氢氧同位素组成对丰沛平原区水循环的指示意义  

Indicative Significance of Hydrogen and Oxygen Isotopic Composition of Water Bodies in the Fengpei Plain to Water Cycle and Evaporation

作　　者：赵祥宇 陈菁[1] 王收 陈丹[1] 周娇 ZHAO Xiangyu;CHEN Jing;WANG Shou;CHEN Dan;ZHOU Jiao(College of Agricultural Science and Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学农业科学与工程学院,南京210098

出　　处：《地球与环境》2024年第1期86-95,共10页Earth and Environment

基　　金：安徽省自然科学基金水科学联合基金重点项目(2208085US09)。

摘　　要：丰沛平原区包括丰县、沛县与铜山区北部,近年来该地区出现地下水超采、地下水氟污染等严重的问题。为调查该地区水循环情况,采集了地表水与地下水样品共28个,分析了氢氧同位素组成的分布规律及其影响因素,并讨论了丰沛平原区浅层地下水与地表水转化关系以及各自的蒸发损失情况。研究结果表明:大气降水的云下二次蒸发程度较小,地下水的蒸发比附近地区更强烈。地下水同位素含量呈现总体沿地下径流方向逐渐富集的趋势,且地下水^(18)O与CO_(2)存在微弱的交换作用导致^(18)O贫化。结合水文地质调查与氢氧同位素特征,推断出河流中上游更倾向于地下水补给地表水,河流下游地表水对地下水大量渗漏。利用两端元法计算得出,总体上地表水受到地下水补给的比例为20%~40%左右,部分地区补给比例达60%以上。河流下游河水对地下水的补给比例大多介于25%~50%不等,部分点位可达90%。采用非平衡分馏条件下的Rayleigh模型计算蒸发比例,河水的蒸发损失约为23%~28%,地下水蒸发损失约为15%~20%。结果可为丰沛平原区及周边相似地区的水资源管理提供科学参考。Fengpei Plain area includes Fengxian County,Peixian County and the northern part of Tongshan District.In recent years,groundwater overdraft and serious fluoride pollution have occurred in this area.In order to investigate the water cycle situation in the region,a total of 28 samples of surface water and groundwater were collected,and the distribution pattern of hydrogen and oxygen isotope composition and its influencing factors were analyzed.The conversion relationship between shallow groundwater and surface water in the abundant plain area,as well as their respective evaporation loss ratios,were discussed.The research results indicate that the degree of secondary evaporation under clouds in atmospheric precipitation is relatively small,groundwater evaporate more strongly than nearby areas.The isotope content of groundwater is gradually enriched along the direction of groundwater runoff,and there is a weak exchange interaction between ^(18)O and CO_(2) in groundwater,leading to ^(18)O depletion.Combined with the hydrological geological survey and hydrogen and oxygen isotope characteristics,it is inferred that the groundwater in the middle and upper reaches of the river is more inclined to supply surface water,and the surface water in the lower reaches of the river leaks a lot to groundwater.It is calculated by the two end member method that the overall proportion of surface water recharged by groundwater recharge is about 20%-40%,even more than 60% at some areas.Most of the recharge ratio of the downstream river water to groundwater ranges from about 25% to 50%,with some points reaching up to 90%.Using the Rayleigh model under non equilibrium fractionation conditions to calculate the evaporation ratio,the evaporation ratio of river water is about 23%-28%,and the evaporation loss of groundwater is about 15%-20%.The results can provide scientific reference for water resource management in the Fengpei Plain area and similar surrounding areas.

关 键 词：氢氧同位素 水循环 蒸发 丰沛平原区 地下水 地表水 

分 类 号：X143[环境科学与工程—环境科学]