煤炭基地复垦村庄土壤重金属污染生态风险评价

Assessment on Ecological Risk of Soil Heavy Metal Pollution in Reclaimed Village of Coal Base

对煤炭基地的复垦村庄进行土壤重金属潜在生态风险评价,可以指出在村庄复垦中应该特别注意的物质,减少煤炭开采后有可能会造成土地污染并提高村庄复垦后的耕地质量。以山西省泽州县西郜村的压煤复垦村庄为研究区域,在分析了该地区土壤重金属含量的基础上,以山西省土壤重金属元素背景值为评价标准,采用潜在危害指数法对土壤重金属污染状况进行评价。研究结果表明,压煤复垦村庄不同层次土壤的综合污染程度范围为6.05~14.92,平均处于中等污染程度;从单个要素上来看,各种重金属污染系数平均值由高到低为:Hg】Pb】As】Cd】Cr,Hg属于较高的污染水平,其重金属潜在风险指数在75.9~275.19之间,有一半样点的潜在生态风险达到了中等程度;Hg潜在生态风险达到了较高污染程度,需要在复垦过程中进行治理。对煤炭基地复垦土壤重金属进行潜在生态风险评价,有助于掌握土壤重金属污染特征和分布规律,为复垦后耕地的重金属污染控制与修复提供一定的依据,促进土地资源的可持续利用。

Assessment on ecological risk of soil heavy metal pollution in reclaimed village of coal base could point out particular substance during the process of village reclamation,which will attach importance to reduce the land contamination caused by coal mining and improve the quality of arable land after village reclamation.A reclaimed village in Zezhou County of Shanxi Province was chosen as the study area.Based on analyzing the heavy metal content of the soil in this area,the background value of soil heavy metals in Shanxi was used as references and the method of potential ecological risk index was adopted to assess the condition of soil heavy pollution.The results were shown as follows:(1)the integrated contamination degree of different depth varied from 6.05 to 14.92 in reclaimed village of coal base,indicating that the average degree of pollution was at middle level;(2)in terms of single element,the average pollution index of various heavy metals was followed as Hg>Pb>As>Cd>Cr,and the potential ecological risk in half of the samples reached the moderate level,which also suggested that Hg pollution level was high and its potential ecological risk index varied from 75.9to 275.19;(3)the potential ecological risk of Hg achieved a higher degree and it needed to be controlled in the process of reclamation.Assessment on ecological risk of soil heavy metal pollution in reclaimed village of coal base could help master characteristics and distribution of heavy metal pollution in soil and provide a guidance for controlling and remedying the heavy metal pollution in arable land after reclamation,which will make a difference on sustainable use of land use.