Work

Probabilistic health risk assessment and source-specific risk analysis of potentially toxic elements in metropolitan surface soils using PMF, geo-detector, and KDE-based Monte Carlo simulation

Year: 2026

Type: article

Abstract: Metropolitan soils are increasingly affected by multiple anthropogenic inputs, resulting in complex patterns of potentially toxic element (PTE) accumulation. However, the mechanisms linking pollution sources, spatial heterogeneity, and the resulting ecological and human health risks remain insufficiently understood. To clarify PTE contamination characteristics and associated risks, 1122 topsoil samples were obtained across the studied metropolitan region in southwestern China. The results revealed that all PTEs, except As and Cd, exceeded their local background values. Spatially, Hg, Pb, Cu, and Zn exhibited localized enrichment hotspots in the east-central urbanized areas. Combined APCS-MLR and PMF receptor models identified five potential sources, including natural background (25.54%), atmospheric deposition (15.13%), agricultural activities (18.64%), industrial manufacturing and urban emissions (19.14%), and mixed traffic–industrial sources (21.55%). PMF provided better model fit and spatial separation than APCS-MLR under the study conditions. Geo-detector analysis revealed that soil type and land use were the dominant factors controlling PTE spatial heterogeneity, with nonlinear interactions further enhancing their explanatory power. According to the potential ecological risk index, low to moderate ecological risk levels were identified in 83.07% of the samples. Hg and Cd were the major contributors to ecological risk, whereas atmospheric deposition represented the highest source-specific ecological risk contribution. Deterministic health risk assessment indicated higher risks for children, with 7.93% of samples exceeding the acceptable non-carcinogenic risk threshold. Carcinogenic risks were acceptable for both population groups. As was the dominant contributor to both carcinogenic and non-carcinogenic risks, and soil ingestion represented the major exposure route. KDE-optimized Monte Carlo simulation further showed that 9.47% of children may experience unacceptable non-carcinogenic risk, while accounting for the empirical distribution and uncertainty of exposure-related variables. Although the health risk assessment was based on total PTE concentrations without considering metal bioavailability, the proposed framework still provides a scientific basis for source-specific pollution control and risk-prioritized soil management in rapidly urbanizing metropolitan regions.

Source: Environmental Impact Assessment Review

DOI: 10.1016/j.eiar.2026.108723