Heavy Metals Contamination in the Tissues of Clarias gariepinus (Burchell, 1822) Obtained from Two Earthen Dams (Asa and University of Ilorin Dams) in Kwara State of Nigeria

Abstract

This study determined the levels of heavy metals contamination in the tissues of 400 Clarias gariepinus obtained from two dams (Asa and University of Ilorin) in Kwara State of Nigeria. C. gariepinus, (both male and female) between the mean weight of 149-154g and total length of between 28-34cm were investigated between the month of September and December, 2018.  Copper (Cu), zinc (Zn), cadmium (Cd), chromium (Cr) and lead (Pb) in flesh, heart, kidney and livers of species from the two dams were determined using Atomic Absorption Spectrophotometer (AAS). The results showed that heavy metals contamination in the tissues sampled from Asa and Unilorin dams were in order of Zinc > Copper > Chromium. Cadmium and lead were not detected. Furthermore, C. gariepinus from Asa dam bioaccumulated heavy metals at higher concentrations than samples from Unilorin dam. Body weight, total length and age were found to be predisposing factors to heavy metals concentrations in the body of fish while sexes had no effect.The heavy metals concentration detected in C. gariepinus sampled from the two dams did not exceed the limits set by WHO and FAO suggesting that the fishes wholesome for human consumption.