基于水化学和氢氧同位素的兴隆县地下水演化过程研究

地下水的补给来源及其水-岩作用过程研究对于识别地下水水化学成分的形成机制、合理开发利用和地下水污染防治具有重要意义。为了了解兴隆县地区地下水水质及其水源涵养条件，为区域地下水污染防治和饮用水源安全提供支持，论文基于兴隆县地下水的水化学和氢氧稳定同位素（δD和δ18O）特征，综合利用Gibbs图解、主要离子比值和统计分析方法，深入讨论了兴隆县地下水的水化学特征、补给来源和水文地球化学演化过程。研究结果表明，兴隆县地下水呈弱碱性，主要为HCO₃—Ca·Mg型水，总溶解固体（TDS）变化范围为52.2~556.8 mg/L，平均值为238.0 mg/L；地下水主要来源于大气降水补给，蒸发作用对地下水水化学组分的影响较小；区域地下水的水化学组分主要受碳酸盐岩组成矿物白云石和方解石的溶解-沉淀过程的控制，受上覆铝硅酸盐矿物水解影响不大；区域东部和南部地下水Sr2+含量较高，推测碳酸盐岩下伏侵入岩及古老变质岩分布对Sr2+富集有一定影响；地表水和地下水水力联系密切，部分区域地下水受人类活动影响，造成地下水NO₃-含量超过饮用水卫生标准限值。

Evolutional processes of groundwater in Xinglong County based on hydrochemistry and hydrogen and oxygen isotopes

The study of the hydrochemical characteristics and water-rock interaction processes of groundwater is of important significance in the evolutional processes, rational development and utilization of groundwater and the prevention of groundwater pollution. This research aims to investigate the groundwater quality and its water conservation conditions in Xinglong County, and to provide support for regional groundwater pollution prevention and safety of drinking water supply sources. Based on hydrochemical and hydrogen-oxygen stable isotope analyses, the hydrochemical characteristics, recharge sources and hydrogeochemical evolutional processes of groundwater in Xinglong County were discussed in detail. The results show that the main hydrochemical type of groundwater is of HCO₃-Ca·Mg type in Xinglong County. The groundwater is mainly recharged by precipitation, and is less affected by evaporation. The Gibbs diagram, major ion ratio method and correlation analysis show that the hydrochemical compositions are mainly controlled by the weathering and dissolution of carbonate rocks such as calcite and dolomite, and is less controlled by silicate dissolution. The content of strontium in groundwater in the east and south of the study area is significantly higher than that in the west, indicating that it may be affected by intrusive dykes and metamorphic rocks. In some areas, groundwater is affected by human activities, resulting in excessive concentration of NO₃- in groundwater. The study may provide an indication of the hydrochemical evolution of regional groundwater and offer technical support for drinking water safety.