电子固体废弃物拆解作坊附近土壤重金属污染特征及风险

Contamination and health risk of heavy metals in soils near e-waste recycling workshops

为评价电子固废拆解作坊对附近农田土壤重金属的污染,选取某典型电子固废拆解作坊集中村落,采集作坊房前屋后农田土壤样品42个,分析了7种重金属(Cd、Cr、Cu、Hg、Ni、Pb和Zn)的浓度水平.结果表明,研究区域内电子废物拆解作坊房前屋后的农田土壤受到了不同程度的重金属污染,其中Cd和Cu为中度污染,Hg为轻微污染.相关性分析和主成分分析表明,农田土壤中Cu、Pb、Ni和Zn的污染主要来自于电子固废焚烧排放的烟尘大气沉降,Cd和Hg主要来自电子固废酸洗废水径流及电子固废长期堆放淋溶.健康风险评价结果显示,尽管儿童和成人的总致癌风险低于10-6,但研究区域儿童的累积非致癌风险超过可接受水平,经口摄入为主要暴露途径,其中重金属Pb对累积非致癌风险的贡献最大.由此,重视手工拆解作坊造成的土壤重金属污染的同时应特别关注Pb污染.

With the development of e -waste recycling business, environmental pollution resulted from it attracted more attention. To evaluate the contamination of heavy metals in soils around e-waste recycling workshops, a total of 42 agricultural soil samples were collected near the workshops. Concentrations and sources of heavy metals （ Cd, Cr, Cu, Hg, Ni, Pb and Zn ） in the soils investigated and analyzed. It was found that the agricultural soils suffered from heavy metal contamination to various extents. Based on single factor pollution index, contamination levels of Cd and Cu were medium, while contamination level of Hg was slight. Based on comprehensive pollution index, comprehensive contamination level of metals was from medium to high. Furthermore, multivariate analysis （ Pearson′s correlation analysis, stepwise regression analysis and principal component analysis） revealed that the concentrations of Cd, Pb, Ni and Zn were elevated by atomospheric deposition from open-burning of e-waste, Cd and Hg were related to surface runoff of acidic wastewater from E-waste washing and leakage from long term storage of e-waste. Health risk assessment showed that the cumulative non-cancer risk for children has exceeded the acceptable level. The most important exposure way was ingestion, mainly from Pb, although cumulative cancer risks for both children and adults were lower than the acceptable level of carcinogenic risks （ 10^-6 ） . Therefore, contamination of heavy metals especially Pb around e-waste recycling workshops should be taken more seriously.