晋中盆地土壤重金属分布特征及生态风险

目的]对晋中盆地土壤重金属分布特征影响及生态风险进行研究和评价,旨在了解该地区土壤污染现状以及为土壤重金属综合治理与防治提供科学依据。方法]对晋中盆地表层土壤进行采样,测定208个土壤样品中Pb,Cr,Cd,As和Hg这5种重金属的含量,采用单因子污染指数、综合污染指数和潜在生态危害指数对盆地污染进行评价,并利用GIS空间分析技术对污染现状进行分析。结果]重金属Pb,Cd,Cr,As和Hg的平均含量分别为20.87,0.316,68.226,10.457和0.129mg/kg,分别为山西省土壤背景值的1.42,3.16,1.23,1.15,5.61倍;单因子污染指数结果显示,Hg和Cd为盆地污染的主要贡献因子,Pb,Cr和As对盆地污染的贡献较少;综合污染指数和潜在生态危害指数结果显示,盆地污染程度较为严重,达到中等污染和重度污染的样点占比共达到95%以上;污染空间分析显示,盆地整体污染程度较深,在盆地北部太原地区和南部孝义、介休市存在明显的污染突出地区。结论]受人类活动影响,晋中盆地土壤重金属污染已较为严重,应引起足够重视。

Effects and Ecological Risk of Urbanization on Heavy Metal Accumulation in Soil of Jinzhong Basin

Objective] To study the distribution of soil heavy metals and evaluate its ecological risk in Jinzhong basin so as to understand the status of soil pollution in this area and to provide a scientific basis for the comprehensive control and prevention of soil heavy metals.Methods] The heavy metals contents of Pb, Cr, Cd, Hg and As in 208 surface soil samples were tested in Jinzhong basin. The single factor pollution index, integrated pollution index and potential ecological hazard index were used to evaluate basin pollution, and the status of pollution was analyzed using GIS spatial analysis technology.Results] The average contents of heavy metals Pb, Cd, Cr, As and Hg were 20.87, 0.316, 68.226, 10.457 and 0.129 mg/kg respectively, which were 1.42, 3.16, 1.23, 1.15 and 5.61 times of the soil background in Shanxi Province. The results of single factor pollution index showed that Hg and Cd were the main contributors to basin pollution, and Pb, Cr and As contributed less to the basin pollution. The results of the comprehensive pollution index and the potential ecological hazard index showed that the basin pollution level was more serious, over than 95% of the sample points reached medium pollution and heavy pollution levels. The spatial analysis of pollution showed that the overall pollution of the basin was severe, and there were obvious polluted areas in the northern of basin, Taiyuan, and in the southern of basin, Xiaoyi and Jiexiu area.Conclusion] Due to the influence of human activities, heavy metals in soils of Jinzhong basin have been seriously polluted and should be paid enough attention.