新疆喀什噶尔河下游平原区地下咸水中碘形态及碘富集成因  

Iodine Species and Causes of Iodine Enrichment in Saline Groundwater in Plain Area of Lower Reaches of Kashigar River

作　　者：孙英 周殷竹 周金龙[1,2,3] 鲁涵 葛婷婷 纪媛媛 Sun Ying;Zhou Yinzhu;Zhou Jinlong;Lu Han;Ge Tingting;Ji Yuanyuan(College of Water Conservancy and Civil Engineering,Xinjiang Agricultural University,Urumqi 830052,China;Xinjiang Hydrology and Water Resources Engineering Research Center,Urumqi 830052,China;Xinjiang Key Laboratory of Hydraulic Engineering Security and Water Disasters Prevention,Urumqi 830052,China;Center for Hydrogeology and Environmental Geology,CGS,Baoding 071051,China;Xinjiang Agricultural Professional Technological College,Changji 831100,China)

机构地区：[1]新疆农业大学水利与土木工程学院,新疆乌鲁木齐830052 [2]新疆水文水资源工程技术研究中心,新疆乌鲁木齐830052 [3]新疆水利工程安全与水灾害防治重点实验室,新疆乌鲁木齐830052 [4]中国地质调查局水文地质环境地质调查中心,河北保定071051 [5]新疆农业职业技术学院,新疆昌吉831100

出　　处：《地球科学》2024年第2期781-792,共12页Earth Science

基　　金：国家自然科学基金资助项目(No.42067035,42007161);新疆农业大学水利工程重点学科项目(No.SLXK2019-10);“新疆水利工程安全与水灾害防治自治区重点实验室”2021年开放课题(No.ZDSYS-JS-2021-10)。

摘　　要：新疆喀什噶尔河位于典型的干旱-半干旱区,河流下游平原区地下水溶解性总固体(TDS)和碘含量异常,严重威胁当地用水安全.以喀什噶尔河下游平原区为研究区,通过对地下水水化学特征、Cl/Br摩尔比、氢氧稳定同位素、赋存环境与水文地球化学作用的分析确定该区地下咸水中碘的分布与碘富集的影响因素.结果表明,研究区地下水碘含量变化范围为<0.40~435.00μg/L(均值为123.50μg/L),其中潜水和承压水碘含量均值分别为58.75μg/L和188.25μg/L,高碘水占比分别为25.0%和75.0%,水化学类型主要为Cl·SO_(4)型和SO_(4)·Cl型.地下水TDS变化范围为3079.13~15249.50 mg/L,主要为中性至弱碱性咸水(87.5%),其次为盐水(12.5%).碘元素的存在形态主要为I^(-)(87.5%),其次为IO_(3)^(-)(12.5%),且无共存形态,亚氧化环境和亚还原环境分别利于碘元素以IO_(3)^(-)和I^(-)形态存在.高TDS、细粒岩性、平缓的地势、地下水浅埋条件及碱性环境均有利于地下水碘的富集.潜水碘富集主要受蒸发浓缩作用和蒸发岩溶解作用的影响,承压水碘富集主要受还原条件下含铁矿物的溶解和冲积-湖积物的影响.Cl^(-)与Cl/Br摩尔比值表明高碘潜水受到一定程度蒸发浓缩作用的影响.Kashgar River in Xinjiang is located in a typical arid and semi-arid area.The abnormal contents of total dissolved solids(TDS)and iodine in groundwater in the lower reaches of the river seriously threaten the local water security.Taking the plain area in the lower reaches of Kashigar River as the study area,the distribution of iodine in saline groundwater and its influence on iodine enrichment were determined through analysis of the hydrochemical characteristics,Cl/Br mole ratio,stable isotopes of hydrogen and oxygen,occurrence environment of groundwater and hydrogeochemical process.The results showed that the iodine content of groundwater in the study area varies from<0.40μg/L to 435.00μg/L(mean 123.50μg/L).The mean iodine content of unconfined groundwater and confined groundwater is 58.75μg/L and 188.25μg/L,respectively,and the proportion of high iodine groundwater is 25.0% and 75.0%,respectively.The main hydrochemical types are Cl·SO_(4) and SO_(4)·Cl.TDS of groundwater ranged from 3079.13 mg/L to 15249.50 mg/L,mainly in neutral to slightly alkaline saline groundwater(87.5%),followed by saline groundwater(12.5%).The main form of iodine is I^(-)(87.5%),followed by IO_(3)^(-)(12.5%),and there is no coexistence form.The existence of iodine in IO_(3)^(-)and I^(-)forms in the suboxidizing environment and the subreducing environment is favorable,respectively.High TDS,fine lithology,gentle topography,shallow burial conditions of groundwater and alkaline environment are all conducive to the accumulation of iodine in groundwater.The iodine enrichment in unconfined groundwater is mainly affected by evaporation concentration and the dissolution of evaporite,while the iodine enrichment in confined groundwater is mainly affected by the dissolution of iron-bearing minerals under reduction conditions and alluvial-lacustrine sediments.The Cl^(-)to Cl/Br mole ratio indicates that the high iodine water in unconfined groundwater is obviously affected by evaporation.

关 键 词：高碘 喀什噶尔河 地下水 咸水 碘形态 水文地球化学作用 

分 类 号：P641[天文地球—地质矿产勘探]