1 = Low risk
1 = Low Frequency
1 = Low importance
3 = Intermediate risk
3 = intermediate
frequency
3 = Intermediate
importance
5 = High frequency
5 = High importance
5 = High risk
5 = There is
a
permit
Significant Impacts are:
•
Impact for which sum values is = or >15
Impact for which (F + I) is > 6
Impact for which P = 5
Characterisation of Significant Impacts Based on
FMENV Criteria
Fig. 6.2: Approach to Impact Assessment Using ISO 14001 Guideline
Chapter Six
Public Interest
/ Perception (P)
1 = Low
interest /
perception
3=
Intermediate
interest /
perception
Table 6.3: Associated and Potential Impacts Evaluation
Project Phase /
Activities
Site Preparation
♦ Bush clearing /
Stumping
Stripping,
♦ Equipment
transport
♦ Dredging
♦ Spoil disposal,
domestic and
industrial wastes
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Rig movement and
positioning
♦
♦
♦
♦
♦
♦
♦
♦
Chapter Six
Impact Ranking and Quantification Criteria
L
R
F
I
P
(F + I)
(L+R+F+I+P)
Associated & Potentials Impacts
Loss of vegetation
Loss of habitat
Surface erosion
Disturbance and interference in communication and
hearing loss
Dredging activities will result in the disturbance of fish
spawning areas and their associated food chain within
the creeks.
Land use conflict
Vibration and emission of pollutants from dredgers
Employment opportunities for skilled and unskilled
local labour
payment for land acquired.
Increased social vices (crime, drug abuse, alcoholism,
promiscuity, broken homes etc)
Increased STIs, abortion, unwanted pregnancies,
HIV/AIDS
Interference with other public and private water
transport activities
Water pollution from increased turbidity of water bodies.
Air pollution
Contamination of water and loss of aquatic life
High noise level
Increased shoreline erosion due to increased water
traffic
Economic losses due to suspension of fishing activities
Overall Impact
Rating
3
3
0
0
0
5
5
3
3
3
1
3
1
1
1
5
3
3
1
1
3
1
1
1
1
6
6
4
2
2
17
15
8
6
6
Significant
Significant
Insignificant
Insignificant
Insignificant
3
3
1
3
1
4
11
Insignificant
0
3
1
3
3
4
10
Insignificant
0
3
0
3
1
5
1
3
1
1
1
1
1
5
1
3
3
5
1
3
2
6
2
4
6
19
4
13
Insignificant
Significant
Insignificant
Insignificant
0
3
3
5
5
8
16
Significant
0
0
5
1
5
1
5
3
5
3
10
4
20
8
Significant
Insignificant
0
0
0
1
1
3
1
1
1
3
3
3
3
3
3
4
4
4
8
8
10
Insignificant
Insignificant
Insignificant
0
3
1
3
3
4
10
Insignificant
0
3
3
3
3
6
12
Significant
1
1
1
3
1
4
11
Significant
3
3
0
1
1
1
3
1
1
1
1
1
1
1
1
1
3
1
3
3
5
1
5
1
3
2
4
2
4
6
11
11
11
7
7
Insignificant
Insignificant
Insignificant
Insignificant
Insignificant
1
1
1
3
3
4
7
Insignificant
Drilling
♦ Exhaust emission
♦ Waste disposal
•
Incidental
♦
♦
♦
♦
♦
•
Hydrocarbon
and chemical
spill
•
Blowout
♦ Fire out break
Decommissioning
and abandonment
Localised increase in ambient concentrations
of air pollutants
Alteration
of
the
physico-chemical
parameters of the ecosystem.
Obstruction of the water way
•
Noise and vibration on site during drilling activities
•
Employment opportunities for the unskilled labour
•
Complaints by local communities for employment
and payment for land acquired
•
Increase in biological and chemical toxicity of water
from discharged chemicals, wastes and materials
including spent muds and chippings, produced
water, oily wastewater, sewage, cooling water and
additives etc.
•
Pollution of water bodies by improper disposal of
drill cuttings and effluents from drilling operations
•
•
•
Chapter Six
Loss of recreational and aesthetic value of site
because of abandoned structures.
Hydrocarbon leak from abandoned wellhead.
Lifting of access restriction and availability of site
for alternative uses.
3
3
1
3
1
4
11
Insignificant
3
5
3
5
1
8
17
Significant
0
3
0
0
0
0
3
3
3
3
3
5
1
3
1
3
1
5
3
3
3
5
1
5
5
3
3
5
1
5
4
6
4
8
2
10
12
15
10
16
6
20
Insignificant
Significant
Insignificant
Significant
Insignificant
Significant
3
5
1
5
1
6
15
Significant
3
5
1
3
5
4
17
Significant
0
3
1
3
1
4
8
3
3
1
3
5
4
15
0
1
1
3
3
4
8
Insignificant
Significant
Insignificant
6.4
Characterisation of Associated and Potential Impacts
The associated and potential impacts of the exploratory drilling project was
characterised based on the FEPA (FMENV) criteria (FEPA, 1995). This is to
enable further description of the nature of impacts. The nature,
characteristics and duration of the various project activities on ecological
components were interpreted as follows:
♦
♦
♦
♦
♦
short term or long term;
beneficial or adverse;
direct or indirect;
immediate or residual;
cumulative or incremental.
The characterisation of the associated and potential impact of the proposed
project is summarised in Table 6.4.
Table 6.4: Characterisation of Associated and Potential Impacts
of the Proposed Exploratory Drilling Project
Project
Phases/Activi
ties
♦ Bush
clearing /
Stumping
Stripping,
♦ Equipment
transport
♦ Dredging
♦ Spoil
disposal,
domestic
and
industrial
wastes
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Chapter Six
of 12
Impact Characterisation
Associated and Potentials Impacts
Loss of vegetation
Loss of habitat
Surface erosion
Disturbance and interference in
communication and hearing loss
Dredging activities will result in the
disturbance of fish spawning areas and
their associated food chain within the
creeks.
Land use conflict
Vibration and emission from dredgers
Employment opportunities for local
labour
Complaints by local communities for
employment and payment for land
acquired.
Unwanted pregnancies
Increased issues of abortions
Increased social vices (crime, drug
abuse, alcoholism, promiscuity, broken
homes etc)
Increased STI’s, abortion, unwanted
pregnancies, HIV/AIDS
Direct, immediate, adverse, long-term, reversible
Direct, immediate, adverse, short-term, reversible
Indirect, cumulative adverse, short-term, reversible
Direct, immediate adverse, long-term, reversible
Direct,
Direct,
Direct,
Direct,
Direct,
immediate,
immediate,
immediate,
immediate,
immediate,
adverse, short-term, reversible
beneficial, short-term
Indirect, immediate, adverse, short-term, reversible
Direct, immediate, beneficial, short-term
Indirect, immediate, adverse, short-term
Indirect, immediate, adverse, short-term reversible
June 2005Page
82
♦ Rig
movement
and
positioning
♦ Exhaust
emission
♦ Waste
disposal
Incide
ntal
discharges
Hydro
carbon and
chemical
spill
Blowo
ut
♦ Fire out
break
Decommission
ing and
abandonment
6.5
•
Interference with other public and
private water transport activities
♦ Water pollution from increased turbidity
of water bodies.
♦ Air pollution
♦ Contamination of water and loss of
aquatic life
♦ High noise level
♦ Loss of biodiversity
♦ Increased shoreline erosion due to
increased water traffic
♦ Economic losses due to suspension of
fishing activities
♦ Localised increase in ambient
concentrations of air pollutants
♦ Alteration of the physico-chemical
♦ Obstruction of the water way
♦ Noise and vibration on site during
drilling activities
♦ Disturbance of habitat
♦ Employment opportunities for the
unskilled labour
♦ Introduction of alien diseases
♦ Complaints by local communities for
employment and payment for land
acquired
♦ Increase in biological and chemical
toxicity of water from discharged
chemicals, wastes and materials
including spent muds and chippings,
produced water, oily wastewater, sewage,
cooling water and additives etc.
♦ Pollution of water bodies by improper
disposal of drill cuttings and effluents
from drilling operations
Loss of recreational and aesthetic
•
value of site because of abandoned
structures.
•
Hydrocarbon leak from abandoned
wellhead.
•
Lifting of access restriction and
availability of site for alternative
uses.
Indirect, incremental, adverse, short-term,
irreversible
Direct, immediate, adverse, short-term, irreversible
Direct, cumulative, adverse, short-term, reversible
Direct, cumulative, adverse, short-term, reversible
Direct, immediate, beneficial, short-term
Direct, incremental, adverse, short-term, reversible
Direct, incremental, adverse, short-term, reversible
Direct, cumulative, adverse, long-term, reversible
Direct, immediate, beneficial long-term.
Environmental Risk Assessment
The environmental risk assessment is presented here to draw attention to the acute
non-routine environmental hazards that may arise during the exploratory drilling
project. Risks addressed include potential effects on the terrestrial, aquatic and air
environment, as well as the health effects on the local population of the nearby
quarters and host communities.
6.5.1 Hemp Process
The Hazard and Effect Management Process (HEMP) is the name given to a
structured methodology for assessing hazards and associated risks where the focus is
on Health, Safety and Environment. The process describes the hazards in four phases;
identify, assess, control and recover.
Chapter Six
of 12
June 2005Page
83
Identify
Assess
Control
Recover
What are the Hazards? What could go wrong?
How likely? What consequence? i.e. what is the risk?
Is there a better way? Controls adequate?
Consequence limited? Recovery adequate?.
The HEMP structured methodology aims to secure awareness of the relevant
hazards and manages the associated risks. A hazard is a potential to harm
and by recognizing and preventing that potential being realised, harm will be
avoided. There are many hazards and associated with each hazard are risks.
Risk is a product of likelihood of occurrence of a hazard and its
consequences. Risk is thus a function of the likelihood or chance of
something going wrong and the security of the potential consequences or
outcome. Mismanagement of one particular hazard can have consequences
that simultaneously impact to a varying degree on several of the broad risk
types for instance, a loss of containment resulting in an oil spill whilst being
primarily an environmental risk can escalate to asset damage or loss of life.
In order to provide additional structure to HEMP as well as “Hazard” the key
terms used include:
•
•
•
•
•
•
Threat
Threat barriers
Escalation
Escalation barriers (or control)
Recovery measures
Potential consequences.
Based on the above considerations the following have been identified as the
applicable risks associated with the proposed exploratory drilling project
♦
♦
♦
♦
Effects of rainstorm, excessive rain and wind speed
Spills,
Dropped objects
Operator / human error
♦ Equipment failure
♦ Waste treatment
♦ Sabotage and Terrorist Activities
♦ Fire out breaks
5 Methodologies
The methodologies used to perform the risk assessment of the exploratory
drilling project are as following:
♦
♦
♦
♦
HAZID (Hazard identification) analysis
HAZOP (Hazard and operability) analysis
Faulty trees or similar cause and effect diagrams
Event trees
The quantitative analysis of this study was carried out using the HAZID technique.
The HAZID analysis is described fully in the SPDC manual EP-95-0312.
Chapter Six
of 12
June 2005Page
84
6 Evaluation of Hazards
Extreme weather and Natural Forces
The greatest concern for weather effects will be during the dredging sweeping
activities when the heavy rainfall / precipitation that often accompanies occasional
high wind may result in greatly increased river discharges giving localized erosion.
This may result in greatly increased leachate, dredge spoil discharge into nearby
creeks and surrounding vegetation. The dredging management plan will address strict
adherence to the use of PPE and stopping the dredging activities if there is risk of
damage to the ground, habitat around the dredging location as well as safety and
health of the workforce during heavy rains is threatened.
Oil spills
There is a potential for minor oil spillage to occur during refuelling
operations of the dredging/ construction equipment. Single incidents of
small volume spills are unlikely to pose a threat to terrestrial and aquatic
habitats. Depending on the spill volume, the impacts shall be localised.
Only repeated instances of small spills may create the potential to impact
the aquatic environment and these shall be prevented by the construction
management plan of operational.
Sabotage and Terrorist Activities
Risks (Table 6.5) from such activities are un-quantifiable and beyond the
proponent’s control. They are acknowledged to be significant enough to
warrant attention in the HSE management plan which will advise managers
on proper proactive responses to all sources of risk in the normal operation
of the dredgers and dredging activities and actual drilling process.
♦ In fighting amongst the communities within this area is high hence, there is high chances of such an incident
occurring
Chapter Six
of 12
June 2005Page
85
June 2005
Page i of xiv
Table 6.5:
Environmental Risk Assessment of the Exploratron Drilling Project
Hazard
Identification
Hazard
Threat
Severe
extreme
weather
or
Heavy
precipitation and
high winds during
the dredging
process.
Assessment of Risk
Controls for Events
Recovery
Comments
Potential
Consequences
Enhanced erosion
from dredged dumps,
leachate and spoil
into nearby vegetation
and water bodies.
Likelihood
Low due to low
incidence of highspeed winds. Heavy
rains are frequent
during wet season.
The area earmarked for
dredging has low
incidence of high wind
speed but high incidence
of rainfall.
Strict adherence to
construction management
plan procedures for
secure and storage of
materials spills
prevention plan and
protocol for safe refuelling
and maintenance
practices. Regular
inspection and
maintenance of dredger
Dredging equipment and
base camp etc, are not
easily accessible to host
communities source
adequate security plan
would be put in place.
Engage and sustain
community consultation
throughout the lifespan of
the project.
Observe MOU signed with
communities.
Ensure adequate payment
for acquired land.
Strict adherence to
SHELL HSE policy and
regulations/protocol for
safe welding practice
Dredging/
Sweeping
activity
Accidents e.g.
unintentional
jettison of
construction
materials
Damage to the
terrestrial
environment.
Moderate
Sabotage
piracy/or
terrorist
activity
Capture of and
damage equipment
Release of potentially
flammable
hydrocarbons and
toxic gas into soil and
ambient air due to
facilities
Unknown
Drilling
Flames and fumes
from welding
activities
Fire out break or
explosion from flame
Low. Third party or
environmental risk
June 2005
Threat Barriers
Escalation
Barriers
Construction
management plan
will address
conditions under
which construction
activities will cease
in order to protect
the environment
Emergency
responses plan.
Spill containment
and recovery plan
maintenance of
storage containers,
availability of
sorbents and
spillage
containment
equipment.
Emergency
response plan.
Contingency plan
for communities
and contact with
communities prior
to dredging
activities
Curative
Measures
Repair and
reinstatement of
affected areas.
Carry out
dredging during
dry season.
This represents
routine hazard which
can be managed by
adequate prevention
and recovery
procedures.
Removal of
sippage and
contamination
and
reinstatement of
affected areas in
terms of oil spill.
This represents
routine construction
hazard that is
managed by
adequate prevention
and recovery
procedure
Calm and
negotiate
Proponent's HSE and
management
construction plan to
address actions to be
taken in the event of
these extraordinary
occurrence
Fire fighting
equipment
available on site
Natural recovery
of small fire.
Reinstatement of
affected areas if
excessively
damaged
This represent a rare
hazard and would be
managed by
adequate preventive
and recovery
procedures
Page i of xiv
CHAPTER SEVEN
7.0
MITIGATION MEASURES
7.1
General
Mitigation measures for the associated and potential impacts identified in Chapter
Six of the report is discussed in this Chapter. The objective of this chapter is to
proffer mitigative measures appropriate for the identified associated and potential
impacts of the exploratory drilling project. The identified mitigation measures are
discussed vis-a-vis the impact to which they apply. A checklist of the mitigation
measures plan by SPDC for the identified Potential Impacts is presented in Table
7.1.
7.2
Best Available Technology
SPDC plans to deploy the best and economically viable technologies throughout the project as
a way of improving life cycle, project economics and reducing environmental hazards.
Consequently, all engineering design, procurement and installation will be in accordance with
the statutory codes and standards. Where inherent risk exist in the execution of the project,
hazards and effects which may result in High (Intolerable) Risk as defined on the SPDC Risk
Matrix have shall be identified, assessed and suitably controlled, and measures shall be taken
to reduce the residual risk to a level As Low As Reasonably Practicable (ALARP), and
appropriate recovery preparedness measures shall be put in place in the event that control is
lost.
Chapter Seven
Table 7.1: Mitigation Measures for Identified Potential Impacts
SPDC shall carry out the following mitigation measures for identified potential and associated impacts:
♦
♦
♦
•
Project
Phases/Activities
Bush clearing /
Stumping
Stripping,
Equipment
transport
Dredgin
g
Spoil disposal,
•
•
Loss of vegetation
Loss of habitat
•
•
•
•
Surface erosion
•
•
•
Disturbance and interference in
communication and
hearing loss
Dredging activities will result in the
disturbance of fish
spawning areas and
their associated food
chain within the
creeks.
Land use conflict
Vibration and emission from
dredgers
Employment opportunities for local
skilled & unskilled
labour
•
d
o
m•
e
s
t
i
c
•
a•
n•
d•
i •
n
d
u
•
s
t
•
r
i
a
l
•
w
a•
s•
t
e
Chapter Seven
Mitigation Measures
Associated and Potentials Impacts
employment and
payment for land
acquired.
Increased social vices (crime, drug
abuse,
alcoholism,
promiscuity, broken
homes etc)
•
•
•
•
•
•
•
•
•
•
•
•
•
SPDC shall minimise size of site clearance and re-vegetate cleared area with plants
SPDC shall use hand cutting to clear vegetation initially-where necessary be selective
in using machinery
SPDC shall incorporate drainage and minimise disturbance to natural drainage
patterns
SPDC shall engineer slopes and drainage to minimise erosion, design for storm
conditions / ensure offsite natural run-off does not wash over site
SPDC shall limit levelling activities
SPDC shall maintain noise levels at site boundary to meet regulatory limit, also the use
of earmuff shall be enforced.
SPDC shall limit dredging activities to minimum needed for safe operation, avoid
dredging within spawning grounds and also use narrow gauge bargers
SPDC shall minimise clearance and land use/base camps to be on barge
SPDC shall develop and implement waste management plan - no discharge of oily
waste
SPDC shall create awareness before commencement of project activities
SPDC shall maintain noise level with regulatory limit and enforce use of earmuff
This is a beneficial impact and shall be enhanced by the employment of a large number
of community members.
Awareness training shall be carried out before commencement of the drilling process,
and workforce movement shall be control e.g. interaction with local communities
Adequate consultation shall be carried out and sustained. Signed Memorandum of
Understanding (MOU) shall be observed by SPDC
This is a beneficial impact and adequate remuneration shall be made to workers on the
project.
Preserve biodiversity encountered and relocate others where necessary and avoid
spawning areas
Create health awareness amongst staff and control their moment within the project
location
♦ Create health awareness amongst staff and control their moment within the project location
♦
Rig
moveme
nt and
positioni
ng
s•
Increased STIs, abortion, unwanted
pregnancies,
HIV/AIDS
♦
Interference with other public
and private water transport
activities
•
The rig and associated facilities shall be clearly marked and illuminated during poor
weather conditions to warn other river users. Consult with local communities regarding
preferred routings/plan movement to minimise interference
♦
Water pollution from increased
turbidity of water bodies
•
Ensure operations are restricted to minimum needed to minimise disturbance of sediment
•
♦
Contamination of water and
loss of aquatic life
High noise level
Existing emergency / spill response actions/contingencies shall be activated for prompt
clean-up operations at the incidence of any spill in the area
SPDC shall maintain all fuel combustion engines at optimal operating conditions to reduce
emission of exhaust gases
The use of earmuffs shall be enforced for all staff working in noisy areas or engaged in the
use of high noise equipment/machine.
Preserve biodiversity encountered and relocate others where necessary and avoid spawning
areas
Maintained regulatory speed limits to avoid undue disturbance of water bodies
SPDC shall consult with local communities regarding preferred routings/plan movement to
minimise disturbance
♦
•
•
♦
♦
♦
Chapter Seven
Increased shoreline erosion
due to increased water traffic
Economic losses due to
suspension of fishing activities
•
•
•
♦ Exhaust emission
♦ Waste disposal
Incidental
discharges
Hydrocarbon
and chemical spill
Blowout
♦ Fire out break
♦ Localised increase in ambient
concentrations of air pollutants
♦ Alteration of the physico-chemical
♦ Obstruction of the water way
•
•
Noise and vibration on site during
drilling activities
•
♦ Employment opportunities for skilled and
unskilled labour
♦ Introduction of alien diseases
•
•
•
•
employment and payment for
land acquired
♦ Increase in biological and chemical
toxicity of water from discharged
chemicals, wastes and materials
including spent muds and chippings,
produced water, oily wastewater, sewage,
cooling water and additives etc.
•
•
Decommission
ing and
abandonment
Pollution of water bodies by improper
disposal of drill cuttings and effluents
from drilling operations
Chapter Seven
•
Loss of recreational and aesthetic
value of site because of abandoned
structures.
•
Hydrocarbon leak from abandoned
wellhead.
SPDC shall develop and implement waste management plans for all wastes generated
in accordance with regulatory requirements and standard practice. All industrial
wastes such as plastics, metals, rubber etc will be segregated on site and collected in
designated containers for final disposal in accordance with the standard waste
management guideline,
•
Drilling cuttings and other solid wastes shall only be dumped after prior treatment to
FMENV and DPR standards.
•
Sanitary wastes shall be evacuated handled by a sewage treatment plant.
SPDC shall consult with local communities regarding preferred routings/plan movement to
minimise disturbance
•
The use of earmuffs shall be enforced for all staff working in noisy areas or
engaged in the use of high noise equipment/machine
•
Control workforce activities, e.g. hunting
•
This is a beneficial impact and shall be enhanced by the employment of a
large number of community members.
•
Awareness training shall be carried out before commencement of the drilling process,
and workforce movement shall be control e.g. interaction with local communities
Adequate consultation shall be carried out and sustained. Signed Memorandum of
Understanding (MOU) shall be observed by SPDC
•
•
•
SPDC shall maintain all fuel combustion engines at optimal operating conditions to
reduce emission of exhaust gases
SPDC shall develop and implement waste management plans for all wastes generated
in accordance with regulatory requirements and standard practice. All industrial
wastes such as plastics, metals, rubber etc will be segregated on site and collected in
designated containers for final disposal in accordance with the standard waste
management guideline,
•
Drilling cuttings and other solid wastes shall only be dumped after prior treatment to
FMENV and DPR standards.
•
Requirements of oil spill contingency/emergency plans shall be met before drilling
commence
Sanitary wastes shall be evacuated and handled by a sewage treatment plant.
•
The rig shall be decommissioned from the site as soon as drilling is completed to
reduce adverse aesthetic effects,
•
SPDC shall re-vegetate site with abandoned vegetation
•
With the exception of the buried wellhead structures all other facilities shall be
decommissioned and removed from site at the end of the project according to standard
procedures for decommissioning of onshore facilities
• Restoration plan for the area shall be followed
• SPDC shall plug the well down-hole and near the surface and remove surface
structures
♦ Lifting of access restriction and
availability of site for alternative uses.
Chapter Seven
•
•
This is a beneficial impact
SPDC shall give out proper instruction to the communities on the use of abandoned area
Final EIA of Opugbene-West Prospect (Tologbene) Exploration Drilling
CHAPTER EIGHT
8.0
ENVIRONMENTAL MANAGEMENT PLAN
8.1
Introduction
Environmental Management is concerned with a planned programme aimed at
ensuring that the envisaged impacts of a proposed project are contained and
brought to an acceptable minimum.
Environmental management provides
confidence on the part of project planners that a reliable scheme has been put in
place to deal with any contingency that may arise during all phases of development,
from conceptual /design stage to abandonment.
Environmental Management incorporated in the statement of General Business
Principles of SPDC, include the following declaration: "It is the policy of Shell
companies to conduct their activities in such a way as to take into account the
health and safety of their employees and of other persons, and to give proper regard
to the conservation of the environment. In implementing this policy, Shell
companies not only comply with the requirements of the relevant legislation but
protection of health, safety and the environment for all who may be affected directly
or indirectly by their activities" (SIPM, 1996).
In the implementation of this policy, every Shell Company thrives to follow a
systematic approach to HSE management to ensure compliance with the law and
achieve continuous performance improvement.
This EMP shall form the key reference document for ensuring that environmental
issues are addressed and should be communicated to all project staff and
contractors involved in the Opugbene-West (Tologbene) Prospect Exploration
Drilling Project. This plan has been developed to meet specific long-term objectives
in line with Shell Nigeria's Quality Management scheme with the following long tem
objectives.
·
·
·
·
·
·
·
·
Ensure compliance with legislation and company policy
Achieve, enhance and demonstrate sound environmental performance built
around the principle of continuous improvement.
Integrate environmental issues fully into the business
Rationalise and streamline existing environmental activities to add value in
efficiency and effectiveness.
Encourage and achieve the highest performance and response from individual
employees and contractors.
Provide standards for overall planning, operation, audit and review
Ensure compliance with the mitigation measures in the EIA report
Provide early warning of the environmental damages resulting from the project
activities so that emergency procedures can be activated to prevent or reduce
deterioration of the environment.
The EMP is presented in a format that includes the following components
Audit procedures
Waste management plan
Resource requirement
Monitoring programme
Responsibilities and training
Oil Spillage and contingency plan
·
·
·
·
·
·
Chapter Eight
June 2005
Page 6 of 7
·
·
8.2
Consultation
Decommissioning and Abandonment Plan
The Shell Approach
It is the policy of Shell companies to conduct their activities in such a way as to
take foremost account of the health and safety of all their employees and other
persons, and to give proper regards to the conservation of the environment. In
implementing this policy, Shell companies shall not only comply with the
requirements of the relevant legislation but promote, in an appropriate manner,
measures for the protection of health, safety, environment and the security of all
who may be affected directly or indirectly by its activities.
The Environmental Management activities instigated by Shell are intended to
implement the above policy and the policy shall be applied at all phases of this
exploration Drilling project.
8.3
Audit Programme
Regular environmental audit shall be conducted during the exploratory drilling
programme. This will ensure that environmental protection and management
procedures are being enforced. The objectives of the audit programme shall be to:
•
•
•
•
8.4
examine compliance with regulatory requirements;
identify current and potential environmental problems during the drilling
process;
make recommendations that would lead to the sustainable management system
of the drilling operation;
check the predictions in EIA and assure implementations and application of
recommended practices and procedures.
Waste Management
Different kinds of waste will be generated in varying quantities throughout the
drilling project. The estimated maximum waste volume from the exploratory well
drilling would be 2,500bbls. These wastes shall be stored in metal containers and
transported to shore in barges. The treatment of the wastes shall be carried out at
SPDC approved Thermal Desorption plant located in Forcados.
The general guidelines for minimisation, handling and disposal of wastes such as
gaseous emissions, effluent discharges, solid waste and noise are described below.
Waste Minimisation
Waste minimisation implies reduction to the possible extent, of the volume or
relative toxicity of liquid or solid wastes. The four principles of waste minimisation
process; recycle, reduce, reuse and recovery shall be adopted as applicable. All
wastes associated with hydrocarbons, oils, hydraulic fluids, oily sump water, oil
based drilling mud, etc. shall be recycled, treated or be placed in an appropriate
facility.
Waste Handling
For proper handling and disposal, wastes must be well defined at source and the
definition transmitted along with the waste until final disposal. All wastes
generated in the course of the exploratory drilling shall be appropriately defined
and documented. The details that would be provided shall include:
• waste stream identification;
• proper waste categorisation;
• waste segregation;
Chapter Eight
June 2005
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•
•
appropriate handling and disposal practice; and
recommended Management practices.
Waste Disposal
All wastes shall be cleared regularly from the site and disposed of accordingly at
the SPDC designated area. Instructions on material safety handling sheet shall be
strictly adhered to and shall form the basis for the disposal of wastes. Adequate
treatment measures shall be undertaken, where applicable, for all waste before
final disposal. All wastes in transit must be tracked by waste consignment note.
The waste consignment note records shall be kept and should include as a
minimum the following information:
• Date of dispatch;
• Description of waste;
• Waste quantity/container type;
• Designated disposal site and method;
• Consignee /driver name and means of transportation; and
• Confirmation of actual disposal (time and date).
8.5
Resource Requirement
Shell considers environmental management as an important aspect of project
procedures. In this project, an Environmental Liaison Officer (ELO) shall be
responsible for all environmental related matters in the course of the drilling of the
exploratory well in Opugbene (Tologbene). The ELO shall ensure compliance with
regulatory standards as well as SPDC HSE guidelines.
Shell recognises the need to use external environmental consultants to
supplement in-house environmental specialists.
To this end, the
environmental consultants shall continue to provide expert advice to the
Shell environmental managers throughout the development of this project.
8.6
Monitoring Programmed
SPDC shall comply with the DPR/FEPA regulatory requirements by establishing an
environmental monitoring programme for the exploratory drilling in Opugbene
(Tologbene). The environmental components to be monitored shall include:
•
•
•
•
ecology (hydro-biology, plankton and fisheries and benthic characteristics);
surface water quality;
air quality;
sediment characteristics (physico-chemical properties)
The exploratory drilling monitoring programme in Opugbene (Tologbene) shall be in
compliance with the mandatory monitoring guidelines and standards published in
1992 by the Department of Petroleum Resources. A summary of the monitoring
programme and methodology is shown in Tables 8.1 & 8.2. In the event of
accidental discharge or spill, SPDC shall immediately effect monitoring for
environmental changes.
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Table 8.1
Monitoring Program for the Prospect Exploration Drilling Project
SOURCE
Drilling
Fluids
♦
♦
♦
♦
♦
♦
♦
♦
Drill Cuttings
Deck
drainage
Blow-out
prevention
fluid
Work-over
fluids/waste
♦
♦
MONITORING REQUIREMENTS
PARAMETER/EFFLUENT
MONITORING FREQUENCY
CHARACTERISTICS
Volume / discharge rate
♦ Record hourly
Toxicity, 96-hour LC50 (for each
♦ Once per mud system
mud type and major additive
proposed for use)
Oil content for based mud
♦ Every 305m of well depth
Petroleum hydrocarbons (aliphatic
♦ Once at the end of the
and aromatic) for oil based mud.
well
pH
Heavy metals e.g. copper, lead,
mercury, nickel, total iron,
vanadium, arsenic, barium, total
chromium.
Grain size distribution
♦ -doSpecific gravity
♦ -do♦ Report daily during
• Volume/discharge rate
discharge and measure
duration of discharge
♦
Every 305m of well depth
• pH
♦
-do• Oil and Grease content
♦ -do• Heavy metals as listed above
Volume
• Record on a daily
Oil and Grease content
basis
• Once per week
• Volume
•
Record monthly
Sanitary
sewage
•
•
Volume
pH
Oil and Grease content
Chlorine
Discharge rate
Residual chlorine
Surface
Water
♦
pH, Temperature
♦
Electrical conductivity, Salinity, Oil
and Grease, Total Organic Carbon
Total Dissolved Solids (TDS)
Total Suspended Solids (TSS)
Biochemical Oxygen Demand
(BOD5)
Chemical Oxygen Demand (COD),
Dissolved Oxygen (DO), Phenols,
Cyanide, Sulphide, Ammonia,
Phosphorus, Salinity, Heavy metals
Noise generation
♦
♦
♦
♦
♦
♦
♦
♦
•
•
♦
♦
♦
♦
Ambient air
Chapter Eight
♦
♦
♦
♦
♦
♦
♦
♦
Estimate monthly
Once per week
Once per week
Once per week
Estimate and record
daily
Once per week
Once per week at suitable
points 5 – 10 m
downstream and
upstream of the drilling
location
-do-do-do
-do-do
Measure noise level at all
noisy locations on the rig
once in two weeks
June 2005
Page 9 of 7
Chapter Eight
7
June 2005
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Table 8.2: Environmental Monitoring Programme for the Exploration Drilling Project
Impact
Parameter
Ambient Air
Quality
Time of
Impact
Site
preparation,
dredging,
drilling
Noise
NOx
SOx
NH3
VOC
TSP
DPR/FEPA
Limits
100 ug/m3
300 ug/m3
200 ug/m3
20 ppm
600 ug/m3
Sampling
Location
Receiving airupwind &
downwind of
site
Site
preparation,
dredging,
drilling
Noise level
80 dBA (8-hr)
Work site and
100m away
Water
quality
(surface &
underground
) and
benthic
fauna
Drilling,
operation &
Abandonment
phases
pH Temperature
Oil & Grease
Salinity COD,
BOD, Turbidity,
TDS, TSS, Odour,
Heavy Metals: Pb,
Fe, Cu, Zn, Cr
As specified in
DPR Guidelines
Section III
E.3.4
Fisheries
Drilling,
Operation &
Abandonment
phases
Drilling,
operational &
Abandonment
phases
Diversity and
Abundance
-
(i) Receiving
water – 500m
upstream &
downstream of
discharge
point; (ii)
Monitoring
Wells onsite &
down-gradient;
Project field
waters
Particle size
Total Organic
Carbon
Oil & grease
Heavy metals:
Pb, Fe, Cu, Zn, Cr
Nutrients,
Inspection of
drainage patterns.
1 km radius of
well heads and
flowline areas
Soil
Impact Indicator
For at least 1
year after
project
commissioning
Sampling
Frequency
Daily (during
site
preparation,
dredging &
drilling and for
1 month after)
Daily (during
site
preparation,
dredging &
drilling)
Daily (during
dredging &
drilling and for
1 month
Postdredging/drilli
ng
6 months after
drilling/flowlin
e construction
Visual
inspection and
soil sampler
Note:
Short-term = Duration of Construction
Long-term = Duration of Operational activities
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Sampling
Method
Air sampler
Monitoring
Duration
Short-term
Monitoring
Personnel
SPDC
Contractor
Decibel Noise
meter
Short-term
SPDC
Contractor
Water sampler,
Turbidi-meter
and pH-meter
Short-term
SPDC
Contractor
Nets & hooks
Short-term
SPDC
Contractor
Short-term
SPDC
Contractor
8.7
Responsibilities and Training
Responsibility for environmental protection lies with Asset holder within SPDC who must
ensure that all environmental considerations are integrated into environmental related
activities. However, Environmental Department shall offers expert advice on protection
measures and waste management.
Responsibility and accountability are clearly defined from senior management who allocates
resources and monitors individuals environmental performance and these individuals have
responsibilities for environmentally sound practices in their workplace and surrounding area.
All staff will be made aware of their responsibilities through induction and training courses.
8.8
Oil Spillage and Contingency Plans
In nearly all aspects of hydrocarbon reserve exploitation there is a potential risk of an accidental event leading to an unwanted
emission or impact. In exploratory drilling the most significant of these is the risk of an accidental spill.
Some specific operations would carry greater risk of accidental oil spill. These include:
• blowout during drilling operation,
• flare fallout during well test, and
• loss of fuel oils during transfer operations.
SPDC has in place an oil spill contingency plan, which is activated regularly, updated with periodic exercises, and supervised
by the Department of Petroleum Resources. This should be expanded to take care of the drilling project.
8.9
Consultation
In line with SPDC’s guiding principle of tackling issues through dialogue, SPDC shall liaise with key stakeholders’ including
local communities as well as regulatory agencies.
8.10 Emergency Response Plan
Compliance to regulatory standards, operations/maintenance codes and specification as well as HSE issues shall form the
basis for the execution of the drilling project. However, accidents could occur as a result of equipment failure, negligence and
sabotage. Consequently, a contingency plan, which is an organised and predetermined course of actions to be pursued in the
event of accidental occurrence, shall be developed as back up to other containment systems put in place to handle such
occurrences.
As a minimum, the following hazardous situations shall be covered:
Appendices 3.1 a-c
June 2005
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•
•
•
•
•
•
•
•
Serious injury or illness;
Hydrocarbon/Chemical spills;
Weather related disasters;
Boat/vessel mishap;
Well blowout;
Collision;
Sabotage and terrorist activities; and
Fire out breaks.
8.11 Remediation Plans after Decommissioning / Abandonment / Closure
The statutory (national) regulations require operators of oil fields to remediate/rehabilitate impacted sites after relinquishing to
a level of satisfaction by the regulators.
Remediation of contaminated/impacted sites creates functional ecosystem for sufficient nutrients to enable satisfactory plant
growth.
In line with this and International/Shell Group standards, at the completion of the exploratory drilling, SPDC standard
procedure for decommissioning shall be invoked. A decommissioning team shall be set up to plan and implement the
guidelines for decommissioning to ensure that the best and practicable methods available to clean up the project site is put in
place and implemented. In carrying out this programme, the following shall be considered.
♦ Subsurface abandonment-the objective here is to isolate formations and prevent fluid migration. Basically, this will involve
cementing a large section of the bore hole and cutting and removal of casing below cellar depth;
♦ Surface facilities abandonment - here, all redundant surface facilities and concrete shall be removed by SPDC. After removal, the
facility will be cleaned and disposed of by land filling at a suitable location;
♦ Field restoration- upon completion (suspension or abandonment), all excavation shall be filled (borrow pits maybe converted to
fishponds by host communities). Beyond this, the procedures to be applied in the restoration of cleared areas shall be the subject
of a detailed integrated study.
This study shall utilise the services of ecological and hydrological specialists who will assist in determining strategies for site
restoration. The goal of the study shall be detailed field-specific restoration plan.
The success of any restoration process is measured by the similarity of the vegetation on the restored land to that of its
surroundings. However, this success is a manifestation of the reinstatement of the physical, chemical, and hydrological
characteristics of the soil bearing in mind that the single most significant factor that will likely inhibit re-vegetation is
Appendices 3.1 a-c
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compaction/cementing of soil surfaces. The ripping apart of the compacted/cemented areas will be a major key to a successful
restoration programme. The restoration operations will take intensive management for a number of years to ensure success.
Appendices 3.1 a-c
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CHAPTER NINE
9.0
CONCLUSIONS AND RECOMMENDATIONS
The Environmental Impact Assessment of Opugbene-West (Tologbene) Prospect Exploration Drilling has been undertaken. The
study site is located west of Agip’s Tebidaba Field. The project area lies in OML 36 in the swamp concession of SPDC, Western
Division. The area is within longitudes 60,000N and 70,000N and latitudes 378000E and 390000E.
The topography of the area is relatively flat, and it is characterized by silty clayey topsoil, coupled with rain forest vegetation.
Annual rainfall in the area ranges from 2500–3000mm, temperature ranged from 24.6°C - 32.0°C with a mean of over 30.5oC.
Monthly relative humidity values are from 67% to 90%. Wind speed values ranged from 2.0m/s to 4.5m/s.
Ambient air quality concentrations of SOx, NOx, and VOC were below detection limits, except at the sampling point close to the
NAOC flowstation where the measured parameters were influenced by emissions from the flowstation.
The ecological species encountered are essentially a mixture of freshwater and brackish forms of phytoplankton, zooplankton
and benthic organisms.
Hydrochemistry values obtained were at background level and well within DPR limits. They was no unusual characteristics in
the chemistry of surface and groundwater samples, the pysico-chemical characteristics of the surface water are normal for
class 1 river in terms of quality ranking, except for the high Turbidity and TSS above the WHO’s/ DPR limits, which is an
inherent characteristics of the waters of the area. There is no indication of anthropogenic elevation of chromium and other
toxic metals in the surface or ground water.
There is no evidence of oil and grease contamination in waters and total hydrocarbon content (THC) was generally below
detection limit and the gross organic pollution was low.
The soils of the area are ‘acid sands’, and a mixture of loamy and clay. Soil under the mangroves consist of saturated organic
material, black to gray in colour, containing silt and clay bands while this is replaced by peaty clay soils (Chikoko) where we
have short, stunted mangroves. Organic carbon content values were all low (<2.5%), this shows that the nutrients content are
low. The nitrate nitrogen in the soils was similarly low in some areas this is attributable to leaching losses and dentrification.
The exchangeable cations in the soil calcium (Ca), Magnesium (Mg), Sodium (Na) and potassium (K) were generally low. The
Appendices 3.1 a-c
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dominant heavy metal was Iron ranging from 160 ppm to 535 ppm, while the hydrocarbon contents were low and generally <
50ppm.
The major land use types in the area are subsistence farming forestry and settlement. The area consists of Mangrove
vegetation (tall ones near the banks of Ikebiri creek and stunted ones at the plains), Raffia palm & mixed rainforest.
Microbiologically, values (<0.10) of ratios of total hydrocarbon utilises count (HYD) to heterotrophic (HET) count in the various
sites is a reflection of the ability of autothrophic microbes in the locations to respond favourably to hydrocarbon
contamination. The underground waters did not contain significant levels of hydrocarbon utilises, indicating insignificant level
of hydrocarbon. In the course of study, the following bacteria were mostly encountered: Pseudomonas fluorescens, Micrococcus
sp and Flavobacterium sp with Penicillium sp. Escherichia coli, Kbebsiella sp, and Proteus sp.
There are three distinct vegetation patterns viz: Rainforest; transition forest and swamp forest. The vegetation is essentially
thick rainforest vegetation from Ikebiri I through Ikebiri II to Okoluba-Ikebiri creek junction. Mangrove provides habitat,
feeding and spawning ground for fishes and many invertebrates. They are also sources of firewood and tannin. Mangrove
grows under adverse conditions and has low floristic diversity.
The project area is not rich in wild life. Four main classes of Vertebrates are represented namely: Reptiles, Amphibians,
Mammals and Birds.
The Field lies within the Niger delta basin early tertiary sediment build up. Two stratigraphic units from the aquifer system;
the Alluvial and the Benin formation (Oligocene – Recent).
The area its environs is drained mainly by the Ikebiri River, which runs in an almost North – South direction and fed by other
smaller creeklets and tributaries which flows in the southward direction. This river is the main water body draining the study
area and it is also the main source of water for domestic and industrial use. There are a few seasonal streams, which includes
the one directly beside Opugbene village. All the rivers within the study area are tidally influenced and are inundated twice
daily by the flood and ebb tides, while their water volumes are greatly reduced in the dry season.
The main communities – Ikebiri I & II and Lobia form the host communities in the proposed project location. The seat of
leadership for the communities is in Ikebiri I, which has a larger population. The setting is basically rural. The major
economic activity of the people is fishing, lumbering and haulage. Basic amenities such as roads, electricity, health facilities
and pipe borne water are generally lacking.
Appendices 3.1 a-c
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The Environmental Impact Assessment indicates that during the exploratory drilling activities the major environmental
components that would be adversely impacted include vegetation, soil, water quality and aquatic life. These impacts are
associated with site preparation, rig movement, drilling and decommissioning/abandonment exercise.
Mitigation measures that will eliminate or reduce the potential adverse impact have been identified and put in place.
An Environmental Management Plan has been developed. It incorporates mitigation plan and monitoring schedule.
All the identified potential adverse impacts of the proposed drilling activities shall be eliminated or reduced through the
application of the mitigation measures contained in this EIA.
Appendices 3.1 a-c
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GLOSSARY AND DEFINITIONS OF TERMS
Air Quality: The concentration in air of one or more pollutants.
Algae: Extremely simple unicellular or multicellular plants which utilise the process of photosynthesis for life.
Aquifer: An underground or water-bearing layer of porous rock, that can transmit appreciable amount of oil or water e.g.
sandstone, in which water can be stored and through which it can flow after it has infiltrated from either the surface or another
underground source.
Bacteria: Class of small organisms usually 1µm in diameter, unicellular or coccoid, do not possess chlorophyll and multiply
rapidly, by division.
Benthos: The plants and animals that live in and on the bottom of a water body.
Biochemical Oxygen Demand: A standard water treatment test, which is an empirical measurement of the relative oxygen
requirement of wastewaters, effluents and polluted waters. It measures the amount of oxygen utilised during a specific incubation
period, usually 5 days, for the biochemical degradation of organic material.
Biodegradation: The ability of natural decay processes to break down man-made and natural compounds to their constituent
elements and compounds, for assimilation in, and by, the biological renewal cycles, is decomposed to carbon dioxide and water.
Biosphere: The transition zone between solid earth and the upper atmosphere, where most living things are found.
Biological concentration: The mechanism whereby filter feeders such as oysters and other shellfish concentrate heavy metals or
other stable compounds present in dilute concentrations in sea or fresh water.
Biological indicator: The use of living organisms of plants and animals to detect environmental changes.
Biomass: The mass of living organisms forming a prescribed population in a given area of earth’s surface. It is usually expressed
in grams per square metre (g/m2)
Bioremediation: The use of biological methods to remediate/restore contaminated land. Typical methods make use of tailored
microbes and break down phenols which are major contaminants.
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Borehole: A hole drilled into the ground to tap an aquifer for water or oil. Once the well has been drilled it must be completed,
that is, the hole is cased to prevent collapse with a slotted casing to allow water to enter.
Carbon dioxide: Gas produced by the complete combustion of carbonaceous materials, by decay of organisms such as aerobic
decomposers, by fermentation, and by the action of acid on limestone. It is exhaled by plants and animals and utilized in
photosynthesis in the carbon cycle.
Carbon monoxide: A colourless odourless gas, lighter than air, formed as a result of incomplete combustion. It is a chemical
poison when inhaled, as it is absorbed into the blood stream where it combines with haemoglobin of blood cells and thus deprive
the brain and heart tissues of oxygen.
Cathodic protection: Cathodic protection works by applying a d.c. power source to reverse the natural flow of electrical current
caused by galvanic corrosion. This stops the steel reinforcement in a structure from rusting.
Chemical Oxygen Demand: The amount of oxygen consumed in the complete oxidation of carbonaceous matter in an effluent
sample. This is done in a standard test, which uses potassium dichromate as the oxidising agent.
Clay: Fine-grained sedimentary rock of low permeability which is capable of being shaped when moist. Consists of fine grains less
than 4 µm in diameter.
Coliforms: A group of bacteria whose absence from drinking water is a guarantee of freedom from pathogenic bacteria.
Contaminant: A compound, which is present in the environment in concentrations higher than the background level, but not
necessarily causing a negative impact.
Contingency plan: A document setting forth an organised, planned and co-ordinated course of action to be followed in order to
prevent pollution incidents, and limit potential pollution in case of fire, explosion or discharges of hazardous waste constituents
which could threaten human health and the environment.
Cost-benefit analysis: A techniques which purports to evaluate the social costs and social benefits of investment projects in order
to help decide whether or not such projects should be undertaken.
Crude oil: Petroleum in its natural form before it is subjected to any refining process.
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Decibel: A logarithmic measure used to compare the sound level of interest with a reference level. If we are concerned with sound
power then reference is made to the smallest sound power that can be heard by someone with normal hearing at 1000 Hz.
Decommissioning: The final closing down and putting into a state of safety of an industrial plant or device when it has come to
the end of its useful life.
Decomposers: Organisms, usually bacteria or fungi, which use dead plants or animals as sources of food. They break down this
material, obtaining the energy needed for life and releasing minerals and nutrients back into the environment to be assimilated by
other plant and animal life.
Dispersion: The dilution and reduction of concentration of pollutants in either air or water. Air pollution dispersion mechanisms
are a function of the prevailing meteorological conditions.
Disposal: The introduction of waste into the environment through any discharge, deposit, emission or release to any land, water or
air by means of facilities designed, constructed and operated so as to minimize the effect on the environment.
Dissolved oxygen: The amount of oxygen dissolved in a stream, river or lake is an indication of the degree of health of the stream
and its ability to support a balanced aquatic ecosystem. The oxygen comes from the atmosphere by solution and from
photosynthesis of water plants.
Ecological indicators: Organisms whose presence in a particular area indicates the occurrence of a particular set of water, soil and
climatic conditions.
Ecology: The study of the relationships between living organisms and between organisms and the environment, especially animal
and plant communities, their energy flows and their interactions with their surroundings.
Ecosystem: The plants, animals and microbes that live in a defined zone and the physical environment in which they live comprise
together an ecosystem. The ecosystem embraces the food chain through which energy flows together with the biological cycles
necessary for the recycling of essential nutrients.
Environment: The air, land, water and other external conditions or influences in which man, animals and plants live or develop.
Environmental audit: This is an account by manufacturers and industries of the products produced and their effects on the
environment - energy use policies, materials use policies, waste output and their effects on the environment.
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Environmental impact: A change in environmental quality. The word ‘impact’ connotes that a value judgement has been made on
the importance of an environmental effect or change.
Environmental impact assessment: An activity designed to identify and predict the impacts of petroleum operations on the
surrounding biogeophysical environment including man’s health and well being and to interpret and disseminate information
about those impacts.
Environmental impact statement: Assembling the results of the environmental impact assessment into a document, which
contains a discussion of beneficial and adverse effects considered to be relevant to the petroleum operations.
Environmental quality: The state of the environment as perceived objectively in terms of measurements of its components, or
subjectively in terms of its attributes such as beauty and worth.
Environmental sensitivity: The susceptibility of a particular environment or area to any disturbance.
Estuary: Tidal coastal body of water where salinity is intermediate between fresh and salt water.
Eutrophication: The natural ageing of a lake or land-locked body of water which results in organic material being produced in
abundance due to a ready supply of nutrients accumulated by man over a period of time.
Fauna: The animals of a distinct region.
Flora: The plants of a distinct region.
Freshwater: Surface and subsurface water in its natural state useful for domestic livestock, irrigation, industrial, municipal and
recreational purposes and which will support aquatic life and contains less than 0.5 ‰ salinity
Fungi: Simple plants either unicellular or made up of cellular filaments; they contain no chlorophyll. They are agents of decay in
all natural organic materials, food, timber, plant debris, etc.
Artificial Gas lift: Associated gas re-injected into a producing oil well, to augment the natural hydrostatic pressure.
Greenhouse effect: The mechanism whereby incoming solar radiation is trapped by a glass sheet or the presence of carbon dioxide
and other greenhouse gases in the atmosphere. As these gases are transparent to solar radiation, the short-wave incoming
radiation is transmitted. However they are opaque to long wave re-radiation from the earth’s surface or from any other object
underneath, thus heat is trapped and the underlying surface is thereby warmed.
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Greenhouse gases: Collective term for those gases that have influence in the greenhouse effect, that is, chlorofluorocarbons,
carbon dioxide, methane, nitrous oxide, ozone and water vapour.
Groundwater: Water occurring within the saturation zone of an aquifer is the only part of all subsurface water, which is properly
referred to as groundwater, or phreatic water. Groundwater may be of variable chemical quality ranging from wholesome potable
waters to highly mineralised brines.
Habitat: The chemical, physical and biological setting in which a plant or animal lives.
Hazardous waste: Refuse which because of its inherent nature and quantity requires special disposal techniques to avoid creating
health hazards, nuisances or environmental pollution. Hazardous wastes are toxins or poisons, corrosives, irritants, strong
sensitisers, flammables, explosives, infectious wastes condemned foods, etc. Flammable wastes include explosive plastics, paper,
paper products and the like.
Hazen unit: A unit of measurement for colour in water. It is based on the colour produced by 1 mg platinum per litre in the
presence of a cobalt-based compound.
Heavy metal: Any of the following elements: antimony, arsenic, beryllium, cadmium, chromium, copper, iron, lead, manganese,
mercury, nickel, selenium, silver, thallium, vanadium, or zinc.
Hydrocarbons: Chemical compounds consisting wholly of hydrogen and carbon.
Hydrogen sulphide: Dense colourless gas with a smell of rotten eggs, which is extremely toxic. It is produced under anaerobic
decay conditions and can accumulate in sewers.
Hydrology: The science concerned with the occurrence and circulation of water in all its phases and modes and the relationship of
these to man.
Inorganic matter: Matter, which is mineral in origin and does not contain carbon compounds, except as carbonates, carbides, etc.
Insolation: The amount of direct solar radiation incident per unit horizontal area at a given level, measured in mW/m2.
LC-50. : The lethal concentration of a substance in air or water necessary to kill 50% of test organisms within a specified time
under standardised conditions.
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LC-50. : The lethal dosage of a substance necessary to kill 50% of a sample population of test animals as determined from
exposure to the substance, by any route other than inhalation within a specified time under standardised conditions.
Leachate: Any liquid, including suspended materials, which it contains, which has percolated through or drained from special
waste facility.
Marine water: Includes estuarine and coastal water, where estuarine means a semi-enclosed coastal body of water having free
connection to the sea and having a chloride ion concentration in excess of 1000 mg/L.
Microbes: Microscopic organisms, usually bacteria of which some are pathogenic, e.g. Salmonella, which is associated with food
poisoning in man. They are essentially scavengers of organic material breaking down dead plant and animal remains sewage and
even toxic wastes that are organic in origin.
Micron: One-millionth of a metre, hence the more correct term micrometre. It is commonly used for particle sizing. Symbol µm in
SI units.
Minamata disease: Minamata is a town on the west coast of Kyushu Island (Japan) where an extreme case of heavy metal
poisoning from methyl mercury ingested in the staple fish diet of the inhabitants caused severe disablement and death between
1953 and 1956. The symptoms include numbness in fingers and lips and difficulty in speech and hearing.
Noise: Sound that is socially or medically undesirable, that is, any sound that intrudes, disturbs or annoys. Very high levels of
sound can cause hearing damage.
Nutrients: The raw material necessary for lives, which are consumed during the metabolic process of nutrition. Their type and
consumption vary according to the particular plant or animal species. The main categories are proteins, carbohydrates, fats,
inorganic salts, minerals and water.
Oligotrophic: An aquatic environment that has low concentrations of nutrients present and therefore has low plant and animal life
productivity.
Organic matter: Material containing carbon combined with hydrogen often with other elements (oxygen, nitrogen), e.g. plastics,
vegetable matter.
Pathogen: A living organism usually a micro-organism that causes disease.
Petroleum: A naturally occurring mixture of predominantly hydrocarbons in the gaseous, liquid or solid phase.
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pH: A measure of the alkaline or acid strength of a substance. The pH value of any solution in water is expressed on a logarithmic
scale to the base 10. It is defined and calculated as the logarithm of the reciprocal of the hydrogen-ion concentration of a
solution.
Photosynthesis: The process whereby plants utilize radiant energy from the sun and carbon dioxide from the atmosphere, in the
presence of chlorophyll, to manufacture organic matter.
Phytoplankton: Free floating minute plants in sea, lake and river surface waters where sufficient sunlight is available for
photosynthesis.
Pig: A scraping tool forced through a pipeline or flowline to clean out accumulations of water, wax, rust, scale, and debris from the
walls of the pipe.
Pollutant: A contaminant exerting significantly adverse effects on biota including ecological systems.
Pollution: Pollution is the introduction into the environment of substances or effects that are potentially harmful or interfere with
man’s use of his environment or interfere with species or habitats.
Recompletion: A drilling process which brings oil and gas wells into production.
Refuse: Discarded materials, substances or objects.
Remediate: To remove, eliminate, limit, correct, counteract, or mitigate the negative effects on the environment or human health of
one or more contaminations.
Receiving water: Any body of surface water into which a discharge of leachate or effluent may flow. Receiving waters wholly
contained within a permitee’s property are not included in this definition, provided that pollutants in such waters cannot be
transported outside the property.
Run-off: The volume of water derived from rain falling on a surface and which does not permeate into the soil.
Salinity: Total amount of dissolved material expressed in terms of kilograms of material per million kilograms of feedwater, that is,
parts per million (ppm) of total dissolved solids.
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Sample: A part of a population selected with the object of estimating some characteristics of the whole population. Can be
random or spot.
Sediment: The deposit of silt and accumulated organic and/or inorganic materials at the bottom of rivers, lakes, seas, etc.
Silt: Normally a wet mixture of particles between 4 and 60 µm diameter often found in the bottom of streams, rivers, etc.
Intermediate between clay and mud.
Species: In botany or zoology, a group of closely-related individuals showing constant differences from allied groups.
Standard deviation: The most common measure of spread or deviation in a set of observations. It is the square root of the average
of the squares of the differences (Variance) of each observation from the mean of those observations.
Tar balls: Lumps of oil, weathered to a high density, semi-solid state.
Total dissolved solids: The solids residue after evaporating a sample of water or effluent expressed in mg/litre.
Toxicity: The capability of a poisonous (toxic) compound to produce deleterious effects in organisms.
Treatment: The handling or processing of special waste in such a manner as to change the physical, chemical or biological
character or composition of the special waste in order to eliminate or reduce the volume, or one or more hazardous properties of
the special waste.
Waste: Any unavoidable material resulting from an up-stream operation for which there is no economic demand and which must
be disposed of.
Waste oil: Automotive lubricating oil, cutting oil, fuel oil, gear oil, hydraulic oil or any other refined petroleum based oil or
synthetic oil where the oils through use, storage or handling have become unsuitable for their original purpose due to the
presence of impurities or loss of original properties.
Weathering: Natural influences such as temperature, wind, light, bacteria, that alter the physical and chemical properties of oil.
Wetland: Any land such as a tidal flat, marsh, swamp, bog or fen which is frequently inundated and for that reason has developed
an organic soil and occurs in an area which is lower lying than its surroundings.
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Ultraviolet radiation: Radiation which falls between visible light waves and X-rays.
slightly less than those of violet light, the limit of the human eye.
The longest UV waves have wavelengths
Variance: A statistical term - the square of the standard deviation.
Volatile organic compounds: Organic compounds, (e.g. ethylene, propylene, benzene, styrene, acetone) which evaporate readily
and contribute to air pollution directly or through chemical or photochemical reactions to produce secondary air pollutants,
primarily ozone and peroxyacetyl nitrate.
Water table: The upper surface of the saturation zone below which all void spaces are filled with water.
Zooplankton: The floating, drifting or weakly swimming aquatic animal life of the open water.
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APPENDIX 1.1
International Environmental Conventions Signed by Nigeria
Appendices 3.1 a-c
YEAR
CONVENTION
1948
Convention of the Intergovernmental Maritime Consultative Organisation
1954
Convention for the Prevention of Pollution of the Sea by Oil (not the 1978
1958
Convention on fishing and conservation of living Resources of the High
1958
Convention on the High Seas
1958
Convention on the Continental Shelf
1958
Convention on the Territorial Sea and Contiguous Zone
1968
African Convention on the Conservation of Nature and nature Resources
1969
Convention on Civil Liability for Oil Pollution Damage (not the 1976 and
1972
Convention concerning the Protection of the World Cultural and Natural
1972
Convention on he Prevention of Marine Pollution by Dumping of Wastes
1973
Convention to Regulate international trade in Endangered species of
1974
International Convention for the Safety of Life at Sea
1979
Convention on Conservation of Migratory species of Wild Animals
1981
Convention for Co-operation in the Protection and Development of the
1982
Convention for Co-operation in the Protection and Development of the
1985
Vienna Convention for the Protection of the Ozone Layer
June 2005
Page 37 of 3
Appendices 3.1 a-c
1987
Montreal protocol on Substances that Deplete the Ozone Layer
1989
Basle Convention on the Control of Trans boundary movements of
1990
Convention on Oil Pollution Preparedness, response, and Co-operation
1992
United Nations Framework Convention on Biological Diversity
1992
United Nations Framework Convention on Climate Change (+ 1997 Kyoto
1994
United Nations Convention to Comfort Desertification in those Countries
June 2005
Page 38 of 3
Nigerian Environmental Laws and Regulations
1956
Act No. 31
Oil pipelines Act
1965
Act No. 24
Oil pipelines Act (Amendment)
1967
Act No. 28
Petroleum Control Act
1968
Act No. 34
Oil in Navigable Waters Act
1969
Decree No. 51
Petroleum Drilling and Production Decree
1969
Petroleum (Drilling and Production) Regulations
1971
Act No. 30
Sea Fisheries Act
1973
Act No. 25
Petroleum Technology Department Fund Act
1978
Act No. 6
Land Use Act
1979
Act No. 99
Associated Gas Re-injection Act
1985
Associated Gas Re-injection (continued Flaring of Gas
1988
Decree No. 58
Federal Environmental Protection Agency Decree
1988
Decree No. 42
Harmful Wastes (Special Criminal Provisions, etc)
1991
National Environmental protection (Effluent
1991
National Environmental Protection (Pollution
1991
National Environmental Protection (Management of
1991
National Guidelines and Standards for Environmental
1991
Decree No. 36
1991
Federal National Parks Decree
Environmental Guidelines and Standards for the
1992
Decree No. 59
Federal Environmental Protection Agency
1992
Decree No. 71
Sea Fisheries Decree
Appendices 3.1 a-c
June 2005
Page 39 of 3
1992
Decree No. 86
Environmental Impact Assessment Decree
1992
Proposed National Guideline and Standards for Waste
1993
Decree No. 94
Nigerian National Petroleum Corporation) Projects
1993
Decree No. 101
Water Resources Decree
1993
Guidelines for the establishment of a Petroleum
1994
Environmental Impact Assessment Procedure for
1995
Petroleum (Drilling and production) (Amendment)
1995
Sectoral Guidelines for Oil and Gas Industry Projects
1995
Sectoral Guidelines for Oil and Gas Industry Projects
1995
Sectional Guidelines for Oil and Gas Industry
1996
Petroleum Refining (Amendment) Regulations
1996
Decree No. 8
Oil and Gas Free Export Zone Decree
SHELL GROUP STATEMENTS ON HSE
Royal Dutch/Shell Group of Companies. Statement of General Business Principles, March 1997
Royal Dutch/Shell Group Business Principles Procedure, March 1997
Royal Dutch/Shell Group Commitment to health, Safety and the Environment, March 1997
Royal Dutch/Shell Group Health, Safety and Environmental Policy, March 1997
Group Procedure for an HSE Management System, March 1997
Group Position on “Global Environmental Standards, June 1998
Appendices 3.1 a-c
June 2005
Page 40 of 3
INTERNATIONAL CODES, STANDARDS AND GUIDELINES
ISO 7731: Danger signals for work places – “Auditory danger signals”
ISO 8201: Acoustics – “ Audible emergency evacuation signal”
ISO 8995: “ Principles of visual ergonomics – the lighting of indoor work system”.
World Health Organization (WHO) Guidelines for drinking water quality.”
Part 1: Recommendations. 2nd ed.
Part 2: Health criteria and other supportive information. 2nd ed
Part 3: Surveillance and control of community supplies. 2nd ed
ISO 6385: “ Ergonomic principles in the design of the work systems”
ISO 9241-1 “Ergonomics requirements for office work with visual display terminals (VDTs)”
Part 1: Guidance on Regulations L23”
UK Health and Safety Executive Code of Practice
“The Control of Legionellosis including Legionnaires’ Disease, second edition”
ISO/CD 11014 “ safety data sheet for chemical products. Part 1: Content and order of sections.
ISO 7730, Moderate thermal environment – “ Determination of the PWV and PPD indices and specification of the conditions for
thermal comfort.”
ISO 13852: “Safety of machinery – Safety distances to prevent danger zones being reached by the upper limbs”
ISO 11429: Ergonomics – “System of auditory and visual danger and information signals”
ISO/DIS 13853: Safety of machinery – “Safety distances to prevent danger zones being reached by the lower limbs”
ISO 13854: Safety of machinery – “Minimum gaps to avoid crushing of parts of the human body”
ISO 11428: Ergonomic – “Visual danger signals – general requirements, design and testing”
ISO 11429: “Ergonomics – System of auditory and visual danger and information signals”
Appendices 3.1 a-c
June 2005
Page 41 of 3
Shell Codes, Standards and Guidelines
Noise Guide – Shell HSE Committee
Management Guidelines for Hearing Conversation
Guidelines for Catering Operations – Shell HSE Committee
Shell Health, Safety and Environment Committee,
“Management Guide to Thermal Stress:.
DEP 31.76.10.10 Gen.: “Heating, Ventilation and Air
Conditioning for plant Buildings”
Drug and Alcohol Abuse
Guidelines – Shell Human Resources and Organization Coordination
AIDS – Employment Guideline - Shell Human Resources and
Organization Co-ordination
Ionizing Radiation – Shell HSE Committee
Health Risk Assessment – Shell HSE Committee
Medial emergency Guidelines for Management – Shell HSE
Committee
SIEP EP 95-0330: “ Drinking Water Guidelines”
HSE Manual – EP 95-0000, SIEP
Health Guidelines for Catering – Shell HSE Committee
Waste Management Guide – Shell HSE Committee
Group HSE Performance Monitoring and Reporting – Shell HSE
Adviser Panel
Appendices 3.1 a-c
June 2005
1991
1991
1991
1991
1993
1993
1993
1994
1994
1995
1995
1995
1996
1998
Page 42 of 3
Appendix 3.0a: Waste Management Procedure
S/
N
1
Waste
Hazard
Origin
*Preferred Disposal Option
*Obtainable Disposal Option
Remarks
Depends on original contents
of drum
Packaging of
lubricating oil, fuel
oil and corrosion
inhibition chemicals
Purge any residue and clean before
selling as scrap or reusing as waste
containers for hazardous content.
Reduce by bulk purchasing;
Reuse by including "Return
to supplier clause" in
purchase contracts
Engine & rotating
equipment's.
I
Potential groundwater & soil
contamination (hydrocarbons
& metals)
Non-hazardous
Sell as scrap if non-hazardous
contents.
Approved washing and recycling of
resultant plastics or metals for
hazardous content.
Crushing and extraction of the Oil
using the Oil Filter Splitting Machine at
the WRD. I.A
Recycling
2
Oil & fuel filter
catridges
H
3
Scrap metals,
metal
chippings,
scrap cables,
Medical wastes
H
Potential health risk
Incineration at I.A
Saver Pit
Wastes
(sediments)
Chemicals
I.H
Incineration at I.A. Gounod
(Medical incinerator).
Store in temporary storage area at
UGHW/23/6 before transporting to
the TDU at Forcados Terminal
Refer to SHOC manual and MSDS
7
Contaminated
debris ,soil
and *oily rags
I, H
Potential groundwater &
surface water contamination
(hydrocarbons)
Type & concentration will
determine hazardous nature Env., Health, Safety
Potential groundwater
contamination - env.
Sick-bay and
First-aid treatment
Routine cleaning of
saver pit
Oil & chemical spills,
clean-up operations
8
Domestic
waste garbage
D
Attracts rodents; fumes from
burning is a nuisance
Logistics centres,
offices, locations
Store in temporary storage area at UGH
W/23/6 before transporting to the TDU
at Forcados Terminal. *Mobile Vikoma
incinerator is being sourced by PSWHSE to handle oily rags.
Segregation and Recycling of
recyclables e.g. plastics, paper, glass
and landfill of non-recyclables
9
Batteries :
Lead-acid,
Nickelcadmium
H
Corrosive – health & safety;
lead or heavy metals may
cause contamination - env. &
health
10
Sewage sludge
H
Potential health risk
11
Used oils(
Lube +
Engineoil )
H
Potential groundwater & soil
contamination (hydrocarbons
& metals)
12
Oily Sludge
H
Potential Environmental
contamination
Vehicles, portable &
emergency electrical
tools, production &
transmission
facilities
Contained sewage
sludge in septic
tanks
Engine & rotating
equipment
lubricating systems,
vehicles
Routine cleaning of
process vessels
4
5
6
Empty drums
Categor
ization
I, H
H
Scrapped equipment
UGH. W/23/6 before transporting to
See SHOC manual & MSDS for
particular chemical
June 2005
Disposal at the Effurun-2-location
Stop disposal of waste into
the bundwall of flare site
the TDU at Forcados Terminal.
*Store oil rags in bins on site.
Stopped disposal of waste
into the bundwall of flare site
Send recyclabes to Waste Recycling
depot (WRD) Ogunu and dispose
non-recyclabe at Ughelli West
Dumpsite.
Dispose food waste at the
composting facility at Jeddo.
Send to Waste recycling depot at I.A
for recycling prior to suitable
disposal option.
Review waste volumes &
sources to reduce; recycle
metals,
glass,
paper
&
plastics; compost food &
Garden waste
Evacuate sewage sludge in septic tank
and transport to Edjeba treatment
plant
Recycling,
Approved incineration
Evacuate sewage sludge in septic
tank and transport to Edjeba
treatment plant
Discharge into flowstation saver pit
Complete biological units will
be installed in the living
quarters in future
To reduce/reuse, conduct
vehicle maintenance at
commercial service stations
UGH. W/23/6 before transporting to
Stop disposal of waste into
the bundwall of flare site
Recycling
* Use Waste consignment notes (WCN) for all disposal.
Legend: H = Hazardous; I = Industrial; D = Domestic
Appendices 3.1 a-c
Extract oil, crush metal and sell as
scrap.
Page 43 of 3
Recycle via manufacturers
Appendix 3.0b:
List of most common wastes and their classification
POSSIBLE WASTE AND CATEGORIES GENERATED
NON-HAZARDOUS
Hazardous
Industrial
Domestic
Asbestos
Bulbs
Garden waste
Blasting grit
Construction debris Kitchen waste (food)
Packaging materials
CFCs
Dredge spoil
Metal cans
Paper
Contaminated soil
Drilling mud
Packaging materials
Plastic
Clinical waste
Furniture
Plastics
Printer toner
Empty oil/chemical drums
Bottles
Fluorescent tubes
Glass
Halons
Oil/fuel filters
Incinerated medical ash
Oily rags
Lead acid batteries
Packaging materials
Ni/cd batteries
Plastics
Office
Glass
Obsolete reprographic materials Tyres
Obsolete chemical
Wires
Organic acid and bases
Wooden pallet
Organic solvent
Scrap metals
Oily sludge
Paints
Sewage sludge
Thinners
Used oils (lube/engine)
Vanishes
Appendices 3.1 a-c
June 2005
Page 44 of 3
APPENDIX 3.0c: Vastes Management Facilities
S/n
o
1.
2.
3.
Facility
Edjeba Phase III
Temporary
Depot/Effurun-2
Asbestos depot.
Edjeba Sewage
Treatment Plant
Waste Recycling
Depot, I.A. Ogunu
4.
Thermal Desorption
Unit, Forcados
Terminal
5.
Jeddo Composting
Facility
Ughelli-W Dumpsite
Effurun 2
6.
7.
8
9
Clinical
Incinerator,I.A.
Ogunu
Transit at WRD I.A
pending transfer to
Mercury Recovery
Technology (MRT),
Ekpan
Appendices 3.1 a-c
Wastes Handled
Asset Owner
Department
Focal point
Ext.
Spent asbestos roofing
sheet &other asbestos
materials
HSW-ENVW
Afolabi, A.G
42548
Office
Location
GXC08,MOA
Sewage sludge
PSW-CVL
G. Oseruvwoja
44297
I.A
Glass, Tyre, Flourescent
tubes,metals, Batteries,
Papers, Plastics, Toner
cartridge
Oily wastes(Oil
Contaminated
sand/sludge,Caked
chemicals )
Strictly food wastes
HSW-ENVW
T.G. Balogun
42535
GXC.04, MOA
PSW-HSE
S.Ukulu
46675
Edj.N3
HSW-ENVW
Karibo,E
42536
GXC.04,MOA
Inert (general) wastes
Ferrous pipes, written-off
generators, discarded
pumps, empty caravans,
non-persistent wastes
Medical waste
PSW-CES
SSW-SUP
Ezuma, W
Emegbagha ,
M.O
47025
44011
Edj-N3
SSW BLDG
G12
MDW-OH
Akujobi,C
47991
Edj-Q2
Mercury in Flourescent
tubes
HSW-ENVW
Afolabi, A.G
42548
GXC08,MOA
June 2005
Page 45 of 3
APPENDIX 5.1
7
Detailed field Sampling and Laboratory Strategies/Methods for the Environmental
Components
Field Work
Field sampling was conducted between January 20-25th, 2000 (dry season) and
13-14th September 2000 (wet season), for all environmental components.
Sampling Rationale
Sampling rationale was dictated by the study objectives which, in essence was to
investigate the current status of the environment around and within the project
area to enable SPDC keep environmental data of it's operational areas against
which future deviations as a results of new development project may be assessed.
As is usual with baseline study, this study was designed to collect truly
representative data of the study area by utilising transect and random sampling
techniques. Sampling points were also randomly selected but with respect to
identified potential pollutant sources while control stations were established far
from the expected zone of influence of existing projects. Socio-economic and
cultural study was focused on the population within the area of study.
Questionnaires were administered in settlements scattered within the study area.
Underground water samples were collected from eight monitoring boreholes drilled
for the purpose. The monitoring boreholes were located based on the foreknowledge
of the ground water flow direction in the area. In all cases the quantities of water
collected for analysis were in accordance with DPR guidelines for physico-chemical
analysis.
Sampling Location
The basic philosophy of the choice of sampling points was to ensure good spread
and representation as appropriate for each discipline. . Sampling points were
selected to give as much as possible a balanced picture of the environmental status
of each site. Samples were collected from the same points as in phase one (dry
season) and analysed using standard methods approved by SPDC and DPR, with
strict compliance to all quality control and quality assurance measures as
contained in the technical proposal, submitted by API to, and approved by, SPDC.
Chemical Programme
Introduction
The overall objective of the chemical programme is to produce a ground database
for a number of parameters in water, soils and sediments. A flow diagram of the
components of the chemical study programme is shown in Fig. 2.1. Water, soil and
sediment samples were collected for laboratory analysis for petroleum
hydrocarbons (THCs), and major trace elements. Water samples were analyzed for
wet chemistry parameters, including biochemical oxygen demand (BOD), chemical
oxygen demand (COD), nutrients, pH, and dissolved oxygen (DO), total alkalinity
(TA), total suspended solids (TSS). In situ field measurements of pH, DO,
conductivity, temperature and transparency were made at each station.
Conductivity and transparency, together with the wet chemistry parameters, were
needed for the interpretation of the biological data collected during the study.
Appendices 3.1 a-c
June 2005
Page 46 of 3
Field and Laboratory Procedures
Water Study
Water is a very vital resource to man. Surface water supports aquatic life, and
serves man's needs of fishing, drinking and recreation. In many communities
ground water is the surest source of clean potable water. Water has to be of the
right quality characteristics to be useful for these purposes.
However, the aquatic environment is a ready receptacle for wastes resulting from
many industrial activities. Unfortunately water is very easily impacted by many of
man’s domestic and industrial activities, which tend to negatively impact the
quality of water resources altering many of its characteristics such as the physicochemical properties, heavy metal burden, e.t.c., thereby making water unfit for
many purposes. The only notable body of surface water in the entire area is the
Ikebiri Creek which is used for all purposes of drinking, fishing and recreation by
the surrounding communities. The groundwater table is also very low. Only very
few groundwater sources in the form of boreholes are located in the entire area.
This limitation of water resources puts a big strain on the resources with regards to
serving the needs of the communities. This further underscores the need to monitor
water quality in the area, as any negative impact on water quality in the area will
have drastic consequences on the communities. Water quality assessment is thus a
vital component of the baseline studies of an environmental assessment.
In Situ: pH, cond., DS
DO , Tem p., T ransp.
W ater Chem istry
Laboratory
CI, TA, Nutrients, T DS
T SS, Colour, T urbidity
T race M etals
Hydrocarbons
Tebidaba Field
Project Area:
Land, Riv er
System s and creeks
Nutrients
T race M etals
Sedim ent and Soils
Hydrocarbons
SO 2 , NO x, O 3 , NH 3 ,
Particulate
Air Q uality
T HC
In Situ: pH, cond.,
Tem p., T urbidity
G round water
Lab: CI, T DS, Nutrients
T race m etals
Fig. 2.1:
Components of the Chemical Study Programme.
Water Quality
For physico-chemical and biological study, twenty (20) water-sampling stations
were established along and within the waterways of the study area. Samples were
collected along the course of rivers and creeks flowing across the study area, from
Appendices 3.1 a-c
June 2005
Page 47 of 3
the same sampling points for the dry and wet season study. At each water sampling
station, composite water samples were taken from the surface and near the bottom
using a Hydrobios 2 litre water sampler. The precaution taken during the sampling
of surface water included avoiding contact with the sides and bottom of the
sampling points since this could detach slime or sludge accumulated there.
Analyses were carried out in the order dictated by the stability of the parameters.
All laboratory procedures were adequately standardised and all instruments
appropriately calibrated. While groundwater samples were collected from the eight
(8) newly dug boreholes in accordance with DPR (1991) quality assurance
guidelines and standards after flushing the boreholes to stability. Samples were
collected directly into clean plastic or glass containers after rinsing with portions of
the water being sampled.
Transfer, storage and preservation: Samples could be subjected to microbial
degradation and transformation, they were therefore analysed at minimum time
after collection. Since, however, storage is necessary, preservatives were used as
necessary. Samples for physico-chemical analysis were stored in ice-chest packed
in well-sealed coolers and then transported conveniently to the laboratory where
they were refrigerated at 4oC until required for physico-chemical analyses.
Samples for heavy metals were appropriately preserved with 1:1 nitric acid and
those for oil & grease with 1:1 sulphuric acid to pH < 2 (see Table 2.2 for details).
Sample identification/coding: To ensure preservation of the integrity of the
sample collected, sample identification/coding were designed on a permanent label
to contain specific details so as to ensure sample authenticity. Samples were
properly sealed, carrying labels with information such as:
•
•
•
•
Identification code or sample number
Date and time of sampling.
Type of preservation
Description of sample
The following physical and chemical parameters were then measured some in situ
and others in the laboratory.
(a)
Temperature
Air and surface water temperatures were determined in situ using a mercury-inglass thermometer while sub-surface water temperatures at depths of between 0.5
and 1 m from the bottom were taken in situ with a temperature probe.
(b) Transparency
Water transparency was determined in situ using a white metallic Secchi disk
lowered into the water and the average of the points of disappearance and
appearance recorded as the water transparency.
(c)
Colour (True)
Colour may be expressed as "apparent" or "true" colour. The apparent colour
includes that from dissolved materials plus that from suspended matter. By
filtering or centrifuging out the suspended materials, the true colour can be
determined. The true colour was determined by a modified method of APHA (1989)
using a HACH model 2000 Environmental laboratory spectrophotometer.
(d)
Total, Dissolved and Suspended Solids
Total solids (TS) are the solid matter in water, also referred to as residue. It has
two components, suspended solids (SS) and dissolved solids (DS). The dissolved
solid component was determined in situ in the field using the HACH dissolved solid
meter.
Appendices 3.1 a-c
June 2005
Page 48 of 3
The field results were cross-checked gravimetrically in the laboratory. Total solids
(TS) in water were determined gravimetrically by evaporating to dryness 100 ml of
unfiltered water in a pre-weighed and pre-dried evaporating basin. Dissolved solids
were determined as above using filtered water and the difference in weight between
total and dissolved solids gave the suspended solids.
(e)
Hydrogen ion concentration (pH)
pH was determined in situ using a Hach-One pH Meter.
(f)
Alkalinity (mg l-1)
Phenolphthalein and total alkalinity were determined using the Hach Digital
Titration Method with phenolphthalein and Bromocresol Green Methyl-Red as
indicators and titrating with 1.600N sulphuric acid. This is a modification of the
titrimetric method of the Standard Methods for the Examination of Water and
Wastewater (APHA, 1989).
(g)
Dissolved Oxygen (DO)
Dissolved oxygen (DO) was determined by the Azide modification of Winkler Method
adapted for the HACH equipment from Standard Methods. Clean 60 ml glassstoppered BOD bottles were filled to overflowing with water samples directly from
source. Fixation in the field was carried out by adding the contents of Dissolved
Oxygen 1 and Dissolved Oxygen 2 powder pillows, and the bottle stoppered and
thoroughly mixed by rotation and inversion until a flocculent brownish precipitate
was produced. The bottles were stored away in darkened containers under water
until required for titration in the laboratory. The content of Dissolved Oxygen 3
powdered pillow (sulphamic acid) was added, thoroughly mixed to dissolved the
brown precipitate, out of which 20 ml aliquots was accurately measured and
titrated with 0.200 N sodium thiosulphate using the HACH Digital Titrator, until
the sample changed from yellow to colourless. With the aid starch indicator,
which, was added as the yellow colour was discharged to faint yellow towards the
end of the titration, this remarkably improved the end point from deep blue to
colourless. The number of digits from the digital counter window multiplied by 0.1
gave the concentration of dissolved oxygen in mg l.-1.
(h)
Conductivity (µScm-1)
This is the capacity of water for conveying electrical current and is directly related
to the concentrations of ionized substances in the water. Conductivity was
measured in situ using a HACH Portable Conductivity Meter.
(i)
Salinity (‰)
Water salinity was determined in situ in the field using an Oceanographic Salinity
Measuring Bridge, Model MC5 equipped with a platinized electrode and supplied by
Kents Industrial Measurements Ltd., Huttington, UK. The field readings were
confirmed in the laboratory by the Harvey's (1955) titrimetric method with an
accuracy of ± 0.1%.
(j)
Sulphate
The procedure employed to determine sulphate is a modification of the Barium
Sulphate Turbidimetric Method using the HACH equipment.
(k)
Available Reactive Phosphorus
Phosphorus as reactive orthophosphate was determined using the stannous
chloride method specially suited for determining low amounts of phosphate
concentrations. In this method molybdophosphoric acid is formed and reduced by
stannous chloride to intensely coloured molybdenum blue. The colour produced
was determined photometrically after correction with a blank at 700nm wavelength.
This is a very sensitive method, which makes feasible measurements down to 7 mg
P per litre.
(l)
Nitrate and Nitrite
The low range nitrate test employed in the analysis of water is the HACH
modification of the cadmium reduction method using a very sensitive chromotropic
Appendices 3.1 a-c
June 2005
Page 49 of 3
acid indicator. The test registers both nitrates and nitrites present in the water
sample.
(m)
Sodium and Potassium
Sodium and potassium were analyzed by flame photometry.
(n)
Calcium
Calcium was determined by the EDTA titration method using CalVer 2 Calcium
Reagent in a HACH modification of the Standard Methods according to APHA
(1989). A 100 ml water sample was taken in a clean titration flask and 2 ml of 8N
KOH was added and swirled to mix. The content of one CalVer 2 Calcium Reagent
indicator was added and the content of the flask titrated with 0.800N EDTA
solution using the HACH digital titrator until the colour changed from pink to blue.
The concentration of calcium hardness is read from the digital counter as mg/L
CaCO3.
(o)
Magnesium
Magnesium hardness (as CaCO3) was determined by subtracting the amount of
calcium hardness from the results of the total hardness test. Total hardness of
water was determined using the ManVer 2 Total Hardness reagent (Eriochrome
black T) as indicator after adding 2 ml of buffer solution. This was titrated with a
standard EDTA titrant until the last reddish tinge disappeared.
Magnesium
hardness was converted to mg/L magnesium by multiplying with 0.243.
(p)
Heavy Metals
The Flame Atomic Absorption Spectrophotometry was used to determine zinc,
Copper, Nickel, Lead, Chromium, Cadmium and Manganese. The water sample is
aspirated through a nebulizer into an air-acetylene flame. Free atoms of the
elements were generated in the flame Resonance line of the element, which was
generated in a hollow cathode lamp, and this was simultaneously passed through
the flame. The absorbance of radiant energy by the element of interest was related
to its concentration in the water sample by the Beer-Lambert law.
Sample Pre-treatment
A preliminary test showed that the levels of metals in the samples were generally
either at background level or below the detection limit of the Atomic Absorption
Spectrophotometer used (Table 2.1). To raise the signal measured to an order
above this detection limit without resort to unnecessarily high electronic scale
expansion with its attendant noise, a pre-concentration step was included in the
analytical procedure. The detection limits achieved are adequate for environmental
decision-making purposes. 200 ml of the sample (filtered when necessary) was
placed in an evaporating dish on a hot plate. It was gently evaporated to about 15
ml and then made up to 20 ml in a standard flask.
Instrument Calibration and Sample Analysis
The instrument was set up and optimized for each metal as recommended by the
manufacturer.
Working standards prepared from dilution of 1000ppm stock
standards, and in concentration range of the same order of magnitude as in the
concentrated samples, were used to standardise the instrument. In cases where
the sample absorbances were very close to the lower end of the linear response
range for the element, the instrument was operated in the absorbance mode.
Otherwise the instrument was operated in the direct concentration mode.
The concentrated samples were aspirated into the flame and absorbances or
concentrations were read as appropriate.
Absorbances were converted to
concentration using the calibration graph for each element. The reference was
double-deionised water concentrated ten-fold as the samples. Allowance was made
for the concentration factor in tabulating final results.
(i)
Vanadium
Vanadium was also analysed by flame atomic absorption spectrophotometry, using
nitrous oxide-acetylene flame and a concentration factor of 20.
Appendices 3.1 a-c
June 2005
Page 50 of 3
(ii)
Mercury
Because of the very poor sensitivity of AAS in flame mode for mercury, the coldvapour mode was used. Here the mercury is reduced to elemental state in aqueous
phase. Taking advantage of the high volatility of elemental mercury, air was used
to sweep the reduced mercury into a cell with quartz window in the path of
mercury resonance line in an atomic absorption spectrophotometer. The peak
absorbance signal is proportional to the concentration of mercury in the sample.
Table 2.1: Detection limit of the Atomic Absorption Spectrophotometer
------------------------------------------------------------------------------------------------Metal
* Sensitivity Check
! Operational Detection Limits
------------------------------------------------------------------------------------------------Lead
25
0.05
Copper
4
0.01
Cadmium
1.2
0.02
Zinc
0.8
0.01
Nickel
7
0.05
Vanadium
75
0.10
Mercury
350
0.002+
Chromium
4
0.05
Manganese
2.5
0.005
* Concentrations, which give an absorbance of 02 at peak instrumental
performance. The current performance level of the instrument used was 80 % of
peak performance level.
! Determined for the instrument used at current optimum performance level.
+ By cold vapour technique without pre-concentration.
Reagents
All reagents used were analytical grade and water was double-deionised water.
(a) Stannous chloride: 75 g of stannous chloride was dissolved by heating in 100
ml 1:1 HCl.
(b) Hydroxylamine hydrochloride: 50g hydroxylamine hydrochloride was dissolved
in 250 ml water.
(c) Mercury Standard: 1.354 mercury (II) chloride was dissolved in one litre
aqueous solution made 5% with respect to nitric acid and 0.01 % in potassium
dichromate.
Procedure
The samples were analysed without pre-concentration. 10.0 ml sample was placed
in the reaction vessel (Fig. 2.3). Two (2) ml stannous chloride and 4 ml
hydroxlamine hydrochloride were added and the reaction vessel was immediately
coupled into the flow system. The ground state mercury atoms generated were
swept by air flowing at a rate of 1200 ml/min into the atom-cell. The absorbance
peak was recorded. The system was calibrated with standards in the range 2.0 ppb
to 40 ppb, each one treated as the samples. The reciprocal of the calibration graph
was used to convert the sample absorbance to concentration.
(iii)
Iron
Iron was determined colorimetrically by the very sensitive ferrozine method of the
HACH spectrophotometer, which allows measurement down to 4 mg/l of the
element in water.
(q) Hydrocarbon Content
Principle
Total hydrocarbon in the water sample was extracted with CCI4 at pH 5. The
height of the C--H stretching band peak at 2950 to 2800 cm-1 was compared with
height of the peaks of standards for quantitative purposes.
Appendices 3.1 a-c
June 2005
Page 51 of 3
Reagents
All reagents used were analytical grade.
(a) Dilute sodium hydroxide acid: 4.0 g sodium hydroxide was dissolved in water.
(b) Dilute hydrochloric acid: Concentrated acid was diluted 10 times with water.
(c) Solid sodium chloride:
(d) Solid anhydrous sodium sulphate.
(e) Silica gel.
(f)
Total hydrocarbon standard: Forcados Natural Crude was used as standard
mixed hydrocarbon.
1.0 of the standard was diluted to 100.0 ml solution in CCl4. This stock standard
was used as 10,000 ppm THC.
INERT
GAS
REGULATOR
SCRUBBER
FLOW METER
READ OUT
DESSICANT
Hg LINE
ABSORPTION CELL
REACTION VESSEL
AAS
Figure 2.2: Cold Vapour sector for mercury determination
Sample Analysis
750 ml of sample was placed in a one litre-separating funnel. The pH of the sample
was adjusted to 5 using diluted hydrochloric acid or diluted sodium hydroxide as
necessary. A pH meter was used to monitor the pH. About 1g sodium chloride was
added to the sample and taken to dissolve. 10ml tetrachloromethane was added to
the separating funnel. The funnel was stoppered and the separating funnel was
shaken gently for 15 min to extract total hydrocarbon from the sample.
The phases were allowed to separate. The tetrachloromethane layer was run
through a filter paper containing anhydrous sodium sulphate into 25ml standard
flask.
The sample was re-extracted with a second 10ml portion of tetrachloromethane.
The extract was also filtered through anhydrous sodium sulphate into 25ml
standard flask. The combined extract was made up to 25 ml.
The diluted extract was run through silica gel column for clean up. The IR
spectrum of the samples was scanned from 3100 to 2800cm-1. The height of the
C--H stretch band at 2850cm-1 was calculated and converted to concentration
using the calibration graph.
Calibration
Appendices 3.1 a-c
June 2005
Page 52 of 3
From the stock standard, 0, 10, 20, 40, 60, 60 80, and 100ppm standards were
prepared as required. The standards were scanned as for the samples and height
of the peak at 2850 cm-1 was plotted against concentration and used as calibration
graph.
Soil and Sediment
Introduction
Sediment-Once water body is impacted, it is usually readily reflected in the quality
of the bottom sediment. Many contamination in water such as heavy metals and
hydrocarbon oils, are accumulated and magnified in the sediment, which is
relatively more stationary than the free-flowing surface water. Sediment study is
thus well accepted as a valuable measure of the long-term quality of aquatic
systems and a useful EIA tool.
This baseline soil study seeks to determine the present physical, chemical and
biological status of Tebidaba field. Soil parameters analysed will be assessed with
reference to standard limits and ascertain its sensitivity to future development
impact.
Soil-Soil is of ecological and economic importance, serving as a support and growth
medium for plants, habitat for soil fauna, and medium of growth for economic
crops, among other functions. A change in the normal characteristics of a given
soil may significantly alter its ability to serve a given function. Construction
activities and the operation of industrial facilities may impact soil properties; hence
soil studies are useful in EIA studies.
In a study to identify the changes in biotic and mineral composition of leaking
natural gas in soil, reported that the soil atmosphere becomes anerobic with large
number of hydrocarbon utilizing and sulphur reducing bacteria present. He also
noted an increase in manganese, which is detrimental to plants, and organic
matter, which makes the soil boggy. Sulphides of hydrogen and iron and
associated “sour gas” smell were also observed to be present with an increase in the
number of nematodes, actinomycetes and fungi when compared with the control.
The soils and sediments of study area were investigated to determine their physicochemical, erosional and nutrient characteristics so as to evaluate the probable
impacts of the activities of the proposed project on them.
Sampling Rationale
The soils along Ikebiri Creek, Okoluba Creek and adjoining canals from Ikebiri I,
Ikebiri II, through Ikebiri market to and around Agip Flow Station were randomly
sampled. Soil samples were sampled at two depths, 0-15cm (Top) and 15-30cm
(Bottom) at each sample point with a stainless steel auger; bulked samples were
thoroughly mixed to get one composite. Soil samples from each sampling location
were further divided into two portions (i) For THC content and (ii) for general
physico-chemical analysis. The representative sub-sample is filled to the mouth of
sample bottle in 500ml amber glass bottles. All soil samples were carefully handled
to avoid cross- contamination from Tebidaba to Warri. A total of twenty six (26) soil
samples were collected during the field operation. The location of the twenty six (26)
soil sampling points was marked on the map. Each sample information and colour
was recorded in the chain of custody forms. Each soil sample is labelled with
sample location, sample identity/ number; sample depth, time, date, and preserved
in cooler containing ice blocks prior to laboratory analysis.
Sediment samples were collected from the water stations within the study
locations. At each location were water was picked, the sediment samples were
collected by means of an Eckman sediment Grab, the same sampling stations was
Appendices 3.1 a-c
June 2005
Page 53 of 3
maintain for both season. After sieving to remove dirt and debris, and draining the
water, the sediment samples were placed in sampling bags, labelled and stored in
an ice-block cooler to prevent microbial degradation of the hydrocarbon.
Soil Colour
Each soil sample colour was determined in the field using munsell soil colour
charts with reference to the combination in the munsell system of time, value and
chrome. The most matching colour is chosen and its three components time, value
and chrome recorded against each soil sample.
Soil Texture and Soil Moisture Content
Soil texture and soil moisture in the field was examined by feel and visual
observation. Confirmatory tests and exact estimate will be carried out in the
laboratory.
Laboratory Analysis
Samples collected from the field were air-dried, crushed (except for those meant for
analyses of NH4+, NO3- and NO2-), passed through 2mm sieve and analysed for
the following physico-chemical parameters. All analysis was carried out using
standard methods (Van Reeuwijk, 1987 and IITA, 1984) with the appropriate
quality assurance protocols.
(i)
Hydrogen ion concentration (pH)
The pH values of the soil and sediment samples were determined by dipping
the glass electrode of a pH meter into a 1:2 soil/water suspension that had
been stirred and allowed to equilibrate for some time.
(ii)
Electrical Conductivity
The conductivity of the saturation extract of the soils was determined using
a Hilgar portable conductivity meter. Results were expressed in Siemens (S)
per cm.
(iii)
Mechanical Analysis
Particle size distributions were determined by the hydrometer method of
Bouyoucus as described by Day (1965); textural classes were obtained from
soil textural triangle shown in Fig 2.4
(iv)
Organic Carbon
This was determined by the Wet combustion method of Walkey and Black
(1934). The organic carbon determined was expressed as percentage of the
sample taken.
(v)
Available Phosphorus
The available phosphorus of the soil was extracted with Bray No. 1 solution
(0.03N NH4F + 0.02N HCl) and the phosphate in solution assayed by the
ascorbic acid-molybdenum blue colour method of Murphy and Riley (1972).
(vi)
Total Nitrogen
The total nitrogen was determined by the micro-Kjeldahl digestion method
(Bremner, 1965). No3-N and NH4-N were analysed using an auto analyzer.
(vii)
Exchangeable Bases
The exchangeable cations were determined by extracting with 1N neutral
ammonium acetate. The calcium and magnesium in the extract were
measured by atomic absorption spectrophotometry while sodium and
potassium were measured by flame photometry.
(viii)
Exchangeable Acidity (EA)
The EA was determined by the KCl method as described by Jackson (1962).
The exchangeable acidity of the soils was extracted with 1M KCl solutions
Appendices 3.1 a-c
June 2005
Page 54 of 3
and titrated for acidity with 0.1M NaOH solutions. Results were expressed
in milli-equivalents per 100 g soil.
(ix)
Effective Cation Exchange Capacity (ECEC)
The effective cation exchange capacity of the soils and sediments were
determined by summation of exchangeable cations and exchangeable
acidity.
(x)
Base Saturation
The Base saturation was calculated using the following equation:
% B . Sat . =
( ECEC − Exch . Acidity ) x 100
ECEC
20
80
2µ
m
60
40
m
rac
tio
n<
CLAY
µ
60
SILTY
CLAY
40
SANDY
CLAY
SANDY CLAY
LOAM
CLAY LOAM
60
SILTY CLAY
LOAM
nt)
rce
(pe
Cla
yf
2-
20
Certain particle size
classes can be subdivided
according to sand size
(e.g. Fine SANDY LOAM)
n
tio
ac
t fr
Sil
(pe
rce
nt)
100
80
SANDY LOAM
SANDY SILT
LOAM
SILTY LOAM
100
100
80
SAND
60
40
20
Sand fraction 60 - 2000 µm (percent)
LOAMY SAND
Figure 2.3: Textural triangle showing the percentages of Clay (below 0.002
MM) Silt (0.002 - 0.05 MM), and Sand (0.05 - 2.0 MM) in the basic
soil textural classes
(xi)
Extractable Ammonium (NH4+)
For the determination of ammonium in the soils, field fresh samples were extracted
with acidified 1.7 M NaCl and the ammonium in the extract assayed by the alkaline
phenate method.
(xii)
Nitrate and Nitrite (NO3-, NO2-)
The nitrate and nitrite nitrogen in the soils was extracted from fresh samples with 1
M sodium acetate solution. Nitrate in the extract was determined by the Brucine
method of Greweling and Peech (1964), while nitrite nitrogen was determined by
the alpha-naphthol method.
(xiii)
Sulphate (SO42-)
The sulphate sulphur in the soil was extracted with a solution of potassium
orthophosphate and the sulphate determined by the turbidometric method.
(xiv)
Heavy metals
Appendices 3.1 a-c
June 2005
Page 55 of 3
The heavy metals in soils and sediments were analysed by first carrying out a
leaching extraction of a weighed portion with 2M nitric acid. Final analysis was by
use of air acetylene Flame atomic spectrophotometry. Blanks were incorporated
into the sample, treatment procedures while other appropriate quality assurance
steps were observed. The final analysis of the soil and sediment solutions and
standard solutions were aspirated, respectively, into the air-acetylene flame of a
Perkin Elmer Atomic Absorption spectrophotometer, Model 403.
(xv)
Hydrocarbon Content
The hydrocarbon content of soil samples was determined by shaking 5 g of airdried soil with 30 ml of carbon tetrachloride and the concentration in mg l-1 of oil
in the extract was determined by means of a spectrophotometer at 420 nm. A
calibration curve was prepared from the readings obtained from known
concentrations of oil standards in the extract.
Vegetation Study
Field Procedure
The rapid assessment method was used to provide information on plant species
composition. All plants within the field of study were identified and listed while the
unidentified ones were collected, pressed and taken to the herbarium for correct
identification using the flora of West Tropical Africa and reference to the herbarium
of specimens in the University of Benin.
The state of health of crops and vegetation were also noted, while infected crops
and vegetation were collected and kept in moisture polythene bags for onward
transfer to the laboratory for further tests. This will include isolation and
characterisation of pathogenic fungi bacteria from infected plant materials. Also,
the vegetation types within and around the NAOC flowstation were determined for
their density and health status. Four transects each of 500m long Oriented North,
South, East and West of the flowstation was used to carry out qualitative and
quantitative assessment of the vegetation. Random quadrants were used to
determine population density of the plant species by counting the number of plants
in each quadrant.
Structure
For the determination of the vegetation structure, the crown diameter of all woody
trees over 3 m in height and 10 cm in girth at breast height were estimated. In
order to quantify the above ground biomass of the herb layer, eight 1 m x 1 m
quadrants were selected along sub-transects in the study sites. All the plant
materials within each quadrant were cut, sub-sampled and taken to the laboratory
for analysis of dry matter according to Chapman (1976). Structural information
was obtained from 80m long transects established within homogenous vegetation
community as described by Muiller-Dombois and Ellenberg, (1974) and Smith
(1990). Information on the economic uses of plants was obtained through oral
interview and literature.
Crop and Plant pathology
The state of health of crops and vegetation were noted while infected crops and
vegetation were collected and kept in moistened polythene bags and transported to
the laboratory for further study.
Laboratory study included isolation and
characterization of pathogenic fungi and bacteria from infected plant materials.
Herbarium and Laboratory Procedure
Unidentified pressed specimens were taken to the laboratory and identified using
the Flora of West Tropical Africa (Hutchinson and Dalziel, 1958 - 1968) and
reference to herbarium specimens in the University of Benin. The plant biomass
Appendices 3.1 a-c
June 2005
Page 56 of 3
was obtained by drying the plant material in the oven at 105°C till they attained a
constant weight. The dry matter to fresh weight ratio of each sample was used to
convert field fresh weight to dry weight.
Air Quality
Choice of Sampling Points
A field reconnaissance visit was first carried out along the entire study site to the
Agip flowstation. Features, which could determine variations in air quality at
different points, were identified, for consideration in the selection of the sampling
points. It was visually observed that there were no significant point sources of
atmospheric pollutants emission in the area. Most of the length of the study site
was located in farmlands/creeks near very small rural communities or villages
where no significant pollution related activity was taking place. There was however,
one location that was of significant interest to require special sampling. This is (i)
the vicinity of the Agip flowstation, which is a crude oil processing plant at the
outskirts of the study site. The flowstation utilise power and /or diesel generators
for energy supply.
There is thus the possibility of some impaction of air quality. Another main points
of likely interest are the two major settlements of Ikebiri I and II, which attract
influx of boat (powered with fossil fuel) movement A control sampling point was
identified at Okuromukpa, a remote village, located some 1-2km away from the
study site. After considering the various features of the study area, the following
five points were selected for air sampling: The proposed flowstation, a location close
to Agip flowstation, Okuromukpa Village, Ikebiri I and II.
(a) Field Procedures
Air sampling field equipment was set up in the field. This comprised an electrically
driven vacuum pump and a box containing air sampling trains for SO2, total
nitrogen oxides (NOx), O3, NH3 and particulate. Sampling was carried out using an
air sampling train mounted on a platform at a height of 1.5-2.5 metres from the
ground. Air was drawn at a flow rate determined by a fitted calibrated critical
orifice, into a series of glass scrubbers fitted with about 10ml absorbent solutions
to absorb specific gases. Sampling was done for about one hour at each sampling
site. With this set up sulphur dioxide, nitrogen oxides etc were determined in the
Tebidaba field. After one hour the solutions in the scrubbers in the sampling train
were poured into glass vials. These were then taken to back to the laboratory and
each analysed by specific standard methods. Typical air sampling trains, with their
components, for SO2 and NOx are shown in Figures 2.5 & 2.6.
(b) Laboratory Procedures
The details of the analytical methods including the principles and laboratory
procedures for the different components are shown below:
(i)
Sulphur Dioxide (SO2)
Principle
The para-rosaniline method West and Gaeke (1956) was used. This method is
essentially specific for sulphur dioxide. It involves the use of a scrubbing solution
containing tetrachloromercurate ion to collect sulphur dioxide from air. The SO2 is
trapped as dichlorosulphitomercurate ion. This complex is stable and is later
reacted with formaldehyde and pararosaniline to produce pararosaniline methyl
sulphonic acid, which has an intense red-violet colour with maximum absorbance
at 548 nm. The sensitivity of the procedure is normally 5 mg/m3. In this exercise
a detection limit of 20 mg/m3 was achieved by scrubbing 30 litres of air through
10 ml of absorbing solution.
Appendices 3.1 a-c
June 2005
Page 57 of 3
Reagents
(a) Absorbing solution: This was prepared from analytical reagent grade
chemicals and double-distilled water. It was prepared by dissolving 10.86 g
mercuric chloride, 0.066g disodium salts of ethylenediamine-tetra-acetic acid
and 6.0g potassium chloride in 1000 ml distilled water.
(b) Sulphamic acid solution: The solution was prepared as required by dissolving
0.6 g sulphamic acid in 100 ml solution.
(c) Formaldehyde: This was also prepared as required by diluting 5 ml 36%
formaldehyde to 1000 ml.
Filter
Critical
Orifice
Air Pump
Trap
Intake
Absorbing Solution
Midget Impinger
Fig. 2.4: Sampling train for Sulphur Dioxide
(d)
(e)
(f)
(g)
(h)
Stock iodine solution: 12.7g iodine and 40.0g potassium iodide were dissolved
in 25 ml water and made up to one litre in a standard flask to give 0.10 N
stock iodine solution. From this solution, 0.010 N iodine was prepared as
required, by diluting 50.00 ml to 500.0 ml.
Starch indicator: A paste of 0.4 g starch and 0.002 g mercuric iodine was
added to 200 ml boiling water and kept boiling to dissolve.
Stock sodium thiosulphate solution: The solution was prepared by using
freshly boiled and cooled distilled water to dissolved 25g sodium thiosulphate.
0.50 g Na2CO3 was added to the mixture before making up to 1000 ml. It
was standardised against dried (180°C) potassium iodate. From this, 0.01 N
solutions was prepared as required by diluting 100 ml of the stock solution to
1000 ml using standard flask.
Standard sulphite-TCM solution: Standard sulphite solution was first
prepared from sodium sulphite (0.5 g sodium sulphite per 500 ml solution
using fresh double distilled water) and standardised by back-titration using
excess iodine and standard thiosulphate solution. The standard sulphite-TCM
solution was then prepared by making up 2.00 ml of the sulphite standard to
100.0 ml in a standard flask using the absorbing solution.
Pararosaniline reagent: 20.0 ml of 0.20% purified pararosaniline and 25 ml of
3 M orthophosphoric acid were diluted to 250 ml with water in a standard
flask.
Laboratory Procedure
(a) Sample Analysis: A minimum of 30 minutes was allowed to elapse after
sampling before analysis commenced. This is recommended to allow for the
complete decomposition of any ozone in the sample. The absorbing solution
Appendices 3.1 a-c
June 2005
Page 58 of 3
was quantitatively transferred into 25 ml standard flask, using minimum
amount of water for rinsing. 1.0 ml of 0.6% sulphamic acid was added and
allowed to react for 10 minutes to destroy any absorbed oxides of nitrogen. 2.0
ml of 0.2% formaldehyde solution and 5 ml pararosaniline solution were then
added to the flask. The mixture was allowed to stand for exactly 30 minutes
before making up to mark with freshly boiled and cooled distilled water. The
absorbance (A2) of the solution was taken at 548 nm in 10 mm cell, using
distilled water as reference. A blank was prepared by similar treatment of 10 ml
of unexposed absorbing solution. A control was also prepared by taking a
mixture of 2 ml standard sulphite-TCM solution and 8 ml absorbing solution
through the same process as the sample solutions. The absorbance of the
blank (Ao) and the control were then measured at 548 nm in 10 mm cell.
Filter
Air
Pump
Trap
Intake
Absorbin
g
Solution
Oxidizer
Frit
Self
Indicator
Silica gel
Fig. 2.5: Sampling train for Nitrogen Oxide
(b) Calibration of Laboratory Procedure: 0.50, 1.0, 2.0, 3.0, 4.0 ml of the sulphiteTCM standard solution were measured into separate 25 ml standard flasks. 9.5,
9.0, 8.0, 7.0, 6.0 ml absorbing solutions were added in that order to the flasks
containing the standards. The colour reaction was carried out as described for
the sample and absorbances were measured at 548 nm in 10 mm cell. A
calibration graph (absorbance vs. concentration of SO2) was plotted and the
calibration factor, reciprocal of the slope of the calibration line, as calculated
and used as the calibration factor.
(c) Calculation:
The ambient SO2 concentration was calculated from the
experimental data as follows:
Con ( µg SO2
As
Ao
F
V
(A s − A o ) x ( 103 ) x ( F )
/ m ) =
V
3
= Absorbance of sample
= Absorbance of reagent blank
= Calibration factor
= volume of sample (ml).
(ii)
Nitrogen oxides (NOx)
Principle
Total nitrogen oxides (nitric oxide and nitrogen dioxide) were determined by the
Griess-Saltzman reaction as described in ASTM standard method D3608.77T
Appendices 3.1 a-c
June 2005
Page 59 of 3
(1977). Essentially, the method involves sampling air at the rate of 0.4 litre/min
for one hour using a sampling train with an oxidant to convert oxides of nitrogento-nitrogen dioxide, and with an absorbing reagent, which immediately converts the
total nitrogen dioxide to a red-violet azo dye, which absorbs at 550 nm. The
procedure operated at a detection limit of 4 mg/m3.
Reagents
(a) Absorbing solution: The absorbing solution was prepared by first dissolving 5.0
g of anhydrous sulphanilic acid in a mixture of 140 ml glacial acetic and 700 ml
water. The mixture was heated to dissolve the sulphanilic acid. The cooled
mixture was transferred into a 2 litre standard flask. 20 ml of 0.1 % N- (1naphthyl)-ethylenediamine dihydrochloric acid and 10 ml acetone were added to
the flask. The mixture was made up to one litre with distilled water and mixed
thoroughly. The solution was stored in a brown reagent bottle and kept in a
refrigerator when not in use.
(b) Chromic acid oxidant: This was prepared by dissolving 17 g of chromium (VI)
oxide in 100 ml distilled water.
(c) 0.1% N- (1-Naphthy1)-ethylenediamine dihydrochloric acid: 0.10 g of the
compound was dissolved in 100 ml of water and stored in a brown bottle. The
solution was normally kept in a refrigerator when not in use.
(d) Standard sodium nitrite solution: A stock solution containing 2.5 g sodium
nitrite was prepared and standardised. The strength of the solution was
adjusted to 2.16 g/litre. From this stock solution a working nitrite standard
solution containing 2.16 mg sodium nitrite per litre (equivalent to 20.0 mg
N02/L) was prepared by dilution as and when required.
Sample Analysis: The absorbances of the red-violet colour of the samples were read at
550 nm.
(b) Calibration of Laboratory Procedure: 0.10, 0.20, 0.40, 0.60, 0.80 and 1.00 ml of
the standard nitrite solution were measured into separate 25 ml standard
flasks. Each one was diluted to mark with the absorbing reagent. After fifteen
minutes, the absorbances of the standards were read at 550 nm. A calibration
graph (Absorbance vs. concentration of NOx) was plotted and the calibration
factor (reciprocal of the slope of the calibration line) was calculated.
(c) Calculation:
The ambient NOx concentration was calculated from the
Conc ( µg NOx /
A
F
V
V
m ) =
3
( A x F x 103 x v )
V
= Absorbance of sample
= Volume of sample (ml)
= volume of absorbing solution (ml)
(iii) Ammonia (NH3)
Principle
Ammonia was absorbed in dilute acid solution and the resulting solution was
treated with Nessler's Reagent. The reagent is alkaline solutions of mercury (II) ion
in the stoichiometric quantity of potassium iodide required to produce tetraiodo
mercurate (II) ion. The product of the reaction between ammonia and this reagent
is yellow to orange-brown, depending on the concentration of ammonia. Its
absorbance is measured at 410 nm for the low end concentration end of the
wavelength range.
The reaction is:
Appendices 3.1 a-c
June 2005
Page 60 of 3
HgI4- + NH3 + 30H- = I-Hg-0-Hg-NH2 + 71- + 2H20
Reagents
(a)
The absorbing solution: The absorbing solution was 0.01 M HCl solution.
(b) Nessler's Reagent: 100 g reagent grade mercury (II) chloride and 70 g reagent
grade potassium iodide were dissolved in about 200 ml ammonia-free distilled
water. The mixture was added gradually and with continuous stirring to a
solution of 160 g NaOH in 500 ml water. The solution obtained was made up to
one litre and stored in a dark borosilicate reagent bottle.
(c) Standard ammonia solution: Stock ammonia standard (1000 ppm) was
prepared by dissolving 3.819 g analar grade ammonium chloride (dried at
100°C) in one litre water in a standard flask.
From this solution, 10.0 ppm ammonia standard was prepared as required by
diluting 10.0 ml to one litre in a standard flask.
(a) Sample Analysis: 2.0 ml of the Nessler's reagent was added to the sample
solution.
10 min was allowed for colour development.
Absorbance
measurement was made at 410 nm.
(b) Calibration of Laboratory Procedure: 0.0 (blank), 2.0, 4.0, 8.0, 10.0, 12.5, 15.0
and 20.0 ml of the ammonia working standard were measured into separate
100 ml standard flasks and made up to mark with ammonia-free water. 10.0
ml of each standard was measured into a tube. 2.0 ml Nessler's reagent was
added to each and absorbances were read at 410 nm. The reciprocal of the
calibration graph was used as the calibration factor. Distilled water used for
preparing the reagent was used as reference.
(c) Calculation:
The ambient NH3 concentration was calculated from the
17 F (A s - Ab ) x 103
Conc ( µg O3 / m3 ) =
V
As = Absorbance of sample
Ab = Absorbance of air blank
F
V
= Volume of sample (ml)
(iv) Particulate
The filter paper was dried at 105°C for one hour. After cooling in a desiccator to
room temperature, it was weighed to the nearest milligram. Particulate level was
calculated as follow:
Conc ( µg / m )
3
=
( Ms
- M o ) x 103
V
Ms = Mass of filter paper after sampling
Mo = Mass of filter paper before sampling
V
= Volume of sample (ml).
Climate
Field monitoring of the micro scale climate of the project sites was carried out by a
weather station set up during the period of the field study.
Wind speed and direction were monitored using a cup anemometer and wind vane
respectively. A rain gauge was used to measure the daily precipitation in the field
while relative humidity was determined using an automatic self-recording
Appendices 3.1 a-c
June 2005
Page 61 of 3
Hydrograph. Temperature data were recorded with the aid of a mercury-in-glass
thermometer.
During the report preparation the laboratory, historical data collected on the
climatic variables were analyzed to provide the general characteristics of the
mesoscale climate of the project area.
Using historical and field data for the region, wind roses (frequency and speed) were
constructed for the different seasons. The main features of humidity examined were
the mean, maximum and minimum relative humidity, all calculated from the
historical data of the project region. On the whole, data on climatic factors were
used to prepare and compute, respectively:
· Wind roses ( a picture of historical wind direction and speed).
· Aridity Index using rainfall and temperature data according to the formula of Ewer
and Hall (1978).
Aridity Index =
12 p
T + 10
where,
p is mean monthly rainfall (mm) and
T is mean monthly air temperature (°C).
· Flood flow maps in relation to seasonal spatial distribution of rainfall.
Ecological Programme
Phytoplankton Composition and Diversity
In each of the 24 water sampling stations, phytoplankton were collected just below
the water surface with a quantitative 55 micron mesh tow net attached to a cowl
with an aperture diameter of 17 cm. Fixed into the inside of the cowl was a flow
meterwhich, measured the flow rate of the water which passed through the net.
Each tow was made for 2 minutes at an approximate speed of 8 km per hour. The
catches were immediately removed from the net, bottled and preserved in a solution
of 4% formaldehyde. The phytoplankton was examined in the laboratory using a
Leitz Orthoplan Universal Wide-field Research Microscope equipped with tracing
and measuring devices. One ml of the concentrated sample was introduced into a
counting chamber and an average of 10 rows counted. The average frequency
distribution of the different species was recorded.
Diversity index D, and
Dominance C° were calculated from the following expressions:
No
D = Nx ,
2
N0
ni
o
C =∑
N
i=1
Where:
Nx = No. of individuals in cells/station,
ni = Importance value for each species,
N = Total of importance values,
No = Number of species in sample.
( )
Zooplankton Composition and Diversity
For qualitative study, zooplankton hauls were made with a 55 micron mesh tow net
fitted with a flow meter. Zooplankton collected was preserved in buffered 4%
formalin in 200 ml plastic containers. For quantitative study forty (40) litres of
Appendices 3.1 a-c
June 2005
Page 62 of 3
water were filtered through a 55 micron mesh plankton net and reduced to 50 ml
concentration. In the laboratory, counting was done in a l ml Koltwitz counting
chamber with grids. Row after row of the counting chamber was examined by
means of an Olympus Vanox Research Microscope and the numbers of individual
species recorded. Zooplankton numbers were computed from the equation:
N x S x 1000
V
Where,
N = number of zooplankton in 1 ml of sample
S = volume of sample (50 ml)
V = initial volume of sample (40L).
Fauna
Macrobenthic fauna are those organisms, which are over 1.0 mm in size, living on
or in the substrate. They may be infauna (living wholly or partially buried in soft or
hard substrates e.g. bottom dwelling annelids, chironomids and bivalve molluscs)
or epifauna (living on the surface, either, crawling as mobile benthic inhabitants or
attached to different types of substrates e.g. crabs; littorinids, barnacles and
oysters attached to the roots of Rhizophora).
The fauna were investigated by the methods outlined below. Two types of sampling
were carried out at each station for the estimation of abundance and diversity of
fauna. Collection of intertidal macrofauna was done with a one square metre
quadrant. Organisms were identified and counted in situ, and specimens, which
could not be identified in the field, were collected and preserved in some quantities
of 40% formaldehyde. For the infauna, an Eckman grab was used to collect the
sediment from 0.0225 square metre areas.
Sorting of organisms from the residue and counting were done under the binocular
dissecting microscope and the compound microscope. Identification was carried
out from whole specimens and prepared slides using relevant identification
manuals and keys. All indices of diversity used in statistical analyses were adapted
from Odum (1971) and Zar (1983).
Fauna of bottom sediments of rivers and creeks
The bottom samples were sieved in the field using a set of Tyler sieves of different
mesh apertures (150 mm, 300 mm, 500 mm, 650 mm, 1 mm and 2 mm). The
sediment sampling stations, which coincided with water sampling stations, are
shown in Fig. 2.2.
Preservation
All organisms collected were preserved in 10% formaldehyde.
Laboratory analyses
All samples collected during the field work were examined using the binocular
dissecting microscope. Identifications were made using relevant identification
manuals and literature.
Statistical analyses
Indices of species diversity and evenness were used to characterize the faunal
community structure.
Collections are believed to be representative of the
community at the site of collection and the numbers of taxa and their relative
abundance are the essential properties. The Margalef's index (d) of taxa richness,
Appendices 3.1 a-c
June 2005
Page 63 of 3
Shannon-Wienner index of general diversity (H) and Evenness (E) were used to
express the descriptive properties.
Margalef's Index (d):
d = s-1/lnN
where,
s = number of taxa
N = total number of individuals
Shannon-Wienner Index (H):
H = NlogN - S nilog ni
N
Where,
N = total number of individuals
K = total number of species
ni = number of individuals in the ith species
The Evenness component of diversity expresses the degree of uniformity in the
distribution of individuals of each taxon in the collections.
E = H/Hmax.
where,
Hmax. = logK (Zar, 1983).
The Slack system was used in the determination of dominant, sub-dominant,
common and rare groups of genera. Taxonomic groups or genera comprising:
15% or more of the total number of individuals collected = Dominant
5 - 14% = Sub-dominant
1 - 4% = common
<1% = Rare.
2.3.5 Fisheries
Delineation of the important species and harvest methodology were arrived at,
through:
1.
Inspection of catches by local fishermen both in the field and in fishing camps,
2.
Interviews of fishermen in camps regarding catch composition and
methodology,
3.
Survey of the fishes on sale within the project environment, and interview with
the fisheries middlemen about the source of their fishes.
Fish Analysis
(a)
Laboratory Analysis
The species collected from the project area were used for laboratory analyses.
Specimens were thawed at room temperature, coded and identified. The following
parameters were determined prior to anatomical examination : Total and standard
length (cm), body weight (g), sex which was confirmed when the fishes were
dissected by noting the presence of testes or ovaries. Each specimen was closely
examined for disease signs and the presence and details of internal parasites.
(b)
Calculation
Fultons condition factor = w/L3 x 100 is an index of the well being for whole fish where,
w = weight of fish
L = length.
Gonado-somatic index: This is the percentage of the whole weight of the ovary (gm)
over the whole weight of the fish (gm). The gonado-somatic index changes in
accordance with the breeding cycle and serve as an independent quantitative
Appendices 3.1 a-c
June 2005
Page 64 of 3
means of determining the season or period of highest gonadal development and
maturity. It is also an indicator of the well being of the gonads.
Length - weight relationship.
The length - weight relationship was calculated using the formula described by Le
Cren (1951):
w = a Lb - - - - - - - (1)
The data were transformed into logarithms before the calculations were made.
Thus equation (1) was transformed into: Log w = log a + b log L - - - - - - (2)
Where,
w = weight of the fish in g
L = Total length of the fish in cm
a = constant and b = an exponential value.
(c)
Gustatory analysis
Questionnaires were given out to families so as to evaluate the taste, flavour, and
quality of the flesh of the fishes of different species collected from the various
stations during the course of this study.
Microbiology
Surface and bottom water, bottom sediments and random soil samples (RSS),
collected into sterile plastic bottles and polythene bags respectively, were kept in a
cooler containing ice-chest and analysed for microbial contents within 12 hours of
collection.
Heterotrophic bacterial counts
The total heterotrophic bacteria in both water and soil were enumerated using
modified yeast extract agar (Cruickshank et al, 1975). Bacteria isolates were
identified according to the scheme of Buchanan and Gibbons (1974).
Determination of Fungal Content
The total fungal counts in the water and soil samples were determined using
Emmons, Binford and Utz's modified Sabouraud Dextrose Agar (Cruickshank, et al,
1975). Isolated fungi were identified based on the associated spores and mycelia
and their growth characteristic on the isolation medium.
Determination of Percentage Petroleum Degrading Bacteria and Fungi
The petroleum degrading bacteria were enumerated on petroleum agar medium
while chloramphenicol was added to this medium for the selective isolation and
enumeration of petroleum degrading fungi. Any bacteria or fungi growing on these
media were regarded as petroleum utilizers or degraders.
The percentage of these counts to the total heterotrophic bacteria or fungal counts
was then calculated to obtain the percentage petroleum degrading bacteria and
fungi respectively in each sample.
Socio-Cultural Programme
The socio-economic/cultural studies in the study area were based on extensive
literature materials and interviews using structured questionnaires.
Appendices 3.1 a-c
June 2005
Page 65 of 3
Field and Laboratory Procedures
Noise
Introduction
Background noise levels are those noise levels, which prevail 90% of the time. In
the rural areas, it is typically 30-40 dBA. In the project area consisting of many
dredge slots; watercrafts help to increase the background noise level.
Noise Survey
Noise level measurements were made with CEL Precision Integrating Sound Level
Meter Type 493, fitted with ½" condenser microphone and windshield.
Measurements were made 1.0-1.5m away from noise sources and the meter was
held at full arm’s length away from observer's body to minimize reflection. Sound
power measurements to determine the sound power of the noise source were made
with the microphone held 25 mm from the radiating surface.
Before
commencement of measurement, and in-between measurements, the meter was recalibrated with CEL Pistonphone.
Socio-economics
The principal objective of this socio-economic study is to identify and examine the
specific effects of the project on the socio-economic life of the inhabitants of the
area. This objective was pursued by carrying out a series of investigations to collect
and collate data on the prevailing situation.
In selecting the communities to sample, the cluster sampling method was used.
Contiguous communities were grouped together and three communities namely,
Agip Community, Ikebiri I and II communities were picked.
Methodology
The socio-economic environment can be identified as including:
(a)
Population structure and dynamics;
(b)
Land use and settlement patterns;
(c)
Labour supply and employment structure;
(d)
Production, income distribution and consumption;
(e) Social organisation and institutions.
Two broad categories of methodologies were utilised in this study, namely,
ethnographic and socio-demographic survey method.
Ethnographic Method
This method entails visiting and interacting with the settlers in the project vicinity
and observing, asking questions and recording gathered information. In some
settlements, where no settlers spoke nor understood English language, services of
interpreters were enlisted. The ethnographic method is ideal for studying social
organisation and institutions such as marriage and family, religion, economy and
polity of the localities and their land/water use and settlement pattern.
Socio-Demographic Survey
In studying the socio-demographic structure and dynamics of the localities, we
concentrated on inquiring into the population structure (age, sex and other
compositional characteristics) and dynamics (birth, death, migration and marriage
rates) of the inhabitants. We emphasised the educational, occupational and work
statuses of the population of the settlements.
Appendices 3.1 a-c
June 2005
Page 66 of 3
Data Collection
Four main methods of data collection were used - namely:
•Questionnaire
•Focus Group Discussion (FGD)
•In-depth Interview (IDI)
•Observation
In the questionnaire method, a questionnaire was administered to the heads of
households in each community. In selecting the heads of households however,
systematic random sampling was adopted.
For the FGD, one session each was conducted in the three communities.
Furthermore, three in-depth interview sessions were held in three communities.
The observable physical features in the communities such as markets, house types,
shrines, and roads were recorded. Where necessary, photographs of these places
were taken.
Hydrogeology
Methodology
Geophysical investigation
Field Techniques
a.
Hydrogeology
Surface hydro-geological mapping was conducted to evaluate surface water
distribution and flow direction in the area.
b.
Geophysical Investigation
The field equipment used in this investigation is the ABEM TERRAMETER SAS 300C in
Combination with the ABEM TERRAMETER 300C BOOSTER and the GEOMAC III FIELD
COMPUTER. Based on the pre-knowledge of the Geology of the Niger delta Basin, the
standard Schlumberger electrode configuration was employed for VES (Vertical Electrical
Sounding) profiling. Measurements were taken at expanding current electrode distance such
that, as in theory, greater penetration depth of the injected electrical current is achieved for
successive readings. The potential electrode position was kept constant for successive
measurements, but changed only when the voltage reading become too small to be
accommodated by the Terrameter’s sensitivity for a VES station measurements. The ratio of
potential electrode separation to the current electrode spacing was kept at 1: 5.
The Geomac III field computer in addition to its use for data acquisition provided a
direct means of ensuring that spurious data were not accepted in error. This is
because it gives an immediate field plot of the apparent resistivity values (which is a
product of the internal resistance as measured by the Terrameter) and the geometric
factors (a parameter dependents on the relative disposition of the potential and
current electrodes i.e. AB/2). This plot is qualitatively interpreted on the field and if
considered satisfactory is accepted and stored in the memory to be recalled and used
for further computation and interpretation. Five (5) VES stations: - VES- 1, 2, 3, 4
and 5 (see Figures 3.12a-e) were run to cover the area under investigation. VES
station spread was between 215m (approximately 705ft) to 464m (approximately
1521.5ft). This spread was limited to the presence of water bodies and other surface
structural obstructions surrounding the site. Only in the station VES-4, was the
maximum current electrode separation of 464m (approximately 1521.5ft) attained.
Appendices 3.1 a-c
June 2005
Page 67 of 3
Interpretation
VES investigation penetrated horizons in which the depth recognition of the
instrument was at infinity. These geoelectrical layers are: 11.10Ωm beyond 10.6m
depth at VES station 1, 14.15Ωm beyond 11.8m depth at VES station 2, 9.55Ωm
beyond 15m depth at VES station 3, 44.56Ωm beyond 35.5m depth at VES station
4 and 39.64Ωm beyond 22.5m depth at VES station 5. Initial interpretation was
done using the curve matching technique. Layer parameter were subsequently
derived and defined for the initial model and used in the computer-assisted
interpretation of the VES station data. Final interpretation was achieved using
linear filters for the computation of apparent resistivity standard curves for a
horizontally stratified earth (Ghosh, 1971).
Boring / Drilling Operations and Measurement of Water Levels
The equipment used were a Rotary Drilling Rig (hand-operated), Water Level
Indicator with metric graduations, Clinometer (directional compass) and Magnify
lens. Other materials used are a measuring steel tape, borehole water sampler and
sterilised sample bottles.
A total of eight (8) boreholes were located and drilled. The boring of the holes were
carried out by hand-operated percussion rig to obtain core samples that are in their
natural state and unpolluted by drilling fluids.
During the boring process, the interim casings (conductor pipes) were gradually
pilled down to prevent possible caving in of the borehole wall. After drilling to the
required depth, the interim casings were withdrawn to give way for installation of
permanent PVC casings and screen. The annular space between the PVC casing
and the drilled hole were later backfilled with granular materials (i.e. gravel
packed), followed by cement slurry. Then, the top of the boring out-side the PVC
casing was cemented for propose seating of the installed casing (cement base).
Thereafter, a surficial elevated pad was constructed to facilitate drainage around
the well installation and to prevent ponding of water in the immediate vicinity and
thus protecting the borehole from being contaminated.
Water Sampling and Analysis
Sampling of core samples and borehole (groundwater) for laboratory analysis was
done during borehole boring operation. Core samples were collected and logged at
regular interval of 1m down to the (first) aquifer depth of each borehole. Measuring,
observing and recording of water levels in boreholes with their corresponding depth
was also carried out using water level meter/indicator. Seven groundwater samples
were also collected from the bored holes.
Subsequently, the surface and groundwater samples were analysed for their
respective cations and anions alongside with other quality parameters at the
analytical laboratory of the Tudaka Laboratory, in Warri.
Quality Assurance
Introduction
Standard Quality Assurance and Quality Control Procedures was applied in
carrying out this study, to eliminate ambiguous data, improve interpretation and to
ensure conferment of data validity and reliability during sample collection,
preservation, storage, transportation, laboratory analysis and data generation and
presentation.
The quality assurance procedures used in this study are highlighted below to
provide information concerning AMBAH procedures and methods of compliance
Appendices 3.1 a-c
June 2005
Page 68 of 3
with quality concerns and requirements. These standards are set by the regulators
(DPR and Federal Ministry of Environment) and meet the requirements of ISO 9002
Standard. They include all activities used to ensure and document the accuracy,
precision, completeness and representativeness of the analytical results and field
observations.
Sample Procedures
Field Sampling
To ensure the accuracy and reliability of in situ field measurements, field
instruments were calibrated prior to use and crosschecked from time to time. The
field portable pH meter was calibrated using pH 4, pH 7 and pH 9 buffer solutions.
The conductivity and dissolved solid meter was checked against TDS/conductivity
solutions whose concentrations are known. Water sample containers were washed
with detergent and thoroughly rinsed first with clean water and finally with distilled
water. DPR (1991) quality assurance guidelines were followed. Samples were
collected directly into clean plastic containers, after rinsing with portions of the
water being sampled. Preservatives were used as necessary. Analyses were carried
out in the order dictated by the stability of the parameter. Water samples for
plankton analyses were preserved in accordance with DPR guidelines of 1991.
Water and soil samples for special analyses were kept and transported in ice chests
before the time for analyses.
Soils /Sediments
Sampling equipment was normally rinsed with water and was further 'washed' with
soil from the area to be sampled to prevent cross contamination. Samples were
stored in fresh polythene bags; aluminium or glass jars as soon as collected.
Drying was carried out in a plastic tray in a clean well-ventilated room. Samples
were adequately spaced while drying to avoid all sort of cross-contamination.
The quality assurance protocol employed for vegetation sampling included:
(i)
Slashing the woody bark to choose the colour of the wood in case of doubt in
species identification and also to determine the latex from the species.
(ii)
In collecting unidentified species, efforts were made to collect samplings with
the flowers, fruits and seeds because these attributes aid identification in
the herbarium.
(iii)
Plant tissues or materials to be pressed were placed inside folded absorbent
sheets in such a way as to avoid unnecessary folds of the parts. These were
then placed in between two boards with corrugated lining, with the press
being fastened with straps or twine while in the field.
(iv)
The adsorbent folder was changed daily to hasten drying and to prevent the
growth of moulds and insect attack on the specimen.
(v)
The specimen collected were preserved by spraying saturated solution of
paradichlorobenzene or 2% alcohol solution of mercuric chloride to prevent attack by
insects or moulds.
(vi)
In the herbarium, plant materials were compared with previously preserved
authenticated collection.
Appendices 3.1 a-c
June 2005
Page 69 of 3
Socio-economics study employed the following quality assurance strategy:
(i)
Community relations were carried out prior to the commencement of the
study.
(ii)
(iii)
(iv)
Field assistant was selected on the basis of his adequate educational
background and ability to speak English and the local languages of the Ijaws
fluently. This guaranteed easy communication with the inhabitants of the
settlements.
Interview was conducted only when it became clear that the interviewee was
convinced that the information being collected was not for tax assessment or
any other adverse purpose.
The interview schedule/questionnaires were pre-tested in and around Warri
and standardized prior to the commencement of the actual fieldwork.
Quality Assurance of Geophysical Studies
VES measurements were taken such that there were six (6) readings for every
logarithmic decade. This gave a very good sampling density, which should enhance
the signal to noise ratio of the field data. The potential electrodes were only
expanded when the potential difference became too low.
Additional precautions taken to assure quality included:
(i) Reduction of contact resistance, especially at large electrode spacing.
(ii) Double electrodes were used for low resistance measurements.
(iii) Possible sources of noise such as metal objects were avoided.
(iv)
An average of four readings at each position was usually taken.
(v)
As a control, it was ensured that increase in the magnitude of current injected
into the ground did not lead to a change in the measured resistance.
(vi)
In the absence of previous geophysical data, the sounding results were
compared with geophysical information collected on existing boreholes,
where available.
Laboratory Procedures
All laboratory procedures were adequately standardised and all instruments
appropriately calibrated. Standard laboratory quality control procedures were
adhered to for wet chemical analyses of water samples.
These included
determination of reagent blanks, use of fresh standards and replicate analysis for
confidence limit, and cleaning of glassware and other containers. Water samples
for hydrocarbon determinations, and microbiological analyses for the above
determinations were similarly treated.
Laboratory Sample Custody
Sample custody is defined as all records and documentation that is required to
trace a sample from point of origin through disposal after analysis. The sample
custody documentation used in this study includes:
Field Notebooks/samples tags
Field sample custody records (Chain of Custody and Analytical Requests)
Laboratory sample receipts logs
Analytical (instrument) logs and worksheets
Appendices 3.1 a-c
June 2005
Page 70 of 3
Final Reports
Sample Disposition logs
Sample Containers and Preservatives
Table 2.3:
Shows the various containers
recommended by DPR Standard.
Parameters
Container
Table 1A: Bacterial Test:
Total and Faecal P,G
Coliform
Table 1B-Inorganic Tests:
Acidity
P,G
Alkalinity
P,G
Ammonia
P,G
and
preservatives
Sample
Volume
Preservation
Max.
Time
100ml
Cool 4oC, 0.008%
NaS203
6 hours
100ml
100ml
100ml
Cool 4oC
Cool 4oC
Cool 4oC, H2SO4 to
pH<2
Cool 4oC
Cool 4oC, H2SO4 to
pH<2
None Required
None required
14 days
14 days
28 days
BOD
COD
P,G
P,G
1 liter
50 ml
Chloride
PH
P,G
P,G
50ml
50ml
Nitrogen, Kjeldahl
and Organic
Nitrate
Nitrate/Nitrite
P,G
1 Liter
P,G
P,G
50ml
50ml
Nitrite
Oil and Grease
P,G
P,G
50ml
1 liter
Organic Carbon
P,G
25ml
Orthophosphate
Dissolved Oxygen
(Probe Method)
Dissolved Oxygen
(Winkler’s Method)
Phosphorous,
Elemental
Phosphorous,
Total
TS
TDS
TSS
Specific
Conductance
Sulphate
Temperature
P,G
G.
top
bottle
G,
top
bottle
G
and
50ml
1 liter
and
1 liter
Cool 4oC, H2SO4 to
pH,2
Cool 4oC
Cool 4oC, H2SO4 to
pH<2
Cool 4oC
Cool 4oC, H2SO4 to
pH<2
Cool 4oC, H2SO4 to
pH<2
Filter immediately
None required
Fix on site, store in
dark
4oC
50ml
used
Holding
48 days
28 hours
28 days
Analyse
immediately
28 days
48 hrs.
28 days
48 hrs.
28 days
28 days
28 hrs
Analyse
immediately
8 hours
48 hours
28 days
100ml
100ml
100ml
100ml
Cool 4oC, H2SO4 to
pH<2
Cool 4oC
Cool 4oC
Cool 4oC
Cool 4oC
P,G
P,G
100ml
100ml
Cool 4oC
None Required
Turbidity
P,G
METALS : C
100ml
Cool 4oC
28 days
Analyse
immediately
48 hours
Hexavalent Cr
P,G
or
Cool 4oC
24 hours
Mercury
P,G
or
Cool 4oC
24 hours
All other metals
P,G
200ml
50g
200ml
50g
100ml
HNO3 pH<2
6 months
Appendices 3.1 a-c
P,G
50ml
P,G
P,G
P,G
P,G
June 2005
7 days
7 days
7 days
28 days
Page 71 of 3
as
TPH
Wide
mouth
glass jars with
teflon liner or
stainless
steel/brass
cylinder
1000ml
Cool 4oC
14 days
LEGEND:
P=PLASTIC ,G=GLASS
2.6.5
Sample Receipt
Upon receipts of samples, the following procedure as enumerated in Table 2.4 is
adhered to:
Table 2.4: Sample receipt chain of custody procedure
Action Required
Inspection of Sample
for breakage
Verification of chain of
custody
Testing for preservative
(pH)
In case
anomaly
of
any
Acceptance of Sample
Logging
Sample preservation
Responsible Person
Sample Management
Officer
Sample management
Officer
Sample Management
Officer
Evidence
Note to Project Co-ordinator
Note to Project Co-ordinator
Open non-conformance record.
Record
result
and
notify
Laboratory manager, Project Coordinator and Client.
Sample Management Open non-conformance chart,
Officer
Record
result
and
notify
Laboratory Manager, Project Coordinator and Client
Sample
Sign the COC, keep a copy and
management Officer
return copy to client.
Sample Management Logbook
and
Databse
on
Officer
Computer.
Sample Management Stored in refrigerators
Officer
Duties and Responsibilities of the Laboratory
The Management of the laboratory is channelled towards ensuring good assurance
attitude, by providing the following: Regular Calibration of Equipment.
All calibration procedures are written down, including description of calibration
standards and schedule for calibration.
Analytical procedures are written and are adopted from the ASTM and APHA
methods as recommended by DPR (DPR Appendix D2, Page 135-136).
Documentation of prevention procedures including a schedule for maintenance
intervals is provided.
Contamination of samples is avoided by keeping the laboratory out of bound to
unanthorised persons and environmental interference.
Appendices 3.1 a-c
June 2005
Page 72 of 3
Control of Data Storage and Recording
Record of submitted samples and completed analysis are kept in separate logbooks in a
manner that ensures for data retrivation and tractability of sample source.
Also, the laboratory data sheets logbooks have provision for the procedures and Names
of persons responsible for the sampling and analysis. All such data sheets are dated
and signed by the analyst and approved by the laboratory Manager.
Data handling through the use of dedicated Pentium 100MHZ computers ensures
minimal data loss.
For every project we handle, data account is opened in our computer data bank to
ensure easy retrieval.
To prevent electronic loss of data on the computer, we also keep hard copies in our
results master files as well as diskette copies.
Data Validation
The Laboratory Manager has the responsibility of carrying out validation activities. As a
general guideline, QA procedures shall be carried out on at least 20% of our workload.
Steps are taken to ensure reliability of results.
Data Verification
Field data sheets were carefully kept and inspected at the end of the day's field work to
make sure that no samples were missed out. Laboratory data for wet chemistry were
subjected to analyses such as plotting of chloride values vs. conductivity or conductivity
vs. TDS to draw attention to those stations whose values fell outside of the observed
range. Such station samples were given closer scrutiny in subsequent data analysis to
see whether the particular values could be explained. If no reasons could be found for
the anomalous values, the conclusion was drawn that the values were in error.
Deficiency Correction
The QA/QC Manager has the responsibility to carry out investigation into out of control
procedures and report it to the laboratory Manager.
When such a deficiency is noted a current log is kept for future reference.
The following investigative shooting procedure is to be carried out each time analytical
laboratory result is found to be unreliable or questionable.
SAMPLING: Review the records of the sampling
SAMPE HANDLING: Check the record for the sample preservation technique, the time of
transit and the condition of the sample upon arrival in the laboratory.
ANALYTICAL PROCEDURE: Check methodology, calibration and maintenance log on the
measurement system used and the raw data that are recorded. Check the reagents
used for quality and date of expiration. Crosscheck the mathematics of all calculations.
Carry a reagent blank through sampling and analytical procedures.
Deficiencies that have been discovered and corrected are recorded in our log filling
system, stating the parameters involved, the problem, the action taken, and the date of
the action and the results of investigation.
Appendices 3.1 a-c
June 2005
Page 73 of 3
APPENDICES 5.2 a to b
Appendix 5.2 a: Wet Season Chemical Properties of Soils
EXCHANGEABLE CATIONS Meq/100g
pH(KCL)
EC(µ
µ s/cm)
Salinity
Organic
Carbon %
N
K
Ca
Mg
EA
IK1-SS1A
1
0-15
4.22
3.42
514
189
0.28
0.74
0.35
1.97
2.21
0.42
5
IK1-SS1B
1
15-30
4.12
3.40
546
197
0.26
0.85
0.27
2.01
1.84
0.55
5
IK1-SS2A
IK1-SS2B
IK1-SS3A
IK1-SS3B
IK1-SS4A
IK1-SS4B
IK1-SS5A
IK1-SS5B
2
2
3
3
4
4
5
5
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
4.12
4.10
4.52
4.45
4.42
4.32
4.44
4.67
3.4
3.2
3.5
3.45
3.54
3.50
3.54
3.58
1406
1334
363
380
386
402
614
604
522
523
136
141
143
153
228
290
0.23
0.25
0.30
0.30
0.34
0.38
0.4
0.38
1.74
1.37
0.85
1.02
1.15
0.86
0.69
0.69
0.27
0.40
0.16
0.15
0.15
0.15
0.09
0.14
2.2
1.89
0.64
0.58
3.5
3.1
0.78
0.65
1.76
1.54
1.06
0.94
1.03
1.02
2.1
2.2
1.2
1.2
0.3
0.35
0.28
0.77
0.21
0.42
7
6
3
3
6
5
3
4
IK-JT-SS6A
IK-JT-SS6B
IK-JTU-SS7A
IK-JTU-SS7B
IK-MKDS-SS8A
IK-MKDS-SS8B
IK-MKT-JT-SS9A
IK-MDT-JT-SS9B
IK-MKT-EDS-SS10A
IK-MKT-EDS-SS10B
IK-AGSS-11A
IK-AGSS-11B
IK-AGSS-12A
IK-AGSS-12B
IK-AGSS-13A
IK-AGSS-13B
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
4.23
4.91
4.28
4.35
5.67
5.64
4.99
4.76
5.35
5.11
5.13
4.84
4.93
4.36
5.52
3.21
3.40
3.56
3.68
3.66
4.38
4.47
4.32
4.29
4.69
4.54
4.09
4.21
4.12
3.36
4.55
2.75
515
535
426
433
760
790
611
629
612
614
1611
1573
736
788
709
694
189
193
158
164
278
294
224
232
228
230
539
536
254
300
295
284
0.5
0.5
0.27
0.40
0.42
0.51
0.5
0.5
0.8
0.83
0.6
0.73
0.4
0.7
0.4
0.5
0.76
0.96
0.60
0.62
1.15
0.96
0.46
0.45
1.70
1.73
0.96
0.74
0.62
1.15
1.02
0.48
0.29
0.37
0.30
0.30
0.40
0.40
0.10
0.29
0.75
0.62
0.75
0.70
0.30
0.41
0.14
0.06
1.56
1.42
1.75
1.48
1.68
1.52
1.48
1.45
2.6
2.0
2.3
1.96
1.82
1.70
3.5
3.02
0.64
0.53
0.32
0.27
0.45
0.38
1.19
0.98
3.03
2.87
2.55
1.42
1.04
0.88
1.16
1.04
0.68
1.1
0.52
0.6
0.11
0.14
0.15
0.16
0.05
0.06
0.68
0.47
0.33
0.45
0.03
0.03
3
4
3
3
3
3
3
3
8
7
7
5
4
4
5
4
SAMPLE
POINT
pH(H2O)
DEPTH(CM)
Samples Code
Appendices 3.1 a-c
June 2005
Page 74 of 3
Appendix 5.2a: Wet Season Chemical Properties of Soils (cont’s)
Depth
(cm)
Fe
Zn
Cu
Cd
Cr
1
1
0-15
15-30
241
230
2.86
2.90
3.38
3.06
0.18
0.14
0.14
0.11
0.2
0.3
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
370
362
248
238
178
180
239
227
255
348
344
332
398
394
164
162
504
5.4
4.89
4.18
3.7
3.93
3.41
7.1
6.6
2.6
1.6
3.6
3.8
5.12
4.85
2.57
2.22
2.79
3.3
2.75
2.88
2.49
1.7
1.7
4.16
3.79
1.88
2.2
1.5
1.34
4.75
4.94
2.65
2.7
2.0
0.11
0.10
0.23
0.18
0.38
0.29
0.40
0.72
0.45
0.29
0.3
0.3
0.52
0.47
0.21
0.18
0.3
0.20
0.17
0.10
0.07
0.06
0.07
0.12
0.9
0.20
0.20
0.50
0.50
0.36
0.31
0.20
0.21
0.50
1.9
1.7
1.6
1.3
0.8
0.8
1.5
1.5
1.7
1.5
1.4
1.1
2.3
2.1
1.1
1.2
0.6
10
15-30
462
2.40
2.0
0.24
0.42
0.4
11
11
12
12
13
13
0-15
15-30
0-15
15-30
0-15
15-30
484
480
522
535
386
411
1.60
1.20
10.2
14.95
4.2
4.4
5.2
4.9
6.9
6.63
3.0
3.81
0.36
0.34
0.55
0.56
0.21
0.08
0.44
0.36
0.33
0.45
0.31
0.56
1.2
1.1
2.3
5.1
1.8
1.3
Samples code
1K1-SS1A
1K1-SS1B
1K1-SS2A
1K1-SS2B
1K1-SS3A
1K1-SS3B
1K1-SS4A
1K1-SS4B
1K1-SS5A
1K1-SS5B
1K-JT-SS6A
1K-JT-SS6B
1K-JTU-SS7A
1K-JTU-SS7A
1K-MKDS-SS8A
1K-MKT-JT-SS8B
1K-MKT-JT-SS9A
1K-MKT-JT-SS9B
1K-MKT-EDSSS10A
1K-MKT-EDSSS10B
1K-AGSS-11A
1K-AGSS-11B
IK-AGSS-12A
IK-AGSS-12B
1K-AGSS 13A
1K-AGSS 13B
Appendices 3.1 a-c
June 2005
Page 75 of 3
Ni
Appendices 3.1 a-c
EC(µ
µ s/cm)
Org
ani
c
pH(KCL)
1
0-15
4.18
3.45
502
1
15-30
4.22
3.49
537
191.70
0.28
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
4.23
4.11
4.59
4.51
4.39
4.42
4.53
4.71
4.20
4.86
4.26
4.32
5.57
5.68
4.96
4.74
5.25
5.31
4.99
4.89
4.88
4.26
5.49
3.05
3.37
3.12
3.45
3.42
3.50
3.54
3.64
3.69
3.41
3.61
3.70
3.69
4.35
4.51
4.31
4.29
4.61
4.63
4.00
4.01
4.02
3.26
4.45
2.68
1386
1314
371
384
384
392
607
611
507
531
408
429
750
793
607
628
609
616
1581
1473
725
755
688
694
510.02
521.13
137.79
143.19
140.59
145.13
223.80
291.90
186.93
192.39
150.42
161.34
279.47
297.14
220.19
231.20
229.81
231.13
529.76
532.16
249.24
289.91
270.82
284.50
0.26
0.28
0.36
0.31
0.38
0.41
0.42
0.37
0.55
0.48
0.32
0.43
0.46
0.54
0.48
0.51
0.86
0.78
0.76
0.69
0.49
0.78
0.49
0.56
June 2005
PPM
B.Sat.
%
0.50
5.82
91.41
<0.1
0.47
0.45
0.25
0.87
0.24
2.47
1.74
0.61
5.93
89.71
3.20
0.41
0.49
0.22
1.63
1.54
0.72
0.97
0.94
0.89
0.55
0.58
0.70
0.83
0.65
0.61
0.98
0.87
0.51
0.49
2.23
2.29
0.87
0.77
0.37
1.40
1.22
0.38
0.36
0.39
0.19
0.21
0.14
0.16
0.13
0.18
0.37
0.43
0.27
0.31
0.42
0.46
0.08
0.41
0.84
0.78
0.73
0.73
0.21
0.35
0.19
0.03
2.15
2.19
0.55
0.61
3.11
2.99
0.80
0.91
1.70
1.76
1.80
1.72
1.61
1.58
1.60
1.58
2.41
2.45
2.53
2.34
1.58
2.31
3.72
3.11
1.80
1.87
1.12
1.15
0.98
1.03
2.38
2.43
0.57
0.62
0.38
0.36
0.37
0.41
0.99
0.87
3.16
3.18
3.10
0.98
0.91
1.03
1.22
0.96
1.17
1.20
0.36
0.40
0.37
0.63
0.18
0.37
0.80
0.93
0.48
0.53
0.15
0.17
0.14
0.16
0.04
0.08
0.09
0.81
0.41
0.52
0.02
0.04
7.11
7.19
2.94
3.16
5.54
5.70
4.04
4.47
4.14
4.57
3.58
3.53
4.14
3.49
3.32
3.21
8.68
8.78
7.32
7.63
3.42
5.61
6.37
4.52
83.54
83.31
87.76
87.34
93.32
88.95
95.55
91.72
80.68
79.65
86.59
34.99
96.38
95.13
95.78
95.02
99.54
99.09
98.77
89.38
88.22
90.73
99.69
99.12
6.59
6.04
0.82
0.87
3.39
3.48
2.13
1.97
7.72
6.93
8.66
8.19
14.24
15.04
0.32
0.34
34.76
35.11
12.05
13.02
43.61
53.53
3.26
39.16
0.42
0.38
0.25
0.28
1.32
1.29
0.44
0.48
0.32
0.43
0.97
0.82
0.86
0.79
0.42
0.39
0.44
0.47
0.32
0.29
0.27
0.96
1.24
3.26
0.72
0.78
0.64
0.69
0.59
0.64
<0.05
0.46
0.17
0.22
1.65
1.56
3.76
3.54
0.43
0.45
1.43
1.34
0.57
0.49
0.87
10.46
0.23
0.63
0.36
0.35
0.15
0.15
1.12
1.12
0.29
0.26
0.70
0.78
1.13
1.19
1.00
1.12
2.18
2.20
1.9
2.0
1.5
1.5
4.44
3.15
4.2
3.8
Page 76 of 3
SO4
ECEC
1.72
PO4
EA
2.50
NH4N
Mg
0.26
0.84
NO3-
Ca
N
a
EXCHANGEABLE CATIONS Meq/100g
K
IK1-SS2A
IK1-SS2B
IK1-SS3A
IK1-SS3B
IK1-SS4A
IK1-SS4B
IK1-SS5A
IK1-SS5B
IK-JT-SS6A
IK-JT-SS6B
IK-JTU-SS7A
IK-JTU-SS7B
IK-MKDS-SS8A
IK-MKDS-SS8B
IK-MKT-JT-SS9A
IK-MDT-JT-SS9B
IK-MKT-EDS-SS10A
IK-MKT-EDS-SS10B
IK-AGSS-11A
IK-AGSS-11B
IK-AGSS-12A
IK-AGSS-12B
IK-AGSS-13A
IK-AGSS-13B
0.32
pH(H2O)
IK1-SS1B
185.09
DEPTH(CM)
IK1-SS1A
SAMPLE
POINT
Samples code
Sal
init
y
Appendix 5.2 b: Dry Season Chemical Properties of Soils
1K1-SS1A
1K1-SS1B
1K1-SS2A
1K1-SS2B
1K1-SS3A
1K1-SS3B
1K1-SS4A
1K1-SS4B
1K1-SS5A
1K1-SS5B
1K-JT-SS6A
1K-JT-SS6B
1K-JTU-SS7A
1K-JTU-SS7A
1K-MKDS-SS8A
1K-MKT-JT-SS8B
1K-MKT-JT-SS9A
1K-MKT-JT-SS9B
1K-MKT-EDSSS10A
1K-MKT-EDSSS10B
1K-AGSS-11A
1K-AGSS-11B
IK-AGSS-12A
IK-AGSS-12B
1K-AGSS 13A
1K-AGSS 13B
Appendices 3.1 a-c
THC
Hg
Pb
Ni
Cr
Cd
Cu
Zn
Fe
Samples code
Depth(cm)
Sample
Appendix 5.2 b: Dry Season Chemical Properties of Soils (cont’s)
1
1
0-15
15-30
238.5
233.50
2.94
2.89
3.24
3.18
0.13
0.11
0.12
0.1
0.31
0.28
5.5
5.47
<0.02
<0.02
<50
<50
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
368.20
359.10
243.40
240.10
180.30
182.10
236.60
228.40
252.40
349.20
337.50
330.10
393.20
389.10
161.90
159.70
499.00
5.17
5.07
3.28
3.21
3.49
3.51
6.51
6.43
1.15
1.12
3.91
3.87
4.71
4.65
2.37
2.32
2.58
2.99
2.88
2.64
2.59
1.7
1.71
3.16
3.11
2.1
2.07
1.46
1.41
4.37
4.29
2.1
2.09
2.11
0.15
0.12
0.13
0.1
0.28
0.29
0.14
0.9
0.25
0.19
0.35
0.3
0.47
0.41
0.17
0.11
0.34
0.22
0.19
0.08
0.07
0.05
0.07
0.1
0.8
0.21
0.18
0.52
0.49
0.32
0.28
0.22
0.18
0.42
1.73
1.65
1.54
1.47
0.86
0.88
1.65
1.59
1.07
1.05
1
1.01
1.88
1.72
1.29
1.22
0.49
3.24
3.19
2.86
2.79
1.71
1.73
2.26
2.21
3.04
3
0.2
0.19
1.64
1.59
3.53
3.48
2.64
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
10
15-30
470.00
2.49
2.09
0.29
0.38
0.39
2.59
<0.02
<50
11
11
12
12
13
13
0-15
15-30
0-15
15-30
0-15
15-30
482.80
480.20
516.20
533.50
383.50
407.40
1.29
1.22
9.18
15.16
4.04
4.64
4.24
4.2
4.9
7.63
3.16
3.67
0.46
0.39
0.49
0.46
0.31
0.07
0.35
0.28
0.3
0.42
0.22
0.62
1.31
1.26
2.77
4.92
1.65
1.1
0.24
0.17
2.25
11.16
6.44
0.5
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<50
<50
<50
<50
<50
<50
June 2005
Page 77 of 3
10000
1000
100
10
1000
100
10
1
1
APPARENT RESISTIVITY(Ohmm)
APPENDICES 5.3 a to d
AB/2(m)
AB/2
1.00
1.47
2.15
3.16
4.64
6.81
10.00
14.70
21.50
31.60
46.60
68.10
100.00
147.00
215.00
App. Resistivity
10.02
9.30
8.20
6.86
6.31
5.75
6.28
7.14
8.30
9.91
10.04
12.65
15.38
19.13
23.24
Model interpretation for VES-1
Resist (Ωm)
Layer
Thickn. (m)
1
7.21
0.3
2
4.16
2.4
3
196.51
10.8
4
11.10
∞
Depth (m)
0.1
2.4
10.6
∞
Appendix 5.3 a: Response data and Curve for VES-1
Appendices 5.3 a-d
June 2005
Page 79 of 4
1000
100
AB/2(m )
AB/2
1.00
1.47
2.15
3.16
4.64
6.81
10.00
14.70
21.50
31.60
46.40
68.10
100.00
147.00
215.00
316.00
App. Resistivty
7.09
6.20
5.19
3.97
3.23
2.89
3.19
4.02
5.24
6.94
9.11
11.85
15.22
19.22
23.66
28.18
1000
100
10
1
1
10
10000
Resist (Ωm)
Layer
Thickn. (m)
1
5.05
0.2
2
2.20
2.1
3
217.62
9.5
4
14.15
∞
Depth (m)
0.2
2.3
11.8
∞
Appendix 5.3 b: Response data and Curve for VES-2
Appendices 5.3 a-d
June 2005
Page 80 of 4
1000
100
10
AB/2(m )
AB/2
1.00
1.47
2.15
3.16
4.64
6.81
10.00
14.70
21.50
31.60
46.40
68.10
100.00
147.00
215.00
316.00
464.00
App. Resistivty
54.11
16.34
7.00
5.36
4.79
4.78
4.63
4.36
3.90
3.35
2.77
2.35
2.07
2.00
2.08
2.36
2.84
Layer
1
2
3
4
1000
100
10
1
1
10000
Resist (Ωm)
Thickn. (m) Depth (m)
534.14
0.2
0.2
4.84
3.7
3.9
1.68
31.7
35.5
44.56
∞
∞
Appendix 5.3 c: Response data and Curve for VES-3
Appendices 5.3 a-d
June 2005
Page 81 of 4
AB/2(m )
AB/2
1.00
1.47
2.15
3.16
4.64
6.81
10.00
14.70
21.50
31.60
46.40
68.10
100.00
147.00
215.00
App. Resistivty
51.65
14.30
8.21
6.42
5.31
5.30
4.98
4.28
3.88
3.64
3.33
3.00
2.87
2.68
2.17
Layer
1
2
3
4
1000
100
10
1
1
10
100
1000
10000
Resist (Ωm)
Thickn. (m) Depth (m)
418.26
0.1
0.2
5.13
4.1
4.3
1.08
21.6
22.5
39.64
∞
∞
Appendix 5.3 d: Response data and Curve for VES-4
Appendices 5.3 a-d
June 2005
Page 82 of 4
APPENDICES 5.4 a and b
Appendix 5.a: Wet Season Physicochemical Characteristics of Surface Water
CHARACTERISTICS
SAMPLING POINT CODE
WS-5
WS-6
WS-7
7.32
7.08
7.38
27.9
27.8
27.0
Temperature, Oc
WS-1
7.09
26.9
WS-2
7.02
27.2
WS-3
7.06
27.9
WS-4
7.09
27.3
Turbidity, NTU
TDS, mg/l
TSS, mg/l
DO, mg/l
BOD5, mg/l
COD, mg/l
Nitrate (NO3-), mg/l
42
65
58
6.4
6.52
10.1
<0.05
131
<0.05
0.04
59
63
70
6.3
7.6
11.2
<0.05
125
<0.05
0.05
45
76
60
6.4
7.36
10.9
<0.05
153
<0.05
0.07
61
68
80
6.5
7.28
11.0
<0.05
137
<0.05
0.06
48
68
63
6.3
7.98
12.2
<0.05
137
<0.05
0.05
46
71
60
6.4
7.27
11.8
<0.05
141
<0.05
0.09
8.04
8.7
10.0
8.04
10.31
25
23
34
28
Bicarbonate (HCO3-), mg/l
Nitrite (NO2-), mg/l
<0.05
16.0
<0.05
18.9
<0.05
21.6
<0.02
<0.02
Phosphate (PO43-), mg/l
Sodium (Na+), mg/l
0.003
PH
Sulphate (SO42-), mg/l
Calcium (Ca2+), mg/l
WS-8
7.67
27.8
WS-9
7.01
27.2
WS-10
7.08
27.4
36
78
48
6.4
7.54
12.0
<0.05
156
<0.05
0.03
45
79
58
6.4
7.64
12.4
<0.05
157
<0.05
0.06
48
66
65
6.0
7.62
12.1
<0.05
132
<0.05
0.02
80
65
100
6.1
7.48
11.7
<0.05
130
<0.05
0.01
5.8
8.7
8.04
9.46
5.3
28
29
35
35
29
31
<0.05
17.3
<0.05
16.3
<0.05
20.1
<0.05
20.1
<0.05
20.2
<0.05
14.4
<0.05
15.8
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
0.004
0.006
0.004
0.005
0.005
0.004
0.004
0.004
0.006
5.31
4.68
4.22
4.44
4.11
5.91
3.86
3.77
4.06
3.61
3.23
2.86
3.53
3.45
3.57
3.35
3.3
3.38
2.74
3.12
4.31
4.93
4.62
4.93
4.46
4.46
4.31
4.15
4.15
3.69
WS = Surface Water
Appendices 5.3 a-d
June 2005
Page 83 of 4
Appendix 5.4 a: Wet Season Physicochemical Characteristics of Surface Water (Cont’d)
Sampling Point Code
CHARACTERISTICS
WS-1
3.36
WS-2
1.86
WS-3
2.70
WS-4
2.14
WS-5
2.43
WS-6
1.40
WS-7
3.26
WS-8
2.53
WS-9
1.87
WS-10
2.15
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Zinc (Zn2+), mg/l
<0.002
0.004
<0.002
<0.002
0.004
0.003
<0.002
<0.002
0.005
<0.002
0.031
0.038
0.026
0.072
0.097
0.057
0.056
0.117
0.081
0.126
Copper (Cu2+), mg/l
<0.002
0.004
<0.002
0.004
0.003
<0.002
<0.002
0.005
<0.002
<0.002
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.05
0.28
<0.05
0.83
<0.05
0.78
<0.05
0.21
<0.05
0.94
<0.05
0.33
<0.05
0.16
<0.05
0.91
<0.05
0.65
<0.05
0.28
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
Lead (Pb2+), mg/l
Total Iron (Fe2+, Fe3+), mg/l
Nickel (Ni), mg/l
Vanadium (V), mg/l
Appendices 5.3 a-d
June 2005
Page 84 of 4
Appendix 5.4 a:
Wet Season Physicochemical Characteristics of Surface Water (Cont’d)
CHARACTERISTICS
PH
Temperature, oC
Turbidity, NTU
TDS, mg/l
TSS, mg/l
DO, mg/l
BOD5, mg/l
COD, mg/l
Sodium (Na+), mg/l
Appendices 5.3 a-d
WS-11
7.03
27.3
WS-12
7.32
27.5
WS-13
7.06
27.8
SAMPLING POINT CODE
WS-14
WS-15
WS-16
WS-17
6.98
7.36
7.11
7.11
27.6
27.4
27.6
27.6
71
68
91
6.2
7.66
12.6
<0.05
138
<0.05
0.01
65
69
78
5.9
7.78
13.2
<0.05
139
<0.05
0.09
46
70
58
6.2
7.27
12.3
<0.05
141
<0.05
0.05
56
66
68
6.4
7.69
13.3
<0.05
132
<0.05
0.06
48
68
70
6.2
8.44
14.5
<0.05
135
<0.05
0.02
50
70
69
6.6
8.21
14.2
<0.05
139
<0.05
0.01
50
67
69
6.7
8.9
14.1
<0.05
136
<0.05
0.33
50
66
70
6.0
3.5
9.0
<0.05
132
<0.05
0.36
50
82
71
6.0
3.6
8.04
<0.05
162
<0.05
0.40
49
65
65
5.9
4.1
9.4
<0.05
129
<0.05
0.37
5.7
6.0
5.5
8.13
6.1
6.3
5.25
6.09
5.9
4.5
36
37
33
28
27
31
30
29
40
29
<0.05
13.4
<0.05
10.4
<0.05
18.1
<0.05
16.2
<0.05
14.4
<0.05
17.9
<0.05
13.8
<0.05
15.2
<0.05
18.1
<0.05
14.0
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
0.006
0.007
0.005
0.006
0.005
0.007
0.006
0.003
0.002
0.004
4.30
5.61
5.91
5.03
6.34
4.44
5.12
3.88
4.92
3.62
1.67
4.21
2.11
4.23
1.40
4.46
2.43
3.38
6.53
3.54
3.12
3.81
3.44
3.81
2.99
4.46
3.42
4.61
4.23
4.18
June 2005
Page 85 of 4
WS-18
7.19
27.6
WS-19
7.61
27.6
WS-20
7.02
27.6
Appendix 5.4 a: Wet Season Physicochemical Characteristics of Surface Water (Cont’d)
CHARACTERISTICS
Lead (Pb2+), mg/l
Zinc (Zn2+), mg/l
Copper (Cu2+), mg/l
Nickel (Ni), mg/l
Vanadium (V), mg/l
WS-11
1.67
WS-12
2.11
WS-13/
1.40
WS-14
2.43
Sampling Point Code
WS-15
WS-16
6.53
3.12
WS-17
2.66
WS-18
4.69
WS-19
4.33
WS-20
5.01
0.01
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
<0.002
0.002
0.003
0.003
0.004
0.006
0.006
0.006
0.004
0.007
0.072
0.094
0.056
0.055
0.14
0.038
0.035
0.007
0.112
0.039
0.003
0.002
0.003
0.003
0.004
0.006
0.03
0.091
0.058
0.079
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.05
0.30
<0.05
0.36
<0.05
0.33
<0.05
0.13
<0.05
0.69
<0.05
0.50
<0.05
0.47
<0.05
0.67
<0.05
0.72
<0.05
1.36
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
WS-7
7.87
28.8
WS-8
7.85
29.7
WS-9
7.86
28.9
WS-10
7.87
29.6
Appendix 5.4 b: Dry Season Physicochemical Characteristics of the Surface Water
CHARACTERISTICS
SAMPLING POINT CODE
WS-5
WS-6
7.13
7.44
28.4
29.0
WS-1
7.00
30.1
WS-2
7.11
29.0
WS-3
7.68
29.1
WS-4
7.90
28.5
21.0
65.0
32.0
4.80
2.70
4.50
<0.05
334
<0.05
0.72
36.0
63.0
49.0
5.30
1.70
4.20
<0.05
112
<0.05
0.69
24.0
76.0
33.0
6.80
1.60
3.0
<0.05
94.0
<0.05
0.52
44.0
68.0
59.0
6.70
2.00
4.80
<0.05
107
<0.05
0.49
25.0
68.0
36.0
7.20
2.80
14.5
<0.05
98.0
<0.05
0.30
26.0
71.0
35.0
7.20
2.40
4.50
<0.05
118
<0.05
0.27
20.0
78.0
27.0
7.50
1.92
4.80
<0.05
102
<0.05
0.08
27.0
79.0
38.0
8.00
2.01
9.80
<0.05
112
<0.05
0.06
24.0
66.0
32.0
6.40
4.84
4.90
<0.05
120
<0.05
0.25
60.0
65.0
80.0
7.20
2.80
9.00
<0.05
118
<0.05
0.21
6.66
6.62
3.30
3.0
3.46
3.42
2.18
2.15
5.40
2.18
25.0
23.0
34.0
28.0
28.0
29.0
35.0
35.0
29.0
31.0
<0.05
16.5
<0.05
10.4
<0.05
9.0
<0.05
9.4
<0.05
8.8
<0.05
13.3
<0.05
9.8
<0.05
13.0
<0.05
13.2
<0.05
12.0
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
Sodium (Na+), mg/l
0.23
0.19
0.04
0.03
0.02
0.02
0.02
0.02
0.02
0.02
6.82
6.80
3.40
4.38
2.36
3.30
4.30
4.30
3.60
3.00
3.60
2.75
2.00
2.10
1.60
1.80
1.80
1.65
2.60
2.30
4.40
4.40
4.20
4.40
2.04
2.02
5.21
4.81
5.15
4.84
PH
Temperature, Oc
Turbidity, NTU
TDS, mg/l
TSS, mg/l
DO, mg/l
BOD5, mg/l
COD, mg/l
Hydrocarbon, mg/l
Appendices 5.3 a-d
June 2005
Page 86 of 4
Appendix 5.4 b: Dry Season Physicochemical Characteristics of the Surface Water (Cont’d)
CHARACTERISTICS
Lead (Pb2+), mg/l
WS-1
5.10
WS-2
5.12
WS-3
3.44
WS-4
1.80
Sampling Point Code
WS-5
WS-6
1.85
5.20
WS-7
2.60
WS-8
5.00
WS-9
2.65
WS-10
2.64
0.015
0.018
0.009
0.0008
0.016
0.012
0.011
0.014
0.013
0.012
Zinc (Zn2+), mg/l
<0.002
0.004
<0.002
<0.002
0.004
0.003
<0.002
<0.002
0.005
<0.002
<0.01
<0.01
<0.01
0.157
0.055
0.054
0.045
0.043
0.036
0.035
Copper (Cu2+), mg/l
<0.002
0.004
<0.002
0.004
0.003
<0.002
<0.002
0.005
<0.002
<0.002
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
Nickel (Ni), mg/l
Vanadium (V), mg/l
<0.05
1.477
<0.05
1.475
<0.05
<0.96
<0.05
<0.87
<0.05
0.246
<0.05
0.838
<0.05
0.245
<0.05
0.835
<0.05
0.820
<0.05
0.822
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
CHARACTERISTICS
SAMPLING POINT CODE
WS-15
WS-16
7.62
7.71
29.1
28.9
WS-11
7.59
29.3
WS-12
7.57
29.5
WS-13
7.81
29.1
WS-14
7.85
28.9
53.0
63.0
73.0
7.60
4.32
9.00
<0.05
123
<0.05
0.47
40.0
51.0
55.0
7.20
2.22
4.75
<0.05
110
<0.05
0.45
25.0
59.0
34.0
6.90
3.84
9.80
<0.05
108
<0.05
0.48
36.0
54.0
49.0
7.10
3.84
9.20
<0.05
113
<0.05
0.46
23.0
56.0.
30.0
7.20
2.36
5.41
<0.05
117
<0.05
0.28
2.16
4.10
4.08
4.09
5.40
28.0
22.0
26.0
24.0
23.0
26.0
29.0
26.0
24.0
23.0
<0.05
15.6
<0.05
11.0
<0.05
12.9
<0.05
11.6
<0.05
16.5
<0.05
14.3
<0.05
16.0
<0.05
12.3
<0.05
10.8
<0.05
11.2
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
0.01
0.01
0.01
0.01
0.02
0.03
0.03
0.02
0.01
0.03
2.80
2.10
2.40
2.20
2.50
2.70
4.40
3.40
3.40
3.00
3.20
2.30
2.20
2.10
2.20
2.70
2.90
2.20
2.20
2.00
6.01
6.00
5.61
5.89
5.21
5.21
5.22
6.01
6.02
4.81
PH
Temperature, oC
Turbidity, NTU
TDS, mg/l
TSS, mg/l
DO, mg/l
BOD5, mg/l
COD, mg/l
Sodium (Na+), mg/l
Appendices 5.3 a-d
June 2005
WS-17
7.71
29.4
WS-18
7.79
29.1
WS-19
7.76
28.9
WS-20
7.65
28.6
25.0
60.0
34.0
6.90
2.46
5.25
<0.05
119
<0.05
0.58
24.0
65.0
33.0
7.40
4.25
9.90
<0.05
119
<0.05
0.30
25.0
60.0
36.0
7.40
4.20
8.80
<0.05
119
<0.05
0.55
27.0
54.0
37.0
7.10
2.86
4.85
<0.05
110
<0.05
0.22
26.0
58.0
34.0
7.00
2.42
4.85
<0.05
116
<0.05
0.25
5.20
5.90
4.90
2.18
2.16
Page 87 of 4
CHARACTERISTICS
WS-11
2.00
WS-12
2.52
WS-13
2.50
WS-14
3.50
Lead (Pb2+), mg/l
0.012
0.014
0.016
0.016
Sampling Point Code
WS-15
WS-16
3.54
2.78
0.014
0.008
WS-17
2.80
WS-18
5.56
WS-19
5.57
WS-20
5.20
0.008
0.025
0.026
0.028
<0.002
0.002
0.003
0.003
0.004
0.006
0.006
0.006
0.004
0.007
Zinc (Zn2+), mg/l
Copper (Cu2+), mg/l
0.041
0.043
0.078
0.0130
0.0133
0.014
0.013
0.014
0.015
0.022
0.011
0.010
0.007
0.021
0.022
0.023
0.024
0.024
0.003
0.003
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.05
0.32
<0.05
0.491
<0.05
0.714
<0.05
0.489
<0.05
0.712
<0.05
1.167
<0.05
1.169
<0.05
0.713
<0.05
0.714
<0.05
0.883
Nickel (Ni), mg/l
Vanadium (V), mg/l
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
<0.05
<0.002
Appendices 5.3 a-d
June 2005
Page 88 of 4
APPENDICES 5.5
Appendix 5.5: Two Season Physicochemical Characteristics of Ground Water
CHARACTERISTICS
PH
Temperature, oC
Turbidity, NTU
TDS, mg/l
TSS, mg/l
DO, mg/l
BOD5, mg/l
COD, mg/l
Sodium (Na+), mg/l
Appendices 5.3 a-d
BH-1/TEB
W
D
7.03
6.7
25.7
27.8
BH-2/TEB
W
D
7.32
6.9
25.3
27.3
BH-3/TEB
W
D
7.06
7.2
25.2
26.9
SAMPLING POINT CODE
BH-4/TEB
BH-5/TEB
W
D
W
D
6.98
7.3
7.36
7.1
26.8
27.0
26.8
27.6
BH-6/TEB
W
D
7.11
7.2
26.7
28.0
BH-7/TEB
W
D
7.11
7.6
26.7
27.4
BH-8/TEB
W
D
7.19
6.8
26.3
27.6
26.4
96.2
39
4.6
6.52
16.2
<0.05
193
<0.05
0.052
21.2
130
43
2.2
4
10.0
0.13
255
<0.05
0.10
24.8
96.8
34
4.6
6.1
15.9
<0.05
194
<0.05
0.018
22.4
142
47
1.6
3.5
8.0
0.11
278
<0.05
0.12
25.2
97
37
4.2
6.3
14.8
<0.05
193
<0.05
0.037
34.1
176
53
2.00
3.4
12.0
0.18
345
<0.05
0.14
27.1
93
40
4.0
6.4
16.8
<0.05
186
<0.05
0.046
29
171
55
1.16
6.5
15.0
0.11
335
<0.05
0.16
28.3
84.3
41
4.9
6.4
17.0
<0.05
169
<0.05
0.03
32
98
32
2.14
4.5
10.0
0.12
192
<0.05
0.12
52.4
76
70
4.4
6.2
16.5
<0.05
150
<0.05
0.04
17
96
31
1.4
8.8
20.0
0.24
188
<0.05
0.14
57
79
80
4.7
6.7
17.8
<0.05
157
<0.05
0.05
18.5
112
32
2.62
9.0
20.0
0.18
219
<0.05
0.27
55
79.6
76
4.0
6.8
18.6
<0.05
159
<0.05
0.03
18.1
118
40
1.83
12.0
25.0
0.17
231
<0.05
0.18
3.3
7.7
3.5
9.7
3.18
13.9
2.86
12.0
3.0
8.39
3.2
7.5
2.8
9.9
3.3
6.1
46
38.3
47.8
42,3
48.2
48
47.2
49
43
28
36.3
28
40
33
42
36
<0.05
23.1
<0.05
46.8
<0.05
23.4
<0.05
52
<0.05
24.0
<0.05
58
<0.05
22.3
<0.05
60
<0.05
20.2
<0.05
35
<0.05
17
<0.05
34
<0.05
14.9
<0.05
40
<0.05
15
<0.05
44
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
<0.02
0.034
0.138
0.004
0.214
0.003
0.210
0.005
0.194
0.022
0.103
0.048
0.120
0.026
0.241
0.025
0.200
7.39
13.6
7.56
15.2
7.2
23.8
7.1
22.2
6.64
9.8
5.54
8.9
5.1
10.7
5.5
12.2
2.70
3.5
2.5
4.8
2.6
7.0
2.2
6.3
2.1
2.5
1.5
3.6
1.8
4.0
1.8
4.4
6.7
7.2
5.2
9.8
6.0
14.2
6.3
12.8
4.6
4.3
3.6
6.6
4.6
6.8
3.5
6.2
June 2005
Page 89 of 4
Appendix 5.5: Physicochemical Characteristics of Ground Water (Cont’d)
CHARACTERISTICS
Lead (Pb2+), mg/l
BH-1/TEB
W
D
5.9
10.4
BH-2/TEB
W
D
5.6
5.3
BH-3/TEB
W
D
6.33
9.4
SAMPLING POINT CODE
BH-4/TEB
BH-5/TEB
W
D
W
D
5.21
5.7
4.3
8.1
BH-6/TEB
W
D
4.2
6.4
BH-7/TEB
W
D
4.9
5.2
BH-8/TEB
W
D
4.6
6.1
0.02
0.032
0.03
0.025
0.01
0.014
0.03
0.020
0.01
0.025
0.03
0.043
0.03
0.043
0.02
0.050
<0.002
0.004
0.002
0.003
0.005
0.003
0.006
<0.002
0.003
<0.002
0.004
1.32
0.054
1.04
1.73
0.94
0.124
1.42
0.078
0.34
0.066
0.85
<0.00
2
0.061
0.005
0.134
<0.00
2
0.065
0.004
Zinc (Zn2+), mg/l
Copper (Cu2+), mg/l
<0.00
2
0.046
0.008
0.003
0.002
0.002
0.008
0.004
0.009
0.008
0.006
0.003
0.006
0.006
0.009
0.008
0.009
0.008
<0.005
<0.02
<0.005
<0.00
5
<0.00
5
<0.005
<0.000
5
<0.005
<0.03
1.05
1.28
<0.05
0.88
1.42
<0.05
3.64
0.87
<0.00
5
<0.05
2.25
<0.02
<0.05
0.09
<0.00
5
<0.05
0.92
<0.02
0.98
<0.00
5
<0.05
2.24
<0.00
3
<0.05
3.0
<0.00
5
<0.05
1.47
<0.05
<0.002
0.08
0.016
<0.05
<0.002
0.06
0.022
<0.05
<0.00
2
0.08
0.008
<0.05
<0.00
2
0.06
0.018
<0.05
<0.00
2
0.07
0.020
<0.05
<0.002
0.06
0.010
<0.05
<0.002
0.08
0.014
<0.05
<0.00
2
0.10
0.018
Nickel (Ni), mg/l
Vanadium (V), mg/l
1.25
0.98
LEGEND W: Wet Season
D: Dry season
Appendices 5.3 a-d
June 2005
Page 90 of 4
1.03
1.08
APPENDICES 5.6 a to f
Appendix 5.6a: Wet Season Phytoplankton Species Distribution (figures in numbers/m3)
TAXA
CYANOPHYTA
Oscillatoria sp.
Microcystis sp.
Anabaena sp
CHLOROPHYTA
Ulothrix sp
Closterium isp.
Desmidium quadrutum
Spirogyra sp.
Oedogonium sp.
Coeastrum microporum
Volvox sp.
Pediastrum sp
Botryococcus sp
Scenedesmus sp
BACILLARIOPHYTA
Coscinodiscus radiatus
Fragillaria sp.
Aulocosira sp.
Gomphonema sp.
Leptocylindrus danicus
Navicula placenta
Nitzschia obtusa
Synedra sp
Amphora sp
Pinnularia sp
Melosira sp
Surirella sp
Ceratium sp
Gomphonema sp
DYANOPHYTA
Peridinium cinctum
EUGLENOPHYTA
Euglena sp.
Phacus sp.
Total number of species
Total number of individuals
Appendices 5.3 a-d
SAMPLING STATIONS
WS8
WS9
WS10
WS1
WS2
WS3
WS4
WS5
WS6
2
3
2
1
1
1
3
2
6
2
1
3
2
1
3
1
2
4
2
7
2
2
2
1
1
2
1
2
2
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
6
4
1
1
3
5
1
2
1
1
4
1
1
1
1
2
2
1
2
1
1
1
2
2
4
2
1
1
8
40
5
20
2
2
7
3
2
1
1
2
-
4
8
7
1
1
2
1
2
-
2
18
11
6
6
1
2
1
1
1
4
26
2
20
4
2
1
1
1
2
1
11
5
1
1
1
1
1
1
1
2
11
3
5
5
1
1
1
18
2
20
14
10
4
2
2
1
1
-
1
-
3
-
2
1
3
-
4
-
-
-
24
115
18
37
18
63
June 2005
23
92
18
42
16
43
WS11
WS12
WS13
WS14
WS15
WS16
3
2
1
-
5
2
1
2
1
2
3
2
-
2
2
2
2
1
2
4
6
2
1
2
2
1
1
1
1
2
1
1
1
-
2
1
2
2
1
1
-
9
1
1
1
1
1
3
2
1
2
3
2
6
1
2
2
1
2
3
2
1
1
1
-
16
19
3
22
3
2
2
1
-
6
2
12
2
12
1
1
4
3
2
1
2
1
1
16
7
2
8
4
2
1
-
17
2
29
10
1
3
2
1
1
1
1
-
16
15
2
19
2
5
3
2
1
1
12
26
3
1
1
2
1
1
10
2
3
30
3
1
1
-
4
12
32
1
1
1
1
1
1
1
-
2
4
1
4
2
2
1
1
1
1
-
2
-
2
-
-
-
2
-
2
-
1
-
-
2
-
2
-
-
2
2
-
2
-
22
95
16
89
22
64
19
66
17
76
Page 91 of 4
19
83
16
66
17
69
19
76
19
35
Appendix 5.6 b: Dry Season Phytoplankton Species Distribution (figures in numbers/m3.)
TAXA
CYANOPHYTA
Oscillatoria sp.
Microcystis sp.
CHLOROPHYTA
Closterium isp.
Desmidium quadrutum
Spirogyra sp.
Oedogonium sp.
Coeastrum microporum
Volvox sp.
Pediastrum sp
Botryococcus sp
Scenedesmus sp
BACILLARIOPHYTA
Coscinodiscus radiatus
Fragillaria sp.
Aulocosira sp.
Gomphonema sp.
Leptocylindrus danicus
Nitzschia obtusa
Synedra sp
Amphora sp
Pinnularia sp
Melosira sp
Surirella sp
Ceratium sp
Gomphonema sp
DYANOPHYTA
Peridinium cinctum
EUGLENOPHYTA
Euglena sp.
Phacus sp.
Appendices 5.3 a-d
SAMPLING STATIONS
WS8
WS9
WS10
WS1
WS2
WS3
WS4
WS5
WS6
3
2
2
3
4
2
3
2
5
5
3
2
2
5
2
2
2
2
2
2
2
2
3
1
2
1
2
6
2
2
2
2
1
1
1
1
1
1
2
2
2
2
2
2
2
5
2
2
1
2
12
32
5
27
5
3
3
1
2
2
-
6
12
5
2
2
2
1
2
1
1
2
15
11
2
3
1
1
1
1
1
3
18
2
17
6
3
1
1
1
2
1
1
15
11
3
1
1
1
1
1
1
1
2
12
3
1
1
1
1
1
1
21
2
23
20
8
4
3
2
2
1
2
-
2
-
-
2
-
-
2
20
116
12
42
15
47
19
77
16
45
23
29
June 2005
WS11
WS12
WS13
WS14
WS15
WS16
3
-
2
2
4
2
3
-
2
2
1
-
3
2
2
2
1
-
2
2
2
2
1
2
2
1
1
1
5
2
2
1
1
2
-
2
6
2
2
2
2
1
2
-
9
27
3
21
5
4
2
1
2
1
2
-
6
2
12
2
15
2
3
1
2
2
2
1
-
15
6
3
8
3
1
1
1
2
1
-
21
2
28
12
1
2
1
1
2
1
1
12
15
2
18
6
1
2
2
2
1
1
12
21
3
2
2
1
1
2
12
3
30
3
3
2
1
-
12
32
2
1
1
1
-
2
3
3
1
1
1
1
2
-
2
-
-
-
2
-
2
-
2
22
113
17
94
2
18
62
17
54
2
17
83
18
73
2
11
63
2
11
63
14
68
2
10
18
Page 92 of 4
Appendix 5.6 c:
The distribution, abundance and occurrence of zooplankton community in the water study
stations (Wet Season); figures in numbers/m3.
SAMPLING STATIONS
TAXA
R O T I F E R A
Brachionidae
Brscionus falcatus
Brachionus patulus
Brachionus quadridentatus
Brachionus calyciflorus
anuraeiformis
Keratella tropica tropica
Asplanchnidae
Asplanchna priodonta
Asplanchna herricki
Asplanchnopus multiceps
Collurellidae
Colurella sp.
Lepadella ovalis
Epiphanidae
Epiphanes clavulata
Proales decipiens
Euchlanidae
Euchlanis dilatata
Filinidae
Filinia opoliensis
Testudinellidae
Testudinella caeca
Horaella brehmi
Appendices 5.3 a-d
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS10
WS11
WS12
WS13
WS14
WS15
WS16
39
15
4
5
61
2
15
90
9
22
3
95
10
3
90
3
8
6
27
11
1
135
18
3
-
138
8
3
-
58
15
44
119
1
18
21
3
160
8
5
-
99
4
1
103
4
-
52
3
-
132
30
-
2
-
2
5
-
-
2
5
-
2
-
2
-
5
2
-
110
1
3
21
4
2
-
39
2
19
-
62
2
21
2
10
57
11
-
13
5
1
4
-
21
4
3
9
2
2
-
3
-
36
2
2
6
1
1
1
1
3
-
2
-
3
-
-
5
14
15
2
2
-
14
-
5
-
3
11
2
3
-
14
-
3
6
-
4
-
1
-
9
-
18
-
21
8
3
5
6
-
6
4
-
3
6
-
2
9
38
6
3
2
3
5
49
11
-
18
-
2
1
-
5
3
9
-
17
2
6
21
-
15
-
-
11
-
21
4
18
11
1
-
2
1
47
1
10
-
-
16
2
-
48
2
-
51
5
6
-
4
-
1
-
13
-
17
3
June 2005
Page 93 of 4
Appendix 5.6 c:
The distribution, abundance and occurrence of zooplankton community in the water study
stations (Wet Season); figures in numbers/m3.(Cont’d.)
SAMPLING STATIONS
TAXA
COPEPODA
Cyclopidae
Eucyclops macrurus
Eucyclops speratus
Haliocyclops troglodytes
Diaptomidae
Tropodiaptomus sp.
Thermodiaptomus sp.
Nauplii larvae
CLADOCERA
Sididae
Diaphanosoma excisum
Diaphanosoma sarsi
Daphinidae
Daphnia longispina
Ceriodaphnia cornuta
Moinidae
Moina micrura
Moina daphnia macleayi
Bosminidae
Bosminopsis deitersi
Bosmina longirostris
Total number of
individuals
Appendices 5.3 a-d
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS10
WS11
WS12
WS13
WS14
WS15
WS16
82
19
14
75
-
67
8
45
26
16
85
70
25
55
48
116
162
75
36
-
24
12
-
15
37
-
12
6
3
6
9
8
137
26
122
15
-
32
39
27
21
15
39
-
6
88
21
18
15
21
12
-
9
4
33
34
-
41
13
39
2
11
5
6
-
-
2
-
12
-
6
12
6
-
2
18
-
-
6
-
27
32
18
17
-
8
3
19
-
5
8
-
11
17
3
3
12
63
-
120
1
24
118
48
92
-
68
29
12
67
27
9
-
23
6
11
-
1
20
-
21
1
12
18
-
3
18
31
15
2
-
6
1
2
13
-
-
8
1
3
-
4
6
12
12
3
2
2
-
18
9
3
6
-
-
4
2
9
-
16
201
27
-
116
6
17
162
114
54
-
80
-
105
6
3
14
315
18
12
62
-
-
144
128
109
65
-
1
26
116
-
136
88
100
66
61
111
42
128
58
100
93
47
141
41
101
168
109
170
57
32
60
23
15
116
184
31
54
107
15
11
30
78
56
27
23
20
23
19
20
26
23
22
17
23
21
20
21
23
24
1578
752
474
657
350
242
1194
950
784
462
682
559
383
647
1820
751
June 2005
Page 94 of 4
Appendix 5.6 d: Wet Season Macrobenthic invertebrate distribution, occurrence and abundance (numbers/m3) in
the water bodies
TAXA
INFAUNA
EPIFAUNA
INFAUNA
Appendices 5.3 a-d
SAMPLING STATIONS
DIPTERA
Polypedilum sp.
Chironomus sp.
Pentaneura sp.
Pentaneura sp.
Chryptochironomus
sp
EPHEMEROPTERA
Baetis sp.
Cloeon bellum
Renatra fusca
Nepa apiculata
ANNELIDA
Lumbriculus sp.
Chaetogaster sp.
Tubifex sp.
Enchytraeus sp
Nais sp.
Total number of
species
Total number of
individuals
June 2005
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS1
0
WS1
1
WS1
2
WS1
3
WS1
4
WS1
5
5
-
6
-
-
3
8
5
3
-
8
-
3
5
-
6
-
3
-
-
3
-
5
-
3
5
-
3
-
3
-
5
-
2
-
-
-
-
2
2
-
2
-
-
2
-
-
2
-
2
-
-
-
-
2
-
-
-
2
-
-
2
2
-
-
-
-
5
-
-
3
3
-
-
-
5
3
-
3
-
5
2
-
-
3
-
-
-
5
3
-
5
-
-
-
6
-
-
-
2
2
-
-
2
-
2
-
-
2
-
2
-
2
-
-
-
-
-
2
-
-
-
2
-
3
-
-
-
2
-
-
-
2
-
2
2
-
2
-
-
-
-
2
-
3
-
-
2
2
-
-
-
3
-
3
2
-
-
-
2
5
2
-
-
3
-
2
-
2
-
-
5
-
2
3
-
3
-
2
-
2
2
-
3
-
2
-
-
3
2
-
5
-
-
-
-
-
-
2
-
-
-
2
-
-
-
-
2
2
-
-
2
2
2
-
2
2
2
-
-
-
2
-
-
8
5
2
4
8
3
9
7
6
7
5
5
6
6
5
7
24
11
8
11
19
7
28
19
18
18
17
20
16
16
17
28
Page 95 of 4
Appendix 5.6 d: Wet Season Macrobenthic invertebrate distribution, occurrence and abundance (numbers/m3) in
the water bodies (Cont’d.)
SAMPLING STATIONS
TAXA
EPIFAUNA
EPIFAUNA
COPEPODA
Cyclopidae
Eucyclops macrurus
Eucyclops speratus
Diaptomidae
Tropodiaptomus sp.
Thermodiaptomus sp.
Naupii larvae
CLADOCERA
Sididae
Diaphanosoma sarsi
Daphinidae
Daphnia longispina
Moinidae
Moina micrura
Bosminidae
Total number of
individuals
Appendices 5.3 a-d
June 2005
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS10
WS11
WS12
WS13
WS14
WS15
WS16
69
27
-
75
-
47
6
43
21
-
83
-
25
-
48
81
162
75
36
-
24
12
-
15
37
-
12
6
3
6
9
8
137
26
122
17
-
32
29
27
21
15
37
-
-
88
21
18
15
21
12
-
9
-
33
24
-
-
-
33
-
-
-
-
-
-
2
-
12
-
6
12
6
-
2
-
-
-
6
-
27
32
18
17
-
-
3
-
-
5
8
-
11
-
3
3
12
63
-
75
-
24
158
48
106
-
68
29
12
67
-
-
-
23
6
11
-
-
20
-
21
-
12
18
-
-
18
21
15
-
-
6
-
-
27
-
-
8
-
3
-
-
6
12
12
-
2
2
-
-
9
3
6
-
-
-
2
9
-
-
323
27
-
107
6
-
162
158
68
-
83
-
157
6
-
-
279
18
12
62
-
-
144
128
109
68
-
-
26
193
-
128
129
92
66
78
60
42
152
58
72
93
47
124
41
22
168
190
173
57
32
60
23
15
116
184
31
54
107
15
11
30
78
68
19
16
18
20
9
11
25
18
20
14
19
16
13
12
18
16
1571
515
412
733
187
296
1184
937
711
397
608
370
410
499
545
702
Page 96 of 4
Appendix 5.6 e:
The distribution, abundance and occurrence of zooplankton community in the water study stations
(Dry Season); figures in numbers/m3.
SAMPLING STATIONS
TAXA
ROTIFERA
Brachionidae
Brachionus falcatus
Brachionus patulus
Brachionus quadridentatus
Brachionus calyciflorus
anuraeiformis
Keratella tropica tropica
Asplanchnidae
Asplanchna priodonta
Asplanchna herricki
Asplanchnopus multiceps
Collurellidae
Colurella sp.
Lepadella ovalis
Epiphanidae
Epiphanes clavulata
Proales decipiens
Euchlanidae
Euchlanis dilatata
Filinidae
Filinia opoliensis
Testudinellidae
Testudinella caeca
Horaella brehmi
Appendices 5.3 a-d
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS10
WS11
WS12
WS13
WS14
WS15
WS16
30
21
63
95
47
27
158
128
58
117
28
88
95
59
72
116
15
-
9
12
3
-
23
8
15
-
21
6
3
-
-
23
-
-
-
-
-
-
6
3
-
-
-
6
-
-
3
-
-
-
-
3
-
-
-
-
-
6
3
-
3
-
-
-
-
-
2
5
-
-
2
-
-
2
-
2
-
5
-
-
122
21
-
39
-
62
18
57
38
-
21
18
-
-
63
-
-
-
2
-
-
-
2
-
5
2
-
-
-
-
2
-
3
-
-
2
-
-
-
-
-
-
3
2
-
-
2
-
-
-
-
2
3
-
5
-
-
2
-
5
-
-
-
3
-
3
-
-
-
-
18
15
2
-
-
-
-
11
2
-
12
-
6
-
-
9
-
-
37
2
6
-
-
-
-
2
-
3
-
-
-
-
18
-
8
5
-
12
-
3
-
9
24
6
3
2
-
5
39
11
-
18
-
3
-
-
5
-
12
-
17
-
-
21
-
15
-
-
11
-
21
-
18
-
-
-
-
63
-
-
27
-
48
-
51
-
-
-
21
17
-
-
2
-
-
-
3
-
2
-
5
-
-
-
-
3
June 2005
Page 97 of 4
Appendix 5.6 e:
The distribution, abundance and occurrence of zooplankton community in the water study stations
(Dry Season); figures in numbers/m3(Cont’d).
TAXA
COPEPODA
Cyclopidae
Eucyclops macrurus
Eucyclops speratus
Diaptomidae
Tropodiaptomus sp.
Thermodiaptomus sp.
Naupii larvae
CLADOCERA
Sididae
Diaphanosoma sarsi
Daphinidae
Daphnia longispina
Moinidae
Moina micrura
Bosminidae
Appendices 5.3 a-d
SAMPLING STATIONS
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS10
WS11
WS12
WS13
WS14
WS15
WS16
69
27
-
75
-
47
6
43
21
-
83
-
25
-
48
81
162
75
36
-
24
12
-
15
37
-
12
6
3
6
9
8
137
26
122
17
-
32
29
27
21
15
37
-
-
88
21
18
15
21
12
-
9
-
33
24
-
-
-
33
-
-
-
-
-
-
2
-
12
-
6
12
6
-
2
-
-
-
6
-
27
32
18
17
-
-
3
-
-
5
8
-
11
-
3
3
12
63
-
75
-
24
158
48
106
-
68
29
12
67
-
-
-
23
6
11
-
-
20
-
21
-
12
18
-
-
18
21
15
-
-
6
-
-
27
-
-
8
-
3
-
-
6
12
12
-
2
2
-
-
9
3
6
-
-
-
2
9
-
-
323
27
-
107
6
-
162
158
68
-
83
-
157
6
-
-
279
18
12
62
-
-
144
128
109
68
-
-
26
193
-
128
129
92
66
78
60
42
152
58
72
93
47
124
41
22
168
190
173
57
32
60
23
15
116
184
31
54
107
15
11
30
78
68
19
16
18
20
9
11
25
18
20
14
19
16
13
12
18
16
1571
515
412
733
187
296
1184
937
711
397
608
370
410
499
545
702
June 2005
Page 98 of 4
Appendix 5.6f:
Dry season Macrobenthic invertebrate distribution, occurrence and abundance (numbers/m3) in the
water bodies
SAMPLING STATIONS
TAXA
INFAUNA
EPIFAUNA
INFAUNA
DIPTERA
Polypedilum sp.
Chironomus sp.
Pentaneura sp.
Pentaneura sp.
Chryptochironomus
sp
EPHEMEROPTERA
Baetis sp.
Cloeon bellum
Renatra fusca
Nepa apiculata
ANNELIDA
Lumbriculus sp.
Chaetogaster sp.
Tubifex sp.
Enchytraeus sp
Nais sp.
Total number of
species
Total number of
individuals
Appendices 5.3 a-d
WS1
WS2
WS3
WS4
WS5
WS6
WS7
WS8
WS9
WS10
WS11
WS12
WS13
WS14
WS15
5
-
6
-
-
3
8
5
3
-
8
-
3
5
-
6
-
3
-
-
3
-
5
-
3
5
-
3
-
3
-
5
-
2
-
-
-
-
2
2
-
2
-
-
2
-
-
2
-
2
-
-
-
-
2
-
-
-
2
-
-
2
2
-
-
-
-
5
-
-
3
3
-
-
-
5
3
-
3
-
5
2
-
-
3
-
-
-
5
3
-
5
-
-
-
6
-
-
-
2
2
-
-
2
-
2
-
-
2
-
2
-
2
-
-
-
-
-
2
-
-
-
2
-
3
-
-
-
2
-
-
-
2
-
2
2
-
2
-
-
-
-
2
-
3
-
-
2
2
-
-
-
3
-
3
2
-
-
-
2
5
2
-
-
3
-
2
-
2
-
-
5
-
2
3
-
3
-
2
-
2
2
-
3
-
2
-
-
3
2
-
5
-
-
-
-
-
-
2
-
-
-
2
-
-
-
-
2
2
-
-
2
2
2
-
2
2
2
-
-
-
2
-
-
8
5
2
4
8
3
9
7
6
7
5
5
6
6
5
7
24
11
8
11
19
7
28
19
18
18
17
20
16
16
17
28
June 2005
Page 99 of 4

June, 2005

Transcription

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