Sources and transportation of mining metals to soil: A case study from the Lala mining area, Southwest China

Soil contamination with toxic metals from mining activities poses a risk to ecological security and human well-being, but research on their transport mechanisms is inadequate. Addressing this, this study combines the PCA-APCS-MLR model, hydrological and soil profile analyses, and geographic detector techniques within the Lala mining area, Sichuan Province, China, to explore the connection between soil metal enrichment and mining activities and to assess soil contamination. We identified three primary sources of metals in soils: geogenic background, mining activities, and industrial emissions. Mining activities are the primary source for Mn (13.6%), Cu (33.9%), Mo (69.1%), and As (40.0%) in soil, while industrial inputs contribute to Pb (63.8%), Zn (67.4%), and Cd (83.6%). Meanwhile, dry and wet deposition drove the dispersal mode of mine metals to the soil in the study area. Specifically, coarse mine wastes primarily settle around the mine sites, whereas fine particulates are carried northward by prevailing southwest winds, leading to northward and long-range transport. Our findings are important for assessing the mining industry's footprint in arid environments.