Spatial distribution and source apportionment of antimony and arsenic in soil of Dongting Lake Basin, China

Antimony (Sb) is widely distributed in the environment through both natural processes and anthropogenic activities, with its associated arsenic (As) contamination as a significant environmental issue in China. To investigate the potential sources and differences of Sb and As, 18,773 surface soils and 4854 deep soils from Dongting Lake Basin were analyzed using Atomic Fluorescence Spectrometry (AFS). The concentrations, spatial distribution, and potential sources of both two elements were systematically analyzed using Moran's I index, Inverse Distance Weighting (IDW), principal components analysis (PCA), and self-organizing map (SOM). Both As and Sb showed higher concentration ranges in surface soils (As: 0.6-385.8 mg/kg; Sb: 0.06-96.25 mg/kg) than in deep soils (As: 0.6-164.3 mg/kg; Sb: 0.22-43.69 mg/kg), indicating surface enrichment. Elevated concentrations of Sb and As were predominantly observed in regions characterized by carbonate rock formations and geological high-background regions where mineral deposits are densely located. Compared to As, Sb exhibits a more homogeneous origin, which is mainly influenced by mineral deposits. The spatial distribution of Sb and As is predominantly influenced by parent materials and mineral deposits, with industrial activities and surface runoff also contributing to their distribution patterns to some extent.