内蒙古土默特左旗地下水化学特征及成因  

Origin and Chemical Characteristics of Groundwater in Tumed Left Banner,Inner Mongolia

作　　者：李浩乾 孟姝蓉 董生旺 董少刚 刘凡瑶 崔亚倩 田国良 LI Haoqian;MENG Shurong;DONG Shengwang;DONG Shaogang;LIU Fanyao;CUI Yaqian;TIAN Guoliang(School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China;Inner Mongolia Key Laboratory of River and Lake Ecology,Hohhot 010021,China;Inner Mongolia First Hydrogeology and Engineering Geology Exploration Company,Hohhot 010020,China)

机构地区：[1]内蒙古大学生态与环境学院,呼和浩特010021 [2]内蒙古自治区河流与湖泊生态重点实验室,呼和浩特010021 [3]内蒙古第一水文地质工程地质勘查有限责任公司,呼和浩特010020

出　　处：《地球与环境》2024年第4期429-437,共9页Earth and Environment

基　　金：国家自然科学基金项目(42267025);内蒙古自治区高等学校科学研究项目(NJZZ23089)。

摘　　要：本文以土默特左旗为例,基于地下水系统理论、利用水文地球化学分析方法,揭示干旱-半干旱区地下水化学特征及其成因。结果表明:(1)研究区地下水整体偏碱性,大多处于还原性环境中;(2)潜水主要水化学类型为HCO_(3)-Ca型水,以及少量Cl-Ca型水、HCO_(3)-Mg型水,HCO_(3)-Na型水与Cl-Na型水;承压水水化学类型主要为HCO_(3)-Ca型水,以及少量HCO_(3)-Na型水、HCO_(3)-Mg型水与Cl-Ca型水;(3)潜水主要受水-岩相互作用、蒸发浓缩作用影响,承压水主要受水-岩相互作用影响;(4)研究区砷的主要来源是河湖相细粒沉积物和大青山富砷岩层,砷化物的主要形态是H_(3)AsO_(3),而铁、锰氧化物的还原性溶解、HCO_(3)^(-)与H_(3)AsO_(3)的竞争吸附以及缓慢的地下水流速是地下水中砷富集的主要原因。Utilizing the groundwater system theory and hydrogeochemical analysis methodology,this study used Tumed Left Banner(Tumote Zuoqi)in Inner Mongolia as an example to reveal the origin and chemical characteristics of groundwater in arid and semi-arid regions.The results show that:(1)The groundwater in the study area was generally alkaline and mostly in a reducing environment.(2)The main hydrochemical types of phreatic water were HCO_(3)-Ca water,with minor amounts of Cl-Ca water,HCO_(3)-Mg water,HCO_(3)-Na and Cl-Na water.The predominant hydrochemical type of confined water was HCO_(3)-Ca water,with minor amounts of HCO_(3)-Na water,HCO_(3)-Mg water and Cl-Ca water.(3)Phreatic water was mainly influenced by water-rock interaction and evaporation,while confined water was mainly affected by water-rock interaction.(4)The main sources of arsenic in the study area were fine-grained river and lake sediments as well as arsenic enriched rock formations in Daqing Mountain.The most prevalent arsenic species was H_(3)AsO_(3).The reductive dissolution of Fe and Mn oxides,competitive adsorption between HCO_(3)and H_(3)AsO_(3),along with slow groundwater velocity were the main causes of arsenic enrichment in groundwater.

关 键 词：地下水 水-岩相互作用 蒸发浓缩 高砷地下水 

分 类 号：X523[环境科学与工程—环境工程] P641.69[天文地球—地质矿产勘探]