Chromium and lead bio-accumulation in relation to physico-chemical parameters in water and fish of Wasai Reservoir, Kano State

Abstract

Heavy metals bio-accumulation in fish organs consumed by man generated issues of public health concern. This study was conducted to determine the levels of Chromium and Lead bioaccumulation in liver and muscles of two fish species (Clarias gariepinus and Oreochromis niloticus) obtained from Wasai Reservoir in relation to physico-chemical parameters of the surface water. Water and fish samples were collected using standard protocols for a period of ten months. Four different locations were mapped out as sampling stations. Heavy metals concentrations in water, liver, and muscles of the two fish species were assessed. The experiment was arranged in completely randomized design with three replications. Data obtained were analysed using Analysis of Variance with Duncan’s New Multiple Range Test used to separate the means that were significant at 5% level. No significant difference was found in the surface water temperature and pH of the water body for a period of ten months. However, significant difference (P≤0.05) was found in pH, DO and BOD among the locations. The high DO and BOD values were found in station A where there is high discharge of agricultural and domestic wastes. The results for the levels of heavy metals in water and fish organs of Wasai reservoir revealed significant difference (P≤0.05) in the levels at different locations with months. More so, the levels of Pb (0.01-0.08 mg/L) and Cr (0.03-0.35 mg/L) bio-accumulation in liver and muscles of the fish showed a pattern of trend in the heavy metals bio-accumulation in the two fish species following the order: Cr˃Pb with their bio-accumulation in liver and muscles of the fish species above tolerable limits. Thus, the highest value of heavy metal in liver (0.17 mg/L) obtained from Wasai reservoir especially during the dry season of the year should not be consumed by the general popula