北京城市公园土壤铅含量及其污染评价

通过对北京市市区 30个典型公园的土壤取样调查 ,测定了表层土壤中铅的含量 ,并以欧盟“土壤环境质量建议标准”对污染状况进行了评价。结果表明 ,北京市区已有部分公园存在铅污染问题 ,其表土的铅含量平均值为 66 2mg/kg ,变幅为 2 5～ 2 0 7mg/kg,污染指数为0 5～4 1。用增长曲线拟合的结果表明 ,土壤铅含量随着公园建园时间的延长呈不断增加的趋势 ,尤其是近几十年来土壤铅含量的增加较快。历史悠久且距离市中心较近的公园土壤铅含量明显偏高 ;对于大多数开放历史较短且相对偏僻的公园而言 ,表土一般都未见明显的铅污染。

Lead concentrations of soils in Beijing urban parks and their pollution assessment

Lead concentrations of surface soils taken from 30 typical parks in Beijing urban area were studied. The pollution index, which was used to assess the situation of soil pollution, was calculated according to the Soil Environment Quality Standard recommendedby European Union. The results indicated that the average concentration of Pb in soils was 66.2 mg/kg, ranging from 25 to 207 mg/kg;the pollution index was ranging from 0.51 to 4.15. It was found that soils from some parks were polluted with Pb apparently. The results of cluster analysis showed that all of theparks could be dividedinto three categories: (1) the parks with a history shorter than 100 years; (2) the parks with a history ranging between 200 and 400 years;and (3) the parks with a history longer than 400 years. Regression analysis was carried out to explore the relationship between two variables of Pb concentrations in soils and the history of parks. Using the "growth curve"to fit the datum, it could be concluded that the two variables were significantly positive correlated (p<0.001). Furthermore, geographical location of the parks was also an essential factor affecting the lead concentrations in the soils. In some parks with longer history and/or near the center of the city, the concentrations of Pb in the soilswere obviously high. However, Pb pollution was not notable in the soils of other parkswith relative short history.