Health Risk Assessment Associated with Consumption of Oreochromis niloticus from Ajiwa Reservoir, Katsina State, Nigeria

Abstract

Ajiwa Reservoir, essential for local fish and vegetable markets, is under threat from agricultural waste and effluents containing heavy metals. This study evaluates the health risks of consuming Oreochromis niloticus from the reservoir by analyzing water and fish samples for cobalt (Co), copper (Cu), manganese (Mn), nickel (Ni), and lead (Pb) using an Atomic Absorption Spectrophotometer (AAS). Samples were collected biweekly from September to December 2023. The mean concentrations of heavy metals in water were Co (0.45±0.23 mg/L), Cu (0.05±0.04 mg/L), Mn (0.06±0.09 mg/L), Ni (0.10±0.07 mg/L), and Pb (0.40±0.18 mg/L), with Co, Mn, Ni, and Pb exceeding WHO standards. Fish tissues showed Co (1.03±0.16 mg/L), Cu (0.13±0.05 mg/L), Mn (0.10±0.19 mg/L), Ni (0.18±0.22 mg/L), and Pb (0.21±0.66 mg/L), with Co, Ni, and Pb above the acceptable limits. Health risk assessments revealed Non-Cancer Risk (HQ>1) and Cancer Risk (>1), indicating significant health hazards from consuming fish from the reservoir. The Bioconcentration Factor (BAF) ranked Cu > Co > Ni > Mn > Pb. The contamination of water and fish with heavy metals in Ajiwa Reservoir poses severe health risks, exceeding WHO standards.