ASSESSMENT OF BIO-ACCUMULATION OF HEAVY METALS IN WATER, SEDIMENT AND TISSUES OF NILE TILAPIA (OREOCHROMIS NILOTICUS) FROM LOWER RIVER NIGER AT GEREGU AJAOKUTA, KOGI STATE

A study was conducted to assess the evaluation of heavy metals in water, sediment and Oreochromis niloticus tissues (gills, viscera and muscle) in Geregu Kogi State. The concentration of heavy metal in the samples collected was determined using Atomic Absorption Spectrophotometer. The result obtained was subjected to Analysis of Variance (ANOVA). Means was separated using Duncan’s Multiple Range Test (DMRT) at 5% probability level. The results of the mean concentration of Iron in Gills, visceral and muscles was 94.70, 81.39 and 69.84 mg/kg respectively; that of Lead was 0.76, 0.53 and 0.75 mg/kg respectively; that of Nickel was 1.74, 1.83 and 0.43 mg/kg respectively; that of Chromium was 0.59, 0.48 and 0.10 mg/kg respectively; that of Cadmium was 0.00, 0.00 and 0.00 mg/kg respectively; whereas that of Zinc was 3.80, 4.70 and 2.44 mg/kg respectively. The bioaccumulation factor (BAF) was low and was within the allowable limits set by WHO. From the result, the levels of metals found in the fish tissues do not pose any particular health risk concern due to low values of Target Hazard Quotient (THQ) obtained for all the metals investigated. From the study it is recommended that regular study of the heavy metals present in fish tissue should be carried out to avoid much higher concentration in the food chain which might be above the recommended level that could cause human health risk.