太原市污灌区土壤重金属分布特征及风险评价

摘要

The pollution status of heavy metals of Pb, Zn, Cu, Ni, Mn, Cr, As, Hg and Cd in soil in sewage irrigation area of Taiyuan city were investigated and assessed in this paper. The results showed that the average contents of heavy metals in the soils were Pb 24.95 mg/kg, Zn 83.86 mg/kg, Cu 28.33 mg/kg, Ni 33.30 mg/kg, Mn 682.16 rng/kg, Cr 80.08 mg/kg, As 12.46 mg/kg, Hg 0.09 mg/kg, and Cd 0.19 mg/kg. The Hg and Cd are the main contamination elements, with the single pollution index of 2.74 and 2.42, which is medium level pollution, and the single ecological risk index are 109.34 and 72.71 respectively, showing this area is in medium ecological risk. The highest pollution index of Hg is 4.89 in Jinyuan district, with the single ecological risk indices of 195.57; the highest pollution index of Cd is 3.09 in Xiaodian district, with the single ecological risk indices of 92.59. The results also indicated that Hg and Cd had caused some relevant ecological risk by comparing the pollution index with the ecological risk indices of heavy metals.%对太原市污灌区土壤重金属Pb,Zn,Cu,Ni,Mn,Cr,A8,Hg和Cd污染现状进行调查和分析,结果表明,该地区重金属平均含量分别为:Pb 24.95 mg/kg,Zn 83.86 mg/kg,Cu 28.33 mg/kg,Ni 33.30 mg/kg,Mn682.16 mg/kg,Cr 80.08 mg/kg,As 12.46 mg/kg,Hg 0.09 mg/kg,Cd0.19 mg/kg.主要污染物为Hg和Cd,单项污染指数分别为2.74和2.42,为中度污染,单因子生态危害系数分别为109.54和72.71,为中度生态危害;晋源区Hg单项污染指数和单因子潜在生态危害系数最高,分别为4.89和195.57;小店区Cd单项污染指数和单因子潜在生态危害系数最高,分别为3.09和92.59.同时,通过污染指数与生态危害系数比较,表明Hg,Cd在构成土壤环境污染的同时,也造成了相应的生态危害.