Spatiotemporal characteristics and Monte Carlo simulation-based human health risk of heavy metals in soils from a typical coal-mining city in eastern China

Mining activities typically discharge considerable amounts of heavy metals into the environment, raising concerns about soil metal pollution, environmental security, and human well-being. Therefore, a systematic regional-scale investigation of soil heavy metal pollution in mining areas is necessary for soil management. In this study, 5817 soil samples from the Huainan coal mining area collected for studies conducted from 2000 to 2021 were compiled to quantify the pollution level and spatiotemporal variation of heavy metals (Cu, Pb, Zn, Cr, Cd, As, Hg, Ni, and Mn). The associated ecological health risk of heavy metals in soil was assessed using the Hakanson ecological hazard index, Monte Carlo simulation in conjunction with the total hazard quotient, and the hazard index. Cd was the top contaminant, followed by Hg. In terms of spatial distribution, heavy metal contamination was more severe in the eastern area of Fengtai and Datong districts, because these districts of Anhui Province are significant industrial regions. In addition, the results of the Monte Carlo evaluation of human health risks showed that the total noncarcinogenic risk of heavy metals in soil is below the acceptable level, while the carcinogenic risk was 5.97% for adults and 15.53% for children. As accounted for 57.4% of noncarcinogenic risk, Cr contributed 36.1% of carcinogenic risk. Compared with adults, children are more vulnerable to the carcinogenic and noncarcinogenic risks posed by heavy metals, with oral consumption being the primary exposure route. This research can provide useful details for protecting the environment and managing soil in a coal mining area.