湖南某铅锌矿区土壤重金属污染及潜在生态风险评价

在湖南郴州某铅锌矿区采集94个表层土样,分析土壤中As、Cd、Pb、Zn的含量及污染程度,并运用hakanson指数法对其进行潜在生态风险评价。结果表明,土壤中As、Cd、Pb、Zn的平均含量分别为89.73 mg/kg、7.69 mg/kg、876.83 mg/kg和1 018.83 mg/kg,均超过国家土壤环境质量三级标准的限定值,其平均污染指数分别为:2.24、7.69、1.75、2.04。研究区综合污染指数为13.76,污染程度为较高污染。土壤重金属元素的潜在生态危害性为Cd>As>Pb>Zn,其中Cd是主要的生态风险的贡献因子。

Fractional distribution and risk assessment of heavy metal contaminated soil in vicinity of a lead/zinc mine

The pollution characteristics of Pb, Cd, Zn, Cu and Ni in soil of lead-zinc mining area were studied. The results indicate that the contamination degree followed the sequence of Cd〉Pb〉Zn〉Ni〉Cu and concentrations of Pb, Cd and Zn exceeded corresponding limits of the Chinese National Soil Environmental Quality Standard III. The soil was extremely polluted by Cd（Iego=5.26）, moderately to heavily polluted by Zn（Iego=2.38）, heavily to extremely polluted by Pb（Iego=4.13）. The results of BCR three-step sequential extraction procedure show that the active Cd, Pb and Zn were relatively high and might exert adverse effects on the plants grown in the soil, while Cu and Ni existed in soil with a relatively stable form. Potential ecological risk results indicate that soils were engaging in a high potential ecological risk by pollution of Cd and should be given rise to concern.