杭州经济技术开发区河渠沿岸土壤中重金属积累特征及其风险评价

Accumulation Characteristics and Risk Assessment of Heavy Metals in Soils of River Banks from Hangzhou Economic & Technological Development Area

[目的]为杭州经济技术开发区土壤重金属污染的防治提供参考。[方法]采集开发区主要河渠沿岸表层土壤,设置27个采样点,检测土壤中Cu、Zn、Pb、Cd和Cr 5种重金属含量。采用单项污染指数、内梅罗综合污染指数和潜在生态风险指数法,对开发区土壤重金属含量进行风险评价。[结果]土壤中Cu、Zn、Pb、Cd和Cr含量平均浓度分别为74.28、142.80、93.15、8.75、177.80 mg/kg。土壤中Cd单项污染指数为14.58,其他重金属均小于1,各重金属的单项污染指数大小依次为Cd>Cu>Cr>Zn>Pb;内梅罗综合指数显示该开发区土壤处于重度污染水平;潜在生态风险评价显示Cd处于极强风险等级,其他重金属均处于轻微危害水平。[结论]Cd污染程度远超过国家土壤二级标准的14倍,应引起高度重视。

[ Objective ] The research aimed to provide a reference for soil heavy metal pollution prevention and control in Hangzhou Economic ＆ Technological Development Area （HEDA）. [ Method] The topsoil samples of 27 plots located in the banks of main rivers were collected in studied area. The contents of five heavy metals, i.e. Cu, Zn, Pb, Cd and Cr, in the topsoils were detected. Single pollution index, Nemerow combined pollution index and Hakanson potential ecological risk index were used to assess ecological and human health risk of heavy metals. [ Result] The average content of Cu, Zn, Pb, Cd and Cr in the soils was 74.28,142.80,93.15,8.75 and 177.8 mg/kg, respectively. In terms of single pollution index, the value of Cd was 14.58, and other heavy metal values were less than 1. The single pollution index of heavy metals in the soils de- creased in the order of Cd 〉 Cu 〉 Cr 〉 Zn 〉 Pb. The Nemerow combined polutionl index results demonstrated that the studied area was at a quite serious pollution level. The Hakanson potential ecological risk index revealed that the heavy metals in soil of HEDA were all at the low risk level except Cd was at a very strong risk level. [ Conclusion] Due to Cd concentration was far exceeding GradeⅡ Criteria of Environmental Quality Standard by 14 times, close attention should be paid.