Risks to Human Health of Exposure to Heavy Metals through Wheat Consumption near a Tailings Dam in North China

Heavy metals can accumulate in nearby farmland soil through leakage of tailings and suspended dust, thereby posing a threat to local agriculture and human health. This study measured the heavy metal content (mercury, Hg; copper, Cu; zinc, Zn; lead, Pb; cadmium, Cd; selenium, Se; manganese, Mn) of farmland soils and wheat from twelve villages near a tailing dam in Baotou, China to evaluate the potential risks to the local ecosystem and human health. The results of the Contamination Factor (Cf) and Geo-accumulation Index (Igeo) indicated serious soil Hg, Se, and Cu contamination. Nemerow Composite Index (NCI) values showed that & PLUSMN;75% of the total sampling sites suffered heavy metal pollution. Soil Potential Ecological Risk Index (IRs) to the west of the tailings exceeded those to the southwest, demonstrating higher levels of Hg and Cd. The Hazard Quotient (HQ) of Mn for adults and children exceeded 3.0, whereas the HQ of Cu for children exceeded 1.0; the Hazard Index (HIs) for both adults and children exceeded 2.0. The results indicate that long-term consumption of wheat grains contaminated with heavy metals in the study area may result in adverse non-carcinogenic health risks, in particular among children. The accumulation of Cd posed carcinogenic risks to human health in two villages (>1 x 10-4). There is an urgent need to regulate the pollution of farmland soil near the tailings dams to mitigate risks to human health.