Monte Carlo and ecological risk assessment of heavy metals in soil from tin mining sites in, Nigeria

Tin mining activities on the Jos Plateau, Nigeria, have raised concerns regarding heavy metal contamination and associated health risks. This study evaluated Pb, As, Cd, Sn, and Sb in 90 surface soil samples from active and abandoned mining sites. Metal concentrations were determined using atomic absorption spectrophotometry, and ecological risk indices (Igeo, CF, PLI, and PERI) were computed. Mean concentrations ranged from 0.06 ± 0.00 to 0.10 ± 0.01 mg/kg for Sb, 0.07 ± 0.01 to 0.12 ± 0.01 mg/kg for Sn, 0.08 ± 0.01 to 0.13 ± 0.01 mg/kg for As, 0.09 ± 0.00 to 0.12 ± 0.01 mg/kg for Cd, and 0.15 ± 0.01 to 0.28 ± 0.05 for Pb. Although mean concentrations of As, Cd, and Pb exceeded selected guideline values, ecological indices indicated low contamination (PERI < 10). Deterministic and Monte Carlo simulations were applied to assess non-carcinogenic (HQ, HI) and carcinogenic (CR) risks for adults and children. Non-carcinogenic risks were within acceptable limits (HI < 1). As ingestion was the dominant contributor to cancer risk. While total lifetime cancer risks remained within the acceptable range (10-6–10-4), children exhibited comparatively higher risks, indicating the need for continuous surveillance and soil‐management interventions.