中文摘要：

为了掌握重金属在简易填埋场底部及周边天然土层扩散情况,选取淮南某简易填埋场开展现场勘查和室内测试分析。在填埋场内、外进行了钻孔勘探、取土样和水样、水位测试等工作,对取得的土样和水样中重金属（Cu,Pb,Cr和Zn）含量及其存在形态进行了测试分析,获得了重金属在土层中沿深度及水平方向的分布规律。测试结果表明：重金属Cu,Pb,Cr在该填埋场下卧土层中总含量未超过国家土壤质量二级标准,重金属Zn在浅部土层中含量超过二级标准,但未超过三级标准。该填埋场历时17 a,垃圾渗滤液中重金属Cu,Pb,Cr在填埋场下卧土层中扩散深度达2 m以上,已击穿了浅部渗透系数较大的耕植土层,Zn扩散深度达3 m以上。填埋场内与渗滤液充分接触的土层中可交换态重金属占总量百分比低于1%,有机态重金属所占百分比明显高于场外背景值,但随深度增加而显著降低,其分布规律与有机质含量测试结果类似。该填埋场深度2 m以下的粉质黏土和老黏土层渗透性低、厚度大,具有良好的阻碍重金属扩散性能。

英文摘要：

Field and laboratory studies are carried out to investigate the degree of soil contamination below and around a simple dump of municipal solid wastes in Huainan.The field program includes borehole investigation,soil and water sampling and measurement of water levels.The soil and water samples are collected to laboratory to determine the contents of Cu,Pb,Zn and Cr and their speciation in the soil strata.The distributions of heavy metal content along both the vertical and horizontal directions are obtained.The test results show that the contents of Cu,Pb and Cr in the strata do not exceed the second-level limits of the national soil quality standard,and the content of Zn in the shallow soil layer exceeds the second-level limit and is smaller than the third-level limit.After 17 years of operation,the heavy metals of Cu,Pb,Cr in leachate have migrated to the depth of more than 2 m,i.e.,breaking through the planting soil stratum.The migration depth of Zn is more than 3 m at the bottom of the waste dump.The percentage of exchangeable heavy metals over the total content is measured to be lower than 1% even for the soil stratum in contact with the leachate.The percentage of organically-bonded heavy metals at the bottom of the waste dump was observed to be significantly greater than the background value.With the increase of depth,the speciation of heavy metals is close to the background value.The silty clay and clay layer at the depth greater than 2 m,with low permeability and a thickness of more than 7 m,is found to act as an effective barrier to the heavy metals.