Model Assessment of Potential Risk Associated with Common Fish Species from Oguta Lake, Nigeria

Abstract

Fish can bioconcentrate heavy metals which become absorbed into the human body through the food chain. In this study, four fish species from Ogutalake were analysed for metal concentration and data subjected to some chemometric assessment. 1g each of the 4 fish samples were weighed and digested in 5mL of nitric acid. The digested samples were analysed for heavy metals using GBC scientific sensAA dual Atomic Absorption Spectrophotometer. Contamination factors were generally low ( Cf<6). However, contamination factors were significant except for manganese, zinc and copper in all fish samples. The pollution load index are in the order Okpo>Ubu>Ifuru>Egu respectively. Okpo showed highest daily dietary intake amongst all fish species with about 0.826 mg/kg/Bw/day in children, while adults EDI had 0.142 mg/kgBWday-1. Other fishes showed much lower values of EDI in the following order: EguMn>Ni>Cd>Cu. Weak positive correlations were exhibited by Ni/Mn (0.26) and Zn/Cd (0.14) while strong positive correlations were between Cd/Mn (0.81) and Zn/Cu (0.83). Significant negative correlations were exhibited between Ni/Zn (-0.96), Ni/Cu (-0.79) and Cu/Mn (-0.64) respectively. The positive and negative correlations suggest that the metals had similar and dissimilar sources of contamination. The study showed that, consumption of fish from Ogutalake could pose health hazards.