IMPACT OF HUMAN ACTIVITIES ON DRINKING WA CT OF HUMAN

Transcription

IMPACT OF HUMAN ACTIVITIES ON DRINKING WA CT OF HUMAN
ISSN 0973 - 8207
Research Article
IMP
ACT OF HUMAN ACTIVITIES ON DRINKING WA
TER QU
ALIT
Y
IMPA
WATER
QUALIT
ALITY
O. Obire1, M. Aguda2 and Ramesh.R.Putheti3
1,2
Department of Applied and Environmental Biology, Rivers State University of Science & Technology,
P.M.B 5080, Port Harcourt, Nigeria, email: [email protected],
3
A member in sigma Xi, The scientific research society,E.mail:[email protected].
Abstract: A total of 30 drinking water samples collected from Kolo creek were analyzed to ascertain
its potability. Physicochemical and bacteriological parameters were determined using standard
methods and the most probable number technique (MPN). Mean values for temperature, pH, BOD5
and total alkalinity were 25.9°C, 6.6, 2.57mg/l and 16.50mg/l respectively. Total culturable
heterotrophs and total coliform MPN were 4.4 x 105cfu/ml and 165/100ml respectively. Total
coliform MPN expressed as a percentage of heterotrophs was 3.75%. Bacterial types and their
frequency of isolation were Bacillus sp. (66.67%), Proteus mirabilis (16.67%), and Streptococcus sp
(16.67%). E. coli was not isolated from the drinking water samples but was isolated from the areas
of human activities. The high levels of BOD, heterotrophs and coliforms indicate that the drinking
water is highly polluted. The presence of faecal organism such as Streptococcus indicated the
contamination of the water with faecal matter implying that the creek water is not safe for drinking.
Keywords: Water, human activities, pollution, bacteria, coliforms.
Introduction
Water from rivers, streams, lakes, ponds,
etc., are used as sources of water supply for
domestic, agricultural and industrial purposes
[1]. Considerable human activities of various
kinds are sources of pollution, producing highly
poisonous wastes such as chemicals and human
wastes including raw excreta (faeces). Faeces
may contain pathogenic microorganisms that
cause many illnesses that range from typhoid
fever, cholera and bacillary dysentery to minor
respiratory and skin diseases [2; 3].
In most developing countries including
Nigeria, there is indiscriminate dumping of
untreated waste into nearby rivers and streams.
The low standards of health in the Niger Delta
region are caused by a general lack of
awareness of good hygiene practices, direct
contamination of beach waters through
bathing and washing, and uncontrolled waste
disposal around the shoreline [4]. Direct
discharge of untreated or raw municipal and
or industrial effluent into rivers and lakes could
contribute to microbial pollution, have negative
effect such as nutrient enrichment, deterioration
of the water quality, destruction of spawning
grounds for aquatic and marine life and general
fish kill and drinking use [5]. Wrong handling
of water for drinking could result in the spread
of diseases and even death [6].
The study area is located on Kolo creek,
which forms the eastern limit of the developing
Yenagoa metropolitan city, the Bayelsa State
capital, located in the central Niger Delta in
Nigeria [7]. Kolo creek extends from latitude
4 o 33′ North of the equator (its mouth) to
latitude 4o58′ North (its source). The creek is
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Journal of Basic and Applied Biology, 2(3 & 4), 2008, pp. 52-58© 2008, by the Centre for Biological Research, Puthalam, 629 602, TN, India
Obire et al., 2008
about 85km long with several communities
located along its banks. The communities
engage in similar economic activities and so
they generate similar waste products
discharged into the creek.
When a river or creek is liable to
pollution through human activities as is the case
with the kolo creek, routine analysis of the creek
water becomes necessary to establish the
constancy of quality or to follow fluctuations
in water quality characteristics. Microbiological
analysis will therefore serve as an index to
establish cases of disease epidemics and
endemics, whose aetiolog y was or is
obscure [8].
No study has been conducted to
ascertain the impact of human activities on the
Kolo creek as it affects use for drinking and local
industry use. Being that Kolo creek serves as a
source, of water for drinking without treatment
and for other domestic and local industrial
activities, it was therefore necessary to conduct
such a study.
The objective of the study was to
determine some physico-chemical parameters,
bacterial population and the types of bacteria
such as coliforms and faecal indicator bacteria
present in drinking water samples from the Kolo
creek. The aim of the study was to assess the
impact of human activities on the water quality
(chemical and bacteriological) of the creek so
as to ascertain its potability and the likely health
hazards associated with the use of the water
for drinking.
Materials and Methods
Description of the study area on Kolo Creek
The choice of the study area was based
on their peculiar nature as a source of drinking
water and as a receptacle of pollution from
human activities. These pollution sources are
common among communities and settlements
along the creeks of the Niger Delta. The stretch
of Kolo creek from which the drinking water
samples were collected is that on which Kolo 1,
Kolo 2, and Kolo 3 communities are located.
These three communities are merged together.
The drinking water station is located upstream
from the areas of human activities. It is free of
any identifiable pollution source and it is from
this station that water for drinking is collected
by the inhabitants. No treatment of the raw
water is carried out before consumption.
An open waste dump is located on the
banks of the creek approximately 100 meters
downstram from the drinking water station.
The dup is a heterogeneous collection of almost
all types of domestic or household wastes or
garbage. They include decomposable organic
materils such as waste from food preparations,
cooked or serving of food or garbage,
fermentable organic wastes such as leaves,
peelings and non degradable materials like
polythene bags. Others include ashes from
burning of wood for cooking, metal cans,
broken glasses, beddings, and old fabrics, dead
household pests such as rats, decomposing
remains of fishes and shells of snails and
periwinkle, bones of animals, plastic scraps and
animal wastes such as poultry droppings.
During runoffs, after rainfall, these wastes and
their reduced products are washed into the creek
directly.
A bathing and washing site is located
approximately 400 meters downstream from
the waste-dump site. Washing of dirty clothes,
farm implements and bathing are carried out
here. Remains of left over food and vegetable
oil from cooking are discharged here. Old
fabrics, polythene, are also found.
A palm oil processing mill is located 40
meters (approximately) downstream. Effluents
from the oil mill are channeled to the creek
through a narrow drainage. Palm oil and the
husks from the milled palm fruits were
sometimes very visible on the water surface
around of this station during sampling. A mini
cassava milling and processing factory is
located approximately 20 meters downstream
of the palm oil mill. Effluent containing starch
from milled cassava is also channeled into the
creek through a narrow drainage. The starch
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Obire et al., 2008
sediments to the bottom and become visible
when the water is agitated at this station. A
“floating toilet” where raw human faeces and
urine are directly discharged without treatment
into the creek is located approximately 50
meters downstream from the cassava mill.
Collection of drinking water samples from the
creek
Water samples for physico-chemical
and bacteriological analyses were collected from
the drinking water station for a period of six
months (March to August 2004).
Sample bottles wrapped in aluminium
foil were sterilized at 150oC in the oven (Model
No. Gallenkamp size one, Made in England)
for 2 hours, prior to the collection of water
samples. Methods adopted in the collection of
water samples were in accordance with [9] and
[10]. During each monthly sample collection,
two sets of water samples were collected using
100 ml sterile glass bottles for bacteriological
determinations. Another two sets of water
samples were also collected for dissolved
oxygen (DO) determination with 60-ml
Winchester glass stoppered bottles. One set of
water samples for DO was fixed with 0.5 ml
each of Winkler I and II reagents in the field
immediately after collection. The other set was
fixed after 5 days of incubation at 20oC for BOD
(Biological Oxygen Demand) determination.
Separate sterile plastic and glass bottles of 500
ml capacity were used for collecting water
samples for other physico-chemical parameters.
Each sample bottle was appropriately labeled
immediately after collection and stored in a
portable cool box containing freezing mixture
of ice blocks and common salt before
transportation to the laboratory for analysis.
Five (5) samples were collected during each
visit. A total of 30 creek water samples were
collected and analyzed during the six-month
sampling period. Due to the distance from the
study site to the laboratory, samples not
analyzed on the day of collection were stored
in the refrigerator at 4oC until the next day.
Determination of Physico-chemical Characteristics
Physico-chemical parameters analyzed
using the Kolo creek water samples included
temperature, hydrogen ion concentration (pH),
turbidity, dissolved oxygen (DO) and
biochemical oxygen demand (BOD).
Temperature was determined at each
sampling sation during each sampling visit
with a mercry thermometer. The pH of the
water sample were determined soon after
arriving at the lboratory using Metler model
691 pH meter mde by Harison, Switzerland,
Type 1,69100 acording to the procedure
specified in [9]. Turidity was determined by
the Nephelometric method (NTU) using a
Model number 2100T Turbidometer, HACH
serial number 46500 – 02).
Microbiological Determinations
Microbiological determinations of the
Kolo creek water samples included cultivation
and enumeration of total culturable aerobic
heterotrophic bacteria using standard medium
of nutrient agar (Oxoid) plates and total
coliform counts using most probable number
(MPN) technique using multiple fermentation
tube method. The medium used was
MacConkey Broth (Oxoid). Isolation and
characterization of culturable aerobic
heterotrophic bacteria using standard
(morphological and biochemical) tests was also
carried out.
Culturing of Drinking Water Samples and
Enumeration of Bacteria
The spread plate technique was applied
using a sterile bent glass-rod [11]. The
inoculated plates were inverted and incubated
at 37oC for 24 hours in a Griffin model number
105 Incubator after which plates were
examined for growth. Discrete colonies which
developed on nutrient agar plates were counted
and the average counts for duplicate cultures
were recorded as total culturable aerobic
heterotrophic bacteria. Pure cultures of bacteria
were obtained by aseptically streaking
representative colonies of different
morphological types, which appeared on freshly
poured nutrient agar plates, and incubated at
37oC for 24 hours.
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Obire et al., 2008
Identification of Bacteria Isolates
Cultural characteristics (which include
patter n of growth, pigmentation and
appearance of isolates on nutrient agar plates)
were observed after 24 hours of incubation at
37oC; Gram staining and biochemical reactions
exhibited by the isolates in test methods adopted
in accordance with those described by [12] and
with reference to [13]. Further identification
was mad by comparison of their cultural,
morpholoical and physiological characteristics
with those of known taxa.
Results
The rane of the means of monthly
values and the oveall mean of the physicochemical parameters and bacterial counts
during the 6 months’ investigation are as
presented in Table 1 below.
Table 1. Range and mean values (mg/l) of
water quality parameters of Kolo creek
drinking water samples
PARAMETER
Temperature (°C)
pH unit
Turbidity (NTU)
Dissolved oxygen (DO)
RANGE
MEAN
28.5 - 24.5
25.9 ± 10.6
6.8 - 6.5
6.56 ± 2.7
20.41 - 9.65
15.71 ± 6.6
5.84 - 3.6
4.50 ± 4.1
BOD5
3.36 - 1.6
2.57 ± 2.4
Total alkalinity
25.0 - 8.6
16.5 ± 7.10
Chloride
364 - 20
129.7 ± 75.8
Sulphate
5.91 - 0.412
2.63 ± 1.2
2.5 - 0.3
1.26 ± 0.6
1550 - 570
898.33 ± 403.4
Phosphate
Total dissolved solids
Salinity
0.599 - 0.005
0.206 ± 0.12
Oil and grease
290 - 110
175.83 ± 76.2
Ammonia
0.34 - 0.02
0.7 ± 0.1
Conductivity (ms/cm)
610 - 220
433 ± 184
6.2 - 3.2
4.4 ± 4.1
>180 - 90
165 ± 68.6
Total bacterial count
(x105cfu/ml)
Total coliform
(MPN/100ml)
The types of bacterial isolated from the
water samples and their frequencies of isolation
in parenthesis are as follows; Bacillus sp.
(66.67%), Proteus mirabilis (16.67%), and
Streptococcus sp (16.67%). Escherichia coli was
not isolated from the drinking water samples.
However, Aeromonas sp, Bacillus sp, Citrobacter
freundii, Enterobacter aerogenes, Enterococcus
faecalis, Escherichia coli, Klebsiella sp, Proteus
mirabilis, Pseudomonas sp, Serratia macescens,
Staphylococcus aureus, Streptococcus sp and Vibrio
sp. were isolated from the areas of human
activities.
Discussion
This investigation has revealed the
physico-chemical characteristics and bacterial
types including total coliform bacteria (MPN),
which are indicators of faecal pollution and of
water quality of Kolo creek. The levels of the
parameters determined have helped to ascertain
the water quality and hence its potability. The
mean values of BOD 5 , phosphate, total
dissolved solids, ammonia, total bacterial count
and total coliform MPN/100ml were far higher
than the maximum allowable limit ( 0 - 0.05,
0.5, 1000, 0.05, 1.0, and 0 respectively) of [14];
[15]; and [16].
The temperature of the water had a
mean value of 25.9 ± 10.6 which is in the lower
limit of the mesophillic range of temperatures.
This is as a result of the unidirectional flow of
the creek. It receives cooler waters from rivulets
and minor water sources that drain water from
cool swamps and lake waters. The pH was in
the slightly acidic range with a mean of 6.56 ±
2.7. Activities of microorganisms within the
dump and other areas of human activities must
have resulted in the pH values reported in the
water samples. The passage of leachate through
soils in a dump-site into a stream has been
reported to increase the pH of stations along
the stream [3] [20].
High turbidity values obtained in the
control and other stations could be attributed
to the draining of materials such as silt from
swamps and rivulets located upstream before
the drinking water station. The overall DO
mean was within the allowable limit (3 – 7mg/
L) of WHO [16] while the BOD5 values (2.57
± 2.4mg/l) were higher. The activities and
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Obire et al., 2008
growth of microorganisms and the presence
of degradable organic matter such as cassava
starch, “eba” and other food wastes like cooking
oil and vegetable matter as well as the direct
discharge of faeces into the creek increased the
amount of oxygen required to degrade them
by the microorganisms present. Contamination
of water with faeces has been reported by [2],
[21] and [17] as sources of organic matter
that could be utilized by microorganisms and
therefore increasing the BOD.
The overall mean of culturable
heterotrophic counts of bacteria are considered
high for drinking water. The high organic
matter regularly discharged into the creek
served as nutrient to the bacteria. This enhanced
the proliferation of bacteria resulting in the
high counts observed. The established presence
of bacteria in water bodies is important as they
are identified as major organisms that break
down waste materials introduced into
waters[21] [18]. High bacterial counts
reported in this study indicate the high level
of pollution influenced by the various human
activities on the banks of Kolo creek. High
bacterial counts are associated with the presence
of high nutrient load.
The bacterial types isolated included
species known to be involved in the degradation
of organic matter. These bacteria such as
Bacillus sp, Esherichia coli, Enterococcus feacalis,
Pseudomonas sp and Staphyloccocus aureus may
have entered the water through the waste
dump during runoff and leaching, at the
bathing and washing site and direct discharges
at floating toilet. This supports the findings of
[3], [20] that the organisms isolated in their
study may have found their way into the water
through leachate from an open waste dump.
Bacteria such as Bacillus and Pseudomonas have
been reported by [19] to be associated with
waste. Most of these bacteria are potential
pathogens that can be acquired through
drinking water polluted by these organisms.
Most waterborne diseases that can result from
drinking water polluted by these organisms
range from gastro-intestinal tract infection that
can be caused by Aeromonas sp., E. coli, Vibrio
sp. Enterobacter sp. Enterococcus sp., Proteus,
Pseudomonas to Serratia sp that are known to
cause urinary tract infections in the young and
elderly. Other diseases caused include wound
and skin infections, respiratory infections and
food poisoning.
Results obtained for total coliform
count (MPN) showed that the drinking water
samples were highly polluted with coliforms.
Occurrence of coliforms in the drinking water
station and the unidirectional flow of the creek
water suggested that the presence of coliforms
may not be due only to pollution from faecal
matter but also to other sources. The presence
of high coliforms in the water renders it unsafe
for drinking purposes [16]. The presence of
E. coli alone and other enteric bacteria isolated
from areas of human activities are sufficient to
conclude that Kolo creek water body is highly
polluted with pathogenic organisms able to
initiate different enteric diseases.
It is worthy to note that a few months
after the completion of this study, there was an
epidemic outbreak of a water-borne disease in
Kolo 1, 2, and 3 Communities (study area). The
epidemic was reported to the Bayelsa State
Government, calling for an investigative team
of health officials to be sent to the communities.
The government responded by sending health
officials including expatriates (doctors without
borders) to investigate and provide prompt
appropriate treatment measures. There was also
the immediate rehabilitation and provision of
borehole water by the government to avert
future occurrences.
Conclussion
The values of the physico-chemical
constituents of the drinking water samples
indicated that Kolo creek water quality was
highly impacted by human activities. Though
pH levels fell within permissible limits for
drinking water, other parameters such as
turbidity, BOD, phosphate, total dissolved
solids, ammonia, total heterotrophs and total
coliform MPN were not within permissible
limits of standards for drinking water.
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Obire et al., 2008
The high bacterial population was as a result
of increased nutrient load from the various
activities along the bank of the creek. These
contributed to the organic pollutant load of the
creek. Bacteria isolated were potential pathogens
of various diseases affecting man and other
animals.
The study revealed a high total bacterial
count in the water beyond the stipulated WHO
standards for drinking water of 0 to 1.0.
Moreover, the presence of Streptococcus sp which
is an indicator of faecal pollution and other
coliform bacteria is sufficient to conclude that
Kolo creek water body is highly polluted with
pathogenic organisms capable of initiating
different enteric diseases. These suggest that
Kolo creek water is bacteriologically unfit for
drinking. The presence of coliforms especially
Streptococcus sp in water renders it unsafe for
drinking purposes.
[4]
[5]
[6]
[7]
[8]
[9]
Acknowledgement
We wish to acknowledge the Bayelsa
State Government in her prompt action in
sending “Doctors without borders” and other
health professionals to Kolo 1, Kolo 2, and Kolo
3 communities and the provision of borehole
water to these communities when we informed
the government of the waterborne epidemic
that resulted in the loss of lives in these
communities.
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