Improved model for human health risk assessment of soil heavy metal(loid)s in a mining area of southeastern China

Heavy metal(loid)s (HMs) in mining soils pose potential health risks through direct exposure pathways. This study assessed the contamination levels and health risks of eight HMs in soils from a mining area using a health risk assessment (HRA) model coupled with Monte Carlo simulations (MCS). Results showed that the mean concentrations of Pb, Cd, As, Hg, Cu, and Zn exceeded the Chinese soil background values, with Hg exhibiting the highest coefficient of variation, suggesting strong spatial heterogeneity likely caused by anthropogenic inputs. Contamination factor ( C f ) analysis classified As, Hg, Cu, and Zn as moderate contaminants. Cd, Pb, and Hg were identified as priority pollutants for soil remediation. Health risk assessment based on two-dimensional MCS revealed that children faced the highest Carcinogenic risk, primarily due to As ingestion, while adult females experienced the highest Non-carcinogenic risk, primarily through dermal exposure. Sensitivity analysis identified ingestion rate ( R ingest ) and skin adherence factor (AF) as the most influential risk parameters. To ensure health safety, children’s soil ingestion should be limited to below 104.189 mg ∙ d −1 , and particular attention should be paid when AF exceeds 2.135 mg·(cm²·day) −1 in adult females. These findings provide a scientific basis for targeted soil remediation and population-specific risk control strategies in mining-impacted areas. • 2-D Monte Carlo improved uncertainty analysis in soil health risk assessment. • The carcinogenic risk exceeded acceptable levels across all populations (TCR > 1 ×10⁻⁴). • Arsenic ingestion posed the highest carcinogenic risk to children. • Dermal contact was the main non-carcinogenic pathway for adult females. • Key exposure drivers were quantified to inform exposure-specific interventions.