Assessment of heavy metals in water and organs (Gills and Muscles) of Clarias gariepinus from Wasai reservoir, Kano State Nigeria

Abstract

This investigation was carried out to assess the levels of heavy metals in surface water and their bioaccumulation in the organs of the African catfish (Clarias gariepinus) obtained from Wasai Reservoir, Kano State of Nigeria. Surface water samples and fish (C. gariepinus) were collected using standard protocols for a period of ten months. Four different locations were mapped out as sampling stations. Heavy metals concentration in water, gills, and muscles of Clarias gariepinus were assessed. The experiment was arranged in a Completely Randomized Design with three replications. Data obtained were analysed using Analysis of Variance with Duncan’s New Multiple Range Test used to separate significant means at 5% level. The result showed significant difference (P?0.05) in the concentration of heavy metals at different locations with months. The result also showed that the levels of heavy metals were higher in location A due to high discharge from mechanic and agricultural activities in the area. More so, the level of heavy metals bioaccumulation in muscles was in the following sequence: Cd ? Pb ? Cr, while in the gills, the trend followed the sequence Pb > Cd > Cr. Thus, with the exception of Cr bioaccumulation in the gills, all the values of heavy metals studied were above tolerable limits.