School of Hydropower & Information Engineering, Huazhong University of Science and Technology, Wuhan, PR China.
Key Laboratory of Groundwater Resources and Environment Ministry of Education, Jilin University, Changchun 130021, PR China; College of New Energy and Environment, Jilin University, Changchun 130021, PR China.
Ecotoxicol Environ Saf. 2019 Jun 15;174:649-657. doi: 10.1016/j.ecoenv.2019.03.024. Epub 2019 Mar 12.
Datong basin is one of the most important agriculture zone of Shanxi Province, China, where intensive fertilizer and pesticide applications cause the groundwater contamination. Hence, it is necessary to carry out groundwater specific vulnerability assessment of nitrate. The prediction accuracy of conventional DRASTIC model for groundwater vulnerability assessment is severely limited by the inherent subjectivity in determining main parameters, rating scales and weighting coefficients. This paper attempts to overcome these problems by changing the evaluation parameters, parameters rating and weight calculation method. Based on the hydrogeological conditions and nitrate pollution characteristics of Datong Basin, the traditional groundwater vulnerability model DRASTIC was improved, called DRSTIC-LE model to assess the specific vulnerability of nitrate, which involves Depth of water table (D), Net recharge (R), Soil media (S), Topography (T), Impact of the vadose zone (I), hydraulic Conductivity (C), land use type (L), and groundwater exploitation (E) as evaluation parameters. And the theoretical weight of each parameter were determined with the aid of the improved weights determination method by the effective combination of the entropy weight method and analytic hierarchy process. Moreover, single-parameter sensitivity analysis was performed to evaluate the effect of each parameter on the groundwater specific vulnerability. According to the results of groundwater specific vulnerability map, very high and high vulnerability mainly situated in central, northern and northeastern portion of study area, with 6.25%, 17.93% of total area, respectively. Also, single-parameter sensitivity analysis represented that I and D are the main parameter which impacts groundwater to pollution while C contributes least to pollution in the Datong basin. The model is validated with the measured nitrate concentration and results have shown better correlation between SVI and nitrate concentration. Additionally, by comparing the correlation between the effective weights and the theoretical weights calculated by the three methods (EW, AHP and EW-AHP method), we can see that prediction accuracy of the EW-AHP method is higher than other methods. The research established the efficacy of EW-AHP method as a method of determining weights and provided a basis for regional control of groundwater nitrate pollution.
大同盆地是中国山西省最重要的农业区之一，由于大量施用化肥和农药，导致地下水受到污染。因此，有必要对硝酸盐进行地下水特定脆弱性评估。传统的 DRASTIC 模型在地下水脆弱性评估中的预测精度受到确定主要参数、评分尺度和权重系数固有主观性的严重限制。本文试图通过改变评价参数、参数评分和权重计算方法来克服这些问题。基于大同盆地的水文地质条件和硝酸盐污染特征，对传统地下水脆弱性模型 DRASTIC 进行了改进，称为 DRSTIC-LE 模型，用于评估硝酸盐的特定脆弱性，涉及地下水位埋深（D）、净补给量（R）、土壤介质（S）、地形（T）、包气带影响（I）、水力传导率（C）、土地利用类型（L）和地下水开采量（E）作为评价参数。并借助改进的权重确定方法，利用熵权法和层次分析法的有效结合，确定了各参数的理论权重。此外，还进行了单参数敏感性分析，以评估各参数对地下水特定脆弱性的影响。根据地下水特定脆弱性图的结果，高脆弱性和极高脆弱性主要分布在研究区中部、北部和东北部，分别占总面积的 6.25%和 17.93%。此外，单参数敏感性分析表明，I 和 D 是影响地下水污染的主要参数，而 C 对大同盆地地下水污染的贡献最小。该模型通过实测硝酸盐浓度进行了验证，结果表明，SVI 与硝酸盐浓度之间的相关性较好。此外，通过比较有效权重与三种方法（EW、AHP 和 EW-AHP 方法）计算的理论权重之间的相关性，可以看出 EW-AHP 方法的预测精度更高。该研究确立了 EW-AHP 方法确定权重的有效性，并为地下水硝酸盐污染的区域控制提供了依据。
