Evaluation and source analysis of heavy metal pollution in farmland soil around a pyrite slag heap in Southern Sichuan Province

Abstract:

To explore the impact of pyrite slag heap on surrounding farmland, 61 soil samples were systematically collected from a pyrite slag heap and surrounding agricultural land in Southern Sichuan Province, and the contents of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb, As, Hg) were determined, and the pollution levels and characteristics of the spatial distribution of eight heavy metals were analyzed. The sources of heavy metals were identified by correlation and principal component analysis, and the risk level of soil pollution was evaluated by a comprehensive ecological risk index and geoaccumulation index. In the soil, the results showed that the contents of Cr, Cu and Cd of the study area exceeded the corresponding national standards, and the contents of Cr, Cd, Pb, and As were significantly higher than the background values, which were 1.56, 1.40, 1.45 and 2.89 times of the background values, respectively. The spatial distribution of Ni, Cu and Zn content was relatively uniform, while the spatial distribution of the other five heavy metals was relatively concentrated. The farmland soil around the mining area was at a medium ecological risk level (150