Archives of Environmental Sciences and Environmental Toxicology (ISSN: 2688-948X)

research article

Seasonal Investigation of Heavy Metal Risk Assessment in Tilapia Oreochromis niloticus From Contaminated River Chanchaga Niger State, Nigeria

Oguh Collins Egwu1*, Osuji Chigoziri Akudo1, Obasi Glory Otuomasirichi1, Amadi Eustace Ugochukwu1, Okpaka Confidence Ogechi2, Nwizia Baribefii Paagolah2

1Department of Biochemistry, University of Nigeria, Nsukka, Enugu State, Nigeria

2Department of Experimental Pharmacology and Toxicology, University of Port Harcourt, River State, Nigeria

*Corresponding author: Oguh Collins Egwu, Department of Biochemistry, University of Nigeria, Nigeria. Tel: (+234)7036017476; Email:

Received Date: 05 September, 2019; Accepted Date: 18 September, 2019; Published Date: 23 September, 2019


The contamination of fresh water with a wide range of pollutants has become a matter of great concern over the last few decades, not only because of the threats to public water supplies but also the damages caused to the aquatic life. This study investigates the Heavy Metal Risk Assessment in wet and dry season’s African Tilapia (Oreochromis niloticus) contaminated with water treatment sludge from river Chanchaga Niger State, Nigeria. Fishes and water samples were collected from river contaminated with sludge (Chanchaga River) and other samples from a private farm (Makolo farm) where there was no sludge served as control during February and June 2019 (dry and wet seasons respectively). The water samples were collected and analyzed for physicochemical properties (dissolved oxygen, electrical conductivity, pH and temperature) using a standard method and concentrations of heavy metal both in fish and water, As, Cd, Cr, Cu, Hg and Pb were analyze using Flame Atomic Absorption Spectroscopy (FAAS). The potential risk from the consumption of these fish was assessed using standard methods and formula. All the samples collected were digested using a modified procedure from the Association of Official Analytical Chemists and were subsequently analyzed using Atomic Absorption Spectroscopy. The physicochemical properties and Heavy metal concentration in water shows a significant different (P<0.05) between the C. river and M. pond during dry and wet season. The mean of concentration of Heavy Metals (As, Cd, Cr, Cu, Hg, and Pb) in O. niloticus from C. river during dry and wet season were 2.73, 3.66, 1.79, 2.27, 3.70, 2.90, and 2.90, 3.84, 2.14, 2.69, 3.91, 2.65 mg/kg respectively and from Makolo farm pond during dry and wet were 0.72, 0.95, 1.05, 0.86, 0.22, 1.01 and 0.82, 0.96, 1.17, 1.01, 0.83, 1.17 mg/kg respectively. Fishes in C. river elicited higher (P<0.05) heavy metals concentrations compare to Fishes in M. pond. The values were all greater than the maximum permissible limit of heavy metal in fish 0.01, 0.05, 1.5, 0.5, 0.01 and 0.3 mg/kg respectively recommended by FAO/WHO except Cr in the control pond which is within the limit. The result of health risk assessment shows that fishes from C. river have a higher risk with average hazard index values greater than one (2.6755) and compared to fish in M. pond with average less than one (0.529). The study concludes that water treatment sludge discharge in C. river can bio accumulate toxic substance such as heavy metals in the fish. The risk assessment shows that fish in C. River are contaminated with heavy metals especially during wet season and could pose health risk from the Contamination.


Heavy metals; Oreochromis niloticus; Risk assessment; Seasons; Water

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