矿业活动对锑矿区土壤的重金属污染特征及生态风险影响

Effects of mining activities on soil heavy metal pollution characteristics and ecological risks in antimony mining areas

为了评价矿业活动和生态修复措施对锑矿区土壤的重金属污染影响,调查了锡矿山锑矿区冶炼区、公路沿线区、采矿区及尾矿区中不同用地性质土壤中Sb、As、Pb及Cd等重金属含量,并用地累积指数法和潜在生态风险指数法对污染程度、潜在生态风险进行了评价。结果表明:锑矿区土壤样品中Sb、As、Pb及Cd的平均含量分别为3619.38、82.20、244.28、30.84 mg/kg,重金属复合污染严重;地累积指数法及潜在生态风险指数法评价表明,锑矿区Sb和Cd污染严重,As、Pb有轻度到中度污染,综合来看,具有极强的生态风险,其中,Sb和Cd是最主要的污染因子。冶炼、开采、运输和堆放等矿业活动使各区域土壤的重金属浓度呈显著区域特征;废矿渣土壤、荒地、林地、底泥、生态修复草地和菜地等土壤样品中的重金属Sb含量依次减小,植物生态修复方法是治理土壤锑污染的一种有效手段。

In order to evaluate the impact of mining activities and ecological restoration measures on soil heavy metal pollution in antimony mining areas,the pollution status and regional characteristics of Sb,As,Pb and Cd in soils of different land properties among smelting area,road nearby ore,mining area and ore tailing area of antimony mine area in Xikuangshan,Hunan were studied,in addition,the ground accumulation index method and the potential ecological risk index method were used to evaluate pollution and ecological risk.It was found that the average contents of Sb,As,Pb and Cd in soil samples in the study area were 3619.38 mg/kg,82.20 mg/kg,244.28 mg/kg and 30.84 mg/kg respectively,and heavy metal compound pollution were serious,the accumulation index method and the potential ecological risk index method indicate that Sb and Cd pollution in antimony ore area is serious,As,Pb has mild to moderate pollution,comprehensive has a strong ecological risk,among which Sb and Cd are the most important pollution factors.Significant regional characteristics was showed by the heavy metal concentration in soils among each areas because of mining activities such as smelting,mining,transportation and stacking;the content of Sb in soil samples decreased successively in residue-field,wasteland,forestland,sediment,grassland and vegetable-field,which indicated that the method of grassland ecological restoration was an effective method to control soil antimony pollution.