Comprehensive evaluation and prediction of heavy metals pollution in mining-affected soils: a case study of Guizhou, China

Heavy metal contamination in soils around lead-zinc mining areas poses serious environmental and public health risks. In Guizhou Province, China, pollution from mining activities continues to affect both soil quality and human health, especially in areas rich in lead-zinc deposits. Despite extensive research, there are still gaps in our understanding of how heavy metals are distributed and their risk levels in both surface and subsoil layers, particularly in terms of how these levels change over time and their impact on vulnerable populations. This study aims to fill those gaps by examining the pollution characteristics and risks associated with heavy metals in soils around a lead-zinc mining area in Shuicheng District, Liupanshui City. We conducted a multi-dimensional analysis using four methods: the geo-accumulation index (I _geo ), pollution load index (PLI), potential ecological risk index (PERI), network environmental analysis (NEA), and Monte Carlo simulation-based health risk assessment. The results revealed severe contamination by Pb, Cd, and Zn in both surface and subsurface soils, with Pb showing the highest risk levels. The PERI indicates that all sampling sites are classified as moderate- to high-ecological risk. The NEA model reveals that Pb, Zn, and Cd pose the highest ecological risks to organisms across all trophic levels; soil microorganisms represent the primary ecological risk sink, accounting for 66.4% of the integrated risk, followed by vegetation, herbivores, and carnivores. Health risk assessments show that children face higher non-carcinogenic and carcinogenic risks than adults, primarily due to exposure to Pb and As. Additionally, our projections predict that the soil’s ability to buffer pollution will decline rapidly within the next 10 years, especially for Hg, stressing the need for immediate mitigation. This research provides critical data for managing risks and developing remediation strategies in mining-impacted areas and highlights the importance of ongoing health monitoring, particularly for children.