生活垃圾焚烧厂周边土壤汞污染特征及评价

生活垃圾焚烧汞污染排放问题一直受到广泛的关注,特别是汞在其周边环境土壤中沉积,可能影响环境和人体健康.以华北某生活垃圾焚烧厂为研究对象,对其周边土壤中汞的含量及分布特征进行了分析,并对土壤中汞的污染状况及对周边人群的健康风险进行了评价.土壤中汞的浓度范围为0.015~0.25 mg·kg-1,平均值为(0.088±0.064)mg·kg-1.土壤中汞的浓度明显受到了风向影响,在焚烧厂西北方向(下风向)上汞的浓度高于东南方向(上风向)上汞的浓度.通过克里格插值绘制的汞等浓度值线图进一步给出了汞在周边土壤中的空间分布特征,图中显示在焚烧厂的周边存在3个浓度相对较高的区域,分别位于焚烧厂的西北偏北、东北偏北、西南偏西方向.单项污染指数及地累积指数评价结果表明焚烧厂部分周边土壤样品受到了一定影响,但健康风险评价表明土壤汞未对当地人群造成健康危害.

Distribution and Assessment of Mercury in the Ambient Soil of a Municipal Solid Waste Incinerator

The emission of mercury (Hg) from the municipal solid waste incineration has inspired widespread attention, especially regarding to the deposition of Hg in the surrounding soil, which is issued to be the potential negative factor of ambient environment and human health. This study mainly focused on the distributions of Hg in the ambient soil of a municipal solid waste incinerator located in North China. The pollution of the mercury and its risks to the local environment and human health were assessed. Results showed that Hg levels were in the range of 0.015-0.25 mg·kg^-1, with an average (0.088±0.064) mg·kg^-1. The concentrations of Hg in the soil were obviously influenced by wind direction and they were relatively higher in the northwest (downwind) comparing with that in the southeast (upwind). The Kriging interpolation method was adopted to create a contour map, which intuitively displayed a spatial mercury distribution in the soil. The regions with a higher Hg concentration are mainly distributed in the north northwest, the north northeast and the west southwest of the municipal solid waste incinerator. According to the evaluation results of single factor pollution index and geoaccumulation Index, some ambient soil samples were polluted by the mercury emission from the municipal solid waste incinerator; however, the results of the health risk assessment showed that the mercury in the soil had not pose a health hazard to the local population.