可鲁克湖-托素湖流域水化学和同位素特征研究

Stable Isotope and Hydrochemical Characteristics of Surface Water and Their Indicative Significance in Keluke-Tuosu Lake Basin

为了解可鲁克湖-托素湖流域内淡、咸水转化关系及其离子来源,文章于2017年分别采集了可鲁克湖、托素湖及河水的枯水期和丰水期水样。利用统计学、Gibbs图和离子比值等方法,分析了水体氢氧稳定同位素和水化学演化机制。结果表明:湖水、河水大部分水体均呈弱碱性(pH均值为8.55)和较强的氧化潜力(ORP均值为52.55 mV)。枯水期到丰水期,可鲁克湖由微咸水转为淡水,托素湖由微咸水转为盐水,河水部分淡水转变为咸水,湖泊和河流的水化学类型以Cl·SO_(4)-Na·Ca·Mg和Cl·HCO_(3)-Na型为主。枯水期痕量金属元素(Fe、Mn、As、Ni)超标率大于丰水期。在蒸发强烈和湖身闭塞的影响下,托素湖最终成为内陆咸水湖,其水体氢氧稳定同位素最为富集(δ^(2)H:-47.91‰~8.64‰,δ^(18)O:-34.18‰~43.24‰),可鲁克湖和河水次之。湖泊水化学成分主要受蒸发结晶影响,其次为岩石风化作用,而河水以水-岩相互作用为主;水质优劣依次为可鲁克湖、托素湖和河水,水质参数表现为Na^(+)、Cl^(-)、SO_(4)^(2-)和NO_(3)^(-)。结果旨在为我国西北流域地表水水质保护提供科学依据。

In order to understand the conversion relationship between fresh and brackish water and the source of ions in the Keluke-Tuosu Lake watershed,water samples were collected from Keluke-Tuosu Lake and the river during dry and wet seasons respectively in 2017.By means of statistics,Gibbs plots and ion ratios,the evolution mechanism of hydrogen and oxygen stable isotopes and water chemistry was analyzed.The results show that most of the lake and river water bodies are weakly alkaline(the pH value is 8.55)and strong oxidation potential(the mean OPR was 52.55 mV).Meanwhile,from dry to abundant water,Keluke Lake is converted from brackish water to fresh water,Tuosu Lake is converted from brackish water to salt water,and some freshwater from river water is converted to brackish water,and the hydrochemical type of lakes and rivers is Cl·SO_(4)-Na·Ca·Mg and Cl·HCO_(3)-Na type predominates.The excess rate of trace metal elements(Fe,Mn,As,Ni)in the dry period is greater than that in the abundant period.Under the influence of strong evaporation and occlusion of the lake body,Tuosu Lake eventually became an inland salt water lake,the stable isotopes of hydrogen and oxygen in the water of Tosu Lake were the most abundant(δ^(2)H:-47.91‰~8.64‰,δ^(18)O:-34.18‰~43.24‰),followed by Keluke Lake and river water.The chemical composition of lake water is mainly affected by evaporation crystallization,followed by rock weathering,while river water is dominated by water-rock interaction.The water quality was Keluke Lake,Tuosu Lake and River Water,and the water quality parameters were Na^(+),Cl^(-),SO_(4)^(2-)and NO_(3)^(-).Based on this,the results aim to provide a scientific basis for the protection of surface water quality in the northwest basin of China.