电子废弃物拆解区周边农田土壤重金属污染及生态风险

Heavy Metal Contamination and Ecological Risks in the Farmland Soils around the E-waste Disassembling Site

采集了典型的电子废物拆解区周边农田土壤,分析了6种重金属元素(As、Cd、Cu、Hg、Pb、Zn)的含量,计算了污染指数、富集因子和潜在生态风险指数,用于评价研究区域生态系统风险。结果表明:研究区域土壤中的Cd、Pb、Cu、Zn含量显著增加,均超出农用地土壤污染风险筛选值标准,超标率分别为Cd 100%、Pb 100%、Cu 91.3%和Zn 26.1%;富集因子值进一步表明,Cd、Cu、Zn、Hg是该区域富集最明显的金属,这可能与电子垃圾活动有关;Cu、Pb、Zn这3种重金属极显著相关(P<0.01),可能具有相同的来源,Cd、Hg、As与其他元素的相关系数较小,可能有电子废物之外的来源;6种重金属综合潜在生态风险指数显示,该区域属于潜在生态风险很强的区域,其中Cd和Hg对生态危害贡献率达到85.54%。

In this study,soil samples collection was conducted in farmland around a typical disassembling site,and the concentrations of six heavy metals(As,Cd,Cu,Hg,Pb,and Zn)were analyzed,calculated the pollution index,enrichment factor and potential ecological risk index,and used them to evaluate the ecological system risk.The results showed that the mean concentrations of Cd,Pb,Cu,and Zn were significantly higher than their standard values of risk screening values in agricultural land,the excess portion was 100%for Cd,100%for Pb,91.3%for Cu,and 26.1%for Zn;the values of enrichment factors further demonstrated that Cd,Cu,Zn and Hg were the most signifi cantly enriched metals in the study area,which might be associated with e-waste activities;Cu,Pb,and Zn in soils may originated from the same source for their highly significant correlation(P<0.01)while Cd,Hg,and As may differ from different sources;the potential ecological risk of 6 heavy metals indicated that this region with much higher potential ecological risks,and the contribution rate of Cd and Hg to ecological risk reaches 85.54%.