广西大厂矿区沉积物重金属污染及风险评价

Heavy Metal Pollution of Surface Sediment in Dachang Mine Area of Guangxi and Its Ecological Risk Assessment

评估了广西大厂锑矿下游地区河流表层沉积物中重金属的污染特征,为合理预防和治理广西大厂矿区下游的重金属污染以及生态系统的修复提供基础资料.结果表明:沉积物中Cd,Cu,Ni,As,Zn,Pb和Cr的平均浓度分别为10.9 mg.kg-1,204 mg.kg-1,247 mg.kg-1,19.3 mg.kg-1,1 329 mg.kg-1,44.0 mg.kg-1和101 mg.kg-1,沉积物中重金属的浓度高低依次为Zn>Ni>Cu>Cr>Pb>As>Cd.用Hakanson潜在生态风险指数法对所调查地区生态风险评价结果表明,7种重金属对所调查地区生态风险的影响程度由高到低依次为:Cd>Cu>Ni>As>Zn>Pb>Cr.所调查地区的表层沉积物中主要生态风险因子是Cd.本研究为该矿区污染控制和治理提供了科学的依据.

Heavy metals are mainly carried in sediment of water body,their contents play important role on the environmental quality of the water body.The heavy metal pollution in sediment of mine area in Guangxi,China was assessed and the basic information of ecosystem recovery in the area was provided.The average contents of heavy metals Cd,Cu,Ni,As,Zn,Pb and Cr are 10.9 mg·kg-1,204 mg·kg-1,247 mg·kg-1,19.3 mg·kg-1,1 329 mg·kg-1,44.0 mg·kg-1 and 101 mg·kg-1 respectively.The pollution extent of heavy metals followed the order： ZnNiCuCrPbAsCd.Ecological risk index presented by Hakanson to assess the potential ecological risk of studied area was utilized.Based on the potential ecological risk assessment results,the surface sediment from the studied area had reached a high ecological risk level,and the order of ecological risk of heavy metals in the decline order was CdCuNiAsZnPbCr.The pollution extent and potential ecological risk of Cd were the most serious among all heavy metals.This study would provide scientific basis for the prevention,control of pollution,and environmental management in mine area in Guangxi,China.