Mining Activities and the Risks Associated with Fish Consumption

Abstract

Freshwater fish may accumulate heavy metals from contaminated aquatic environments, thereby creating potential health concerns for populations that depend on fish as a dietary protein source. This study assessed selected heavy metals and associated health risks in edible fish samples from Jibia Dam, Jibia Local Government Area, Katsina State, Nigeria, an area affected by illegal mining activities. Eight samples each of Clarias gariepinus, Ameiurus nebulosus and Tilapia zilli were obtained from commercial anglers and analysed for Fe, Pb, Cd, Cu, Mn, Zn and Ni using spectrophotometric procedures after ashing and acid digestion. The daily intake of metals, target hazard quotient (THQ), health risk index (HRI), incremental lifetime cancer risk (ILCR) and cumulative incremental lifetime cancer risk (ΣILCR) were calculated for children and adults using the stated exposure assumptions. The results showed that mean Pb concentrations in Ameiurus nebulosus and Tilapia zilli exceeded the maximum allowable concentration, whereas the Pb concentration in Clarias gariepinus and the concentrations of the other assessed metals in all three species were within the stated safety limits. The THQ values for individual metals were below 1 in both children and adults, suggesting no appreciable non-carcinogenic risk from single-metal exposure under the adopted assumptions. However, the HRI values for Ameiurus nebulosus and Tilapia zilli exceeded 1 in children, indicating potential concern from combined metal exposure in this group. The ILCR values for Ni, and the corresponding ΣILCR values, exceeded the acceptable cancer risk range in both children and adults. These findings indicate that fish consumption from Jibia Dam may present health concerns, particularly in relation to Pb exposure and Ni-related carcinogenic risk, and support the need for periodic monitoring of fish from the area.