Assessment of heavy metals biomagnification in selected aquatic fauna from New Gusau Reservoir, Northern Nigeria

Abstract

This study aimed to assessing the concentration of Copper (Cu), Cadmium (Cd), Iron (Fe), Lead (Pb) and Zinc (Zn) in the muscle of the selected aquatic animals: Snail (Gabiella africana), Frog (Rana esculenta), African catfish (Clarias gariepinus) and Tilapia (Tilapia zilli), obtained from New Gusau Reservoir, for eighteen (18) months. The Reservoir, receives effluent from three effluent channels namely; Yar Dole (YDL), Yar Dantse (YDS) and Yar Rumfa (YRF). The selected animals were collected with the help of artisanal fisher men and identified to species level based on standard taxonomic keys. Analysis done included concentrations of Cu, Cd, Fe, Pb, and Zn, in muscles tissue, using Atomic Absorption Spectrophotometer (AAS).The mean concentration of Cu in the tissues was 0.92±.126, 0.90±.124, 0.93±.116, 1.35±.113mg/kg and for Zn were 0.99±.139, 1.09±.154, 2.29±.218, and 2.51±.178 mg/kg for catfish, Tilapia, Frog and Snail, respectively. All selected animals investigated were accepted standard limit set by European Commission (EC), World Health Organization (WHO) and Food and Agriculture Organization (FAO). The mean concentrations of Fe was 7.12±.567, 5.32±.602, 15.96±1.549, 15.55±.894mg/kg and that of Pb were 0.01±.002, 0.09±.014, 0.01±.007, 0.04±.013 mg/kg for catfish, Tilapia, frog and snail, respectively. The concentrations of Fe, in snail and in frog muscles were higher compared to catfish and tilapia. Cd was not detected in all the studied animals. The research suggested that the animals may be safe for human consumption.