Environmental Contamination and Health Risk Assessment to Toxic Elements in an Active Lead-Zinc Mining Area

Non-ferrous metal mining and smelting has emitted large amounts of associated toxic elements into the environment and poses potential health risks to human health. In this study, local residents' and miner's hair and urine samples were collected as bioindicators to assess the health risks and soil, vegetable, rice, and surface water samples were also collected to calculate the probably daily intake of the lead (Pb), zinc (Zn), copper (Cu), and arsenic (As). The results showed that all the collected paddy and vegetable soils were contaminated according to the assessment of impact index of comprehensive quality. About 32% of the rice samples exceeded the As concentration limit of the national food safety standards, but the other toxic element concentrations in rice and all the toxic elements in the vegetables were lower than the threshold limits. Multi-pathway intake of toxic elements and target hazard quotient showed rice was the most dominate pathway of the toxic element exposure, accounting for 68-82% of the total exposures. The excessive daily exposure to the toxic elements posed a high non-carcinogenic risk for residents. Hair Cu and As concentrations exceeded the Chinese resident normal hair concentrations by factors of 1.7-6.0, especially for the miners. The implication of this study is that proper mitigation strategy on toxic element pollution and human toxic element exposure is to reduce the intake of local agricultural products, especially rice and soil remediation are encouraged to improve the health of local residents.