Heavy metal accumulation risk and source analysis in soils of antimony mining areas

Co-contamination of heavy metals from antimony (Sb) mining poses significant threats to soil quality and human health. Although many studies have examined Sb sources, few have provided quantitative source apportionment combined with population-specific risk assessment. This study examined a representative Sb mining area in southwestern China through an integrated approach. The methodology combined Positive Matrix Factorization (PMF), Monte Carlo Simulation (MCS), the geo-accumulation index (I_geo), the enrichment factor (EF), the modified Nemerow pollution index (I_NI), and health risk assessment models. Results indicated a mean Sb concentration of 125.61 mg·kg^-1, nearly 50 times the regional background value (2.50 mg·kg^-1), with pronounced spatial variability (CV = 246.97%). PMF analysis revealed three major sources: regional mixed sources (36.8%), natural geological sources (30.1%), and industrial point sources (33.1%). MCS results suggested high ecological risks for Cd and Sb, with associated probabilities of 94.43% and 83.45%, respectively. The probability of non-carcinogenic risk (HI > 1) in children reached 85.61%. The total carcinogenic risk (TCR) exceeded acceptable thresholds for all individuals, with children showing higher susceptibility. Natural geological sources accounted for 57.9% of carcinogenic risk and 62.3% of non-carcinogenic risk in children. These findings underscore the urgent need for targeted pollution control and remediation strategies to mitigate both ecological and human health risks in Sb mining areas.