Study on heavy metal pollution of multi-stage aged domestic waste landfill in plain area
Based on investigation of eight heavy metal elements including Cu,Zn,Ni,Cd,Pb,Hg,As,and Cr in a waste landfill and its surrounding farmland in the suburbs of a certain city in Jiangsu Province,the distribution characteristics of those heavy metal el-ements in soil have been studied,and heavy metal pollution risk of soil has been evaluated by Nemerow index method and potential eco-logical risk index method.Contents of Cu,Zn,Ni,Cd,Pb and Cr in the surface soil of the landfill site are higher than the local back-ground values,while contents of Hg and As are relatively low.The overall variability of heavy metal elements is high,and contents are significantly affected by human activities.Pollution of surface soil inside the landfill site is severer than that of deep soil inside the land-fill site and its surrounding area.There is an obvious correlation of heavy metal pollution between inside and outside the landfill site.E-valuation results of both methods indicate that Cd,Cu,and Hg have good consistency in the surface and deep layer,and the internal and external landfill site,and have a high pollution risk,which should be paid special attention to.There is a significant difference in the ecological risk assessment results of Hg and Zn with both methods,which may be related to the assignment of heavy metal toxicity.
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