基于复合指数法的土壤重金属污染评价

Assessment of Soil Heavy Metal Pollution Based on Compound Index Method

土壤重金属污染评价是土壤重金属污染防治的重要依据。常用的单因子指数法无法直观反映综合污染状况。为了更为有效、合理地开展土壤重金属评价工作,采用复合指数法对研究区进行评价,该方法通过将单因子指数法评价结果进行空间叠加处理分析,可得到复合种类指数和复合等级指数。复合种类指数可以表示存在污染的元素种类和复合污染的区域,复合等级指数表示复合污染的程度。结果表明:该研究区复合污染的面积依次为:单元素污染>双元素污染>三元素污染>四元素污染。其中单一污染物为As,双元素复合污染物分别为As、Cd或As、Hg;三元素复合污染物分别为As、Cd、Hg或As、Cd、Pb或As、Hg、Pb;四元素复合污染物分别为AS、Cd、Hg、Pb。各程度的污染面积由大到小依次为:轻度污染>中度污染>重度污染。当地复合污染问题较为严重,政府部门应尽快采取措施进行治理。复合指数法能更为全面、客观、综合的反映评价区的实际污染状况,应加以推广和利用。

The assessment of soil heavy metal pollution is an important evidence and guidance for soil heavy metal pollution prevention and control.The commonly used single factor index method cannot directly reflect the comprehensive pollution status.In order to carry out the evaluation of soil heavy metal more effectively and reasonably,the compound index method was used to evaluate the soil heavy metal contamination level of the study area.Compound type index and compound level index can be obtained by calculation.The compound type index can indicate the types of contaminated elements and the area of composite pollution.The compound level index indicates the degree of compound contamination.The results show that the area of compound contamination in the study area is single element pollution>dual elements pollution>three elements pollution>four elements pollution.Among them,the Single element pollutant is As,the dual elements compound pollutants are As and Cd or As and Hg,the three elements compound pollutants are As,Cd and Hg or As,Cd and Pb or As、Hg and Pb,the four elements compound pollutants are AS,Cd,Hg and Pb.The pollution area of different levels is slight pollution>moderate pollution>heavy pollution.The compound pollution problem of this area is serious.And the government should take measures to solve the problem as soon as possible.The compound index method can reflect the regional soil environmental quality more objectively and reasonably.It is suggested that it should be popularized and used in practical work.