重庆市万州区浅层地下水化学特征及控制因素

Hydrochemical characteristics and possible controls of shallow groundwater in Wanzhou District,Chongqing

浅层地下水作为重庆市万州区居民生活用水和工农业生产用水的主要来源,是推动该区社会经济可持续发展和维持区域生态环境稳定的重要保障.为研究重庆市万州区浅层地下水化学特征及控制因素,于2021年10月采集浅层地下水样品56组.综合运用数理统计、Piper三线图、Gibbs图、离子比例关系、Pearson相关性分析、因子分析和水文地球化学模拟等方法,对万州区浅层地下水化学特征、离子来源和控制因素进行分析.结果表明,研究区浅层地下水以淡软水为主,且呈弱碱性,阴阳离子以HCO^_(3)^(-)、Ca^(2+)为主,浅层地下水类型以HCO_(3)-Ca为主;由研究区中部至边缘地区,阴离子类型由HCO_(3)型向HCO_(3)·SO_(4)、HCO_(3)·Cl·SO_(4)和Cl·SO_(4)型演变,阳离子类型由Ca型向Ca·Mg、Na·Ca和Na·Ca·Mg型演变;浅层地下水离子主要来源于碳酸盐岩、硅酸盐岩和岩盐溶滤;浅层地下水化学组分受岩石溶滤作用、正向阳离子交换作用和人类活动作用控制;水文地球化学模拟结果表明,沿浅层地下水流向,浅层地下水离子浓度呈递增趋势,岩盐、方解石和白云石均发生溶解,西部浅层地下水的阳离子交换作用强于东部.研究结果可为重庆市万州区浅层地下水资源的合理开发利用、生态环境保护和经济圈的建设提供科学依据.

Shallow groundwater,as the main source of domestic water and industrial and agricultural production water for residents in Wanzhou District,Chongqing,is an important guarantee for promoting the sustainable socio-economic development of the area and maintaining the stability of the regional eco-environment.In order to study the hydrochemical characteristics and control factors of shallow groundwater in Wanzhou District,Chongqing,56 sets of shallow groundwater samples were collected in October 2021.Comprehensive use of mathematical statistics,Ternry diagram,Gibbs diagram,ion proportional relationship,Pearson correlation analysis,factor analysis methods and hydrogeochemical simulation are used to analyze the hydrochemical characteristics,ion sources and control factors of shallow groundwater in Wanzhou.The results showed that:The shallow groundwater in the study area are dominated by fresh and soft water,and it was weakly alkaline,the anions and anions are dominated by 3 and Ca^(2+),and the type of shallow groundwater is dominated by HCO_(3)-Ca;From the middle to the edge of the study area,the types of anions evolve from HCO_(3) to HCO_(3)·SO_(4),HCO_(3)·Cl·SO_(4) and Cl·SO_(4),and the types of cations evolve from Ca to Ca·Mg,Na·Ca and Na·Ca·Mg;The ions of shallow groundwater are mainly originated from filtration of carbonate rocks,silicate rocks and halite;The chemical components of shallow groundwater are controlled by rock dissolution,positive cation exchange and human activities;The results of hydrogeochemical simulation showed that along the flow direction of shallow groundwater,the ion concentration in shallow groundwater was increasing,halite,calcite and dolomite were dissolved,the cation exchange effect of shallow groundwater in the west was stronger than in the east.The research results can provide a scientific basis for the rational development and utilization of shallow groundwater resources,eco-environmental protection and the construction of economic circles in Wanzhou District,Chongqing.