某磷矿城镇土壤重金属污染及空间变异特征

The Pollution and Spatial Variability of Soil Heavy Metal in Phosphate Mining Town

文章以南方某磷矿城镇为研究对象,采用现场采样与实验室分析方法测定了土壤中Cu、Zn、Pb、Cd、Ni、Cr、As和Hg的含量,并对当地土壤重金属污染现状、潜在生态风险及空间变异特征进行研究。结果表明,该研究区内土壤综合污染程度较低,但As和Cd存在一定风险。污染指数法评价结果表明,该地区土壤以清洁和尚清洁为主,局部地区存在中度和轻度污染;土壤中各元素的污染程度为As>Cd>Cu,Ni、Zn、Pb、Cr、Hg无污染。潜在生态风险评价法结果表明,研究区部分土壤样品Cd存在中等风险,其他元素均处于低风险水平。地统计半方差函数结果表明,土壤中8种重金属具有中等程度的空间相关性,虽受人为因素的影响,但未破坏原有空间格局,其中As主要受自然因素影响,Cd同时受自然和人为因素的影响。在置信水平95%,允许相对误差10%的要求下,该研究的采样分析样品数能反映当地土壤的实际情况,为磷矿城镇土壤污染防治提供了依据。

In order to study the metals pollution situation,potential ecological risks and spatial variability in soil in South phosphate mining town,the total elemental concentrations of Cu,Zn,Pb,Cd,Ni,Cr,As and Hg in the topsoil were analyzed by field sampling and laboratory analysis.The results showed that the soil in phosphate mining town was low polluted by heavy metals,but there were still some risks in As and Cd.The results of pollution index showed that the soil mainly to clean and still clean,partially to moderate and light pollution,the polluted degress were As>Cd>Cu,Ni、Zn、Pb、Cr and Hg were unpolluted.The results of potential ecological risk revealed there was a medium risk of Cd in some soil samples in the study area,another elements were at low risk levels.The result of semivariance analysis showed the metal concentrations were mid-class correlated,although by some human factors,but the original spatial pattern was not destroyed,and As was mainly affected by natural factors,Cd was both affected by natural and man-made factors.On the confidence level of 95%and allowable error of 10%,the sampling number in the paper can reflect the actual situation of the local soil,and provide foundation for soil pollution prevention on phosphate town.