Heavy metals pollution and potential ecological risk in soils around Pb/Zn mine area in Hunan Province

To investigate the soil pollution by heavy metals after the collapse of the tailing dam,the concentrations of Pb,Zn,Cu,Cd,As in agricultural soils collected from a Pb /Zn mine area in south Hunan province were determined,and the single method index and Hakanson's ecological risk index were employed. The results indicated that the average concentrations of Pb,Zn,Cu,Cd,As in soils were 566. 82,285. 90,69. 00,10. 29,670. 12 mg·kg-1,respectively. The single method index demonstrated that those agricultural soils were polluted seriously by heavy metals,especially Cd. The order of potential ecological risk for heavy metals was CdAsPbCuZn,while Cd and As were the dominant contributors for ecological risk. The present study demonstrated that the agricultural soils still were contaminated by heavy metals after more than 20 years.