某搬迁铜冶炼企业原址用地土壤重金属污染空间分布特征及风险评价

Spatial Distribution Characteristics and Risk Assessment of Heavy Metal Pollution in Soil of a Relocation Copper Smelting Enterprise

文章以某搬迁铜冶炼企业原址的核心生产区作为研究区域,共采集土壤样品816份。在详细调查研究区域土壤重金属污染状况的基础上,通过单因子污染指数法、内梅罗综合污染指数法和潜在生态风险指数法对研究区域土壤中的重金属污染状况和潜在生态风险进行了风险评估。运用统计分析结合地理信息系统(GIS)插值方法研究了该场地土壤中重金属污染的空间分布特征,结果表明:研究区域内土壤受到砷(As)、铅(Pb)、钴(Co)、镉(Cd)和铜(Cu)五种元素不同程度的污染;单因子污染指数Pi最大值由大到小依次为As>Cd>Pb>Cu>Co。内梅罗综合污染指数评价结果表明,研究区域内污染在空间分布上呈集中趋势,而且随着地层深度的增加,污染占比和污染等级均呈下降趋势。潜在生态风险评价结果显示,研究区域内As和Cd存在极强潜在生态风险;Pb的潜在生态风险等级为强;Cu和Co为中等潜在生态风险。随着地层深度的增加,各风险等级占比均逐渐降低。研究区域总体呈现自上而下污染面积逐渐减小、污染浓度逐渐降低的趋势,其中土壤As的污染情况最为严重和普遍。

A total of 816 soil samples were collected from the core production area of a copper smelting enterprise.Based on the investigation results of soil heavy metal pollution in the study area,the risk assessment of soil heavy metal pollution and potential ecological risk were evaluated by single factor pollution index,Nemerow comprehensive pollution index and potential ecological risk index.The spatial distribution characteristics of heavy metal contamination in soil were studied by statistical analysis combined with GIS interpolation.The results showed that the soil in the study area was polluted by As,Pb,Co,Cd and Cu in different degrees.The maximum value of single factor pollution index Pi from high to low was As>Cd>Pb>Cu>Co;the evaluation results of Nemerow comprehensive pollution index showed that the pollution in the study area presents a concentrated trend in spatial distribution.And with the increase of stratum depth,the proportion of pollution and the pollution level decreased gradually.Potential ecological risk assessment results showed that As and Cd had high potential ecological risk.Pb had a strong potential ecological risk;Cu and Co had medium potential ecological risk.With the increase of depth,the proportion of each risk level decreased gradually.In the study area,the pollution and concentration decreased gradually from top layer to bottom layer.Among them,As contamination in soil was severe and generally detected.