陈家冲垃圾填埋场地下水环境健康风险评价

垃圾填埋是目前国内处理城市生活垃圾的主要方式,由垃圾渗滤液引发地下水环境污染已成为当前主要的水环境问题之一。选择武汉市陈家冲垃圾填埋场为研究对象,通过对该区周边地下水布孔取样和监测,分析了垃圾填埋场对其周围地下水环境的影响。结果表明:研究区地下水的主要污染因子为Pb、Cd和Fe,且各污染物的浓度与采样深度、井距呈负相关关系。垃圾填埋场产生污染的影响范围主要在距离800m以内、深度小于5.5m的地下水。为进一步了解该区地下水对人体健康危害的风险程度,对研究区地下水进行了水环境健康风险评价,结果显示:研究区各采样井地下水的总风险值在2.71×10~(-4)/a~7.12×10~(-3)/a,均超过国际辐射防护委员会(ICRP)推荐的最大可接受值5.0×10~(-5)/a,主要风险因子为基因毒物质Cd和Cr(VI)以及躯体毒物质硝态氮;其中,Cd和硝态氮所致的健康风险值超标率100%,而Cr(VI)的健康风险值超标率为50%,对暴露人群存在健康危害风险。此外,对男性和女性健康风险值的研究显示,研究区地下水环境中污染物的男性健康危害风险值普遍高于女性。

Study on shallow groundwater quality impacted by Chenjiachong Sanitary Landfill

Landfill is currently the primary way to handle the municipal refuse in China. However, the groundwater quality will be deteriorated by landfill leachate, which may become one of the main sources for the current water pollution. In this study, a municipal landfill in Wuhan City was selected to investigate its effects on the adjacent groundwater environment. Groundwater samples were collected from eight boreholes and these samples were analyzed to assess the current groundwater quality in the studied area. The results show that groundwater samples are mainly polluted by Pb, Cd and Fe. The pollutant concentrations increase with the decrease of sampling depth and the decrease of the distances between sampled wells and landfill site. The groundwater pollution impacted by landfill leachate was mainly within a distance of 800 meters and a depth of 5.5 meters. The human health risk assessment was performed to further investigate the potential human health risk exposure to the polluted groundwater in the studied area. The results show that the total risk values of the studied groundwater samples are within a range of 2.71×10-4 a-1 ~ 7.12×10-3 a-1, which is higher than the value recommended by the International Commission on Radiological Protection(ICRP), 5.0×10-5 a-1. The human health risk was mainly induced by exposure to pollutants including Cd, Cr(VI) and nitrate. Cd and nitrate of all the studied groundwater samples were with a potential human health risk higher than 5.0×10-5 a-1 and 50% of the samples were with a potential human health risk, induced by Cr(VI), higher than the recommend ICRP value. In addition, the results show that men''s health risk value is generally higher than women exposure to the polluted groundwater.