为了更好地掌握新疆玛纳斯河流域地下水中As、F、I的分布及富集成因，通过相关性分析和地球化学模拟，分析了高As、高F、高I地下水的水化学特征及空间分布状况;结合地质条件和地下水赋存环境进一步阐明地下水 As、F 和 I 的来源、迁移与富集的水文地球化学过程。结果表明:地下水砷、氟、碘含量变化范围分别为1。13～41。35 µg/L、0。06～8。02mg/L、<0。025～0。249mg/L，地下水As、F、I超标分别为62。9%、45。7%、45。7%，有31。4%的地下水砷氟碘均超标。砷氟碘共富集的地下水主要分布在玛纳斯河流域东部靠近沙漠边缘的平原区，水化学类型主要为HCO3·SO4·Cl-Na型。自山前单一结构潜水区至平原承压水区，地下水As含量沿流向先增大后在沙漠边缘区减小，水平方向上，地下水的淋滤作用导致南部富As岩层中的As向平原承压水区富集，且碱性条件下SO42-的还原有助于As的解吸附;地下水F含量沿地下水流向逐渐增大，在古尔班通古特沙漠边缘达到 2。5mg/L。高HCO3-、高Na+、高pH值的地下水还原环境是F从含水层基质向地下水释放的重要原因;地下水I含量沿地下水流向整体呈上升趋势，在承压水区潜水中主要受蒸发浓缩作用的影响，在承压水中主要受岩石风化作用的影响。砷氟碘共富集地下水主要分布于 100～310m 的承压水中。在封闭的承压含水层，碱性还原环境下矿物溶解与沉淀和水岩相互作用是地下水砷氟碘共富集的主要机制。
Distribution and co-enrichment of arsenic,fluorine,and iodine in groundwater of the Manas River Basin in Xinjiang
Groundwater is one of the major water sources for production,living and agricultural irrigation in the Manas River Basin in Xinjiang.Due to the influence of regional environmental background and long-term effect of human activities,high arsenic(As),Fluoride(F)and iodine(I)in groundwater is the main issue of groundwater quality.To better understand the distribution and enrichment genesis of As,F and I in groundwater in the Manas River Basin,the hydrochemical and spatial distribution of groundwater with high As,high F and high I were analyzed via correlation analysis and geochemical simulation.Moreover,source,migration and enrichment processes of groundwater As,F and I were further clarified with the combination of geological conditions and groundwater occurrence environment.Results showed that the variation ranges of As,F and I in groundwater are 1.13 to 41.35µg/L 0.06 to 8.02mg/L,and<0.025 to 0.249mg/L,respectively.Over-limit rate of groundwater As,F and I were 62.9%,45.7%and 45.7%,respectively.Groundwater samples high in As,F and I had the over-limit rate of 31.4%.Groundwater with the co-enrichment of As,F and I was mainly distributed in the plain area near the desert edge in the eastern part of the Manas River Basin with the primary hydrochemistry type of HCO3·SO4·Cl-Na.From single structure phreatic in the piedmont area to confined groundwater in the plain area,groundwater As increased along the flowpath and decreased near the desert edge.Horizontally,groundwater leaching led to the enrichment of As from As-rich strata in the piedmont area in the south to the confined groundwater area,and the reduction process of SO42-under alkaline environment contributed to the desorption of As.Groundwater F increased gradually along the flowpath,reaching 2.5mg/L at the edge of Gurbantunggut Desert.Reduction environment with high HCO3-,Na+and pH was the major reason for F release from aquifer matrix to groundwater.Groundwater I showed an increase trend along the flowpath generally.Enrichment of I in phreatic water in the confined water area was mainly affected by evaporation and concentration,while that in confined groundwater was mainly affected by rock weathering.Groundwater with As-F-I co-enrichment was mainly distributed in confined groundwater at the depth of 100 to 300m.In the closed confined aquifer,,mineral dissolution and precipitation and water-rock interaction under alkaline-reducing environment were the main mechanism for groundwater As-F-I co-enrichment.
arsenicfluorideiodineco-enrichment genesishydrochemistrythe Manas River Basin
NETL
NSTL
万方数据
