贵阳市城郊菜地土壤重金属污染评价

Assessment on heavy metals pollution of suburban vegetable soil in Guiyang

在土壤重金属污染评价中,重金属污染因子权重的确定是影响土壤环境质量评价结果的关键因素。本研究采用改进层次分析法确定权重的加权平均法,对贵阳市城郊菜地土壤重金属污染进行综合评价,同时结合GIS对研究区土壤重金属污染的空间分布特征进行分析。结果表明:贵阳市城郊菜地土壤中Zn、Cd、Pb、Cu、As和Hg的单因子污染指数平均值均小于1,土壤重金属污染综合指数平均值为0.3320,总体属于本底级;土壤重金属综合污染指数的空间分布显示,贵阳市城郊菜地土壤重金属污染指数主要呈现出中部低,南部和东北部部分地区高的规律,但研究区菜地土壤均未受到这6种重金属的明显污染。

Determining weights of heavy metal contamination factors is important in the soil environment quality assessment.To make comprehensive pollution assessment of heavy metals of suburban vegetable soil in Guiyang,the weighted mean of evaluation index was determined by optimized analytic hierarchy process（AHP）,and the spatial distribution characteristics of soil heavy metals in the study area was analyzed based on GIS.The result showed that the average single factor pollution index of Zn,Cd,Pb,Cu,As and Hg in study area was less than 1,and the integrated pollution index of soil heavy metals was 0.3320,which meant the soil in study area belonged to bottom level.The space distribution of the integrated pollution index of soil heavy metals revealed that the south and northeast parts of the region had higher pollution index than the central part in Guiyang,but the vegetable soil in the study area was not polluted by these six heavy metals.