典型工业退役场地土壤重金属污染及风险评价

On Assessment of Heavy Metal Pollution and Risk in a Typical Retired Industrial Site

采用单因子指数法、富集系数、浸出毒性试验、Hankanson潜在生态危害指数法及健康风险评价法，对重庆城区内某企业退役场地车间表层土及下层土、居民区表层土及厂区附近土壤的重金属污染现状及其风险进行了评价。结果表明，研究区域内Hg ，As ，Zn和Pb的富集系数部分大于1，表现出一定程度的富集。单因子污染指数表明，土壤重金属含量均未超出A ，B级标准限值；另外，除居民区重金属潜在生态危害程度属中度外，其余地区属于轻度生态危害，以Hg的潜在生态危害最突出，其次是Cd ，这主要与 Hg和Cd的毒性系数较高有关。人体对几种重金属吸收量的排序大小依次为Zn ，Pb ，Cu ，Ni ，Cr ，As ，Hg≈Cd 。同时，儿童和成人对几种重金属的3种摄入方式大小依次为：直接摄入量，经皮肤吸收摄入量和呼吸摄入量。从致癌风险角度看，几种重金属致癌风险系数都在10－6～10－4基准范围内。

T he assessment of soil heavy metal pollution by means of single index ,enrichment coefficient , leaching pollution index ,potential eco‐risk index and health risk coefficient have been conducted for differ‐ent soils including surface and section soils of factory workshops ,surface soils of residential and also neighboring areas of a retired site of a factory in municipal Chongqing .The results show in investigated ar‐eas ,the enrichment coefficient of Hg ,As ,Zn and Pb are all higher than 1 ,exceed environmental back‐ground value by a certain extent .Also by means of single pollution index method ,heavy metals in soils all are not exceeded the limitation of A and B level standards .In addition ,potential eco‐risk in residential are‐as is relative higher as compared with other areas showing a lower level （mild eco‐risk） .Moreover ,the eco‐risk accounted for Hg is most significant following Cd pollution ,which mainly due to the high toxicity index of Hg and Cd .The order of heavy metal intake of human is Zn〉Pb〉Cu〉Ni〉Cr〉As 〉 Hg≈Cd . Meanwhile ,the order of heavy metal intake pathways suggesting direct intake 〉 skin intake〉 respiration intake is similar between children and adults .In addition ,consideration of carcinogenic risk ,several heavy metals show values were in the range of 10 6 10 4 of standard limitation .