X市土壤重金属污染空间特性分析与风险评价

主要采用内梅罗综合指数和潜在生态风险指数对X市土壤重金属Cd、Hg、As和Pb污染程度进行评价,并通过地统计学、地理信息系统(GIS)评价法以及空间自相关分析法研究土壤重金属分布空间特性。结果表明:X市土壤中Cd、Hg、As和Pb质量浓度均值分别为0.509 8、0.162 8、8.774 7、34.601 5mg/kg,受人为影响较大,特别是As和Pb;内梅罗综合污染指数得出,有8.8%、5.2%、7.8%样点分别属于轻度、中度和重度污染;总潜在生态风险指数得出,有8.7%、5.2%样点分别存在中等危害和强危害生态风险;Cd、Hg、As和Pb都存在较强的空间自相关性,总体上呈现南高北低或东高西低分布的现象,东南部的p镇有较严重的土壤重金属污染问题。

Spatial characteristics and risk assessment of heavy metal pollution in soil of X City

The pollution levels of Cd,Hg,As and Pb in soil of X City were mainly evaluated by Nemero comprehensive pollution index and potential ecological risk index,and soil spatial characteristics were studied by geostatistics and geographic information system(GIS)evaluation as well as Moran’s I index.Results showed that:the mean mass concentrations of Cd,Hg,As and Pb were 0.509 8,0.162 8,8.774 7 and 34.601 5 mg/kg,respectively,which was mostly affected by human influence especially As and Pb.The Nemero comprehensive pollution index showed 8.8%,5.2%and 7.8%of the samples belonging to mild,moderate and heavy pollution levels.The total potential ecological risk index showed 8.7%and 5.2%of the samples existing medium and strong hazard.Cd,Hg,As and Pb all had strong spatial autocorrelation with a distribution of high in the south and low in the north or high in the east and low in the west.There was a serious soil heavy metal pollution problem in the southeast like p town.