Distribution, Sources, and Risks of Heavy Metal Contamination in Farmland Soils Surrounding Typical Industrial Areas of South Shanxi Province, China

This research investigated the characteristics and risks associated with heavy metal contamination in farmland soils surrounding an industrial aggregation area in Yuncheng City, southern Shanxi Province. It analyzed the concentrations and spatial accumulation patterns of eight heavy metal elements, employed principal component analysis (PCA) to identify sources, and assessed both the ecological and health risks. The results revealed the following: (1) The mean concentrations of Pb, Cd, As, Hg, Cr, Zn, Cu, and Ni in the study area were 26.1, 0.29, 13.4, 0.05, 61.4, 72.94, 27.15, and 32.33 mg·kg^-1, respectively. These concentrations were elevated above local background levels but remained within Chinese regulatory thresholds for agricultural soil. According to the geoaccumulation index, only Cd was classified as slightly polluted, while the other elements were essentially uncontaminated. The Nemerow comprehensive pollution index indicated light pollution. The potential ecological risk index identified Cd and Hg as the primary contributors to ecological risk, indicating moderate contamination. (2) Source apportionment results revealed that As, Cr, and Ni originated from industrial-natural sources; Cd, Zn, and Cu were linked to industrial production; and Pb and Hg were attributed to mining and traffic sources. (3) Health risk assessments suggested that non-carcinogenic risks for adults and children (0.28 and 0.51, respectively) were within safe limits. However, the carcinogenic risk for children (1.02 × 10^-4) exceeded the acceptable threshold, while the level for adults (4.67 × 10^-5) remained acceptable. This study provides a scientific basis for preventing, controlling and remediating local heavy metal contamination in soil.