The Acute toxicity of cassava waste water were investigated on Clarias gariepinus using a renewable static bioassay with emphasis on comparing the bioaccumulation pattern of Zinc, Manganese, Copper, Cadmium and Lead in the head-vertebrae part and flesh. Alteration in swimming activity and feeding, respiratory disturbance, anaemic morphology, skin lesion and death were observed in the exposed fishes and these varied greatly significantly (p<0.05) with increase in concentration to the test ceffluent. The bioconcentration of metals analyzed in the head-vertebrae part and the flesh differs significantly (p<0.05) with the higher metal concentration in the head-vertebraa part than the flesh. The result showed that on average, the level of bioconcentration of metals was in the order of Zn > Mn > Cu > Cd with Pb undetected in all in the samples analyzed. The head-vertebrae part and flesh were found to have the highest concentration of Zinc at 7.86ppm and 7.61ppm and lowest concentration of Copper at 0.04ppm and 0.35ppm respectively. It can be deduced that fish can bioconcentrate heavy metals from their environment if polluted, which can result into impairment of natural population size and invariably a source of these metals to man. Therefore, measures should be taken to avoid pollution of this sort as it might indirectly affect human health through food chain.

Keywords: Acute toxicity, heavy metals, head-vertebrae, flesh, cassava waste water, Clarias gariepinus