摘要
通过对奎屯河流域61组地下水水样、2个钻孔中44组不同深度沉积物样品中化学组分的分析,研究了该区水文地球化学特征及其对砷运移的影响.结果表明,研究区地下水中As浓度为未检出−444.40μg·L^(−1).高砷地下水主要分布在研究区下游还原环境的冲积细土平原区,水化学类型主要为SO_(4)·HCO_(3-)Na型和Cl·HCO_(3-)Na型.在还原环境的地下水中,无机As(Ⅲ)占总溶解性砷的22.7%.研究区C1、C2钻孔沉积物As含量为8.36-28.41 mg·kg^(−1)、8.69-21.01 mg·kg^(−1)(均值分别为15.26 mg·kg^(−1)、12.54 mg·kg^(−1)).黏土层As含量较高,砂层中As含量较低,表明沉积物中As含量与岩性关系密切.As通常在Fe、Mn含量高的沉积物中富集,但在强还原环境下,As与Fe、Mn含量呈现负相关.地下水中As的运移不仅受Fe/Mn的氢氧化物的还原溶解影响,还受PO_(4)^(3-)和HCO_(3)^(-)竞争吸附的控制.As(Ⅴ)是地下水中As的主要存在形式,大量的As(Ⅴ)可以减弱地下水中As在空间上的迁移能力.本研究为深入揭示研究区高砷地下水成因机理与地下水砷污染的防控提供科学依据.
Based on the analysis of chemical elements of 61 groundwater samples and 44 sediment samples at different depths in 2 boreholes,groundwater geochemical characteristics and their influences on arsenic(As)mobilization in Kuitun River Basin were studied.The results showed that groundwater As concentration ranged from 0 to 444.40μg·L^(−1).High as groundwater mainly occured at the alluvial plain area with reduction environment in the lower reaches of the study area.The main Hydrochemical types of high As groundwater were SO_(4)·HCO_(3-)Na and Cl·HCO_(3-)Na.In reducing environment,inorganic As(Ⅲ)accounts for 22.7%of the total dissolved As in groundwater.Sediment As content of C1 and C2 borehole in the study area were 8.36-28.41 mg·kg^(−1) and 8.69-21.01 mg·kg^(−1),with mean values 15.26 mg·kg^(−1)and 12.54 mg·kg^(−1),respectively.Sediment As content in clay layer is high,while that in sand was low,which indicating As content in sediments was closely related to lithology.Arsenic was mostly enriched in sediments with high Fe and Mn content,while As content was negatively correlated with that of Fe and Mn under strong reduction environment.The mobilization of As in groundwater is not only affected by the reduction and dissolution of Fe-Mn hydroxides,but also controlled by the competitive adsorption of PO_(4)^(3-) and HCO_(3)^(-).As(Ⅴ)was the main existence state of As in groundwater.A large amount of As(Ⅴ)could reduce the spatial mobilization of As in groundwater.These results could provide direct evidence and insights for the causes of arsenic-rich groundwater in study area.
作者
江军
鲜虎胜
李巧
陶洪飞
姜有为
马合木江·艾合买提
JIANG Jun;XIAN Husheng;LI Qiao;TAO Hongfei;JIANG Youwei;MAHEMUJIANG·Aihemaiti(College of Water Conservancy and Civil Engineering,Xinjiang Agricultural University,Urumqi,830052,China;Xinjiang Hydrology and Water Resources Engineering Technology Research Center,Urumqi,830052,China)
出处
《环境化学》
CAS
CSCD
北大核心
2021年第6期1775-1786,共12页
Environmental Chemistry
基金
国家自然科学基金(41762018)
新疆维吾尔自治区“天山青年计划”青年博士科技人才培养项目(2020Q079)
2020年度新疆农业大学大学生创新项目资助.
关键词
奎屯河流域
高砷地下水
沉积物
地球化学特征
砷运移
Kuitun River basin
high-arsenic groundwater
sediments
geochemical characteristics
arsenic mobilization
