深圳红坳渣土受纳场污染及人体健康风险评价

Risk Assessment of Environmental Pollution and Human Health in Hong’ao Construction and Demolition Waste Landfill in Shenzhen

该文以深圳红坳渣土受纳场土壤为研究对象,通过原子吸收分光光度法及电感耦合等离子体质谱(ICP-MS)测定土样中Cu、As、Zn、Ni、Cr、Cd、Hg、Pb的含量,同时采用单因子指数法结合内梅罗综合指数法对该受纳场土壤重金属污染状况进行了分析,为城市渣土受纳场资源再利用及重金属污染防治提供了一定的理论依据。结果表明,重金属综合污染指数远大于3,处于严重污染级别。8种重金属中Cr污染最为严重,在受纳场中普遍存在,可能来源于受纳场中的建筑渣土和生活垃圾。采用《超级基金场地风险评价指南》中的场地健康风险评价模型对受纳场造成的人体健康风险进行评价,结果显示,在非致癌风险方面,8种重金属各自的非致癌风险商以及总体非致癌风险商均<1,受纳场的重金属污染对人体产生的健康风险可以忽略;在致癌风险方面,Cr、As产生的致癌风险值>1×10-6,对人体有一定的致癌风险。另外,重金属的累计致癌风险值超出累计可接受致癌风险水平,其中,以重金属Cr贡献的致癌风险为主。

The contents of Cu,As,Zn,Ni,Cr,Cd,Hg,and Pb in the soil samples taken from Hong’ao Construction and Demolition Waste(CDW)Landfill,Shenzhen were determined by atomic absorption spectrophotometry and inductively coupled plasma mass spectrometry.Based on the results,the single factor index combined with Nemero comprehensive index method were used to evaluate the degree of heavy metal pollution in the CWD landfill.The findings might provide information on the reuse of urban waste soil and the prevention and control of heavy metal pollution.The results of the pollution index evaluation show that the comprehensive pollution index of heavy metals is much larger than 3,being in a serious pollution level.Cr pollution is the most serious among the eight heavy metals,which is common in the CWD landfill and possibly originates from building dregs and domestic refuse.The site health risk assessment model according to the Risk Assessment Guidance for Superfund(RAGS)was used to evaluate the human health risks caused by the heavy metal in the CWD landfill.The results suggest that the non-carcinogenic risk of each of the eight heavy metals is not related to the non-carcinogenic risk.The comprehensive non-carcinogenic risk index is less than 1,and the health risks caused by heavy metal pollution in the field are negligible.In terms of carcinogenic risk,the risk of carcinogenicity of 5 heavy metals in sensitive populations is in the order as Cr>As>Cd>Pb>Ni,and the carcinogenic risk values of Cr and As exceed the acceptable carcinogenic risk level of single heavy metal,indicating that these two heavy metals have a certain effect on the human body.In addition,the cumulative carcinogenic risk value exceeds the cumulative acceptable carcinogenic risk level,while Cr mainly contributes to carcinogenic risk.