区域地下水污染预警：以巴伊盆地平原区为例

地下水污染预警是区域地下水污染防治的有效手段. 将地下水水质现状、地下水水质变化趋势和地下水污染风险三者耦合的地下水污染预警模型应用于巴里坤-伊吾盆地平原区,实现地下水水质状态预警和趋势预警相结合的区域尺度地下水污染预警研究. 采用基于综合权重的TOPSIS法进行地下水水质现状评价,通过计算得出的18眼原位地下水水质监测井的趋势度插值结果分析地下水水质变化趋势,利用迭置指数法将地下水脆弱性图、地下水污染荷载图和地下水功能价值图空间叠加得到地下水污染风险分布图. 结果表明,研究区地下水水质以良好和较好为主,且2011~2022年间呈稳定状态,地下水污染风险整体较低. 地下水污染预警级别整体较低,重警和巨警区分别占研究区总面积的16.4%和17.5%,主要分布在伊吾县的下马崖乡和巴里坤县的三塘湖镇北部、大红柳峡乡、大河镇,区域内出露的第四系沉积物以砂卵砾石为主,孔隙发育,透水性强,对污染物的截留和吸附能力较弱,工农业和生活产生的污染物易渗漏至地下水含水层,造成地下水水质较差和地下水污染风险较高,最终导致部分区域地下水污染预警级别高. 地下水污染预警研究为开展地下水污染修复提供重要的理论依据.

Early Warning of Regional Groundwater Pollution： A Case Study for Plain Area of Barkol-Yiwu Basin

Groundwater pollution early warning is an effective means for regional groundwater pollution prevention. The groundwater pollution early warning model coupled with the current situation of groundwater quality, groundwater quality variation trend, and groundwater pollution risk were applied to the plain area of Barkol-Yiwu Basin, and the regional scale groundwater pollution early warning was realized by combining the early warning of groundwater quality status and trend. The TOPSIS method based on comprehensive weight was used to evaluate the current situation of groundwater quality. The variation trend of groundwater quality was analyzed by calculating the trend interpolation results of 18 in-situ groundwater quality monitoring wells. The groundwater vulnerability map, groundwater pollution load map, and groundwater function value map were superimposed using the superposition index method to evaluate groundwater pollution risk. The results showed that the groundwater quality was good and relatively good, and the poor groundwater quality in some areas was mainly affected by the shallow groundwater depth and the large porosity of the vadose zone. Groundwater quality was stable from 2011 to 2022, mainly due to the leakage of wastewater generated by industries and agriculture into groundwater, resulting in the deterioration of groundwater quality in some areas. Groundwater pollution risk was generally low, and the dual effects of high vulnerability and high pollution load of groundwater led to local areas with high pollution risk. The early warning level of groundwater pollution was generally low, and the heavy and highly heavy warning areas accounted for 16.4% and 17.5% of the study area, respectively, mainly distributed in Xiamaya Township of Yiwu County and northern Santanghu Town, Dahongliuxia Township, and Dahe Town of Barkol County. The quaternary sediments exposed were mainly sandy pebbles, with developed pores and strong water permeability. The interception and adsorption capacity of pollutants were weak. Pollutants produced by industries, agriculture, and life easily leaked into groundwater aquifers, resulting in poor groundwater quality and high risk of groundwater pollution, which ultimately led to a high early warning level of groundwater pollution in some areas. The research on early warning of groundwater pollution provided an important theoretical basis for the development of groundwater pollution remediation.