Bioaccumulation and Human Risk Assessment of Heavy Metals in Oreochromis niloticus and Clarias gariepinus Fish Species from the Golinga Reservoir, Ghana

Abstract

The Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) from the Golinga reservoir in Northern Ghana are consumed as an  alternative source of protein. In the current study, levels of selected metals (As, Cd, Fe, Co, Cr, Cu, Mn, Mo, Ni and Pb) in the two fish species and the fish  condition were determined, and potential human health effects assessed. The metal concentrations in the edible fish muscles ranged from 0.16 mg kg⁻¹  (Mn) to 101 mg kg⁻¹ (Pb). The weight-length relationships showed that both fish were growing isometrically, and bioaccumulation of metals from the  reservoir was considered insignificant with bioconcentration factors below 100 except for Mn, whose value was 161 in the gills of Oreochromis niloticus.  The health risk assessment showed that Pb, Cd and As had Target Hazard Quotient values above 1 for both fish species, with that of As being as high as  19.6 for Oreochromis niloticus. The target cancer risk values for As, Cd, Cr and Pb were above the non-risk threshold of ≤10⁻⁶, indicating the risk of  cancer developing over the years due to fish consumption. The metal concentration in the fish in the reservoir should therefore be constantly monitored  and potential health risks associated with frequent consumption of the fish assessed.