非正规垃圾填埋场土壤和地下水重金属污染特征与评价

Characteristics and Assessment of Heavy Metal Pollution in Soil and Groundwater of Informal Landfills

为了解非正规垃圾填埋场土壤和地下水重金属污染状况,以江西乱石湾垃圾填埋场周边土壤和地下水为研究对象,对研究区进行采样分析,应用内梅罗综合污染指数法和美国环保局地下水健康风险评价模型对该垃圾填埋场土壤和地下水中重金属污染物进行含量特征分析与评价。结果表明,Cr (Ⅵ)、Cd、Cu、Pb重金属是填埋场土壤中的主要污染物,区域所有采样点的内梅罗综合污染指数平均值为2.20,说明土壤受中度重金属污染;Cr (Ⅵ)是填埋场地下水的主要污染物,所有采样点的综合污染指数平均值为0.89,说明地下水总体处于警戒线等级;致癌健康风险值在2.32×10^-4~1.69×10^-3/a之间,是国际委员会推荐值的4.64~33.8倍,致癌风险水平为Cr(Ⅵ)> Ni > As > Cd;非致癌健康风险值在2.54×10^-10~9.72×10^-9/a之间,致癌类重金属的个人年健康风险值是非致癌类重金属的105~106倍,说明该区域的致癌风险极大,应引起重视。

In order to understand the contamination situations of heavy metals in contaminated soil and groundwater of informal landfills, an informal landfill, Luanshiwan Landfill in Jiangxi Province, was selected and its surrounding soil and the groundwater were studied to analyze heavy metal pollutants and to assess risks by using the Nemerow index method and the USEPA health risk assessment model. The results showed that Cr(VI), Cd and Cu were the main heavy metal pollutants in landfill soil while Cr(VI) was the main heavy metal pollutant in groundwater. The average Nemerow Index for all sampling points in this area was 2.20, showing that the soil was slightly polluted, the average comprehensive pollution index of all sampling points was 0.89, indicating that the groundwater was generally at the warning level. The carcinogenic health The carcinogenic health risk levels in groundwater trended as Cr(VI)> Ni > As > Cd, with risk values between 2.32×10^-4~1.69×10^-3/a which is 4.64~33.8 times of the recommended value of ICRP and105~106times higher than the non-carcinogenic risk level values of 2.54×10^-10~9.72×10^-9/a, indicating that the carcinogenic risk levels in this area are very high and high attentions need to be paid.