基于水化学和氢氧同位素的东宫河流域不同水体转化关系研究

Transformation Relationship of Different Water Body in Donggong River Basin Based on Hydrochemistry and Hydrogen-Oxygen Isotopes

为明晰秦皇岛东宫河流域水环境特征,以该流域大气降水、地下水及地表水为研究对象,通过对水化学和氢氧稳定同位素样品测试及特征分析,揭示其时空变化特征及大气降水、地下水和地表水的相互转化关系.结果表明:①东宫河流域地下水(第四系孔隙水、岩溶水、裂隙水)和地表水(河水、泉水)的水化学类型,枯水期较丰水期丰富.丰水期水化学类型主要以HCO3-Ca型、HCO3·SO4-Ca型和HCO3-Ca·Mg型为主;枯水期水化学类型以HCO3-Ca型、HCO3-Ca·Mg型、HCO3·SO4-Ca型、HCO3·SO4-Ca·Mg型为主.②研究区第四系孔隙水和泉水的离子含量变化受季节影响较大,枯水期离子含量变化较丰水期显著;岩溶水和裂隙水各离子含量变幅较小,基本趋于稳定.岩溶含水层和裂隙含水层中富含石膏,为SO42-的主要来源;Na^+和Cl^-主要来源于易溶解盐NaCl,Ca^2+和Mg^2+主要来源于方解石的风化溶解.③东宫河流域地下水、地表水及大气降水之间存在密切的水力联系,针对氢氧同位素的组成分析表明,大气降水为地下水和河水的主要来源;不同泉水补给来源存在差异性,泉水主要接受岩溶水补给,同时也受蒸发作用影响;第四系孔隙水接受大气降水和河水的双重补给;裂隙水主要接受山区降水径流补给.研究显示,东宫河流域不同水体中离子含量受降雨量、温度和地质背景等影响,不同水体间联系密切,相互补给排泄.

In order to ascertain the water environment characteristics of the Donggong River Basin in Qinhuangdao,the atmospheric precipitation,groundwater and surface water in this basin were taken as the research objects.Through the analysis of its water chemistry and hydrogen-oxygen stable isotopic characteristics,the characteristics of its temporal and spatial changes and the characteristics of atmospheric precipitation,groundwater and surface water are revealed.The results show that:(1)The water chemistry of groundwater(Quaternary pore water,karst water,fissure water)and surface water(river water,spring water)in the Donggong River Basin are more abundant in dry periods than in wet periods.The water chemistry types in the rich season are HCO3-Ca type,HCO3·SO4-Ca type and HCO3-Ca·Mg type mainly;the water chemistry types in the dry season are HCO3-Ca type,HCO3-Ca·Mg type,HCO3·SO4-Ca type,HCO3·SO4-Ca·Mg type mainly.(2)The change of ion content in Quaternary pore water and spring water in the study area is greatly affected by the season,and the change in ion content in dry season is more significant than in wet season;the ions in karst water and fissure water have a small change range and tend to be stable.The karst aquifer and bedrock fissure aquifer are rich in gypsum,which is the main source of SO42-;Na^+and Cl^-mainly come from the easily soluble salts NaCl,Ca^2+and Mg^2+mainly come from the weathering dissolution of calcite.(3)There is a close hydraulic relationship between groundwater,surface water and atmospheric precipitation in the Donggong River Basin,analysis of the composition of hydrogen and oxygen isotopes shows that atmospheric precipitation is the main source of groundwater and river water,and the spring water mainly comes from karst water replenishment and is affected by evaporation;pores water receives dual recharges from atmospheric precipitation and river water;fissure water is mainly recharged from mountain runoff.The studies have shown that the ion content in different water bodies of the Donggong River Basin is affected by rainfall,temperature and geological background.Different water bodies are closely connected and complement each other for excretion.