河南某尾矿库土壤重金属污染特征及风险评价

Pollution Characteristics and Risk Assessment of Heavy Metals in a Tailing Pond of Henan

通过对某尾矿库土壤的采样调查,测定了土壤中5种重金属(Pb、Zn、Cd、Cr、Cu)的含量和形态特征,并采用地累积指数法和潜在风险危害指数法探讨了研究区土壤重金属的污染程度。结果表明:土壤中重金属均超过河南省土壤背景值,以Cd超标最严重;Cd与Pb、Cu与Zn、Cr同源性较高;可交换态中Pb和Cu的所占比较高,5种金属主要赋存形态为残渣态;评价显示土壤中Cd已达到重度污染,其余元素生态风险程度均为低级,采样区域整体处于很强生态风险等级,农田区更是达到极强生态风险等级。

The sampling survey of soil in a tailing pond was conducted in this paper. It measured concentrations and morphological characteristics of five kinds of heavy metals in the soil （Pb, Zn, Cd, Cr, and Cu） and explored the pollution levels of heavy metals in research soil by using the method of geo-accumulation index and potential risk hazard index. Results showed that all heavy metals in the soil had exceeded the soil background value of Henan Province, and Cd was over standards the most seriously; Cd had high homology with Pb, Cu, Zn and Cr; Pb and Cu had higher proportion of exchangeable form, and five metals mainly existed in the form of residual state; the evaluation showed that Cd in the soil had reached severe pollution level, and the degree of ecological risk was the most serious, while other elements had lower ecological risk. The sampling areas were at a strong ecological risk level, and the farmland area even reached the highest ecological risk level.