某铅锌矿区土壤重金属形态分布及污染风险评价

摘要

对某铅锌矿区土壤的铅、镉、锌、铜和镍的污染特征进行了研究。结果表明，5种重金属的污染程度依次为：镉>铅>锌>镍>铜，其中铅、镉和锌的浓度超过了国家土壤环境质量标准Ⅲ的浓度限值。土壤受镉污染极大，受锌污染中度至严重，受铅污染严重至极严重。BCR顺序提取形态分析结果表明，活性镉、铅和锌的含量较高，可能对土壤中的植物生长产生不利影响，而铜和镍以相对稳定的形式存在。潜在生态危害结果表明，镉污染导致土壤潜在着极大的生态风险，应当引起重视。%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.