巴里坤-伊吾盆地平原区地下水污染风险评价

开展地下水污染风险评价研究是地下水污染防控的重要环节.以巴里坤-伊吾盆地平原区地下水为研究对象，构建DRSTIW模型进行地下水脆弱性评价；根据污染场地调查资料和土地利用类型划分点源和面源污染，进行地下水污染荷载评价；考虑地下水的原生价值、经济价值和生态价值进行地下水功能价值评价；利用ArcGIS的地图代数功能生成地下水污染风险评价图，采用ROC曲线验证地下水污染风险评价结果，通过计算G指数得到地下水污染风险空间冷热点分布，结合重心和标准差椭圆对热点变动情况进行定量分析.结果表明，研究区地下水污染风险整体较低，高污染风险区和较高污染风险区仅占研究区总面积的6.8%，主要位于伊吾县的淖毛湖镇、盐池镇，巴里坤县的奎苏镇、石人子乡、花园乡和兵团红山农场，该区域内地下水埋深较浅，土壤表层和包气带介质透水性能较强，吸附能力较差，加之污染源分布较集中，使得污染物易于迁移富集，在地下水高脆弱性和高污染荷载的双重作用下导致局部区域地下水污染风险升高.受人类活动影响，地下水污染风险在空间上存在一定的集聚现象，整体表现为由西北向东南演变的趋势.地下水污染风险评价结果为划分地下水污染防治区提供重要参考.

Groundwater Pollution Risk Assessment in Plain Area of Barkol-Yiwu Basin

Groundwater pollution risk assessment is an important part of groundwater pollution prevention and control. Taking groundwater in the plain area of Barkol-Yiwu Basin as the research object, the DRSTIW model was constructed to evaluate groundwater vulnerability. According to the survey data of contaminated sites and land use types, point source and non-point source pollutions were classified, and the groundwater pollution load was evaluated. The primary value, economic value, and ecological value of groundwater were considered to evaluate the functional value of groundwater. The groundwater pollution risk assessment map was generated by using the map algebra function of ArcGIS software. The ROC curve was used to verify the risk assessment results of groundwater pollution. The spatial distribution of cold and hot spots of groundwater pollution risk was obtained by calculating the G index, and the change in hot spots was quantitatively analyzed by combining the center of gravity and standard deviation ellipse. The results showed that the groundwater vulnerability was generally low. The gentle terrain slope, shallow groundwater depth, and strong aquifer permeability made it easy for pollutants to enter the aquifer, resulting in high groundwater vulnerability in the northwest of Santanghu Town, the southeast of Dahongliuxia Township, and Kuisu Town in Barkol County. The groundwater pollution load and groundwater functional value were generally low, whereas the point source and non-point source pollution caused by industrial and agricultural production and life would increase the groundwater pollution load in local areas, and the human economic activities and habitat quality levels would affect the distribution of high groundwater function value areas. Groundwater pollution risk was generally low; very high and high pollution risk areas only accounted for 6.8% of the study area, mainly distributed in Naomaohu Town and Yanchi Town of Yiwu County, Kuisu Town, Shirenzi Township, Huayuan Township of Barkol County, and Hongshan Farm of Corps. The shallow groundwater depth, strong permeability of soil surface and vadose zone media, poor adsorption capacity, and concentrated distribution of pollution sources made it easy for pollutants to migrate and enrich in these areas. Under the dual influence of high vulnerability and high pollution load of groundwater, the risk of groundwater pollution in local areas increased. Affected by human activities, there was a certain spatial agglomeration of groundwater pollution risk, and the overall trend was from northwest to southeast. The results of groundwater pollution risk assessment provided a scientific reference for the division of groundwater pollution prevention and control areas.