典型石灰岩区地下水污染途径分析

Analysis of groundwater pollution pathways in typical limestone areas

贵州岩溶山区具有典型“双重”空间结构,以贵州某填埋场地区域的地下水系统为研究单元,从水文地质结构角度出发,通过收集控制点、水文地质钻探、地下水位及水质动态监测数据,并综合典型受污染地下水系统的环境水文地质数据,研究典型石灰岩区地下水污染的途径,重点针对污染物进入潜水地下水途径进行分析论证。结果表明:按照自上而下的水文地质空间结构情况,填埋场污染物进入潜水地下水的途径可归纳为4大途径6个亚途径,各途径污染物运移介质分别为大气降水-渗滤液、大气降水-表层岩溶水、大气降水-表层岩溶水-渗滤、渗滤液、表层岩溶水-潜水和潜水;其中以大气降水作为污染物运移介质的污染途径均具有间歇性,而潜水饱水带内完成的污染物迁移、运移途径(途径4)是该类石灰岩区地下水污染的重要途径。研究结论为岩溶山区地下水污染治理提供依据。

Guizhou karst mountainous area has a typical"dual"spatial structure.Taking the groundwater system of a land-fill site in Guizhou as the study unit,the research unit is based on the hydrogeological structure,collecting control points,hydrogeological drilling,groundwater level and water quality dynamic monitoring data,and integrating the environmental hydrogeological data of typical contaminated groundwater systems to study the pathways of groundwater pollution in typical lime-stone areas,focusing on the analysis and demonstration of the pathways of pollutants into submerged groundwater.The results show that,according to the top-down hydrogeological spatial structure,the landfill contaminants enter submerged groundwa-ter through four major pathways and six subpathways,and the contaminant transport media for each pathway are atmospheric precipitation-leachate,atmospheric precipitation-surface karst water,atmospheric precipitation-surface karst water-percolation,leachate,surface karst water-submerged and submerged,respectively;The contamination pathways that use at-mospheric precipitation as a contaminant transport medium are all intermittent in nature,while the contaminant migration and transport pathway(pathway 4)completed within the submerged water-filled zone is an important pathway for groundwater contamination in this type of limestone area.The findings of the study provide a basis for groundwater pollution management in karst mountains.