泰安市城区土壤重金属污染特征及风险评价

为了解泰安市城区土壤重金属污染特征,对采集的30件土壤样品中6种重金属含量进行测定,利用单因子污染指数法、内梅罗综合污染指数法、地累积指数法和潜在生态风险指数法开展污染状况评价。结果表明：土壤中As、Cd、Cu、Pb、Hg、Ni的平均含量分别为6.72、0.066、20.33、18.19、0.031和19.92 mg.kg^-1,其中As、Cd、Cu、Pb、Ni的平均含量均低于泰安市和山东省土壤背景值,Hg的平均含量略高于泰安市土壤背景值,变异系数大于0.6,其含量受人类活动影响较大,空间分布差异性较大；除Hg的单因子污染指数为1.03,严重污染、中度污染、轻微污染和无污染采样点数量占比分别为3%、7%、23%和67%,其他重金属单因子污染指数平均值小于1,为无污染状态；重金属内梅罗综合污染指数平均为1.58～1.64,整体属于轻污染水平；土壤重金属累积较轻,多数为无污染状态,Hg的最大地累积指数为1.29,达中等-强污染(3级)；综合生态风险指数RI的范围为39.96～191.81,平均值为77.60,综合生态风险等级为轻微,为低生态风险区,Hg为引起风险的主要因子；Cu、Ni含量较低,富集主要受土壤母质和自然过程的控制；Pb、Cd、As主要来源于自然背景因素,部分受人类活动影响；Hg的污染来源于化肥、塑料地膜和含重金属的无机农药使用,受农业活动和居民生活影响较大。

Pollution characteristics and risk assessment of heavy metals in soil in urban area of Tai

In order to understand the characteristics of heavy metal pollution in soil in the urban area of Tai"an, the contents of 6 kinds of heavy metals in 30 soil samples were determined. The pollution status was evaluated by single factor pollution index method, Nemero comprehensive pollution index method, geological accumulation index method and potential ecological risk index method. The results show that the average contents of As, Cd, Cu, Pb, Hg and Ni in soil are 6.72, 0.066, 20.33, 18.19, 0.031 and 19.92 mg.kg^-1; The average contents of As, Cd, Cu, Pb and Ni are lower than the soil background value of Tai"an City and Shandong Province; the average content of Hg is slightly higher than the soil background value of Tai"an City, its content is greatly affected by human activities, the spatial distribution is quite different. Except that the single factor pollution index of Hg is 1.03, the number of sampling points with serious pollution, moderate pollution, slight pollution and no pollution accounts for 3%, 7%, 23% and 67% respectively. The average comprehensive pollution index of nemerol is 1.58~1.64, which belongs to the light pollution level as a whole; The accumulation of heavy metals in soil is light, and most of them are in a pollution-free state. The maximum geological accumulation index of Hg is 1.29, reaching medium to strong pollution (grade 3); The range of comprehensive ecological risk index RI is 39.96~191.81, with an average value of 77.60; The comprehensive ecological risk level is slight, which is a low ecological risk area, and Hg is the main factor causing the risk. The content of Cu and Ni is low, and the enrichment is mainly controlled by soil parent material and natural process; Pb, Cd and As are mainly derived from natural background factors and partially affected by human activities; Hg pollution comes from the use of chemical fertilizer, plastic film and inorganic pesticides containing heavy metals, which is greatly affected by agricultural activities and residents"life.