孟加拉西南部全新世冲积含水层中砷的富集与迁移过程研究

发布时间：2021-04-05 04:23

　　地下水砷（As）异常是饮用水的主要威胁之一,由于广泛分布,已成为全球关注的热点问题。地下水砷异常在孟加拉国已成为严重的环境地质和危害公共健康问题之一。据报道,孟加拉国饮水型地下水砷中毒常是世界范围内人口密度最高的砷中毒事件。在孟加拉国,高砷地下水（>10μg/L）常发生在全新世冲积含水层。论文的主要研究目的是通过对孟加拉西南部全新世冲积含水层地下水的水化学特征和水文地球化学演化过程及其对As迁移富集过程的主控因素分析,揭示区域高砷地下水的形成机理,并与中国北方大同盆地的高砷地下水水化学特征及形成机理进行了对比分析,指出其异同点。本次研究,共在孟加拉西南部采集78个井深范围为21¹13m的地下水样品（2015年50个,2017年28个）,进行主要离子、微量元素分析及氢氧同位素分析。在此基础上,借助多元统计分析,如层次聚类分析（HCA）和因子分析（FA）,识别沉积含水层中地下水形成的主要水文地球化学过程及影响砷迁移富集的主要控制因素。研究结果表明,孟加拉西南部2015年采集的50个地下水样品As浓度范围为6.05⁵90.7μg/L,平均值为... 

【文章来源】：中国地质大学湖北省 211工程院校 教育部直属院校

【文章页数】：215 页

【学位级别】：博士

【文章目录】：
Selected Publications
Curriculum Vitae of Md. Enamul Huq
摘要
abstract
Chapter 1 Introduction
    1.1 Background
    1.2 Statement of the problems
    1.3 Significance and objectives of the study
    1.4 Rational, context and scope of the study
    1.5 Scientific contribution
    1.6 Thesis structure
Chapter 2 Theoretical Background and Literature Review
    2.1 Introduction
    2.2 Evolution and occurrence of As in groundwater
    2.3 Chemical form of As
    2.4 Groundwater As and threat to the public health
    2.5 Sources of As
        2.5.1 Primary sources
        2.5.2 Secondary sources
        2.5.3 Tertiary/irrigational re-circulation
    2.6 As mobilization
        2.6.1 Reduction of metal oxides and hydroxides
        2.6.2 Reduction of As（V） to As（III）
        2.6.3 Biogeochemical processes and organic matter
        2.6.4 Pyrite oxidation hypothesis
        2.6.5 Competitive ion exchange mechanism
    2.7 Literature review and research gap
Chapter 3 Research Methodology
    3.1 Study area
        3.1.1 Location
        3.1.2 Climate
        3.1.3 Hydrogeological setting
        3.1.4 Geology and lithology
    3.2 Groundwater sampling
    3.3 Groundwater analysis
    3.4 Statistical and spatial analysis
Chapter 4 Distribution and hydrochemical characteristics of high As groundwater
    4.1 Introduction
    4.2 Spatial distribution of high As groundwater
    4.3 Hydrochemical characteristics
        4.3.1 Contents of major ions and physical parameters
        4.3.2 Hydrochemical type
        4.3.3 Comparison of hydrochemical data collected in two different years
        4.3.4 Trace metals （TMs）
        4.3.5 Variation of TMs concentration over time
    4.4 Stable isotope geochemistry
        4.4.1 Recharge sources of groundwater
Chapter 5 As enrichment and mobilization in groundwater of Southwestern Bangladesh
    5.1 As sources
    5.2 Influential factors of As enrichment
        5.2.1 Geographical location and climatic condition
        5.2.2 Runoff conditions
        5.2.3 p H values
        5.2.4 Redox environment
        5.2.5 TDS
    5.3 The processes responsible for As enrichment and mobilization
        5.3.1 Redox
        5.3.2 Role of p H
        5.3.3 Evaporation
        5.3.4 Role of ions and TMs to mobilize As
        5.3.5 Adsorption-desorption and ion exchange process
        5.3.6 Microbial processes of As mobilization
        5.3.7 Other factors
    5.4 Co-occurrence of As and salinity
    5.5 Groundwater quality with respect WHO, USEPA and Bangladesh standards
Chapter 6 Comparison of hydrogeochemical behavior in Datong Basin, China and Southwestern, Bangladesh
    6.1 Introduction
    6.2 Brief introduction of Datong Basin
    6.3 Hydrogeochemistry
        6.3.1 Datong Basin, China
        6.3.2 Southwestern, Bangladesh
        6.3.3 Differences between Datong Basin, China and Southwestern Bangladesh
    6.4 Arsenic occurrence in groundwater
        6.4.1 Datong Basin, China
        6.4.2 Southwestern Bangladesh
        6.4.3 Differences between Datong Basin, China and Southwestern Bangladesh
    6.5 As release and enrichment
        6.5.1 Datong Basin, China
        6.5.2 Southwestern Bangladesh
        6.5.3 Differences between Datong Basin, China and Southwestern Bangladesh
Chapter 7 Conclusion and Recommendation
    7.1 Conclusions
    7.2 Recommendations
    7.3 Limitations and future work
References
Acknowledgements



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