Geochemical Contamination, Potential Sources, and Ecological and Human Health Risks in Mining Soils of

Mining-induced accumulation of potentially toxic elements (PTEs) threatens soil quality and environmental health, yet integrated assessments across contrasting mineral deposits and mining statuses remain limited. This study investigated the distribution, geochemical enrichment, potential sources, ecological risks and oral human health risks of Cd, Cr, Cu, Ni, Pb and Zn in 120 surface soil samples collected from active and abandoned Pb–Zn and limestone mines in Ebonyi State, Nigeria. Pseudo-total PTE concentrations were determined using aqua-regia digestion and flame atomic absorption spectrophotometry. Contamination indices, ecological and human health risk models, principal component analysis (PCA), PERMANOVA and multivariate regression were applied. Lead and Zn concentrations were highest in active Pb–Zn mines, reaching 4240.13 and 3401.39 mg kg⁻¹, respectively. Thirteen of 18 active–abandoned comparisons were significant after false discovery rate correction (q < 0.05). Pollution load indices ranged from 3.78 to 19.34, while potential ecological risk indices ranged from 185.54 to 1124.13, with Ameka active mine exhibiting the greatest cumulative contamination and ecological risk. The first three principal components explained 80.68% of elemental variability, while PERMANOVA confirmed significant differences among sites (R² = 0.516; p = 0.0002). Children's partial oral hazard indices ranged from 0.987 to 2.201, exceeding unity at four locations, with Cd contributing 95.2–98.0% of the calculated hazard. These findings demonstrate persistent contamination in active and abandoned mines and highlight the importance of integrated geochemical assessment, targeted remediation and child-focused exposure monitoring.