水化学和环境同位素对济南东源饮用水源地地下水演化过程的指示

济南东源水源地属于岩溶裂隙水,是济南市的主要供水水源.以济南市东源水源地为研究区,通过对研究区地下水和地表水的主要离子含量、氢氧同位素比值分析,揭示了东源饮用水源地地下水的补给来源、地表水的影响及水岩作用过程.结果表明,区内地下水水化学类型相似,阳离子以Ca~(2+)为主,阴离子以HCO_3~-和SO_4~(2-)离子为主;大气降水是该地区地下水和河水的主要补给来源,且经历了不同程度的蒸发作用.地下水化学组分主要受水-岩作用的控制,方解石和石膏等贫镁矿物的溶解沉淀以及上覆第四系地层硅酸盐矿物的水解是区内地下水水化学组分的主要来源;部分地段河水污染渗漏补给地下水,造成地下水污染,主要超标指标为总硬度、NO_3~-、NH_4~+、SO_4~(2-)、Fe和Mn.

Indicators of Groundwater Evolution Processes Based on Hydrochemistry and Environmental Isotopes: A Case Study of the Dongyuan Drinking Water Source Area in Ji'nan City

The Dongyuan groundwater source area, which is the main drinking water source of Ji''nan City, is karst fissure water. To identify groundwater recharge sources, the influence of surface water, hydrochemical evolution, hydrochemical and isotopic components (²H and ¹⁸O) of groundwater and surface water samples collected from the Dongyuan groundwater source were investigated.The results showed that the hydrochemical characteristics of groundwater were similar, and the main ions were Ca²⁺, HCO₃^-, and SO₄^2-. The groundwater, which suffered evaporation to varying degrees, was recharged mainly by precipitation. The hydrochemical composition of regional groundwater is mainly controlled by water-rock interactions, including dissolution/precipitation of carbonate minerals in the limestone aquifers and hydrolysis of silicates minerals in the quaternary aquifers, above the limestone aquifers. In some areas, groundwater was polluted by infiltration of river water. The main indicators of groundwater pollution that exceeded groundwater quality standards were total hardness, NO₃^-, NH₄⁺, SO₄^2-, Fe, and Mn.