Geochemical Fingerprint and Risk Assessment of Potential Toxic Elements in Agricultural Soils near a Manganese Mine
Abstract
Contamination by potentially toxic elements (PTEs) was assessed in an abandoned Mn mining area in Northern Greece, with 25 sites located within the wider mine area and 12 reference sites. Pseudo-total concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined and evaluated using contamination indices and probabilistic ecological and human health risk assessment. In mine-affected soils, Mn exhibited the highest mean concentration (815.3 mg kg−1), followed by Zn (99.5), Pb (50.8), Ni (30.1), Cu (22.9), Cr (15.0), and Cd (1.05 mg kg−1). Contamination indices indicated predominantly low-to-moderate contamination, mostly with Cd, Pb, and Mn. There was a 78.69% probability of low ecological risk (potential ecological risk index < 150) in mine-affected soils and a 21.31% probability of moderate risk, while the risk quotient was also elevated, with a median of 3.01. Human health risks were negligible (90th percentile hazard indices ≤ 0.020 and carcinogenic risks ≤ 4.2 × 10−7). Principal component analysis offered a two-factor solution accounting for 70.87% of variance, with PC1 scores negatively correlated with distance from the mine (r = −0.895). The overall PTE profile differed significantly between the two sites. Linear discriminant analysis provided complete discrimination, retaining 100% classification accuracy under leave-one-out cross-validation. Overall, historical Mn mining effects remain detectable in the area.