青海湖夏季水化学特征及其影响因素  

Hydrochemical characteristics and influencing factors of the Qinghai Lake in summer

作　　者：柴思帆 卜玉强 卜红梅[1,2] CHAI Sifan;BU Yuqiang;BU Hongmei(Key Laboratory of Water Cycle and Related Surface Processes,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing,100101,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing,100049,China;Forestry and Grassland Bureau of Inner Mongolia Autonomous Region,Hohhot,010020,China)

机构地区：[1]中国科学院地理科学与资源研究所陆地水循环及地表过程院重点实验室,北京100101 [2]中国科学院大学资源与环境学院,北京100049 [3]内蒙古自治区林业和草原局,呼和浩特010020

出　　处：《环境化学》2025年第1期199-211,共13页Environmental Chemistry

基　　金：第二次青藏科考专项(2019QZKK0403);国家重点研发计划项目(2019YFA0607102)资助。

摘　　要：为探明夏季青海湖湖周水体的水化学特征及其影响因素,本研究采用统计方法,结合Piper三线图、Gibbs图和离子比值法,分析了青海湖夏季水体离子空间分布差异特征、水化学特征和水体氢氧同位素特征,从而揭示了自然过程和气候条件对青海湖水化学特征的影响.结果表明:(1)青海湖夏季水体理化指标及其离子含量具有空间变化特征.布哈河入湖口和尕海处的离子含量与主湖区差异明显.与历史同期相比,夏季湖水中的pH、TDS和EC值有所降低;与冬季和封冻期湖水相比,青海湖夏季湖水中EC、TDS的含量升高,Cl^(−)、Mg^(2+)、Na^(+)和K^(+)的含量也分别升高了2.02 g·L^(−1)、0.36 g·L^(−1)、1.9 g·L^(−1)、0.097 g·L^(−1),而Ca^(2+)含量则降低了1.9 mg·L^(−1).各变量之间的相关分析结果表明,青海湖夏季湖水水化学组成受蒸发浓缩作用和岩石条件的影响,而盐度对水化学特征影响较大.(2)青海湖夏季水体的水化学类型为NaCl型,湖水中Na^(+)/(Na^(+)+Ca^(2+))和Cl^(−)/(Cl^(−)+HCO_(3)^(−))的均值分别为0.99和0.87,表明青海湖夏季水中离子主要受蒸发结晶作用控制;离子之间的线性回归分析表明,布哈河入湖口处的(Na^(+)+K^(+))/(Ca^(2+)+Mg^(2+))值最低,表明该处水化学主要受碳酸盐风化作用影响,而其他点位处的水化学主要受蒸发结晶作用影响.(3)青海湖夏季水中δD和δ18O值(−42.2‰—11.5‰和−6.78‰—2.31‰)的分布特征和氘盈余值(d-excess=−6.98‰—12.1‰)表明,布哈河入湖口处(d-excess=12.1‰)受当地降水的影响较为强烈,而其他采样点处湖水中的δD和δ18O值受蒸发结晶作用影响较大;尕海的δD和δ18O值(分别为−4.80‰和0.15‰)相比其他点位较低,可能是受到底部地下水补给的影响.该研究为青海湖流域水环境保护和生态治理提供了科学决策依据.In order to investigate the hydrochemical characteristics and influencing factors of the water around the Qinghai Lake in summer,this study analyzed the spatial distribution differences of water ions,hydrochemical characteristics and the stable isotopic compositions(δD andδ18O)of lake-water in the Qinghai Lake in summer by using statistical methods and combining with Piper's trilinear diagram,Gibbs diagram and ion ratio method,thus revealing the influence of natural processes and climatic conditions on the hydrochemical characteristics.The results showed that:(1)The physical and chemical indicators and ion contents in the water of Qinghai Lake in summer had spatial differences.The ionic contents at the inlet of the Buha River and the Gahai are distinctly different from that of the main lake.The pH,TDS and EC values in the lake water in summer were lower than that in the same period of history.Compared with the lake water in winter and during the freeze-up period,the contents of EC and TDS were elevated in the summer lake water of Qinghai Lake,as well as the contents of Cl^(−),Mg^(2+),Na^(+)and K^(+)were elevated by 2.02 g·L^(−1),0.36 g·L^(−1),1.9 g·L^(−1)and 0.097 g·L^(−1),respectively,while the content of Ca^(2+)was reduced by 1.9 mg·L^(−1).The correlation analysis between the variables showed that the hydrochemical composition of the summer lake water in Qinghai Lake was influenced by evapotranspiration and concentration and rock conditions,while salinity had a greater influence on the hydrochemical characteristics.(2)The hydrochemical type of the Qinghai Lake in summer was NaCl type.The mean values of Na^(+)/(Na^(+)+Ca^(2+))and Cl^(−)/(Cl^(−)+HCO_(3)^(−))were 0.99 and 0.87,indicating that the water of the lake in summer were mainly controlled by evaporation and crystallization.The linear regression analysis between ions showed that the(Na^(+)+K^(+))/(Ca^(2+)+Mg^(2+))value at the inlet of the Buha River was the lowest among the sampling sites,indicating that the hydrochemistry at the sa

关 键 词：青海湖 水化学特征 影响因素 

分 类 号：X-1[环境科学与工程] O6[理学—化学]