the federal republic of igeria post impact assessme t

THE FEDERAL REPUBLIC OF IGERIA
POST IMPACT ASSESSMET STUDY OF THE OIL
SPILLAGE I GOI, RIVERS STATE
REPORT
By
BRYJARK EVIROMETAL SERVICES LIMITED
PORT HARCOURT, IGERIA
February 2008
STUDY TEAM
Dr S A Braide
Project Coordinator and
Environmental Chemist
Prof. A C Chindah
Hydrobiologist
Prof. E N Amadi
Environmental Microbiologist
Mr S C Nleremchi
Soil Chemist
Mr H Uyi
Field Scientist
Mr N Nario
Field Assistant
2
POST IMPACT ASSESSMET STUDY
OF THE OIL SPILLAGE I GOI, RIVERS STATE
TABLE OF COTETS
Page
EXECUTIVE SUMMARY
5
Chapter One: ITRODUCTIO
1.1
Objectives
1.2
Scope
1.3
Study Strategy
7
Chapter Two: DETAILED METHODOLOGY
2.1
Soil Studies
2.2
Aquatic Studies
2.3
Quality Control
9
Chapter Three: RESULTS
3.1
Soil Studies
3.2
Aquatic Studies
3.3
Sediment Studies
3.4
Petroleum Hydrocarbon Studies
17
Chapter Four: COCLUSIOS
35
References
37
Appendices
39
PHOTO-plate
49
3
4
EXECUTIVE SUMMARY
October 2004 a pipeline owned by Shell Petroleum Development Company Limited of
Nigeria burst and spilled crude oil into the environment around Goi, an ancient Ogoni
community in Rivers State. Since it was in the wet season and the tide was full, the oil spread
beyond the spill point, polluting the environment and destroying the natural resources of an
area covering over forty hectares. The oil also caught fire. This fire lasted three days. Within
this period, the fire burnt canoes, fishing ponds and vegetation, causing additional damage.
Concerned with the damage caused by the spill, Environmental Rights Action (ERA)
commissioned a team of scientists from Bryjark Environmental Services Limited, Nigeria to
carry out post impact assessment studies of the oil spillage.
The main objectives of the study include:
- establishing the existing quality of surface water within the study area;
- obtaining scientific identification, qualification and characterization of existing micro and
macro flora and fauna;
- establishing existing soil quality, identifying vegetation and assessing diseases and state of
plant health within the study area;
- assessing the environmental impact of the spillage;
- making necessary recommendations on the remediation of the area.
The objectives were achieved through detailed field and laboratory studies in June 2007, using
standard acceptable international methods.
The study has shown that the Oruma study area is impacted by hydrocarbon from either the
spill source or previous incidents of existing SPDC activities in the area.
Since the post impact assessment study has been undertaken twenty four months after the
spill, there has been a significant decrease in the hydrocarbon concentration especially in the
surface water based on the relatively dynamic nature of the water system in the area.
However, the concentration range of 0.48 – 1.29 milligram/liter of Total Petroleum
Hydrocarbon (TPH) recorded in the surface water can exert negative impact on the resources
of the area and the recruitment potential of the system.
The results of studies show that generally, the study area has a fairly poor composition and
poor amount of benthic communities (various organisms in the sediment system) when
compared to areas of similar ecological system. This is as a result of the hydrocarbons
retained in the sediments and soils of the area.
Previous studies have shown that oil trapped in soils and sediment persists much longer and is
likely to cause more environmental problems than oil in water. It is therefore likely that the
ecological problems associated with the hydrocarbon concentration in the sediment of the
study area persist for a much longer period since cleansing mechanism is slower. The absence
of adult inter tidal organisms such as mudskippers, poor distribution of small sized
mudskippers poor composition and poor amount of benthic communities, suggests that the
presence of oil appears to have affected the abundance and distribution of these organisms.
This further suggests poor recruitment potential and the consequent impact the utilization of
the natural resources by the communities.
5
The oil spill occurred with a fire outbreak resulting in plant species, especially mangrove
plants being damaged. This also impacts negatively on the economy of the community
especially for the persons that whose livelihood depends on the natural resources in the area.
The ecological implication is very high since the area impacted is about forty hectares and the
oil is still retained in the environment.
6
CHAPTER OE: ITRODUCTIO
October 2004 a pipeline owned by Shell Petroleum Development Company Limited of
Nigeria burst and spilled crude oil into the environment around Goi, an ancient Ogoni
community in Rivers State. Since it was in the wet season and the tide was full, the oil spread
beyond the spill point, polluting the environment and destroying the natural resources of an
area covering over forty hectares. The oil also caught fire. This fire lasted three days. Within
this period, the fire burnt canoes, fishing ponds and vegetation, causing additional damage.
Concerned with the damage caused by the spill Environmental Rights Action (ERA)
commissioned a team of Scientists from Bryjark Environmental Services Limited, Nigeria to
carry out post impact assessment studies of the oil spillage.
1.1 OBJECTIVES
The main objectives of the study include:
- establishing the existing quality of surface water within the study area;
- obtaining scientific identification, qualification and characterization of existing micro and
macro flora and fauna;
- establishing existing soil quality, identifying vegetation and assessing diseases and state of
plant health within the study area;
- assessing the environmental impact of the spillage;
- making necessary recommendations on the remediation of the area.
These included the impact or the cleaning rate of the environment and qualifying and
quantifying the impact of the spill on the environment.
The objectives were achieved through detailed field and laboratory studies.
1.2 SCOPE
The scope involved collection of water, sediment and soil samples from impacted and control
study stations to investigate the existing characteristics of the study area for the determination
of the water, sediment and soil quality in the study area three years after the oil spill.
1.3 STUDY STRATEGY
Based on the observations made during the reconnaissance visit to the study area,
hydrodynamics of the water system, and information obtained from informed members of the
community, study stations were established (Fig. 1.3.1). The study stations were established in
such a manner that impacted and control areas (based on visible signs of oil as well as areas
affected by the fire) were covered.
7
Fig. 1.3.1: Study Stations in Goi Study Area
8
CHAPTER TWO: DETAILED METHODOLOGY
2.1 SOIL STUDIES
The soil studies involved assessing existing literature and on-ground status of soil
physiochemical parameters, soil microfloristic composition and oil content. Soil study stations
were established as indicated in Fig. 1.3.1.
Representative samples from five random grab samples per study station were composited, air
dried and sieved through 2 µm mesh sieve prior to analysis in the laboratory.
2.1.1 Soil Physiochemistry
The following analyses were carried out:
All samples were subjected to complete analyses for total hydrocarbon content, pH, E.C.,
organic carbon, total nitrogen, mineral nitrogen (NH4, N02, N03) exchangeable cations (Na, K,
Ca, Mg), available phosphorus and mechanical analysis for soil/sediment texture.
Samples collected from the different study areas were air-dried and sieved using a 2 ptm
sieve. The fine earth was then used for the analyses. The followings describe the methods
used for the different analyses carried out on soils and plant samples:
pH
The pH values of the soils and sediment samples were determined in the laboratory using an
EIL Model 720 pH meter. The pH was determined by dipping the electrode into a 1:25 soil/
water suspension that had been stirred and allowed to equilibrate for about I hour.
Electrical Conductivity (E.C.)
The E.C. of soil and sediment samples were determined on the filtrate obtained after filtering;
the suspension used for the pH determination. The conductivity bridge used for the
measurement was the Griffin Conductance bridge. Conductivity was expressed as ps/cmHydrocarbon Content
The hydrocarbon contents of the samples were determined by shaking 5g of a representative
sample with 10 ml of toluene and the concentration of hydrocarbon extracted determined by
the absorbance of the extract at 420nm in a Spectronic 20 Spectrophotometer. Hydrocarbon
concentrations in the samples were then calculated after reading the concentration of the
hydrocarbons in the extract from the spectrophotometer.
Exchangeable Cations
Two and half grams portions of a finely ground representative sample were shaken in a
conical flask with 25 ml of 1M ammonium acetate for about I hour and filtered into plastic
cups. The filtrate was used for the determination of sodium (Na+), potassium (K+) and calcium
(Ca++) by flame photometry, and magnesium (Mg++) manganese (Mn++) and iron (Fe++), by
Perkin Elmer Atomic Absorption Spectrophotometer. The concentrations of the cations were
calculated after taking due note of the dilution factors and expressed in milligram equivalent
per 100g soil (meq/100g soil).
Total Nitrogen
Two and half grams of a representative air dried sample were accurately weighed into Tecator
9
digestion flasks and a catalyst mixture containing selenium, CuS04 and Na2SO4 was added
followed by 10 ml of concentrated analytical grade sulphuric acid. The contents of the flask
were mixed by gentle swirling and digested on a Tecator block until the digest cleared (light
green or grey colour). Heating was continued for another one hour and the digest allowed to
cool. The digest was transferred quantitatively with distilled water to a 150 ml volumetric
flask and made up to mark with distilled water. Aliquots of this were then taken and used for
the determination of ammonium-nitrogen using an auto-analyser. The percentage nitrogen
contents of the soil was then calculated after taking into account the different dilution factors.
NH4+. NO2- and N03Ammonium, nitrite and nitrate-nitrogen were determined in the extracts by shaking 5g of a
representative sample with 50ml of IM K2SO4. Aliquots of this extract were used for
ammonium-nitrogen determination by nesslerization.
Nitrite-nitrogen was determined by the Greiss-Ilosvay method using alpha-napthylamine and
sulphanilic acid and nitrate-nitrogen was determined by the phenoldisulphonic acid method.
Nitrite concentrations were generally low and so did not require removal by decomposition
with sulphamic acid before nitrate determination.
Organic Carbon
Carbon was determined by the wet combustion method of Wakely and Black (1934). One
gram of finely ground representative sample was weighed in duplicate into beakers. 10 ml of
potassium dichromate solution was accurately pipetted into each beaker and rotated gently to
wet the soil sample completely. This was followed by the addition of 20 ml of concentrated
H2SO4 using a graduated cylinder, taking a few seconds only in the operation. The beaker was
rotated again to effect more complete oxidation and allowed to stand for 10 minutes before
dilution with distilled water to about 200-250 ml. 25 ml of 0.5M ferrous ammonium sulphate
was then added and titrated with OAM potassium permanganate under a strong light.
Available Phosphorus (Bray P-1)
Available phosphor-us in the samples was determined by weighing Ig of a representative
sample into extraction flask. This was followed by the addition of 10 ml of Bray P-1
extracting solution (0.25M HCI & 0.03M NH4F) and shaking immediately for 1 minute and
filtered. 5 ml of the filtrate was then pipetted into 25 ml volumetric flask and diluted with
distilled water followed by 4 ml of ascorbic acid solution (0.056 g ascorbic acid in 200 ml
molybdate-tartarate solution) and diluted to volume. This was allowed to wait for at least 30
minutes for full colour development before reading from the spectronic 20 at 730 nm.
Phosphorus (P043-) concentrations were then calculated after reference to a standard curve.
2.1.2 Soil Microbiology
Soil microorganisms were estimated by the soil dilution plate method in which serial dilutions
of a soil sample in sterile distilled water were plated on a suitable agar medium. One gram of
each sample of previously air-dried soil was added to and shaken with 10 ml sterile distilled
water in a McCartney bottle, to give soil suspension at a dilution of 10-1. A clean sterile pipette
was used to transfer 1 ml of the soil suspension to another McCartney bottle containing 9ml
sterile distilled water; the contents of the bottle were gently shaken together to give a soil
suspension dilution of 10-2. Further series of dilutions were carried out to give a dilution of
10-4 to 10-6. Details of the media composition are presented in the aquatic microbiology
section of this report.
10
2.2 AQUATIC STUDIES
2.2.1 Water Physiochemistry
The aquatic physiochemical studies were designed to describe the existing characteristics of
the study environment that constitute reliable measurable indices in natural environmental
status. Thus, any change caused by the oil spill and related activities in the study area can be
effectively determined.
To achieve these objectives, seven aquatic sampling stations were established as shown in Fig.
1.3.1. The stations, therefore, included areas likely to be impacted in case of any accidents
and those not likely to be affected, i.e. control areas. The coordinates of the study stations are
presented in the Table 2.2.1.
Table 2.2.1: Coordinates for Goi Study Stations
S/o.
Station o.
E
1
Goi 1
04o 38’ 43.1”
007o 15’ 58.0”
2
Goi 2
04o 38’ 38.4”
007o 15’ 57.4”
3
Goi 3
04o 38’ 38.4
007o 15’ 59.5”
4
Goi 4
04o 38’ 32.9”
007o 15’ 59.7”
5
Goi 5
04o 38’ 33.5”
007o 16’ 07.1”
6
Goi 6
04o 38’ 43.4”
007o 16’ 03.6”
7
Goi 7 (Chief’s Pond)
04o 38’ 35.1
007o 16’ 05.7”
2.2.1.1 Sample Collection
All water samples were collected subsurface (15-25 cm) and below the surface (with the
depths recorded). The containers were opened to fill and closed below the water. All
containers were always rinsed at least three times with the water being sampled before sample
collection. The samples were then transported to the laboratory for analyses.
Samples for metal analyses were preserved by adding HN03 to the samples until the pH was 2.
Glass containers were used for the collection of samples for hydrocarbon analysis. These were
immediately preserved in ice-cooled boxes and transported to the laboratory.
2.2.1.2 Field Measurements
The following parameters were measured in the field using appropriate field meters:
The pH, conductivity and Dissolved solids, Temperature and Salinity of water were measured
with Horiba Multi probe field meter.
The field meter was always properly checked and calibrated before and after sampling. Date
and time of sampling were also recorded.
2.2.1.3 Laboratory Measurements
The parameters measured in the laboratory include: alkalinity, suspended solids, P04-3, N03-,
NH4+, N02-, S042- and total hydrocarbon content. Details and principles of the methods used are
as follows:
Phosphate
Phosphate was determined by the stannous chloride method (APHA 1998, Galley et al.,
1975). Phosphate in water reacted with ammonium molybdate in acidic medium to form
molybdophosphuric acid which was reduced to molybdenum blue complex by stannous
11
chloride. The intensity of colour was measured at 690 nm using a Spectronic 20.
Sulphate
Sulphate was determined by the turbidimetric method (APHA 1998). The sulphate was
reacted with barium ion in the presence of sodium chloride-hydrochloric acid solution
containing glycerol and ethyl alcohol. This resulted in the formation of colloidal barium
sulfate which was measured at 420 nm.
Total Alkalinity
Total Alkalinity was determined by titrating water samples (100 ml) with 0.02N sulphuric
acid solution using methyl orange as the indicator (APHA, 1998).
Ammonium Nitrogen
This was determined by the phenol-hypochlorite method (APHA, 1998). Alkaline phenol and
hypochlorite catalysed by sodium nitropruside, reacted with ammonia to form indophenol
blue complex. The intensity of the colour was measured at 630 nm.
Suspended Solids
This parameter was measured by the gravimetric method (APHA, 1998). Water samples, 200
ml were filtered through pre-weighed 0.5 u membrane filters. The filters were then dried to
constant weight in an oven at 103 – 105oC.
Chloride
Chloride was measured titrimetrically (Argentometric Method) in slightly alkaline solution
with silver nitrate (AgN03), solution in the presence of potassium chromate as indicator
(APHA, 1998).
Biochemical Oxygen Demand (BOD)
The BOD of water samples collected was determined using the modified oxygen
depletion/Winkler's method (APHA, 1998). This is an empirical test in which standardized
laboratory procedures are used to determine the relative oxygen requirements in waste water,
effluents and polluted waters. It is a titrimetric procedure based on the oxidizing property of
dissolved oxygen.
Two sets of samples were collected; one set for immediate dissolved oxygen (DO)
determination and the other for incubation for 5 days at 200C. Prior to titration, each of the
samples (250 ml) was fixed, and 2 ml of concentrated H2SO4 also added to aid liberation of
iodine equivalent to the original DO content in the sample. The samples were then titrated
with a standard solution of thiosulphate. Waste water samples were diluted with dilution
water. The difference between initial and 5 day DO gives the BOD mgL-1.
2.2.1.4 Determination of Total Petroleum Hydrocarbon by GC
This standard operating procedure (USEPA 8270B) was adopted. This provides an accurate
and precise method for extraction, isolation, and concentration of selected organic compounds
from soil and sediment samples. It achieves analyte recoveries using less solvent and taking
significantly less time. Final extracts were used in the quantitative determination of polycyclic
aromatic hydrocarbons (PAHs), aliphatic hydrocarbons and total petroleum hydrocarbon
(TPH) by chromatographic procedures. This procedure was used to extract soil and sediment
samples for gravimetric determination of extractable organic material (EOM).
Total Petroleum Hydrocarbons (TPH) concentrations were determined using Gas
Chromatography Agilent 6890N Gas Chromatographs with flame ionisation detector (USEPA
12
8270B). The hydrocarbons in the samples were determined by comparing the areas and
retention times of all identified peaks based on standards used.
2.2.1.5 Determination of Poly aromatic hydrocarbon by GC
Polyaromatic Hydrocarbons (PAH) concentrations were determined using Gas
Chromatography Agilent 6890N Gas Chromatographs with flame ionisation detector (USEPA
8270B). The hydrocarbons in the samples were determined by comparing the areas and
retention times of all identified peaks based on standards used.
2.2.2 Microbiology
Microorganism (bacteria, fungi, etc.) respond quickly to changes in the physiochemical status
of their environments (terrestrial or aquatic). Such effects may be reflected in changes in their
numbers and/or diversity. By a combination of various data analytical methods, the
relationship between such changes in diversity/numbers (and even distribution) and
biophysiochemical factors could be established. Also, apart from their use in assessing change
in the environment, a knowledge of the numbers of microbes in any ecosystem is required
especially in petroleum exploitation since they constitute the first line of defense against oil
contamination or pollution. The numbers and proportions of such microorganisms that are
capable of degrading petroleum hydrocarbon could provide an index of measuring the
recovery potential or pollution status of the system.
Sample Collection
Subsurface and bottom water, and sediment samples in the case of aquatic studies and soil
samples in the case of terrestrial studies were collected at sites identical to those of chemical
studies. This was to enhance correlation (by statistics) of microbiological and chemical data
for effective interpretation of results.
Water samples were collected in 250 ml presterilized glass bottles with stoppers and analysed
within 4 hours of collection. Sediment samples were also similarly collected using a bottom
sampler (where applicable). Handling conditions were as applied for water samples.
Soil samples were collected at two depths (0 - 15 and 15 - 30cm) using an auger of 9cm
diameter.
Sample Analysis
Subsurface water samples were analysed for total aerobic, heterotrophic and
petroleumutilizing bacteria, total fungi and petroleum-utilizing fungi. These parameters were
screened by plating out (spread plate method) Iml of diluted sample on each of the
appropriate media described below, using sterile 1-ml pipettes. Sediment and soil samples
were also similarly treated except that Ig portions were suspended in 9 ml of sterile dilution
blank and diluted appropriately.
Media for Cultivation and Enumeration of Microorganisms
Total Aerobic Heterotrophic Bacteria
Total aerobic heterotrophic bacteria were cultivated and enumerated on nutrient again in
plates. All samples were incubated after inoculation at 28-300C and counted after 24h.
Petroleum-utilizing bacteria
Petroleum-utilizing heterotrophic bacteria were cultivated at 250C on petroleum agar with the
following composition:
Difco agar - 15g
13
Ammonium Chloride, NH4Cl - 0.5g
Dipotassium hydrogen phosphate, K2HP04 - 0.5g
Disodium hydrogen phosphate, Na2HP04-12H20 - 2.5g
(or 7. 1 g of anhydrous salt)
Engine oil/diesel mixture (1 : 3 ratio) - 0.5%.
Estuarine salt solution - 750 ml
Distilled water - 250 ml
pH - 7.6.
The estuarine salt solution (artificial seawater) was prepared by dissolving in 1000ml of
distilled water the following:
Sodium Chloride, NaCl - 10g.
Magnesium Chloride, MgCl2 - 2.3g.
Potassium Chloride, KCI - 0.3g.
2.2.3 Phytoplankton
Phytoplanktons occupy the lowest trophic level which other life forms in the aquatic
ecosystem depend directly or indirectly on as a primary food source. Their utilization of
inorganic and/or organic elements in the environment and species richness, species diversity,
density and distribution which reflect the nutrient status and any fouling compound
introduced into the ecosystem, justify their study. Therefore, the following were considered
during the study:
(i)
the assessment of the taxa and the abundance of the species;
(ii)
the evaluation of the distribution; and
(iii) evaluation of the relationship of abundance, composition and distribution to
physiochemical parameters.
Phytoplankton samples were collected using a one litre translucent plastic bottle to collect the
subsurface water sample and immediately fixed with Iml of laboratory prepared Lugol's
iodine solution. This was later transferred to the laboratory.
In the laboratory, the samples were allowed to stand for a minimum of 24 hours before the
supernatant were pipetted off until a 50ml concentration volume was achieved. From the 50
ml concentrated sample, I ml of properly homogenised subsample was transferred into a
Sedgewick Rafter counting chamber using Starnple pipette. The organisms were identified
and enumerated under a binocular microscope (140 - 144 x).
2.2.4 Zooplankton
Zooplankton organisms comprise the juvenile and larval stages of larger animals such as crab
zoea, shrimp zoea, fish larvae/embryo, vegiller larvae of molluscs, and the permanent
zooplankton (Holoplankton) such as copepods, euphausids, jelly fish and chaetognaths. These
organisms mostly feed on particles in the water, and therefore, concentrate smaller
phytoplankton, some other zooplankton and debris. By their feeding process they may ingest
oil particles in places where there is oil pollution.
Some of them have been shown to concentrate the oil particles, others metabolize and break
them down (Gardner et al. 1979). At some concentrations of the oil, some of these organisms
die. Mironov (1972) showed that the young Acartia clausii and Oithona nana died after 3 to 4
days immersion in seawater containing up to 10 ml/L of oil, while their adults and some other
copepod species suffered accelerated death after longer exposure. Mironov also observed that
planula larvae of coelenterates, larvae of fish, polychaete and crustaceans have all been very
sensitive, and at concentrations of 10-100 ppm in seawater, may not metamorphose. These
zooplankton have been found to make up the bulk of food material for most juvenile and
14
pelagic fish species, (Fagade and Olaniyan, 1972). Thus, zooplankton not only indicate the
effect of low levels of oil and chemical pollution in the water body, which might not be lethal
to the higher organisms, they also play very important role in the food chain and energy flow
within the water bodies.
Zooplankton sampling was carried out with the aim of identifying the various taxa of the
zooplankton. The various taxa at several chosen stations would be enumerated, with which an
index of their abundance in relationship to the level of pollutants, (mainly -petroleum and
chemical) could be established.
Subsurface water samples were collected in 101itre plastic buckets and poured through a 55
mesh size plankton net fifty times. The net samples (representing 5001itres of water) were
washed into 20ml sample collecting bottles and immediately fixed in 10 percent formalin.
In the laboratory, samples were made up to a uniform volume of 100ml using distilled water.
Following a thorough agitation and homogenisation, 1ml sub-samples were taken using a
Stampel Pipette and transferred to a graded 1 ml counting chamber for observation under a
binocular microscope with magnification of 40 to 400x. The organisms were simultaneously
identified and enumerated and results entered on analysis sheets.
2.2.5 Epipelic Algae
Epipelic algae are used as biological indicator organisms in various pollution related studies.
Their consideration for such studies is related to their being sessile, always present in water
column; some are associated with specific pollutants and are comparably more predictable
than the plankton (Pudo 1985 and 1989).
The species list and taxa abundance will be used to indicate any change in the aquatic
environment caused by stressed conditions.
Epipelic community were sampled by scrapping artificial and/or natural substrates which are
permanently or occasionally submerged in water. The scrapping was restricted to a quadrant
of 2cm2. The scrapped content from substratum, was emptied into a vial bottle. The aggregate
sample was then fixed with 5 percent formalin.
In the laboratory, the samples were made up to 50mls, out of which Iml sub-sample was
analysed under a microscope. All organisms encountered within the counting chamber were
identified and enumerated. This procedure was repeated twice for each sample. The results
obtained were expressed as organism per unit area.
2.2.6 Benthic Macrofauna
Macrofaunal grab samples were sieved immediately after retrieval and the grab contents
emptied on to the sieving table and screened through a 0.5 mm mesh sieve using seawater.
The sediment and faunal material retained by the sieve were then transferred to a sealed
plastic container, labeled and fixed in 10% buffered formalin solution for transport to the
laboratory.
In the laboratory samples were sorted and all stained fauna removed and further preserved in
50% propyl alcohol or formalin. These were identified to the lowest possible taxonomic level
under a stereo and/or compound microscope and individuals of each taxonomic group were
counted and recorded.
15
2.3 QUALITY COTROL
The methodology and procedures for sample collection, storage/handling and analysis were
such that dependability and reproducibility are assured.
Field Data
To assure the accuracy and reliability of in situ field measurements, field instruments were
calibrated prior to use and cross-checked from time to time. Field portable pH meter was
calibrated using pH4, pH7 and pH9 buffer solutions. The conductivity and dissolved solids
meter were checked against solutions of known conductivity and dissolved solids provided by
the manufacturers. The sound level meter was calibrated with a pistonphone prior to
commencement of measurements. Water sample containers were washed with detergent and
thoroughly rinsed, first with clean water and, finally, with distilled water. Water and soil
samples for special analysis were kept frozen or refrigerated before the time for analysis.
Biological specimens for tissue analysis were wrapped in clean aluminium foils and stored in
portable ice coolers.
Laboratory Data
Samples for wet chemical analysis were refrigerated and immediately analysed for nitrate and
phosphate contents. Standard laboratory quality control procedures were adhered to for wet
chemical analysis of water samples. These included determination of reagent blanks, use of
fresh standards and replicate analysis for confidence limit, and cleaning of glass wares and
other containers. The same procedures were used on water samples for hydrocarbon
determinations.
Data Verification
Data Verification was done at several points of the collection and analysis process. Field data
sheets were carefully kept and inspected daily. Data which did not fall within the expected
range (especially in relation to water samples) were noted, and when possible the stations in
question were resampled. Laboratory data for wet chemistry were subjected to analysis to
draw attention to the stations whose values fell outside the observed range. Such stations were
subjected to further scrutiny during data analysis so as to provide explanation for the values.
If no reason was found from the anomalous values, the conclusion was that the values were in
error. Such erroneous values were detected and deleted through this method.
Quality Assurance Plan
A quality control program was established from the onset of the project to ensure the validity
and comparability of data. Every effort was made to adhere to the goals of this program
throughout the course of the study.
Detailed procedural guidelines for sampling and analysis were made available to each
member of the study group. Field data sheets were not only be used to record pertinent
environmental and ecological observations but also serve as checklists for detailing each step
in sample collection, preservation, and sample storage. This assisted in recording the exact
number of samples collected at each station, ensured proper labelling and preservation. These
data sheets were used for sample analysis, data verification and data analysis.
A logbook was also maintained throughout the field and laboratory-based studies for
recording movements, handling, types of samples, laboratory procedure, date of collection,
starting and completion dates of analysis and the personnel.
16
CHAPTER THREE: RESULTS
3.1 SOIL STUDIES
3.1.1 General Soil Description
The soils of the study area comprise the saline mangrove soils of the sedimentary basin of the
Niger Delta. The mangrove soils are of recent alluvium which are acid silty-clay to fine loamy
occurring almost off the shoreline. They are dark gray consisting of marine sediments and
having undecomposed fibrous roots and other vegetative materials giving rise to the name
known locally as “chikoko” soils (Anderson 1996). The salinity of the soils is high being
inundated by salt water from the ocean as such supports vegetation that are tolerant to high
salinity contents which mainly are the mangrove species and Nypa palms. At low tide the
soils are exposed revealing many holes and tunnels that houses marine organisms. There are
hard, soft and very soft muddy areas with distinct vegetation types having textural classing
varying between loamy sand and high clay content.
3.1.2 Soil Microbiology
Heterotrophic bacterial counts in the Goi ranged from 1.40 x 106cfu/g to 1.10 x 107cfu/g. All
the Goi samples were generally very low in petroleum-degrading bacteria (%PDB/HB <0.01
%). Figure 3.1.1 shows the logarithmic values.
Goi soil
8
7
Logarithmic value
(count, cfu/g)
6
5
4
Heterotrophs
3
PDB
2
1
0
1
2
3
4
5
6
7
Stations
Figure 3.1.1: Logarithmic counts of heterotrophic and petroleum-degrading bacteria
by site for the Goi soil samples.
3.1.3 Soil Physiochemistry
The soils which are dominated by marshes and swamps are mainly loamy sand to clay
texturally with some areas having high content of sand (86 – 90%) and clay (65 – 70%). The
soils are very strongly to strongly acid in reaction (pH 2.75 to 4.29) in the top and bottom
samples (Appendix 3.1.1). This is because the pyrite is converted to sulphuric acid during the
process of drying the soils. Electrical conductivity values (2880 – 16400 µS/cm) are high with
corresponding high salinity contents (1.4 – 9.7%) which indicates the soils are salty. This is
due to inundation by the seawater.
17
Organic carbon content is low (<2%) around Stations 1 – 3 with low available phosphorus
and mineral nitrogen. This may be attributed to the nature of the soils being sandy with very
low silt and clay contents. In the areas of Stations 4 to 7 recorded very high organic carbon
content (4.00 – 4.62%) with high nitrogen reserve as is indicated in the low carbon-nitrogen
ratio (6 - 9). Nitrate result is moderate (20.1 – 23.8 µg/g) with nitrite levels being below 10
µg/g and ammonium levels between 18.8 20 µg/g indicates good nitrification processes and
there are no adverse reactions taking place in the soil. This could be enhanced by the
treatment processes of the contaminated areas and the land exposure to air at low tides.
Available phosphorus is moderate. Exchangeable cations are high occurring in the order of
Mg > Ca > K >Na. The high Mg content indicates the seawater influence. Cation exchange
capacity ranged from 21.0 to 27.4meg/100gsoil is moderately high indicating moderately high
soil fertility.
3.1.4 Pollution Status
Figure 3.1.2 show total hydrocarbon (oil) concentrations in surface and subsurface soils of the
study site. The area is highly vulnerable to oil spill due to numerous oil activities being
carried out in the area. The hydrocarbon levels detected varied from low pollution (104.7 1095.1 mg/kg) to medium (1182.4 - 853.1 mg/kg) and high (24,476.4 - 47,338.6 mg/kg)
(NDES, 2001). The oil spilled here will persist for long time because of the clean up difficulty
and biodegradation will be poor and slow due to anaerobic system of the environment despite
the treatment processes going on.
Top
Bottoms
THC (mg/kg)
50000
45000
40000
35000
30000
25000
20000
15000
10000
5000
0
1
2
3
4
5
Stations
6
7
Fig. 3.1.2: Total Hydrocarbon levels in the
Study Area
18
DP R .
S td.
3.2 AQUATIC STUDIES
3.2.1 Surface Water Physiochemistry
Results of physiochemical properties of water samples collected around Goi community are
presented in Appendix 3.2.1. The surface water pH varied from slightly acid (6.3) around the
Spill source (Goi 01) to neutral (7.0) around Stations 04 and 06. This may be attributed to
precipitation and surface run off being relatively acidic entering the area during the season.
Electrical conductivity values (970 – 13400 µS/cm) indicate that the water is brackish as
shown by the salinity content (0.4 – 7.8 ‰). The wide range is caused by the influence of
freshwater on the upstream stations since the samples were collected at ebbing tide. Turbidity
values are below 5 NTU in all stations sampled probably because the water is calm and clear.
Dissolved oxygen value was high ranging from 9.74 – 29.64mg/l with corresponding low
oxygen demand (2.84 – 19.90mg/l) indicating that the surface water body had not been
affected adversely. Nitrate and phosphate levels ranged between 0.10 – 0.15 mg/l and <0.05 –
0.63 mg/l respectively which could be attributed to surface run-off from hinterland. The
nutrient concentrations in the water system were sufficient to encourage active primary
productivity (Kiel, 1997). The total alkalinity (20.0 – 42.0 mg/l CaCO3) and total hardness
(72.81 – 1283.72 mg/l CaCO3) were high indicating sufficient buffering capacity to neutralize
changes of the hydrogen ion (H+) toxicity as well as hardness of the water (O’ Halloram and
Giller, 1993).
Generally, the physicochemical characteristics indicated moderately low organic load, low
hydrocarbon contamination and hence low pollution of the surface water body. The reasons
and implications are presented in the general discussion section of this report.
Surface Water Microbiology
The heterotrophic bacterial counts for the Goi water samples ranged from 3.42 x 103 cfu/ml to
7.28 x 104 cfu/ml. Proportions of petroleum-degrading bacteria were generally low, being less
than 0.01 % of the total heterotrophic bacteria. Figure 3.2.1 shows the logarithmic values.
Goi water
5
4.5
Logarithmic value
(count, cfu/ml)
4
3.5
3
2.5
2
Heterotrophs
PDB
1.5
1
0.5
0
1
2
3
4
5
6
7
Stations
Figure 3.2.1: Logarithmic counts of heterotrophic and
petroleum-degrading bacteria by site for the Goi water samples.
19
3.2.3 Phytoplankton
Phytoplanktons occupy the lowest trophic level which other life forms in the aquatic
ecosystem depend directly or indirectly on as a primary food source. Their utilization of
inorganic and/or organic elements in the environment and species richness, species diversity,
density and distribution which reflect the nutrient status and any fouling compound
introduced into the ecosystem, justify their study.
The main phytoplankton groups detected in the Goi study area were Bacillariophyceae
(diatoms), Cyanophyceae (blue green algae), Chlorophyceae(green algae), Euglenophyceae
(euglenin), Dinophyceae amounting to a total of 70 species (Appendix 3.2.2). The diatoms
contributed 53% of the phytoplankton species followed by blue green algae (23%), Euglenin
(9%) and green algae (9%) contributing equal number of species each and the least being
dinophyceae (6%) (Fig 3.2.2).
Euglenophyceae
9%
Dinophyceae
6%
Chlorophyceae
9%
Bacillariophyceae
53%
Cyanophyceae
23%
Fig. 3.2.2: The relative contribution of species by different
phytoplankton taxonomic groups.
The species demonstrated relatively uniform distribution with values ranging from 53 - 56
species and the differences between stations were not significant (R2 = 0.18) Fig. 3.2.3.
Species richness
64
62
60
y = 0.8x + 52.533
R2 = 0.18
58
56
54
52
50
48
1
2
3
4
5
Station
Fig. 3.2.3: The distribution of species richness at
the different study stations.
20
6
The community structure for the major family groups demonstrated a consistent pattern for
each of the stations with the distribution in a decreasing order of Bacillariophyceae (43.5 63.6%) > Cyanophyceae (26.1 - 53.1%) > Euglenophyceae (1.8 - 3.5%) > Chlorophyceae (0 3.0%) > Dinophyceae (0 - 1.1%) Fig. 3.2.4.
100
Rel. comp.(%)
80
60
40
Goi-6
Goi-5
Goi-4
Goi-3
Goi-2
0
Goi-1
20
Station
Bacillariophyceae
Cyanophyceae
Euglenophyceae
Dinophyceae
Chlorophyceae
Fig.3.2.4: The relative proportion of major taxonomic
groups to the phytoplankton population.
The phytoplankton densities recorded a minimum of 562 at Goi-1 and maximum of 714 at
Goi-4 but the differences were not significant (R2 = 0.05) Fig. 3.2.5.
The results for the ratio of cyanophyceae and phytoplankton densities for all the stations were
far from unity as the ratios stood at a ranged of 0.28 - 0.53 and variation between stations
were not significant (Fig 3.2.5)
Abundance
y = -18.4x + 801.07
R2 = 0.05
Ratio of cyan: total
y = -0.0289x + 0.5028
phyto
R2 = 0.2859
0.5
800
0.4
600
0.3
400
0.2
200
0.1
3
-1
Abundance (x10 indiv./l )
1000
0.6
0
Ratio
1200
0
1
2
Abundance
3
4
5
6
Ratio of cyanopyceae: total abundance
Fig. 3.2.5: The distribution of phytoplankton densities and ratio
of cyanophyceae to phytoplankton abundance at the study
stations.
21
3.2.4 Zooplankton
Zooplankton organisms comprise the juvenile and larval stages of larger animals such as crab
zoea, shrimp zoea, fish larvae/embryo, vegiller larvae of molluscs, and the permanent
zooplankton (Holoplankton) such as copepods, euphausids, jelly fish and chaetognaths. These
organisms mostly feed on particles in the water, and therefore, concentrate smaller
phytoplankton, some other zooplankton and debris. By their feeding process they may ingest
oil particles in places where there is oil pollution.
Some of them have been shown to concentrate the oil particles, others metabolize and break
them down (Gardner et al. 1979). At some concentrations of the oil, some of these organisms
die. Mironov (1972) showed that the young Acartia clausii and Oithona nana died after 3 to 4
days immersion in seawater containing up to 10 ml/L of oil, while their adults and some other
copepod species suffered accelerated death after longer exposure to 10ml/L or after 5 to
6minutes in I ml/L. Mironov, (1972) observed that planula larvae of coelenterates, larvae of
fish, polychaete and crustaceans have all been very sensitive, and at concentrations of 10-100
ppm in seawater, may not metamorphose. These zooplankton have been found to make up the
bulk of food material for most juvenile and pelagic fish species. (Fagade and Olaniyan, 1972).
Thus, zooplankton not only indicate the effect of low levels of oil and chemical pollution in
the water body, which might not be lethal to the higher organisms, they also play very
important role in the food chain and energy flow within the water bodies.
The community integrated species for the different components of the zooplankton at the
stations sampled is summarized in Appendix 3.2.3. The majority of the community was
composed of zooplankton, which showed a quite unstable distribution of species amongst the
different groups along the stations studied. In all, a total of 19 species were observed with
copepoda contributing 42%, Rotatoria 37%, others such as obelia larvae and nematode -11%,
while the cirriped, and economic larval forms each contributing 5% (Fig. 3.2.6).
others
11%
Cirreped
5%
Economic larval
forms
5%
Copepoda
42%
Rotatoria
37%
Fig. 3.2.6: The relative contribution of species by different
zooplankton taxonomic groups
The zooplankton, copepoda species such as, Diaptomus oregonensis , Copila mirabilis ,
Harparticoid copepods and Copepoda nauplii and rotatoria species Asplanchna brightwelli
were heterogeneously distributed within the stations. Similarly, the species richness showed a
more homogeneous distribution as values ranged between 10 species and 13 species (Fig.
3.2.7).
22
Species richness
14
Species richness
12
10
8
6
4
2
0
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Fig. 3.2.7: The distribution of zooplankton species
richness at the different study stations
The community structure is dominated by copepod and constituted 65.5 - 73.7% , followed by
Rotatoria with 18.9 - 31.0% and others 0 - 12.5%. The cirreped (0 - 4.3%) and economic
larval forms (0 - 1.9%) contributed poorly in the zooplankton structure and had patchy
distribution (Fig. 3.2.8).
100%
Rel. Comp.
80%
60%
40%
20%
0%
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Station
Copepoda
Rotatoria
Economic larval forms
Cirreped
others
Fig.3.2.8: The relative proportion of major taxonomic groups
to the zooplankton population
Generally low densities of zooplankton abundances were recorded with a minimum of 20 Oruma 6 and a maximum of 57 in Oruma 5. However the differences between the stations
were not significant (R2 = 0.02) Fig. 3.2.9.
23
Abundnace
y = -2.0857x + 52.467
R2 = 0.16
50
40
Abundnace (x 10
2
indiv . L -1 )
60
30
20
10
0
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Fig. 3.2.9: The distribution of zooplankton densities
at the study stations
The phytoplankton species assemblages in the system and the distribution of species richness,
community structure pattern and abundance appeared similar to what is reported for
equivalent un-impacted environment in the region (RPI, 1985, Chindah and Pudo, 1991) .
Nonetheless, the abundance of phytoplankton fell short in a magnitude of two to three times
the values expected for comparable un-impacted habitat (RPI, 1985 and NDES,2000 ,
Ecosphere 2002, NDDC 2004, Chindah and Braide, 2004)
Similarly the species observed in the study area appeared normal for such habitat but the
observed unstable distribution of species in the area especially the noticeable poor occurrence
of larval forms particularly those of copepods (copepod naupli) that usually constituted over
50% of the copepod population in equivalent unimpacted habitat (RPI, 1985, NLNG, and
NDES, 2000). This implies that the recruitment potential of the zooplankton particularly the
copepoda has been depressed or impaired, perhaps due to reproductive (spawning) failure as a
result of impact of the crude oil. The effect on the zooplankton population, community
structure, and abundance is far reaching. This paradigm change in the zooplankton
community could impact negatively on the habitat organizational structure, may cause
generation gap and impact the aquatic food organization.
3.2.5 Periphyton
Periphytons are used as biological indicator organisms in various pollution related studies.
Their consideration for such studies is related to their being sessile, always present in water
column; some are associated with specific pollutants and are comparably more predictable
than the planktons (Pudo 1985 & 1989). The species list and taxa abundance are used to
indicate any change in the aquatic environment caused by stressed conditions.
The periphyton had a total of 49 species with Cyanophyceae (21 species) recording the
highest number of species in all stations, followed by Bacillariophyceae (18 species) while
Chlorophyceae and Eugenophyceae each had 5 species (Appendix 3.2.4 and Fig. 3.2.10).
24
Cyanophyceae
Euglenophycea
e
10%
43%
Other
20%
Bacillariophycea
e
37%
Chlorophyceae
10%
Fig. 3.2.10: The number of species observed for
each of the major taxonomic group
The total species richness was relatively low for all the stations and homogenously distributed
as values ranged between 10 and 13 species. The linear regression analysis demonstrated that
the species richness of each lake stations was significantly related (Fig. 3.211).
Species richness
Species richness
14
12
10
8
6
4
2
0
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Fig. 3.2.11: The distribution of species richness
along the study stations
The dominant species in the periphyton community were Gleocapsa chrococcoides,
Gleocapsa rupestris,Microcystis aeuroginosa, Aphanothece microscopica, Aphanothece
saxicola, Phormidium uncinatum. The periphyton community of the system was
predominated by Cyanophyceae that contributed more than 65% of the population at each of
the station (65.1 – 79.3%). Other important group in the community was Bacillariophyceae
that contributed 17.6 – 32.2% for the population while Chlorophyceae and Euglenophyceae
combined, contributed less than 4.1% at each of the stations (Fig. 3.2.11). The ratios of
Cyanophyceae to total periphyton were close to unity (high) with values between 0.65 - 0.79
(Fig. 3.2.13). Periphyton population showed abundance in the range of 1500 – 2500 x104
indiv/cm2 (Fig. 3.2.14).
25
80.0
70.0
Rel. Comp.
60.0
50.0
40.0
30.0
20.0
10.0
0.0
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Bacillariophyceae
17.6
17.7
32.2
28.0
18.8
23.5
Cyanophyceae
79.3
78.2
65.1
68.9
79.3
72.6
Chlorophyceae
0.7
1.1
0.6
0.8
0.5
1.2
Euglenophyceae
2.5
2.9
2.2
2.2
1.4
2.7
Fig. 3.2.12: The relative proportion of major taxonomic groups to the
periphyton population
0.9
0.8
0.7
0.6
0.5
0.4
ratio
0.3
0.2
0.1
0
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Station
ratio of cyanophyceae: total periphyton
Fig. 3.2.13: The ratio of cyanophyceae and periphyton
abundance at each of the study stations
26
Abundance
4
x10
ind./ cm2
3000
2500
2000
1500
1000
500
0
Goi-1
Goi-2
Goi-3
Goi-4
Goi-5
Goi-6
Fig. 3.2.14: The distribution of periphyton densities at the
study stations
The poor species assemblage of the periphyton with 49 species and the dominance of the
population by cyanophyceae particularly by species such as Gleocapsa chrococcoides,
Gleocapsa rupestris,Microcystis aeuroginosa, Aphanothece microscopica, Aphanothece
saxicola, Phormidium uncinatum is not congruent with studies on similar unpolluted
environment in the Niger Delta region (Chindah,1998). The alteration in the community
structure with blue greens dominant in the current study area is a major departure from trends
in previous studies of unpolluted habitats (Chindah et al. 1993 a and b, Chindah, 1999a,
Chindah, and Nduaguibe, 2003). Pudo and Fubara, (1988) and Chindah, (1998) observed
similar preponderance of blue green algae in crude oil impacted unstable saline environment
where the algal group (blue green) under such unfavourable sticky smeared oil condition
opportunistically dominate the periphyton community. This scenario may impact negatively
on biota that depend on the periphyton directly or indirectly as their food source.
27
3.3 SEDIMET STUDIES
3.3.1 Physiochemical Properties of the Related Sediments
Appendix 3.3.1 shows physiochemical properties of the related sediments. Texturally the
sediments vary from fine sand in the areas of Stations 01 to 03 and clay from Station 04 to 07.
The area with very high clay fractions (>70%) indicates that the sea bed is quite capable of
oxidizing and retaining pollutants, thus removing them from the food web (Bohn et al 1979).
Organic carbon content is very low (1.02 – 1.12%) around Stations 01 to 03 with very high
sandy fractions (>90%) and low carbon/nitrogen ratio (7 – 9). This indicated high rate of
humidification processes. Mineral nitrogen and available phosphorus were low, probably
caused by the receding tide. The nitrite value ((0.7 – 0.9 µg/g) indicated that there were no
adverse reaction occurring in the seabed. However, around Stations 04 to 07 the organic
carbons are high (3.96 – 4.40%) with high nitrogen reserve (0.36 – 0.51%). The
carbon/nitrogen ratio ranged from 6 to 9 indicating high rate of humidification especially
when the tide recedes and the soils are exposed to the atmosphere. These areas are rich in
nutrient reserve with available phosphorus and nitrate concentrations ranging from 14.4 –
15.8 µg/g and 18.8 – 21.1 µg/g respectively. This showed that there areas could encourage
growth of seabed organisms. Oil and grease concentrations in the sediments ranged from
318.50 mg/kg at station 07 to 4952.01 mg/kg in Station 01 (pollution source). These values
suggest anthropogenic input since they are generally above the biogenic level of 50mg/kg.
The values also suggest the oil introduced into the environment is still reasonably present
despite the dynamics of the water system. The slow rate of their removal could also be
attributed to the long periods inundation by the seawater slowing down rate of biodegradation.
3.3.2 Sediment Microbiology
Heterotrophic bacterial counts for the Goi samples ranged from 1.44 x 105cfu/g to 8.0 x
106cfu/g. The proportions of petroleum-degrading bacteria in the Goi samples were generally
very low and were either <0.01% or 0.01%. Figure 3.3.1 shows the logarithmic values.
Heterotrophs
PDB
Goi sediment
7
6
5
Logarithmic value
(count, cfu/g)
4
3
2
1
0
1
2
3
4
5
6
7
Stations
Figure 3.3.1: Logarithmic counts of heterotrophic and
petroleum-degrading bacteria in Goi sediment samples.
28
3.3.3 Benthic Fauna
Benthic organisms are those found in the sediments of surface water which are usually the
ultimate sinks of everything that goes into water. The distribution of the benthic organisms
normally reflects the nutrient status among other features as well as the degree of pollution of
the sediments.
The benthic fauna obtained in this study were 13 species and belonged to 3 major groups
namely Polycheates (70%), Gastropoda (15%), and Crustacea (15%) with the Polycheates
contributing greater proportion of the species (Appendix 3.3.2 and Fig. 3.3.2).
Gastropoda
15%
Crustacea
15%
Polycheates
70%
Fig 3.3.2: The number of benthic fauna species observed
for each of the major taxonomic group.
The polycheates were considered to be more important groups in the community than others
due to their wide distribution particularly !ereis diversicolor that occurred in all the stations.
The distribution of species richness between the stations ranged from a minimum of 4 species
(at stations Goi-2, Goi-3, and Goi-4) and the maximum of 7 species at Goi-7.
Species richness
species richness
8
7
y = -0.2x + 5.5333
6
R = 0.10
2
5
4
3
2
1
0
1
2
3
4
5
6
Fig 3.3.3: The distribution of benthic fauna species
richness along the study stations
The regression analysis
29
Rel. Comp.
indicated that between station and distribution of the species was not significant (R2 = 0.10)
(Fig 3.3.4).
100.0
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
Goi-1
Goi-2
Goi-3
Goi-4
Polycheates
Gastropoda
Crustacea
Goi-5
Goi-6
Fig. 3.3.4: The relative contribution of major benthic fauna to
the population for the study stations
Relatively, there were few species in constituting the total number of individuals and they
lacked predominant species. In the study area, total mean densities of benthic fauna ranged
from 10 – 43 individuals/1000cm3 of sediment (Fig. 3.3.5). The distribution of densities was
significantly greater at stations Goi 1 to 3 (26 – 43) and in a magnitude of about two fold
greater than densities observed for stations Goi 4 to Goi 6 (Fig. 3.3.4). Infaunal densities were
more significant (R2 = 0.64) that that of species richness (R2 = 0.1). Generally, the benthic
fauna for the study stations were considerably of low abundance comparable to the similar to
non impacted ecological zones in the Niger Delta region.
y = -5.4x + 43.4
R2 = 0.64
50
3
Densities (no. of indiv./1000cm )
Densities
45
40
35
30
25
20
15
10
5
0
1
2
3
4
5
6
Fig. 3.3.5: The distribution of benthic fauna at the study
stations
30
The low number of species observed in the benthic community for all the stations is expected
in such unstable salinity condition where fluctuations vary remarkably within and between
seasons. However, the poor distribution of species appeared to be associated with the crude oil
effect as light to moderate oiling can smother them because apart from direct effect on the
organisms, indirectly oil can prevent gas exchange between the species and atmosphere. Some
of the organisms can not withstand anaerobic condition and this may be responsible for the
poor distribution observed. This poor distribution of species has been reported in estuaries
impacted by crude oil in the region (IPS, 1994, Snowden and Ekweozor. 1987, Ekweozor ,
1989). The lack of the crustaceans especially Uca tangeri a common mud dwelling crab, the
poor occurrence of other crustacean forms such as Sesarmid crabs, gastropods
(Tympanotonous fuscatus and !eritina species) that are common in equivalent ecological
areas in the region is a clear demonstration of the impact of the crude oil spill on the benthic
community (Hart and Chindah, 1998).
31
3.4 PETROLEUM HYDROCARBO STUDIES
3.4.1 Total Petroleum Hydrocarbon in Surface Water
The results of Total Petroleum Hydrocarbon (TPH) concentrations in the water samples from
Goi are presented in Table 3.4.1. The results show that TPH values range from 0.48 – 1.29
mg/l with a mean value of 0.70 mg/l.
Table 3.4.1: Total Petroleum Hydrocarbon Concentrations
in Water Samples from Goi
S/o.
Study Station
TPH (mg/l)
1
Goi 1
0.67
2
Goi 2
0.48
3
Goi 3
0.51
4
Goi 4
0.84
5
Goi 5
0.49
6
Goi 6
0.59
7
Goi 7
1.29
3.4.2 Polyaromatic Hydrocarbon Concentrations in Surface Water
Polyaromatic hydrocarbon concentrations in the water samples from Goi are presented in
Table 3.4.2. The table shows that polyaromatic hydrocarbons were not detected in any of the
surface water study stations in Goi.
Table 3.4.2: Polyaromatic Hydrocarbon Concentrations in Surface Water
in the Study Area (mg/l)
S/o.
Parameter
Goi 1 Goi 2 Goi 3 Goi 4 Goi 5
1
Naphthalene
ND
ND
ND
ND
ND
2
2-Methylnaphthalene
ND
ND
ND
ND
ND
3
Acenaphthylene
ND
ND
ND
ND
ND
4
Acenaphthene
ND
ND
ND
ND
ND
5
Fluorene
ND
ND
ND
ND
ND
6
Phenanthrene
ND
ND
ND
ND
ND
7
Anthracene
ND
ND
ND
ND
ND
8
Fluoranthene
ND
ND
ND
ND
ND
9
Pyrene
ND
ND
ND
ND
ND
10
Benzo(a)anthracene
ND
ND
ND
ND
ND
11
Chrysene
ND
ND
ND
ND
ND
12
Benzo(b)fluoranthene
ND
ND
ND
ND
ND
13
Benzo(k)fluoranthene
ND
ND
ND
ND
ND
14
Benzo(a)pyrene
ND
ND
ND
ND
ND
15
Dibenzo(a,h)anthracene ND
ND
ND
ND
ND
16
Benzo(g,h,i)perylene
ND
ND
ND
ND
ND
17
Indeno(1,2,3-d)pyrene
ND
ND
ND
ND
ND
Goi 6
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Goi 7
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
3.4.3 Total Petroleum Hydrocarbon in Sediment
The results of Total Petroleum Hydrocarbon (TPH) concentrations in the sediment samples
from Goi are presented in Table 3.4.3. The results show that TPH values range from 10.6 –
50.9 mg/kg with a mean value of 35.13 mg/kg.
32
Table 3.4.3: Total Petroleum Hydrocarbon Concentrations
in Sediment Samples
S/o.
Study Station
TPH (mg/kg)
1
Goi 1
34.4
2
Goi 2
24.2
3
Goi 3
50.0
4
Goi 4
30.9
5
Goi 5
50.7
6
Goi 6
45.1
7
Goi 7
10.6
3.4.4 Polyaromatic Hydrocarbon Concentrations in Sediment
Polyaromatic hydrocarbon concentrations in the sediment samples from Goi are presented in
Table 3.4.4. The table shows that polyaromatic hydrocarbons were generally not detected in
any of the study stations in Goi except Goi 2 low concentrations of some components of
polyaromatic hydrocarbons were recorded.
Table 3.4.4: Polyaromatic Hydrocarbon Concentrations in Sediments (mg/kg)
S/o.
Parameter
Goi 1 Goi 2 Goi 3 Goi 4 Goi 5
1
Naphthalene
ND
ND
ND
ND
ND
2
2-Methylnaphthalene
ND
ND
ND
ND
ND
3
Acenaphthylene
ND
0.05
ND
ND
ND
4
Acenaphthene
ND
0.11
ND
ND
ND
5
Fluorene
ND
0.20
ND
ND
ND
6
Phenanthrene
ND
0.10
ND
ND
ND
7
Anthracene
ND
0.38
ND
ND
ND
8
Fluoranthene
ND
0.21
ND
ND
ND
9
Pyrene
ND
0.19
ND
ND
ND
10
Benzo(a)anthracene
ND
0.22
ND
ND
ND
11
Chrysene
ND
0.62
ND
ND
ND
12
Benzo(b)fluoranthene
ND
0.64
ND
ND
ND
13
Benzo(k)fluoranthene
ND
ND
ND
ND
ND
14
Benzo(a)pyrene
ND
0.40
ND
ND
ND
15
Dibenzo(a,h)anthracene ND
ND
ND
ND
ND
16
Benzo(g,h,i)perylene
ND
1.10
ND
ND
ND
17
Indeno(1,2,3-d)pyrene
ND
ND
ND
ND
ND
33
Goi 6
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Goi 7
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
3.4.5 Total Petroleum Hydrocarbon in Soil
The results of Total Petroleum Hydrocarbon (TPH) concentrations in soil samples from Goi
are presented in Table 3.4.5. The results show that TPH values range from 27.7 – 161.0
mg/kg.
Table 3.4.5: Total Petroleum Hydrocarbon Concentrations
in Soil Samples
S/o.
Study Station
TPH (mg/kg)
1
Goi 1
30.2
2
Goi 2
27.7
3
Goi 3
38.2
4
Goi 4
57.3
5
Goi 5
161
6
Goi 6
41.3
7
Goi 7
94.3
Polyaromatic hydrocarbon concentrations in the soil samples from Goi are presented in Table
3.4.6. The table shows that polyaromatic hydrocarbons were generally low in all the study
stations in Goi except Goi 3 where none was detected.
Table 3.4.6: Polyaromatic Hydrocarbon Concentrations in Soil (mg/kg)
S/o.
Parameter
Goi 1 Goi 2 Goi 3 Goi 4 Goi 5
1
Naphthalene
ND
ND
ND
ND
0.16
2
2-Methylnaphthalene
0.11
ND
ND
ND
0.06
3
Acenaphthylene
0.10
0.05
ND
ND
0.10
4
Acenaphthene
0.23
0.05
ND
ND
0.08
5
Fluorene
0.35
0.23
ND
ND
0.29
6
Phenanthrene
0.21
0.14
ND
ND
0.27
7
Anthracene
0.49
0.69
ND
ND
0.53
8
Fluoranthene
0.23
0.26
ND
ND
0.46
9
Pyrene
0.26
0.11
ND
ND
0.19
10
Benzo(a)anthracene
0.34
0.36
ND
0.12
0.47
11
Chrysene
0.50
0.35
ND
0.11
0.51
12
Benzo(b)fluoranthene
0.57
0.37
ND
0.18
0.57
13
Benzo(k)fluoranthene
0.54
0.28
ND
ND
0.37
14
Benzo(a)pyrene
0.84
0.85
ND
ND
0.79
15
Dibenzo(a,h)anthracene 0.71
0.34
ND
0.77
2.11
16
Benzo(g,h,i)perylene
0.50
0.27
ND
0.53
0.68
17
Indeno(1,2,3-d)pyrene
1.09
0.84
ND
ND
1.52
34
Goi 6
ND
0.04
0.04
0.16
0.29
0.21
0.28
0.07
0.09
0.16
0.53
0.84
0.71
1.38
1.43
0.47
0.63
Goi 7
ND
0.06
0.10
0.24
0.39
0.36
0.49
0.20
0.35
1.33
1.13
2.36
3.11
7.82
1.21
1.73
2.46
CHAPTER FOUR: COCLUSIOS
The study has shown that the Goi area is impacted by hydrocarbon. The hydrocarbon
concentration in the study area is generally above biogenic levels, suggesting introduction of
hydrocarbon from either the spill source or previous incidents of existing SPDC activities in
the area.
This assessment study has been undertaken 32 months after the spill of October 2004. There
are indications there has been a significant decrease in the hydrocarbon concentration since
the spill occurred. This decrease may have been fastened by the relatively dynamic nature of
the water system in the area.
Hydrocarbon concentrations
The concentration of Total Petroleum Hydrocarbon (TPH) recorded in the surface water of the
study area is 0.48 – 1.29 milligram/liter. This concentration has a negative impact on the
resources of the area and the recruitment potential of the system.
The presence of hydrocarbon in soils and sediments of the study area is partly responsible for
the stress observed in the ecology of the environment. This is based on the results of field
observation, epipelic algae (algae that grow on the surface of intertidal mudflats or
substrates), benthos (sediment organisms) and intertidal pool communities (intertidal mudflat
pools that are exposed at low tide with juvenile organisms) where the presence of oil appears
to have affected the abundance and distribution of the organisms.
Previous studies have shown that oil trapped in soils and sediment persists much longer and is
likely to cause more environmental problems than oil in water. It is therefore likely that the
ecological problems associated with the hydrocarbon concentration in the sediment of the
study area persist for a much longer period since cleansing mechanism is slower.
The results of studies show that generally, the study area has a fairly poor composition and
poor amount of benthic communities (various organisms in the sediment system) when
compared to areas of similar ecological system (IPS, 1989).
The results also suggest that the adult intertidal organisms such as mudskippers must have
either been exterminated by the oil or escaped from the spill area. The presence of poorly
distributed small sized mudskippers in the study area, suggests that there is evidence of
recruitment of juvenile mudskippers in the impacted area. These results suggest the oil
introduced into the environment must have caused the absence and or poor distribution of
organisms usually seen in such areas of the Niger Delta (NDES 2001).
Field observations suggest that the area is recovering gradually (Photo Plate).
Impacts on fish
Oil spills result in fish kills and reduced fish abundance in any impacted environment.
Furthermore, the staining of fishing gears with oil renders the gears unsuitable for reuse by
the fishermen. This results in the reduced fishing activities and hence a drastic reduction in
the earnings of fishermen.
35
The critical value for oil that can induce toxic effects has been a cause for concern. The
recruitment potential in the water body can be adversely affected through deformations in
exposed eggs and fish larvae. Concentrations as low as 50 ugl-1 of oil can already cause these
deformations (FOH, 1984). This is several times lower than the range 0.48 – 1.29
milligram/liter reported in the area.
Adult fish are able to avoid oil-tainted water masses, because they can perceive the presence
of oil in very low concentrations. In the event of an oil spill, fish may be exposed to
concentrations of oil in water that may be too low to cause death but high enough for the oil
to accumulate in the fish.
Impact on plants
Oil spill in aquatic environment generates varying ecological responses from plants ranging
from outright mortality to wilting of the plants, defoliation of plant leaves, loss of reproductive cycle and species loss. The magnitude of impact varies, depending on the quantity spilled,
spread, and habitat type, physiographic nature of the area, containment and cleanup measures
adopted.
At the time of the study, there was evidence of the regeneration of mangrove plants indicating
that the older plant species had been destroyed by the spill.
In Goi, the oil spill occurred with a fire outbreak. In such cases usually more plant species,
especially mangrove plants, are damaged. The economic impact both at short and long term
basis depends largely on the timber and non-timber forest products impacted on. This
therefore impacts negatively on the economy of the community especially for the persons
whose livelihood depends on the natural resources in the area. The ecological implication is
difficult to quantify. In dry and flooded zones of the Niger Delta there have been cases of
disappearance of rare and endangered wild life species resulting in biodiversity loss (IPS
1994, NDES 2001).
36
REFERECES
Anderson B (1966) Report on the soils of the Niger Delta special area. A publication of the
Niger Delta Development Board, Port Harcourt, Nigeria.
APHA, (1998). Standard methods for the examination of water and waste water. 201h Ed.
APHA-AWWA-WPCF, Washington.
Chindah , A. C. (1998). The effect of industrial activities on the periphyton community of
upper New Calabar River, Nigeria. Water Res. 32 (4) , 1137 to 1143.
Chindah, A. C. and Nduaguibe, U.. (2003). Effects of tankfarm waste water on water quality
and periphyton lower Bonny River, Niger Delta, Nigeria. Journal of !igerian Environmental
Society (JNES) 1 (2), 206 – 222.
Chindah, A.C. and Pudo J. (1991). A preliminary checklist of algae found in plankton of
Bonny River in Niger Delta, Nigeria. Fragm flor. Geobot 36(1), 112 - 126.
Chindah, A.C. Hart, A.I., Braide, S.A., Amadi (1993b). The Epibenthtic algal community of
the Bonny estuary Nigeria. Acta Hydobiol 35(4), 307 - 320.
Chindah, A.C., Braide S.A.; Amadi . and Osuamkpe, A. (1993a). Investigations into the
Epipelic algal community of Elechi creek at Bonny Estuary, Niger Delta, !igeria Intern. J. of
Biochemiphysics 2(1 & 2), 119 - 124.
Chindah, A.C. and Braide, S. A (2004) The physiochemical quality and phytoplankton
community of tropical waters: A case of 4 biotopes in the lower Bonny River, Niger Delta,
Nigeria. Caderno de Pesquisa . Ser. Bio. Santa Cruz do Sul Vol 16 (2), 7-37
Department of Petroleum Resources (2002), environmental guidelines and standards for the
petroleum industry in Nigeria (EGASPIN).
Ekweozor, I.K.E, (1989). A review of the effect of oil pollution in West African environment.
Discovery and Innovation. 1(3): 2-14.
Ecosphere (2002). Environmental Impact Assessment for the Nigeria LNGPlus Project,
Volume 1: Baseline Report. Volume 2: Impact Assessment (Environmental, Social and Health
Assessment).
Fagade S 0, Olaniyan C I O. (1972) The biology of the West African shardn Ethmalosa
fimbriata (Bowditch) in the Lagos lagoon. Nigerian J. of Fish BioI. 4, 519 -534.
FOH (1984) The fate of oil and its effects in the sea. The Norwegian marine pollution
research and monitoring program.
Gardner W S, Lee R F, Tenore, K R and Smith L W. (1979). Degradation of selected
polcyclic aromatic hydrocarbons in coastal sediments: importance of Microbes and
polychaete Worms. Water, Air and Soil pollution. 339-347.
37
Hart A. I. and Chindah A. C. (1998). Preliminary study on the benthic macrofauna associated
with different microhabitats in mangrove forest of the Bonny estuary, Niger Delta, Nigeria;.
Acta HyProfoiol.,40 (1) ,9 – 15.
IPS - Institute of Pollution Studies (1989). Environmental Data Acquisition of some NNPC
Operational Area . Institute of Pollution Studies Rivers State University of Science and
Technology RSUST/IPS/TR/89/03.
IPS - Institute of Pollution Studies (1994). Ekulama II oil spill: Post impact assessment study.
Institute of Pollution Studies Rivers State University of Science and Technology, RSUST-IPS
—94-03, pages i-v, 1-200.
Mironov 0 G (1972) Effect of oil Pollution on the flora and fauna of the black sea. In Marine
Pollution and Sea Life ed. Runo M, FAO Fishing News Book, London. pp 222-224
Kiel, G. (1997). Environmental engineering. McGraw-Hill publishing company,
England.
NDES - Niger Delta Environmental Survey (2001). Ecological zonation and habitat
classification. 2nd Phase Report 2, Vol.1: 1-66.
O, Halloran, J. and P.S. Giller (1993). Forestry and the ecology of streams and rivers: lessons
from abroad. Irish Forestry 50.35 –52.
Pudo J. (1985) Investigation on algae in the oil spilled region of bonny river. In S. Nokoe (ed)
The Nigerian Environments: Ecological limits of Abuse. Proc. Of the Annual Conf. And
General Meeting of the Ecological Society of Nigeria (ECOSON) held at the Rivers State
University of Science and Technology, Port Harcourt, 3rd to 5th May, 1985.
Pudo 1. (1989) Ecological consequences of crude oil water pollution, Southern Nigeria. Gosp.
Wodna, 486.4: 85-87.
Pudo J, and Fubara D M J. (1988) Studies on Periphyton Algae in the Petroleum Oil Spillage
Area of the Niger Delta aquatic System. Verh. Int. Ver. Limnol.;23: 2259-2261.
Snowden, R. J and I. K. E. Ekweozor. 1987. The impact of a minor spillage in the Estuarine
Niger Delta. Marine Pollution Bulletin 18 (11): 595-599 Fish and fisheries
Wakely, A. and Black I.A. (1934) An Examination of Degtjarett Method for Determining Soil
Organic Matter and Proposed Modification of the Chromic Acid Titration Method, Soil Sci.
37, 29 - 38.
38
007o15’
58.4”
007o15’
56.3”
007o15’
57.8”
007o15’
59.5”
007o16’
07.1”
04o38’
40.7”
04o38’
40.7”
04o38’
36.3”
04o38’
32.1”
04o38’
33.5”
01
02
03
04
05
07
06
E
Identity
(Treated area)
15-30
0-15
007o16’
02.7”
04o38’
40.4”
0-15
15-30
007o16’
02.7”
15-30
7730
3180
2880
2910
4960
7450
6980
3110
3.35
4.29
9800
5800
2.75 14500
9800
3.80 16400
2.93
‰
1182.37
8027.92
104.71
1095.11
445.02
1046.49
2294.94
4646.60
2722.51
8551.48
7089.88
5.5 27288.76
3.1 47338.56
8.5
5.6
9.7
‰
4.05
4.10
4.00
4.22
4.62
4.16
4.18
4.40
1.20
1.28
1.82
2.01
1.18
1.19
THC Org.C
mg/kg
6.9 24476.44
4.2
1.5
1.4
1.4
2.6
4.0
3.8
1.5
EC Sal.
µS
/cm
4.98 12000
3.11
15-30
0-15
4.02
4.21
15-30
0-15
4.12
3.40
15-30
0-15
3.74
3.82
15-30
0-15
3.48
pH
0-15
depth
cm
(Treated area)
04o38’
42.6”
(Near fish pond)
Co-ordinates
Sample
0.60
0.60
0.62
0.64
0.66
0.65
0.60
0.66
0.12
0.14
0.20
0.20
0.13
0.15
T
7
7
6
6
7
6
7
7
10
9
9
10
9
8
ratio
C:
Appendix 3.1.1:
Physiochemical Properties of Soil in Goi, Rivers State (June, 2007)
15.4
16.1
15.8
16.8
15.8
16.0
15.4
15.6
3.0
3.4
3.8
4.5
3.0
3.5
Av.P
39
21.2
23.8
21.4
22.6
22.3
23.0
20.1
20.5
4.6
5.6
6.2
6.4
5.0
5.8
O-3
8.0
8.3
6.8
7.4
7.5
8.2
7.6
7.8
1.0
1.1
1.2
1.3
1.0
1.2
O2-
µg/g
19.6
20.1
19.8
21.2
19.4
20.0
18.8
19.6
3.8
4.6
3.6
5.0
3.9
4.8
H+4
30.5
34.1
32.4
33.2
32.8
33.9
30.4
32.6
5.4
6.4
6.5
7.0
5.5
6.5
SO42-
18.0
18.7
19.0
18.6
20.8
19.0
18.6
18.2
3.2
3.8
3.7
4.1
3.8
4.0
K+
12.5
13.0
13.8
14.4
13.6
12.8
12.4
12.2
2.8
3.0
3.4
3.6
3.3
3.3
a+
23.0
22.3
26.2
25.8
26.2
24.6
22.1
20.8
5.8
6.4
6.8
7.0
6.2
6.9
Ca2+
25.8
27.7
27.8
28.8
29.1
27.9
26.0
26.2
7.8
8.2
8.6
9.2
8.0
8.0
Mg2+
Meg/100gsoil
21.0
26.0
26.6
27.4
26.5
23.2
24.8
25.4
11.0
12.2
11.8
12.4
11.0
11.2
2.5
2.8
17.4
11.4
2.7
3.0
3.6
2.7
87.0
84.0
80.0
80.0
86.0
88.0
CEC Sand
27.5
27.2
44.1
46.1
27.1
26.7
30.6
27.0
5.0
8.0
6.0
4.0
4.0
3.1
Silt
%
70.0
70.0
38.5
42.5
70.2
70.1
65.8
70.3
8.0
8.0
14.0
16.0
10.0
8.9
Clay
Clay
Clay
Silty
Clay
Silty
Clay
Clay
Clay
Clay
Clay
Loamy
sand
Loamy
sand
Sand
loam
Sand
loam
Loamy
sand
Loamy
sand
Class
Textural
007o15’
57.4”
007o15’
59.5”
007o15’
59.7”
007o16’
07.1”
04o38’
38.4”
04o38’
38.4”
04o38’
32.9”
04o38’
33.5”
02
03
04
05
007o16’
05.7”
04o38’
35.1”
07
(Fish pond)
007o16’
03.6”
04o38’
43.4”
06
(Near fish pond)
007 15’
58.0”
o
o
04 38’
43.1”
E
Co-rdinates
01
Sample
station
6.7
7.0
6.8
7.0
6.8
6.7
6.3
pH
13400
970
8490
11000
11800
6900
3330
EC
µ S/cm
5
1
1
1
2
3
1
Turb.
TU
7.8
0.4
4.6
6.3
6.8
3.7
1.6
sal.
‰
9880.0
679.0
5943.0
7700.0
8260.0
4830.2
2331.0
TDS
5.00
9.74
6.54
8.85
3.15
4.80
6.54
DO
40
2.84
3.65
5.68
4.47
19.90
6.09
4.47
BOD
0.15
0.10
0.14
0.15
0.11
0.09
0.14
O3-
mg/l
0.47
<0.05
0.51
0.48
0.50
0.63
0.60
PO43-
288.1
13.3
33.2
112.9
192.5
65.1
33.2
SO42-
Appendix 3.2.1:
Physicochemical Properties Surface water contaminated sites in Goi, Rivers State (June, 2007)
1033.20
115.10
1159.20
1108.80
1436.40
970.20
693.00
Cl-
29.0
20.0
40.0
38.0
42.0
30.0
20.0
∑Alk.
1283.72
72.81
881.36
1034.64
1130.44
670.60
344.88
∑Hard
mg/lCaCO3
65.14
6.90
38.32
55.95
59.78
57.48
42.15
Ca2+
58.44
Mg2+
273.48
13.56
191.68
218.32
239.36
128.56
mg/l
<0.02
<0.02
<0.02
1.07
0.40
2.81
<0.02
THC
ppm
Appendix 3.2.2:
Phytoplankton species and the count for the respective species at the study stations.
Goi
1
Goi
2
Goi
3
Goi
4
Goi
5
Goi
6
Bacillariophyceae
Aulocosera
granulata
3
2
5
M.
moniliformis
8
23
Bacillaria
paradoxa
2
Biddulphia
aurita
5
3
B.
longicruoris
9
3
Coscinodiscus
centralis
36
53
C.
rothii
36
98
C.
lacustris
6
9
Cyclotella
striata
7
15
8
5
C.
meneghianiniana
5
6
3
15
7
3
Ditylum
brightwellii
18
30
69
62
34
23
Diploneris
ovalis
12
42
4
6
Amphora
ovalis
4
5
5
6
6
Amphiprora
alata
5
9
5
6
!itzschia
angustata
6
!.
gracilis
!.
linearis
!.
closterium
2
!avicula
cryptocephala
8
3
3
!.
cuspidata
5
8
7
!.
placentula
!.
minima
!auderia
sp.
Chaetoceros
gracilis
57
C.
didymus
6
Hantzschia
amphioxys
Pinnularia
maior
P.
interrupta
Rhizosollenia
alata
Rhizosolenia
styliformis
Pleurosigma
elongatum
17
9
9
10
6
5
6
2
6
8
3
12
8
12
54
62
23
98
58
30
51
62
4
9
6
19
14
5
3
2
5
6
9
8
10
15
5
4
6
2
2
2
3
3
2
4
2
36
58
34
67
18
6
23
3
12
2
21
5
2
6
19
24
41
9
3
33
9
2
9
2
48
6
4
23
67
21
34
P.
angulatum
12
3
5
Gyrosigma
acuminatum
Planktonella
4
7
2
5
sol
3
4
6
Thalassiosira
nordenskioeldii
9
4
6
Thalassionema
nitzschioides
8
3
8
4
Tabellaria
fenestrata
7
8
12
Surirella
robusta
5
9
324
Bacillariophyceae
4
3
9
15
25
27
7
12
3
25
418
414
489
363
394
53
138
142
66
103
89
2
3
Cyanophyceae
Oscillateria
sancta
O.
suscapitata
6
3
O.
simplissima
2
5
7
3
3
O.
terebirformis
12
11
7
18
54
21
O
brevis
O
chalybaea
O
limosa
O
griseo-violavea
Phormidium
uncinatum
144
264
213
72
108
39
Ph.
molle
1
18
5
9
Ph.
ambiguum
2
27
24
3
6
Merismopedia
elegans
2
6
9
6
13
Spirulina
spirlinoides
5
3
6
7
11
Spirulina
rhaphidioides
4
5
2
Spirulina
laxissima
2
Gleroscapsa
sp.
Cyanophyceae
1
39
3
5
2
12
228
511
410
186
300
191
3
5
6
Chlorophyceae
Scenedesmus
quadriuncauda
Scenedesmus
denticulatus
Scenedesmus
acutus
Scenedesmus
arcutus
Closterium
lunula
4
4
2
5
3
2
2
3
Cosmarium
Chlorophyceae
5
0
42
0
4
7
21
12
Euglenophyceae
Euglena
acus
9
5
18
Phacus
candata
1
2
6
Trachelomonas
dastugei
5
Trachelomonas
acanthophora
8
Trachelomonas
cebea
Trachelomonas
planctonica
6
5
6
3
3
2
2
10
Euglenophyceae
18
2
3
2
5
4
6
19
22
26
25
3
6
3
19
Dinophyceae
Ceratium
tripos
Ceratium
furca
Protoceratium
reticulatum
6
Dinophysis
acuminata
2
Dinophyceae
0
43
11
6
4
3
7
3
0
Appendix 3.2.3:
Zooplankton species and the count for the respective species at the study stations.
Goi
1
Goi
2
Goi
3
Goi
4
Goi
5
Goi
6
12
7
6
3
25
4
5
2
16
3
8
Copepoda
Copepoda nauplii
Calanus finmarchicus
3
Diaptomus oregonensis
2
4
Eucalanus bungii
4
4
Oithona nana
8
12
7
3
9
2
2
11
3
2
1
5
11
3
Copila mirabilis
Harparticoid copepod
Oncaea curvata
Copepoda
2
31
38
27
32
42
19
8
2
6
7
5
4
Rotatoria
Asplanchna brightwelli
Brachionus caudatus
Lucane aquila
2
2
Lucane nana
Euchlanis proxima
3
3
Euchlanis triquetra
2
2
1
4
1
1
1
2
1
2
2
3
Kellicottia striata
Rotatoria
13
44
10
8
9
15
9
Appendix 3.2.4:
Periphyton species and the count for the respective species at the study stations.
Taxa
Goi
1
Goi
2
Goi
3
Goi
4
Goi
5
Goi
6
Bacillariophyceae
Achnanthes
affinis
23
53
63
71
56
81
Achnanthes
echrenbergii
18
24
102
18
18
24
Eunotia.
Gracilis
11
9
12
10
11
3
Eunotia.
Microcephala
76
98
54
162
123
128
!avicula
bacillum
16
21
56
8
14
29
!avicula
enestrat
28
72
36
36
47
42
!avicula
enestr
2
6
15
16
!avicula
minima
27
18
33
6
36
105
!itzschia
linearis
69
36
33
69
36
39
!itzschia
closterium
6
15
37
21
10
Pinnularia
interrupta
12
36
45
42
18
36
Pinnularia
appendiculata
6
27
27
2
6
27
Pleurosigma
elongatum
12
7
9
6
3
5
Pleurosigma
angulatum
5
21
24
9
17
21
Tabellaria
fenestrate
6
9
48
6
10
Cymbella
affinis
9
18
Cymbella
cumbiformis
6
Ditylum
brightwelli
5
335
451
5
3
8
3
15
6
5
3
9
523
562
437
577
12
3
12
18
Cyanophyceae
Anabaena
flos-aquae
6
Aphanozemenun
flos-aquae
15
35
46
54
34
22
Gleocapsa
chrococcoides
102
180
213
269
368
136
Gleocapsa
turgida
14
22
Gleocapsa
rupestris
171
195
78
154
171
195
Gleocapsa
magma
18
39
12
28
45
78
Microcystis
aeuroginosa
675
906
258
492
507
834
Aphanothece
microscopica
168
231
144
161
267
207
Aphanothece
saxicola
72
108
54
33
132
57
Oscillatoria
limosa
63
39
9
9
14
39
O.
terebriformis
33
48
27
9
33
48
45
3
O.
chalybalea
48
6
33
34
O.
brevis
12
6
24
Phormidium
molle
16
34
14
Ph.
Tenue
3
5
Ph.
Forseolarum
7
9
3
Synechocystis
aquatilis
24
12
21
Synechocystis
salina
15
34
Merismopedia
elegans
54
48
22
21
27
48
Phormidium
uncinatum
23
52
33
69
102
16
Ph.
Molle
3
7
11
16
1.513
1.989
1.385
1.841
1.779
5
2
6
27
11
29
3
6
24
48
6
12
6
16
54
8
1.059
5
6
24
12
8
Chlorophyceae
Closterium
lineatum
C.
gracile
C.
incuruum
4
Scenedesmus
acuminatus
6
Sc.
quadricanda
3
Chlorophyceae
2
3
27
6
15
2
13
29
3
6
9
17
Euglenophyceae
Euglena
acus
E.
oblonga
13
E.
caudata
3
Phacus
caudatus
2
Ph.
pleuronectes
Euglenophyceae
21
46
9
8
3
6
3
2
3
5
3
17
17
11
5
3
11
9
07
06
05
04
03
02
01
Sam
ple
Iden
tity
1.10 0.16
1.12 0.13
4.51 1200 2094.24
(Fish pond)
8
4.10 0.52
7
8
4.40 0.62
5.42 1780 1078.32
8
9
7
7
3.96 0.50
4.20 0.52
433.21
5.58 2510
C:
T Ratio
4.81 5590 4952.01
THC Org.C
1.02 0.14
EC
%
4.70 4580 2286.90
pH
Mg/kg
007o16’03.6”N
4.31 1630 1505.24
04o38’43.4”E
o
007 16’05.7”N
6.06 1990 318.50
04o38’35.1”E
(Near fish pond)
007o15’58.0”N
04o38’43.1”E
007o15’57.4”N
04o38’38.4”E
007o15’59.5”N
04o38’38.4”E
007o15’59.7”N
04o38’32.9”E
007o16’07.1”N
04o38’33.5”E
Coordinates
µS/c
m
14.4
15.1
15.8
14.6
1.6
1.4
1.7
Av.P
µg/g
18.8
19.8
20.5
21.1
2.8
3.1
3.0
47
7.8
6.4
7.9
6.8
0.7
0.8
0.9
19.0
18.8
19.5
18.2
2.0
2.2
2.1
O-3 O2- H+4
Appendix 3.3.1:
Physicochemical Properties of the Related Sediments (June, 2007)
28.6
30.1
32.8
24.8
2.8
2.6
3.0
SO42-
17.8
16.2
18.3
14.0
3.0
2.8
3.2
K+
10.8
11.4
12.3
12.0
3.0
2.8
3.0
20.4
19.8
20.8
21.0
4.8
5.0
4.9
24.8
25.6
26.3
24.2
6.0
5.8
6.3
a+ Ca2+ Mg2+
Meg/100g Soil
25.8
26.1
25.2
24.6
8.4
8.2
8.6
2.5
3.8
2.7
3.6
90.0
80.0
90.3
CEC Sand
25.0
25.2
27.0
30.2
3.2
15.0
3.0
Silt
%
72.5
71.0
70.3
66.2
6.8
5.0
6.7
Clay
Clay
Clay
Clay
Clay
Loamy
Sand
Sand
Sand
Class
Textural
Appendix 3.3.2:
The benthic fauna species and number of individuals at the study stations
Taxa
Stations
Goi
1
Goi
2
2
3
25
19
2
3
Goi
3
Goi
4
Goi
5
Goi
6
Polycheates
Nereis virens
Nereis diverisicolor
Nereis pelagiea
1
29
3
9
Nepthys capensis
2
Glycera longipinus
1
Glycera convoluta
2
3
12
9
1
Platenereis dumerilii
Nephthys lombergi
3
1
3
1
1
3
1
Capitella ccapitata
Polycheates
43
26
32
7
16
15
Crustacea
Sesarma huzardi
1
Sesarma alberti
1
Crustacea
0
0
0
0
2
0
0
0
Gastropoda
Neritina sp.
1
Tympanotonus fuscata var radula
2
3
3
3
Gastropoda
0
48
0
49