河南永城市日月湖治理区水化学和氘氧同位素特征

The analyses of deuterium oxygen isotope and hydrogeochemical characteristics at Riyue Lake Restoration Zone,Yongcheng City,Henan Province

河南省永城市日月湖生态景区治理工程在给永城市人民带来一个优美生态环境的同时,治理区地形、微地貌、水文及水文地质等条件也发生了变化,尤其是开挖后浅层地下水直接出露地表形成湖水,其水质相比之前埋藏于地下会发生改变。论文在阐述永城市日月湖景区水文地质条件的基础上,重点分析了治理区湖水、河水和浅层地下水的水化学和氘氧同位素特征。分析结果表明,湖水的水化学类型为HCO3-SO4-Na(Mg)型;河水水化学类型以SO4-HCO3-Na型为主;浅层地下水的水化学类型为HCO3-Na-Mg型或HCO3-Mg-Na型,个别水样中Cl-含量较高,水化学类型为HCO3-Cl-Na(Mg,Ca)。湖水和地下水的水化学类型更接近,说明浅层地下水是湖水的重要补给来源。河水的TDS最高,浅层地下水TDS其次,湖水的TDS相对最低。研究区不同水体的氘氧同位素的分析结果说明,湖水受蒸发作用影响同位素富集;河水氘氧同位素与降水和地下水比较接近,其补给来源为大气降水和地下水;地下水除接受大气降水补给及雨季受河水补给外,还接受区域较高处的侧向径流补给,既有近源补给,也有远源补给。

While the restoration project of the Riyue Lake Ecological Scenic Spot in Yongcheng City,Henan Province provided essential environmental benefits to local residents,conditions in the area including topography,land use,hydrology,and hydrogeology had changed. For instance,excavation activities forced shallow groundwater to the surface,contributing to the formation of lake water and causing water quality change. On the basis of establishing hydrogeological conditions of the Riyue Lake area,this paper focuses on analyzing the hydrogeochemistry,hydrogen and oxygen isotopic characteristics of different types of water,including lake water,river water,and shallow groundwater. The result shows that the lake water features HCO3-SO4-Na( Mg) hydrochemical type,the river water mainly features SO4-HCO3-Na type,and the shallow groundwater features HCO3-Na-Mg type or HCO3-Mg-Na type. Individual water sample contains high level of Cl-concentration and is HCO3-Cl-Na( Mg,Ca) hydrochemical type. Among the results,the hydrochemical characteristics between lake water and groundwater are closely associated,suggesting that the shallow groundwater essentially supplies the recharge of lake water. River water has the highest TDS,followed by shallow groundwater TDS,and lake water has the lowest TDS. The analysis of hydrogen and oxygen isotopes in different types of water suggests that isotope enrichment in lake water is affected by evaporation. Moreover,the isotope types identified in river water are similar to isotope types in rain precipitation water and groundwater,suggesting the latter two as sources of river water. In addition to receiving recharge from atmospheric precipitation and seasonal river water,groundwater also receives lateral runoff recharge from remote higher area,which includes both near-source and remote-source.