Mercury Contamination in Locally Harvested Fish Species and Potential Health Implications

Mercury contamination in aquatic ecosystems is a worldwide issue due to the health risks associated with eating contaminated fish. The present study was carried out to measure the mercury (Hg) levels in different tissues of locally harvested fish and to assess the potential human health risks associated with their consumption. Fifty-two fish samples (northern pike (Esox lucius), walleye (Sander vitreus), and white bass (Morone chrysops)) were dissected, and tissue samples were individually homogenized and measured for total mercury using a Milestone DMA-80 tri-cell analyzer. Among the species studied, the highest mean Hg concentrations in the muscles and kidneys were observed in northern pike, while the highest Hg concentrations in the livers and gills were noted in white bass. The liver consistently showed the highest mercury accumulation across all species. The Hg levels in almost 50% of the northern pike muscle tissue samples exceeded the limit (0.5 μg/g) set by the European maximum permissible concentration for foodstuffs. Correlation analysis revealed a strong positive correlation between the Hg concentration in the muscles with both the weight and length of walleye and white bass. Human health risk assessment was estimated by the maximum allowable daily fish consumption (CRlim), maximum allowable monthly fish meal consumption (CRmm), individual risk assessment, and the target hazard quotient (THQ). The average monthly consumption limit (CRmm) ranged from two to four meals for adults and one to two meals for children. Individual risk assessment showed potential health risks associated with the regular consumption of northern pike and white bass, followed by walleye, for both adults and children. The mean hazard quotient (THQ) values exceeded one for all species in both adults and children, which indicates potential health risks associated with fish consumption. Across all species studied, children experienced higher risk than adults, suggesting greater susceptibility to potential health effects from the consumption of the studied fish. Lastly, the mercury levels should be regularly monitored, especially in piscivorous fish like northern pike, for pollution control and human health protection.