危险废物填埋场地下水污染风险评价中指标权重计算方法优化比选

为了探究适用于危险废物填埋场地下水污染风险评价的指标权重计算方法，选用层次分析法、熵权法、层次分析-熵权法进行计算，并通过我国37家危险废物填埋场地下水污染风险评价结果与地下水中苯浓度的拟合验证对权重计算方法进行分析比选.结果表明:①3组权重计算结果中，含水层渗透系数和包气带渗透系数均为最重要的指标，危险废物填埋场所处地层介质类型是影响地下水污染风险最显著的因素.在建设危险废物填埋场时，选址需优先关注含水层及包气带介质类型，必要时应采取更高性能的防渗技术手段；②3组场地风险指数（R）和污染指数（C）线性拟合R2值排序为层次分析-熵权法（R2=0.84）>层次分析法（R2=0.75）>熵权法（R2=0.51），因此采用层次分析-熵权法得出的危险废物填埋场地下水污染风险评价结果与实际污染状况匹配度更高，构建的风险评价方法更能准确预测地下水污染风险；③当各指标权重由大到小依次加和至总权重为0.96时，层次分析-熵权法可包含12项指标，且权重分配更为均衡，不易受到单个指标缺失的影响，由此建立的综合指数计算方法更加可靠.研究显示，层次分析-熵权法是更适用于危险废物填埋场地下水污染风险评价的指标权重计算方法，构建的污染风险评价方法结果准确、易操作，在一定程度上可为危险废物填埋场地下水污染的风险评价及运行管理提供支持. 

Optimized Comparison and Selection of Index Weight Calculation Methods in Hazardous Waste Landfill Site Groundwater Pollution Risk Assessment

The index weight calculation method, including the analytic hierarchy process, entropy weight method, and analytic hierarchy process-entropy weight method, were applied to the risk assessment of groundwater pollution in hazardous waste landfill sites. A fitting comparison was made between the groundwater pollution risk assessment results of 37 hazardous waste landfills nationwide and the groundwater benzene concentration. Among the three sets of weight calculation results, the permeability of aquifers and vadose zones are the most important indicators, and the type of underlying stratum medium in the hazardous waste landfill sites is the most significant factor affecting the risk of groundwater pollution. When constructing a hazardous waste landfill site, priority should be given to the types of media of aquifers and vadose zones, and enhanced performance of anti-seepage technical measures should be conducted when necessary. The linear fitting R2 values between site risk index R and pollution index C of the three groups are ranked as follows: analytic hierarchy process-entropy method (R2=0.84)>analytic hierarchy process (R2=0.75)>entropy method (R2=0.51). The results of the hazardous waste landfill groundwater pollution risk assessment obtained by the analytic hierarchy process-entropy method are more closely matched to the actual pollution status. Based on this, the risk of groundwater pollution can be more accurately predicted. When the weights of each index are added up from the highest to lowest to reach a total weight of 0.96, the analytic hierarchy process-entropy method can contain 12 indexes, and the weight distribution is more balanced, and it is not easily affected by the lack of a single index. The comprehensive index calculation method developed is more reliable. This study shows that the analytic hierarchy process-entropy method is a more suitable method for groundwater pollution risk assessment of hazardous waste landfill sites. The developed pollution risk assessment method is accurate and easy to operate. To a certain extent, it can support the risk assessment and operation management of groundwater pollution in hazardous waste landfill sites.