基于多层次集对分析的退役铀尾矿库区浅层地下水污染风险评价

退役铀尾矿库区浅层地下水污染风险评价体系存在不足。根据库区污染物的垂向迁移过程划分3个理想层并逐层进行污染风险分析,整合常用地下水污染风险的评价方法建立评价指标体系。为降低评价系统的不确定性,在采用层次分析法确定各层指标权重的基础上,由指标层确定系统层的综合指数,将该综合指数当作观测值通过直线形测度函数确定系统层未知测度评价矩阵,由此建立了污染风险评价等级与集对分析联系数的对应关系,并进行集对势分析呈现风险态势,构建退役铀尾矿库区浅层地下水污染风险评价体系。通过评价实例验证了构建的退役铀尾矿库区浅层地下水污染风险评价体系可行,评价结果属于中等污染风险等级,且集对势分析结果表明实际系统的污染风险态势较低。

Multilevel set-pair analysis for groundlayer surface water pollution risk in the uranium-rejected tailing reservoir

Considering the inadequacy of the risk assessment system of the shallow groundwater pollution in the rejected uranium tailing reservoir area,the present paper attempts to divide the pollution process into 3 proper layers in accordance with the vertical migration or sinking of the pollutants below the surface of the area and then begins to analyze its pollution risk layer by layer. Since the pollution risk assessment index system can be used for the purpose by integrating the common methods of the risk assessment of the shallow groundwater pollution to reduce the uncertainty of the evaluation system by using an improved assessment method in the following 3 parts. The first part is to calculate the composite index of each factor of the system layer by multiplying the score of each index with its corresponding weight which can be determined through the analytic hierarchical process (short for AHP),while the second part is to determine the unascertained measure evaluation matrix of the system layers. Based on the aforementioned five evaluation levels,it would be possible to find each element data in the evaluation matrix,the data value of the composite index can be taken as the linear unascertained function of those observed. The last part is to the connection number of the set pair analysis (SPA) which shows the actual level of the pollution risk assessment and the risk situation through the set pair potential analysis. Thus,it would be possible to gain the weights of the system layer's items by AHP with the connection number worked out via the evaluation matrix. Thus,the evaluation sample can help us to find that the value data of the composite index Ri should be equal to 7. 377 7,7. 933 8,3. 832 3 and 7. 748 0,respectively. Once the risk is divided into five grades,it would be possible to gain a 5-element connection number whose value is 0. 036 7,which means the pollution risks belongs to the third grade. At the same time,it can be determined that the risk evaluation system of the shallow groundwater pollution in the rejected uranium tailing reservoir we have adopted proves to be feasible. And,finally,the set pair potential e ＞ 1,indicates that the pollution risk of the actual system turns out to be rather low.