Bioaccumulation of Heavy Metals by Clarias gariepinus (African Catfish) in Asa River, Ilorin, Kwara State
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Date
2019-03-22
Journal Title
Journal ISSN
Volume Title
Publisher
Pure Earth: Journal of Health and Pollution
Abstract
Background. Harmful wastes and other dangerous industrial by-products constitute major
sources of environmental pollutants in Nigeria. Industrial pollutants discharged into the
environment contain organic and inorganic pollutants in dissolved, suspended and insoluble
forms. Fishes are known for their innate potential to bioaccumulate heavy metals in their
muscles and various organs.
Objectives. The present study aimed to assess the bioaccumulation status of heavy metals in
selected organs and tissues of African catfish in Asa River, Ilorin, Kwara State, Nigeria.
Methods. Three sampling points (A (upstream), B (point of discharge) and C (downstream))
were selected in relation to industrial effluents that enter the river. African catfish were
randomly harvested from each site using fishing nets at the three sampling points. The
samples were digested and subjected to atomic absorption spectrophotometric analysis.
Statistical analysis of data was carried out using the Statistical Package for the Social Sciences
(SPSS) version 20 and two-way analysis of variance (ANOVA) to compare data among sites
and organs.
Results. The present study found that the bioaccumulation level of heavy metals in selected
organs and tissues of African catfish in Asa River, Ilorin, Kwara State, Nigeria was very high
and the level of accumulation of heavy metals increased downstream. Accumulations were
much higher during the dry season (especially in the month of February) and relatively low
during the peak of the rainy season.
Conclusions. Heavy metals at elevated levels in the aquatic environment can accumulate
in fish tissues and organ, and therefore fish from the Asa River are not fit for human
consumption.
Description
In Nigeria and throughout the globe,
industries are crucial to economic
development and play an important
role in raising living standards.
Pollution of the aquatic environment
with heavy metals has become a
worldwide problem because the
metals are indestructible and most
have toxic effects on organisms.1-3
Heavy metals enter rivers and lakes
from a variety of sources such as rock
and soil directly exposed to surface
water, in addition to the discharge of
treated and untreated liquid wastes
into water bodies. These harmful
wastes and other dangerous industrial
by-products constitute major sources
of environmental pollutants.2
Most
industrial pollutants discharged into
the environment contain organic and
inorganic pollutants in dissolved,
suspended and insoluble forms.3,4
Effluents discharged into the water
bodies may affect fish and other
aquatic organisms, either directly or
indirectly. Most rivers and freshwater
streams are seriously polluted by
industrial waste water discharged from
factories. A large amount of water
used in industry turns into wastewater
that pollutes surface and groundwater,
posing health hazards. Heavy metal
ions do not degrade into harmless end
products and are toxic to humans and
the surrounding environment.
The African catfish is a large, eel-like
fish, usually of gray or black coloration
on the back, fading to a white belly. It
is nocturnal, like many catfish. It feeds
on both living and dead animal matter.
Keywords
Citation
Opasola, O.A, Adeolu, A.T, Iyanda, A.Y, Adewoye, S.O and Olawale, S.A (2019). Bioaccumulation of Heavy Metals by Clarias gariepinus (African Catfish) in Asa River, Ilorin, Kwara State. Journal of Health and Pollution, 9(21): 1-10.