电子垃圾拆解区表层土壤重金属水平分布特征及其污染评价

Characteristics of Horizontal Distribution and Pollution Assessment of Heavy Metals in the Surface Soil from Typical E-Waste Dismantling Region

根据电子垃圾拆解较为集中的浙江温岭地区表层土壤的环境现状调查和检测分析结果,分析了表层农田土壤中6种重金属Cu、Pb、Zn、Cd、Ni、Cr和pH值的水平分布特征。结果显示,Cu、Zn、Pb、Cd水平分布特征相似,高浓度聚集区出现在温岭市西北区域的大溪镇、泽国镇和横峰街道,这与产业类型分布和元素性质相关;同时Ni与Cr也具有较为明显的相关性,高值区主要分布在横峰街道、泽国镇、箬横镇、新河镇。采用内梅罗综合指数法和单因子评价法对研究地区表层土壤中6种重金属和pH值污染水平进行了评价。以农用地土壤污染风险管控标准为评价标准,发现研究区域表层农田土壤样品中重金属Cd存在局部污染的特征,表层农田土壤中Cd的污染程度和电子垃圾拆解区的分布存在相关性,是研究该区农田土壤Cd污染的主要来源,也是研究区主要的土壤环境风险之一。Based on the environmental status investigation and analysis results of the surface soil in Wenling, Zhejiang Province, where electronic waste dismantling is concentrated, the distribution characteristics of six heavy metals—Cu, Pb, Zn, Cd, Ni, and Cr—as well as pH values in the surface agricultural soil were analyzed. Results indicate that the horizontal distribution characteristics of Cu, Zn, Pb, and Cd are similar. Those sample sites with higher contamination levels were located in the northwest region of Wenling City, including Daxi Town, Zegu Town, and Hengfeng community. Research data shows local industry types and elemental properties may be responsible for these findings. In addition, Ni and Cr also have significant correlations, with high-value areas primarily distributed in Hengfeng Street, Zegu Town, Bixi Town, and Xinhe Town. For those six heavy metals and pH values, the Nemerow composite index method and single-factor evaluation method were used to assess samples from the study area. Using the risk control standard for soil contamination of agricultural land as the criterion, it was found that the pollution degree of Cd in the surface agricultural soils is related to the distribution of e-waste dismantling region;Cd is the main source of Cd pollution in the study area and one of the main environmental risks.