基于改进AHP 与GIS 的白银区耕层 土壤重金属污染评价

重金属污染因子权重在土壤重金属污染评价中,是影响环境质量评价结果的关键因素。基于改进层次分析法,根据重金属对人体的危害程度,计算土壤重金属污染物在土壤环境质量评价中的权重,并将其应用于加权平均综合指数法,结合地统计学软件,对白银区耕层土壤重金属污染状况进行了评价。结果表明,白银区耕层土壤中5种重金属污染由高到低排序依次为：As、Zn、Cu、Cr、Pb;耕层土壤综合污染指数平均值为0.48,污染等级总体为安全级;经相关性分析,Pb与Zn、Pb与Cu、Zn与Cu之间具有极显著的正相关性;土壤重金属污染空间分布特征显示,白银区除中部和东南部部分地区处于玷污、污染水平外,其余大部分地区耕地耕层土壤处于安全级;本底级、安全级、玷污级、污染级分别占全区耕地面积的24.83%、70.33%、2.72%、2.12%。

Heavy Metals Pollution Evaluation of Arable Layer Soil in Baiyin Based on Improved AHP and GIS

Determining weights of heavy metal contamination is important in the soil environment quality assessment. Weights of heavy metal contamination were computed according to impacts of heavy metals on human health by using improved classical analytical hierarchy process (AHP) in the soil environment quality assessment. Aiming at the problem of soils heavy metal pollutions in Baiyin which is a resources city and a typical mining city, the author evaluated the effects of heavy metals of cultivated land by GIS and weighted mean method. The results showed that: among the 5 heavy metals, the variation degree from big to small was As, Zn, Cu, Cr, Pb. The integrated pollution index of soil heavy metals was 0.48, which meant the soil in study area was security. The correlation analysis showed extremely significant positive correlation between Pb and Zn, Pb and Cu, Zn and Cu. The space distribution of soil heavy metals pollution revealed that most of the arable layer soil in Baiyin District was at security level, only the central and southeastern parts of the region was at light pollution levels. Finally, the result of grade evaluation of the heavy metal pollution of cultivated land showed: bottom level, safety level, tarnished level, pollution level accounted for 24.83%, 70.33%, 2.72%,