某典型工业聚集区遗留地土壤重金属污染特征及健康风险评价

Assessment of Heavy Metals and Human Health Risk in Surface Soils in a Legacy Land of Typical Industrial Agglomeration Area

为查明某典型工业聚集区遗留地周边表层土壤重金属污染状况及对人体健康的风险,采集25个表层土壤样品,对土壤中的Cd,Pb,As,Hg和Cr含量进行了分析。采用地累积指数法和修正的潜在生态风险指数法对土壤中重金属的累积程度和潜在生态风险进行了评价。应用美国环境保护部(USEPA)健康风险评价模型和《建设用地土壤污染风险评估技术导则》(HJ25.3—2019)评估了人群暴露土壤重金属的健康风险,同时对土壤中重金属进行来源解析。结果表明,Cd,Hg,As,Pb和Cr的平均浓度均高于区域土壤背景值。Hg,Pb和Cd元素在人类生产、生活活动的影响下,累积效应明显;潜在生态危害程度达到“高”生态危害等级。Hg和Pb含量分布不均匀,工业生产、交通运输及商业等活动的干扰较为强烈。各重金属元素风险值均值均低于可接受危害商,Pb和Cr的非致癌健康风险值超过可接受危害商的点位比例分别为40%和20%。手口摄入途径是重金属致癌风险的主要途径,Cr,As和Cd的总致癌风险指数均值在人们可接受的致癌风险范围内,但12%的点位Cr三种暴露途径的总致癌风险指数大于10^(-4),应引起足够的重视。

In order to find out the pollution status of heavy metals in the topsoil around the legacy of a typical industrial agglomeration area and the risk to human health,25 topsoil samples were collected and the contents of Cd,Pb,As,Hg and Cr in soil were analyzed.The accumulation degree and potential ecological risk of heavy metals in soil were evaluated by the geo-accumulation index method and modified potential ecological risk index method.The USEPA health risk assessment model and the technical guidelines for soil pollution risk assessment of construction land(HJ25.3—2019)were used to assess the health risk of human exposure to heavy metals in soil,and the sources of heavy metals in soil were analyzed.The results show that the average concentrations of Cd,Hg,As,Pb and Cr are higher than the regional soil background values.The cumulative effects of Hg,Pb and Cd elements are obvious under the influence of human production and living activities.The potential ecological hazard degree reaches the high ecological hazard level.The contents of Hg and Pb are unevenly distributed,and the interference of industrial production,transportation and commercial activities is relatively strong.The risk values of all heavy metals are lower than the acceptable hazard quotients,and the percentages of non carcinogenic health risk values for Pb and Cr exceed the acceptable hazard quotients,which are 40%and 20%,respectively.Hand and mouth intake is the main way of heavy metal carcinogenic risk.The total carcinogenic risk indexes of Cr,As and Cd are within the acceptable carcinogenic risk ranges,but the total carcinogenic risk index of 12%point for Cr exposure routes is over 10^(-4),which should be paid enough attention.