Source identification and risk analysis of potentially toxic elements (PTEs) in rainwater runoff from a manganese mine (south central Hunan, China)

Potentially toxic elements (PTEs) in manganese ore areas are prevalent in rainwater runoff and pose amajor threat to human health. In this study,field investigation and geostatistical analysis methods ofPositive Matrix Factorization (PMF) and Geographic Information System (GIS) were used tosystematically study the pollution in rainwater runoff from a manganese mining area in Xiangtan,China, to evaluate source contributions in the health risk assessment of PTEs. The averageconcentrations (mg/L) of six PTEs were: 0.3357 (Mn), 0.0450 (Ni), 0.0106 (Cu), 0.0148 (Zn), 0.0068 (Cd)and 0.0390 (Pb). The Coefficients of Variation (CV) for Mn and Zn were>180% and>130%, with theother analytes having values below 70%. The GIS and PMF analysis produced more refined spatialsource apportionments, such as mining, smelting, transportation, agricultural production and naturalsources. The results of the health risk assessment showed that the non-carcinogenic risk wasnegligible, and the carcinogenic risk was potentially dangerous but acceptable for both adults andchildren. In addition, the children’s total carcinogenic risk value was greater than that of adults,highlighting their vulnerability. This study demonstrates the potential of PMF to provide a framework tospatially prioritize treatment objectives within the mining region to improve environmental conditions