Spatial distribution and risk assessment of pollutants in a tailings pond for gold mining in Pinggu District, Beijing, China

摘要

Cyanide and potentially toxic elements in tailings from gold mining can cause serious pollution, and harm the surrounding environment through rainfall seepage and leakage from tailings ponds. In this study, 40 surface soil samples were collected from the Liujiadian tailings pond basin in Pinggu District, Beijing, and the contents of cyanide, Sb, As, Cd, Cu, Pb, Zn and Hg were determined. A spatial distribution map of these pollutants was drawn, the pollution degrees of cyanide, Sb, As, Cd, Cu, Pb, Zn and Hg were evaluated, and the ecological risk degrees of As, Cd, Cu, Pb, Zn and Hg were preliminarily evaluated. The pollution sources were analysed using multivariate statistical methods. The contents of potentially toxic elements in 17 plant samples collected in the study area were analysed, and the pollution levels were evaluated. The results show that the seriously polluted areas are mainly around the tailings pond and its downstream areas, and the pollution degree decreases with increasing distance. Arsenic, Pb and Cd are the main pollutants, followed by cyanide, Cu and Zn. Antimony and Hg occur as minor pollutants. The potential ecological risk of the whole study area is very high, and the high ecological risk area is around the tailings pond and its downstream areas. The risk is mainly associated with As and Cd. The multivariate statistical analysis results show that pollution mainly comes from the tailings pond, and agricultural activities have a certain impact. According to the detected potentially toxic element concentrations in the 17 plant samples, the plants are essentially not polluted by potentially toxic elements.