Studies on the effect of abattior and industrial effluents on the heavy metals and microbial quality of Aba river in Nigeria

Abstract

Levels of lead, iron, zinc, copper, arsenic, cobalt, chromium, manganese, mercury and cadmium, as well as the microbial profile were determined in water samples from Aba River. Physico-chemical examinations revealed that manganese (0.03 mg/l), zinc (4.81 mg/l) and copper (0.19 mg/l) were below the maximum allowable levels set by the United States Environment Protection Agency (USEPA), while lead (0.064 mg/l), iron (0.81 mg/l), arsenic (0.1 mg/l) chromium (0.006 mg/l) and mercury (0.009 mg/l) were high but not significantly. The implication is that waste assimilation capacity of the river is high, a phenomenon attributable to dilution, sedimentation and depuration. Quantitative examinations of the microorganisms present revealed that as many as 2.05 x 10 8 viable bacterial (cfu/ml) were present. The predominant bacterial forms include Staphylococcus species, Streptococcus faecalis, Escherichia coli, Salmonella species, Bacillus and Clostridium species implying that the abattoir wastes discharged into the river may have had a significant impact on the river ecosystem.

Full text

African Journal of Biotechnology Vol. 4 (3), pp. 266-272, February 2005
Available online at http://www.academicjournals.org/AJB
ISSN 1684–5315 © 2005 Academic Journals
Full Length Research Paper
Studies on the effect of abattior and industrial effluents
on the heavy metals and microbial quality of Aba river
in Nigeria
O.U. EZERONYE* and A.O. UBALUA
Department of Biological Sciences, Michael Okpara University of Agriculture, Umudike P.M.B. 7267, Umuahia, Abia
state, Nigeria.
Accepted 13 September, 2004
Levels of lead, iron, zinc, copper, arsenic, cobalt, chromium, manganese, mercury and cadmium, as
well as the microbial profile were determined in water samples from Aba River. Physico-chemical
examinations revealed that manganese (0.03 mg/l), zinc (4.81 mg/l) and copper (0.19 mg/l) were below
the maximum allowable levels set by the United States Environment Protection Agency (USEPA), while
lead (0.064 mg/l), iron (0.81 mg/l), arsenic (0.1 mg/l) chromium (0.006 mg/l) and mercury (0.009 mg/l)
were high but not significantly. The implication is that waste assimilation capacity of the river is high, a
phenomenon attributable to dilution, sedimentation and depuration. Quantitative examinations of the
microorganisms present revealed that as many as 2.05 x 10
8
viable bacterial (cfu/ml) were present. The
predominant bacterial forms include Staphylococcus species, Streptococcus faecalis, Escherichia coli,
Salmonella species, Bacillus and Clostridium species implying that the abattoir wastes discharged into
the river may have had a significant impact on the river ecosystem.
Key words: Waste assimilation, effluent, low level metals, pollution.
INTRODUCTION
Aba River is an important economic river in Nigeria. Aba
town lies between latitude 50 03’N to 50 07’ and
longitude 70 17’E to 70 24’E in Abia State of Nigeria.
The river is used for various human activities including
car washing and fishing. People living within the
upstream vicinity draw water from the river for drinking.
The river originates from the northern Ngwa hinterland of
Aba and stretches down to Cross rivers state where it
empties with its creeks into the Atlantic Ocean. The river
receives wastes from the industries and abattoirs sited
along its course.
Effluent discharges into receiving waters and the
*Correspondingauthor. E-Mail: ezeronyeob@yahoo.com.
cumulative hazardous effects on the environment have
received much attention due to rapid industrialization in
modern society. Industrial and abattoir wastes containing
high concentration of microbial nutrients would obviously
promote an after growth of significantly high Coliform
type and other microbial forms, both in the effluent and
the receiving waters (Ezeronye and Amogu, 1998).
Process water from cosmetic, detergent and textile
industries contain a lot of heavy metals, which when in
super-abundance causes a disruption in the ecological
balance. Moreover, allochthonous and autochthonous
influences could make concentration of heavy metals in
the water high enough to be of ecological significance.
Furthermore, bio-concentration and magnification could
lead to toxic levels of these metals in organisms, even
when the exposure level is low.

Ezeronye and Ubalua 267
Figure 1.Total viable of micro-organisms isolated from Aba river in dry season.
The proven toxicity of high concentrations of heavy
metals in water to organisms and wild life poses the
problem of ultimate disequilibria in the natural ecological
balance (Babich and Stoczky, 1985) Under such
conditions the toxicity of a moderately toxic metal could
be enhanced by synergisms and organisms population
may decline (Laws, 1981). Apart from destabilizing the
ecosystem, the accumulation of these toxic metals in the
aquatic food is a potent threat to public health. The Mina
Mata Bay epidemics in Japan remain a classic example.
This work was carried out in order to establish the
existing levels and assess the pollution profile, as well as
to examine the assimilative capacity of the water body in
Aba River. Similar studies have been conducted in the
Lagos Lagoon, Igboba River in Benin and in Niger/Delta
River all in Nigeria (Okoye et al., 1989; Kakuku, 1985).
The data could be helpful in defining future waste
management practices in the area in terms of quantity of
waste to be discharged. This work could be of relevance
to the Federal Environmental Protection Agency (FEPA)
in the enactment of environmental protection laws in
Nigeria.
MATERIALS AND METHODS
Sampling
Five different water samples were each collected with 1-liter sterile
polyvinyl chloride (PVC) plastic water bottles at a depth of 1 meter
below the water surface from the five designated sampling points in
Aba River. At each sampling point, three water samples were
drawn at random from three points and pooled. Dry season
(November/December to March) samples were collected in
January while Rainy season (March/April to December) samples
were collected in July. The time for the collection of the two
seasons’ samples was 11.00 am in the morning. The samples were
subsequently placed on ice in a cooler and transported to the
laboratory for analysis. The importance of samples collection at the
upstream and downstream points was for comparative studies.
Physicochemical analysis
Determination of heavy metals in the water samples was done
using the Atomic Absorption Spectrophotometer (AAS, Unican lab.
Services, York Street, UK) as described in the manufacturer’s
instruction manual.
Total viable count (cfu/ml x 10
6
0
0.08
0
.06
10
50
90
130
0.06
0.07 0.07
0.06
0.06
102
98
106
0.08
0.09
0
.09
0.07 0.07
Upstream
1
Upstream
2
Abattoir
Sampling
points
Downstream 1
Downstream 2

268 Afr. J. Biotechnol.
Table 1. Seasonal mean values of the heavy msetal levels in surface sediments of Aba river.
EPA MAXIMA
a
Up
stream 1
Up
stream 2
Abattoir
Down
stream 1
Down
stream 2
Total
Mean
Pb
Dry Season 0.04 0.12 0.08 0./08 0.06 0.38 0.08+0.03
Rainy Season
0.05 0.04 0.08 0.04 0.04 0.06 0.26 0.05+0.02
Fe
Dry season 0.82 0.96 0.88 0.84 0.84 4.34 089+0.06
Rainy season
0.1 0.84 0.68 0.68 0.88 0.64 3.72 0.74+0.12
Zn
Dry season 3.80 6.80 6.40 4.20 4.20 25.4 5.08+1.40
Rainy season
5.0 3.64 4.62 6.48 3.80 4.20 22.7 4.55+1.14
Cu
Dry season 0.18 0.24 0.24 0.20 0.18 1.04 0.24+0.03
Rainy season
1.0 0.08 0.20 0.12 0.18 0.12 0.7 0.14+0.05
As
Dry season 0 0.12 0.06 0.06 0.04 0.28 0.06+0.04
Rainy season
0.05 0 0.04 0.02 0.04 0.04 0.14 0.03+0.02
Mn
Dry season 0.65 0 0.12 0.06 0.06 0.04 0.28 0.02+0.02
Rainy season
0 0.04 0.02 0.04 0.04 0.4 0.03+0.02
Hg
Dry season 0.01 0 0 0.02 0.02 0.05 0.01+0.02
Rainy season
0.002 0 0 0 0.02 0.02 0.04 0.01+0.03
Key: All values are in mg/l
Co, Cr and Cd were not detected in all the samples for both seasons
a: source; EPA (1976) (EPA
Table 2. Seasonal total viable count (10
6
cfu/Ml) Of microorganisms Isolated From Aba river.
PLATES
UP
STREAM 1
UP
STREAM 2
ABATTOIR
DOWN
STREAM 1
DOWN
STREAM 2
TOTAL
MEAN
(i)
Dry season 0.06 0.06 102 0.08 0.07 102.28 20.5
Rainy season 0.06 0.06 109 0.07 0.07 109.25 54.6
TOTAL 0.12 0.12 211 0.16 0.12 211.5.52 75.1
MEAN 0.06 0.06 105 0.08 0.06 37.6
(ii)
Dry season 0.07 0.06 98 0.09 0.07 98.28 19.7
Rainy season 0.06 0.07 104 0.07 0.06 104.26 20.9

Ezeronye and Ubalua 269
Table 2. contd.
TOTAL 0.13 0.12 202 0.16 0.13 202.54 40.6
MEAN 0.06 0.06 101 0.08 0.66 20.3
(iii)
Dry season 0.07 0.06 106 6.09 0.06 106.29 21.3
Rainy season 0.06 0.07 90 0.75 0.07 90.26 18.1
TOTAL 0.12 0.12 196 0.16 0.13 196.54 18.1
MEAN 0.06 0.06 98 0.08 0.07 19.7
GRAND
TOTAL
0.12 0.12 203 0.16 0.13 617.59
GRAND
MEAN
0.06 0.06 101 0.08 0.07 205.86
Key: Each value represents the mean of three replicates. 106 dilution factor was used for the upstream 1, 2 and
downstream 1 and 2 water samples but values were converted to a common dilution factor (106).
Microbiological analysis
Direct microscopic examination of each water sample was done by
the standard microbiological procedures (International Commission
on Microbiological Specification for Foods (ICMSF, 1988) before
culturing the samples on appropriate media. The total viable count
(TVC) of mesophilic aerobic bacteria was determined by the pour
plate technique. Serial (10- fold) dilution of each sample was done
prior to inoculation on plate count Agar (Merck) and incubation at
25
o
C for 48 h. The microbial load (cfu/ml) of each sample was
estimated by the method of Yongming et al. (1996).
Bacterial colonies (representing the most numerous colonial
types) were picked at random from plates containing the highest
countable dilution. Bacterial isolates were characterized by the
methods of Harrigan and McCance (1976) and Speck (1976).
Identification was based on Bergey’s Manual of Systemic
Bacteriology (Krieg and Holt, 1984). The ability of the organisms to
produce oxidase, catalase, coagulase and metabolize glucose by
both fermentation and oxidation were tested. Sugar fermentation
assays and the ability of the isolate to utilize exogenous nitrate
were also carried out. In addition the ability of the organisms to
produce indole-methyl red and utilize nitrate was determined.
Lipase hydrolysis, lecithinase and proteinase activities were also
carried out.
RESULTS
The result obtained from the analysis of the
physicochemical quality of the water samples are
presented in Table 1. The range of mean values of the
metals for both seasons are: Pb (0.05- 0.08 mg/l); Fe
(0.7-0.9 mg/l); Zn (4.6-5.1 mg/l); Cu (0.1-0.2 mg/l), As
(0.14-0.06 mg/l); Mn (0.02-0.03 mg/l); Cr (0.004-0.008
mg/l) and Hg (0.008-0.01 mg/l). The concentrations of
the heavy metals were observed to be higher between
the upstream 2 and Downstream 1.
Results of microbiological analysis of the various
samples are shown in Table 2. The mean total viable
count for the bacterial colonies ranged between 0.059 x
10
6
to 1.01 x 10
8
cfu/ml (Figures 1 and 2). The highest
bacterial count was observed at the abattoir site followed
by the downstream 1 (Figures 2 and 3) in the dry season.
The abattoir site recorded the highest number of
microorganisms isolated, followed by the downstream 1.
The same pattern was observed for rainy seasons
sample as represented in Figure 3. Bacillus species were
predominant while Vibrio species were the least in
number among all the isolates. Amongst the Gram-
positive bacteria isolates were Streptococcus faecalis,
Staphylococcus spp, Clostridium and Bacillus spp. All the
organisms isolated were coagulase positive with the
exception of Clostridium species.
DISCUSSION
The average levels of manganese (0.03 mg/l), zinc (4.81
mg/l) and Cu (0.19 mg/l) determined were below the
United States Environmental Protection Agency
maximum in marine waters (USEPA, 1976) and are
comparable to those obtained in the Niger Delta waters
(Kakuku, 1985). cobalt and cadmium were below
detectable limits. Levels of Pd (0.06 mg/l), Fe (0.81 mg/l),
arsenic (0.1 mg/l), chromium (0.01mg/l) and mercury
(0.01 mg/l) were high but not significantly (p  0.05). The
metal average seasonal levels are presented in Table 3.
Analysis of variance (ANOVA) did not reveal significant
spatial variations in the levels of any of the metals,
neither did the least significant difference (LSD) show
any significant seasonal variations (p  0.05). Anderson

270 Afr. J. Biotechnol.
Figure 2. Total Viable count of organisms isolated from Aba river in rainy season.
Table 3. Faecal microbial count (10
4
cfu/ml) of dry and rainy season water samples.
Up
stream 1
Up
stream 2
Abattoir Down
stream 1
Down
stream 2
Total Mean
Escherichia coli
Dry season 0.06 0.05 0.01 0.09 0.09 0.30 0.06
Rainy season 0.04 0.04 0.09 0.06 0.04 0.27 0.05
Salmonella spp
Dry season 0.03 0.06 0.07 0.04 0.04 0.02 0.05
Rainy season 0.03 0.03 0.05 0.03 0.03 0.17 0.03
Streptococcus
faecalis
Dry season 0.03 0.02 0.03 0.02 0.02 0.12 0.02
Rainy season 0.04 0.02 0.03 0.02 0.02 0.01 0.03
Shigella spp
Dry season 0.09 0.06 0.01 0.03 0.03 0.22 0.04
Rainy season 0 0 0.09 0 0 0.09 0.05
Vibrio spp
Dry season 0.08 0 0 0 0.08 0.16 0.03
Rainy season 0 0 0.06 0 0 0.06 0.01
Clostridium spp
Dry season 0.02 0.03 0.01 0.05 0.03 0.14 0.03
Upstream 1
Count
Upstream 2
Abattoir
Sampling points
Downstream 1
Downstream 2
0
Total viable count (cfu/ml x 10
6
0.08
0.06
10
50
90
130
0.06 0.06 0.06
0.07
0.06
0.06
109
104
90
0.07 0.07
0.08
0.06 0.06
0.07

Ezeronye and Ubalua 271
Table 3. contd.
Rainy season 0.02 0.02 0,08 0.03 0.12 0.17 0.03
Other Organisms
Staphylococcus spp
Dry season 41 40 43 32 26 182 36
Rainy season 39 37 40 26 22 164 33
Bacillus spp
Dry season 41 40 44 38 33 196 39
Rainy season 38 36 41 36 32 183 37
Key: The faecal organisms originally of (10
2
dilution factor) were converted to ( 10
4
) which is the dilution factor for other organisms.
(1987) reported that the toxicity of heavy metals occur
when present in superabundance. In addition, the
fundamental problem with heavy metals according to
Chapman (1996) is that some of them are needed by
microorganisms in trace amounts, when present in
excess they denature enzymes thus inhibiting the
microbial metabolism.
High lead levels in Aba River could be traced to urban
and industrial wastes and high petrol-lead used by
vehicles in Nigeria (Arah, 1985; Arah, 1987). Wastes
management in urban and industrial centers in Nigeria,
such as Aba has remained very unsatisfactory. Inflow
waters to the Aba River have been found polluted with
untreated industrial wastes, which are carelessly
discharged, directly, or indirectly into the river. One other
important source of industrial lead pollution is the expired
motor batteries. Lead and other pollutants, whether in the
air, or on land, ultimately end up in the aquatic systems.
There was no correlation between the individual
organisms in Table 2 and the heavy metals while the
correlation analysis between the heavy metals and total
count of microorganisms did not reveal significant effect
(p  0.05). The result indicated some variations in the
bacterial population of the station in the two sessions.
These variations suggest the impact of human activities
and natural changes. The low bacterial count at the
upstream 2 when compared to the other sites may be
due to reduced human activities, sedimentation and
depuration. The relatively high coliform counts at the
abattoir may be connected with high rate of cattle
defecation near the site. The introduction of wastes from
the abattoir and the surface run-off into the site during
the rains is also a contributory factor. The presence of
Escherichia coli, Streptococcus. faecalis and Shigella
spp in this study give credence to these findings. In
addition the presence of Clostridium spp in all the sites
further confirms the human faecal contamination of these
sites. Costridium spp have been shown to be better
indicator of human faecal contamination in tropical
surface waters (Fujioka and Shizumura, 1985). The
isolation of E. coli throughout the sites is an indication of
recent human contamination. The presence of Bacillus
and Clostridium species, which are mostly soil
inhabitants, showed contamination from overland run-off.
The presence of Salmonella and Shigella species at
most of the sites and Vibrio species at the abattoir and
the coliform counts of all the sites not falling within
internationally recommended standard is of public health
concern (Ezeama and Nwankpa, 2002).
The low levels of metals determined could be ascribed
to dilution, sedimentation and depuration. Although the
water flow in Aba River is limnethic in some area with
little or no upwelling during the rainy season, immense
volumes of fresh water passes through the river. The
Aba River forms the major outlet for water draining a vast
watershed, hence the influx has force and short
residence time in the river. The short residence time of
the influx means that most of the input materials are
discharged along with the water. Slow flow conditions
enhance sedimentation, especially in the presence of
high levels of iron and manganese in the system as
observed from the analysis of sediments (Okoye et al.,
1989). This sedimentation would likely become the more
important mechanism for removing heavy metals and
other pollutants from the water at low tide and during the
dry season when the influx of fresh water is very minimal.
Thus the cumulative impact is that heavy metal levels are
kept low in spite of high fluxes from industrial and urban
wastes, including the immense urban run-off.
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