Assessment of trace metal concentration and health risk of artisanal gold mining activities in Ijeshaland, Osun State Nigeria— Part 1

Abstract

This present study assessed the trace metal concentrations and human health risks associated with the activities of artisanal gold miners in Ijeshaland, Osun State, Southwestern Nigeria. Environmental samples, including surface water (rivers and streams), groundwater, bottom sediments, fish (Tilapia) and floating plants (ferns) were collected between 2011 and 2012 and analyzed for important parameters using standard procedures. Fifty four environmental samples were collected and analyzed for essential and nonessential trace metals. Data collected were subjected to simple descriptive and inferential statistics. Health risk indexes of noncarcinogenic and carcinogenic adverse effects of trace metals were determined in water and fish samples. Results of metal concentrations revealed Al (305±950μgL−1) and Fe (0.31±0.56mgL−1) in surface water higher than the World Health Organization (WHO) permissible limits in drinking water. The hazard quotient (HQ) values of Al and Fe (from surface and ground water), Mn (from groundwater) and Pb (from fish) were higher than 1.0 indicating noncarcinogenic adverse effects. The cancer risk (CR) values of Cd and Cr in groundwater, surface water and fish samples ranged between 7.9×10−4 and 1.0×10−2 thereby establishing their carcinogenic effects. The CR values of Ni and Pb in water consumed by infants and children were also higher than the acceptable limits of 1.0×10−4. The results allow us to assert that the activities of the artisanal gold miners clearly affect human health.