[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 SO42-. 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+, SO42-, Fe, and Mn.