关键词: 土壤污染, 内梅罗指数, 污染负荷指数, 生态风险

Abstract: In order to assess the enrichment characteristics，and pollution levels and ecological risks，ecological pollution risks of heavy metals (As,Cd,Cr,Cu,Ni,Pb,and Zn) in the topsoil around rare tailings in Baotou region，the wetland located on the southern rim,and farmlands located on the west side of tailings were chosen as study plots.While the relatively non-polluted Xiaobaihe Yellow River wetlands,and the farmland soil about eight kilometers apart from the western tailing dam were chosen as control plots.All of the heavy metal contents were measured using the National Standard Methods.Their pollution levels and ecological risks were assessed using Comprehensive Pollution Index,Pollution Load Index,Geoaccumulation Index,and Ecological Risk Index.The result showed that all of those heavy metal contents were higher than the background values of China and Inner Mongolia.Among them,Cd and As showed the most serious pollution,and the As contents exceeded the National Standard II (GB15618-1995).Both the heavy metal pollution levels and the potential ecological risks in soils around the tailings were significantly higher than that in the control plots.The pollution levels of wetland soils were significantly higher than that of farmland soils,and decreased with the distances of tailings.It was concluded that this rare tailing was the root cause of heavy metal pollution in the surrounding soils.This study explicated the pollution levels and ecological risks of heavy metals in this area,which could provide a scientific basis for the local land resources protection and ecological restoration.

Key words: Soil pollution, Nemero index, Pollution load index, Ecological risk