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Hydrogeochemical evaluation and statistical analysis of groundwater of Sylhet, north-eastern Bangladesh

Acta Geochimica 2019年第3期38卷 440-455页

作者： Nasir Ahmed Md.Bodrud-Doza S.M.Didar-Ul Islam Manzoor Ahmad Choudhry Md.Iftakharul Muhib Anwar Zahid Shahadat Hossain Md.Moniruzzaman Nipa Deb Md.Abdul Quaiyum Bhuiyan isotope hydrology Division Institute of Nuclear Science and Technology Atomic Energy Research Establishment Department of Environmental Sciences Jahangirnagar University isotope hydrology section Department of Nuclear Sciences and Applications International Atomic Energy Agency Groundwater hydrology Bangladesh Water Development Board

To investigate the hydrogeochemical characteristics of groundwater 23 shallow, 30 intermediate and 38 deep wells samples were collected from Sylhet district of Bangladesh, and analyzed for temperature, pH, Eh, EC,DO, DOC, Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, SO_4^(2-), NO_3^-,HCO_3^-, SiO_2^-, Fe, Mn and As. Besides, 12 surface water samples from Surma and Kushiyara Rivers were also collected and analyzed to understand the influence into aquifers. Results revealed that, most of the groundwater samples are acidic in nature, and Na–HCO_3 is the dominant groundwater type. The mean value of temperature, EC,Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, NO_3^- and SO_4^(2-) were found within the range of permissible limits, while most of the samples exceeds the allowable limits of Fe, Mn and As concentrations. However, relatively higher concentration of Fe and Mn were found in deep water samples and reverse trend was found in case of As. The mean concentrations of As in shallow, intermediate and deep wells were 39.3, 25.3and 21.4 lg/L respectively, which varied from 0.03 to148 lg/L. From spatial distribution, it was found that Fe,Mn and As concentrations are high but patchy in northern,north-western, and south-western part of Sylhet region. The most influential geochemical process in study area were identified as silicate weathering, characterized by active cation exchange process and carbonate weathering, which thereby can enhance the elemental concentrations in groundwater. Pearson's correlation matrix, principal component analysis and cluster analysis were also employed to evaluate the controlling factors, and it was found that, both natural and anthropogenic sources were influencing the groundwater chemistry of the aquifers. However, surface water has no significant role to contaminate the aquifers,rather geogenic factors affecting the trace elemental contamination. Thus it is expected that, outcomes of this study will provide useful insights for future groundwater monitoring and

关键词： Arsenic Groundwater Hydrogeochemistry Multivariate statistics Spatial distribution

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isotope and chemical geothermometry and its applications

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Science China(Technological Sciences) 2001年第S1期44卷 16-20页

作者：庞忠和 1. isotope hydrology section International Atomic Energy Agency Vienna Austria

The Na-K-Mg Geoindicator created by Giggenbach (1988) is convenient to use but it is still based on the empirical geothermometry equations and discrepancy for different cation geo-thermometers is observed. In fact, the location of the curve of 'full equilibrium' is different if a different Na-K geothermometry equation is used. The difference is pronounced for temperatures lower than about 220℃. A case study on the Zhangzhou geothermal field of SE China resulted in a reliable estimate of reservoir temperature of 150℃ by the SO4-H2O pair Oxygen-18 isotope geothermometer. This has provided an example of attained equilibrium of the marine sulphate in the geothermal system in the low-medium temperature range (<150℃). A recent refinement of the theoretical geothermometry was achieved by the FixAl method, which provides the possibility to identify and solve problems such as an erroneous analytical value of Aluminium, and influence of processes such as mixing and degassing, and therefore makes it possible to reconstruct most of the 'lost equilibrium' in geothermal systems.

关键词： isotope geothermometry geothermal resources Zhangzhou China.

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isotope hydrogeochemical models for assessing the hydrological processes in a part of the largest continental flood basalts province of India

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Geoscience Frontiers 2022年第2期13卷 200-213页

作者： Md.Arzoo Ansari Jacob Noble Archana Deodhar U.Saravana Kumar isotope and Radiation Application Division Bhabha Atomic Research CentreTrombayMumbai 400085India isotope hydrology section Division of Physical and Chemical SciencesInternational Atomic Energy Agency(IAEA)ViennaAustria

Continental Flood Basalts(CFB)occupy one fourth of the world’s land ***,it is important to discern the hydrological processes in this complex hydrogeological setup for the sustainable water resources development.A model assisted isotope,geochemical,geospatial and geophysical study was conducted to understand the monsoonal characteristics,recharge processes,renewability and geochemical evolution in one of the largest continental flood basalt provinces of *** modelling and stable isotopes were used to assess the monsoonal *** distillation model were used to understand the climatic conditions at the time of groundwater *** parameter models(LPM)were employed to quantify the mean transit time(MTT)of *** and geochemical models were adopted to understand the geochemical evolution along the groundwater flow path.A geophysical model was used to understand the geometry of the *** back trajectory analysis confirms the isotopic finding that precipitation in this region is caused by orographic uplifting of air masses originating from the Arabian *** isotopic data of groundwater showed its meteoric origin and two recharge processes were discerned;(i)quick and direct recharge by precipitation through fractured and weathered basalt,(ii)low infiltration through the clayey black cotton soil and subjected to evaporation prior to the *** data showed that the groundwater is a renewable source and have shorter transit times(from present day to<30 years).The hydrogeochemical study indicated multiple sources/processes such as:the minerals dissolution,silicate weathering,ion exchange,anthropogenic influences *** the chemistry of the *** on the geo-electrical resistivity survey,the potential zones(weathered and fractured)were delineated for the groundwater ***,the study highlights the usefulness of model assisted isotopic hydrogeochemical techniques for underst

关键词： Stable isotopes Groundwater recharge Hydrological processes Modelling Deccan Traps

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Study of groundwater mixing using CFC data

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Science China(Technological Sciences) 2001年第S1期44卷 21-28页

作者：韩良丰庞忠和 1. isotope hydrology Laboratory International Atomic Energy Agency P.O. Box 100 A-1400 Vienna Austria 2. isotope hydrology section International Atomic Energy Agency P.O. Box 100 A-1400 Vienna Austria

CFCs (Chlorofluorocarbons) are sensitive tools in the study of groundwater mixing. Based on results of CFC concentrations, the extent of mixing can be identified by three methods: 1. discrepancy between apparent ages determined by individual CFC compounds; 2. inconsistency between CFC concentration ratios and their respective apparent ages; and 3. correlation between the concentrations of two CFC compounds for a group of samples. The principle of determination of mixing ratios and apparent CFC water age in the case of a two component mixing of CFC-containing water with CFC-free water is described.

关键词： CFC groundwater mixing two-component

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isotope and chemical geothermometry and its applications

Isotope and chemical geothermometry and its applications

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中国科学院地质与地球物理研究所2001学术年会

作者：庞忠和 isotope hydrology section International Atomic Energy Agency

The Na-K-Mg Geoindicator created by Giggenbach(1988) is convenient to use but it is still based on the empirical geothermometry equations and discrepancy for different cation geothermometers is *** fact,the location of the curve of"full equilibrium"is different if a different Na-K geothermometry equation is *** difference is pronounced for temperatures lower than about 220℃.A case study on the Zhangzhou geothermal field of SE China resulted in a reliable estimate of reservoir temperature of 150℃by the SO-HO pair Oxygen-18 isotope *** has provided an example of attained equilibrium of the marine sulphate in the geothermal system in the low-medium temperature range(<150℃).A recent refinement of the theoretical geothermometry was achieved by the FixAl method,which provides the possibility to identify and solve problems such as an erroneous analytical value of Aluminium,and influence of processes such as mixing and degassing,and therefore makes it possible to reconstruct most of the"lost equilibrium"in geothermal systems.

关键词： isotope geothermometry geothermal resources Zhangzhou China

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Formation mechanisms of megadunes and lakes in the Badain Jaran Desert,Inner Mongolia

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Chinese Science Bulletin 2006年第24期51卷 3026-3034页

作者： CHEN Jiansheng ZHAO Xia SHENG Xuefen DONG Haizhou RAO Wenbo SU Zhiguo State Key Laboratory of hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing 210098 China isotope hydrology Institute of Hohai University Nanjing 210098 China Geotechnical Research Institute of Hohai University Nanjing 210098 China

Field observations demonstrate that calc-sinters occurred in the lakes of Badain Jaran Desert. 87Sr/86Sr ratios,14C,δ 13C and mineral com-positions of calc-sinters,and 3He/4He,4He/20Ne,δ 18O,δ D,pH and TDS of water from springs and lakes are analyzed in detail. The results indicate that the lake water is supplied through deep fault zone. The “ker-nel” of stabilized dunes in the Badain Jaran Desert perhaps consists of calc-sinters and calcareous ce-mentation layers. Deep-seated groundwater effuses from this “kernel” and recharges to lakes in desert. Precipitation and snowmelt water from the Qing-hai-Tibet Plateau is fed into the Badain Jaran Desert,Gurinai,Wentougaole and Ejinqi areas through the Xigaze-Langshan Fault zone. The isotopic composi-tions of groundwater in the Alax Plateau are abnor-mal due to the strong evaporation of the Gyaring and Ngoring lake water in the headstream of the Yellow River. Groundwater dissolves dissoluble fractions of rocks during its transportation through the fault zone and flows out of the mouth of spring in the Badan Jaran Desert. The dissoluble fractions are finally de-veloped into calc-sinters and calcareous cementation layers around the spring. Calci-sinters are gradually largened and eventually emerge on the surface of lake water. Eolian sands accumulate on the surfaces of calc-sinters and calcareous cementation layers,and eventually develop into dunes. Invasion of magma causes an increase in the temperature of groundwater within the faults. Groundwater evapora-tion provides water vapor for the formation of humid stabilized dunes during its upwelling. Rhizoconcre-tions found in Yihejigede indicate that the dune was formed and remained immovable 4700 years ago. The height of the megadunes is proportional to thermal quantity carried by the groundwater.

关键词：内蒙古沙漠湖泊泉水泉华断裂带地下水同位素成分形成机制

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Effects of river width changes on flow characteristics based on flume experiment

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Journal of Mountain Science 2016年第2期13卷 361-368页

作者： WANG Xie-kang WANG Bing-jie LIU Xing-nian Zhang Li-qiong State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University hydrology and Hydraulics section South Florida Water Management District

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

关键词： Gradual channel transition Flow pattern Experimental study Numerical simulation

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Refining aquifer heterogeneity and understanding groundwater recharge sources in an intensively exploited agrarian dominated region of the Ganga Plain

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Geoscience Frontiers 2024年第4期15卷 134-147页

作者： Abhinav Patel Shive Prakash Rai Nijesh Puthiyottil Abhinesh Kumar Singh Jacob Noble Rajesh Singh Dharmappa Hagare U.D.Saravana Kumar Nachiketa Rai Kossitse Venyo Akpataku Department of Geology Institute of ScienceBanaras Hindu UniversityVaranasiUttar Pradesh 221005India isotope and Radiation Application Division Bhabha Atomic Research CentreTrombayMumbai 400085India Environmental hydrology Division National Institute of HydrologyRoorkeeUttarakhand 247667India School of Engineering Design and Built EnvironmentWestern Sydney UniversityAustralia isotope hydrology section Division of Physical and Chemical SciencesInternational Atomic Energy Agency(IAEA)ViennaAustria Department of Earth Sciences Indian Institute of TechnologyRoorkeeUttarakhand 247667India Laboratory of Organic Chemistry and Environmental Science Department of ChemistryUniversity of KaraPO Box 404KaraTogo

Densely populated region of Ganga Plain is facing aquifer vulnerability through waterborne pollutants and groundwater stress due to indiscriminate abstraction,causing environmental and socio-economic *** address long-term groundwater resilience,it is crucial to understand aquifer heterogeneity and connectivity,groundwater recharge sources,effects of groundwater abstraction *** this con-text,present study aims to understand factors responsible for vertical and spatial variability of groundwater chemistry and to identify groundwater recharge sources in an intensively exploited agrarian region of the Ganga *** of chemometric,statistical,and isotopic analysis categorises the alluvial aquifer into zone 1(G1;ground surface to 100 m)and zone 2(G2;>100 m-210 m).The group G1 samples are characterized by a wide variation in hydrochemical species,noted with pockets of F-and NO3-rich groundwater,and fresh to more evolved water types,while group G2 groundwater is characterized by a sharp increase in freshwater types and limited variation in their isotopic and hydrochemical *** G1 groundwater chemistry is governed by soil mineralogy,local anthropogenic inputs(SO42-,Cl-,and NO3-),and manifested by multiple recharge sources(local precipitation,river,canal water,pond).The G2 group is dominated by geogenic processes and mainly recharged by the local *** signatures confirm more evolved water type for group G1 in northwestern region,while fresh-water type covers the rest of the study *** rich groundwater is attributed to sodic water under alkaline conditions and enrichedδ18O values emphasizing role of evaporation in F-mobilization from micas and amphiboles abundant in the *** findings provide insight into potential groundwater vulnerability towards inorganic contaminants,and ground water recharge *** outcome of this study will help to develop aquifer resilience towards indiscriminate groundwater extrac

关键词： Stable isotopes Hydrogeochemical attributes Groundwater recharge sources Ganga Plain

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DYNAMIC CORRECTION OF ROUGHNESS IN THE HYDRODYNAMIC MODEL

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Journal of Hydrodynamics 2009年第2期21卷 255-263页

作者： BAO Wei-min ZHANG Xiao-qin QU Si-min State Key Laboratory of hydrology-Water Resources and Hydraulic Engineering College of Hydrology and Water Resources Hohai University Nanjing 210098 China

Based on the hydrodynamic model and the Xinanjiang model, the fiver stage forecasting model has been proposed. But its performance is not satisfactory as applied to estuary areas. River roughness is a sensitive parameter in the hydrodynamic model, and its value is related to some substantial uncertainties in the tidal fiver. According to roughness tests, a new method of roughness dynamic correction was developed to improve the performance of the stage model. The method was focused on the usage of observed data for the studied section, and its parameters were analyzed. Nested with the dynamic correction of roughness, the stage model was applied to the tidal reach of the Caoe River. The results demonstrate that the roughness dynamic correction can improve the simulation accuracy of the stage model, and especially has the capacity of reducing the errors at peak stages.

关键词： hydrodynamic model Xinanjiang model roughness test roughness dynamic correction nesting-modeling Caoe River

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砂-凹凸棒土竖向隔离墙材料的压缩及渗透特性试验研究（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2019年第3期20卷 218-228页

作者： Wen-bing ZHANG Wen-bo RAO Lei LI Ye LIU Shuai WANG Ke JIN Fang-wen ZHENG Institute of isotope hydrology College of Earth Sciences and EngineeringHohai University College of Resources and Environment Henan Agricultural University

目的:压缩性和渗透性是垃圾填埋场竖向隔离墙材料的2个重要指标。本文旨在探讨不同凹凸棒土添加量对砂-凹凸棒土隔离墙材料压缩性和渗透性的影响,并在Kozeny-Carman方程的框架下建立经验公式来预测砂-凹凸棒土隔离墙材料的渗透系数。创... 详细信息

目的:压缩性和渗透性是垃圾填埋场竖向隔离墙材料的2个重要指标。本文旨在探讨不同凹凸棒土添加量对砂-凹凸棒土隔离墙材料压缩性和渗透性的影响,并在Kozeny-Carman方程的框架下建立经验公式来预测砂-凹凸棒土隔离墙材料的渗透系数。创新点:1.系统全面地研究了不同凹凸棒土添加量对砂-凹凸棒土隔离墙材料压缩性和渗透性的影响;2.建立经验公式,预测砂-凹凸棒土隔离墙材料的渗透系数。方法:1.通过固结试验和刚性壁渗透试验,得出不同凹凸棒土添加量对砂-凹凸棒土隔离墙材料压缩性和渗透性的影响(图3和4,表1);2.通过公式推导,建立经验公式来预测砂-凹凸棒土隔离墙材料的渗透系数(公式(3)和(4))。结论:1.压缩指数(Cc)和回弹指数(Cs)均随回填料中凹凸棒土含量(Ap)的增加而增大,且Cc和Cs与Ap均有很好的线性关系:Cc=0.0062Ap+0.0161(r2=0.9914),Cs=0.0009Ap-0.0058(r2=0.9888)。2.用Casagrande和Taylor方法计算的固结系数(Cv)值均随回填料中凹凸棒土含量的增加而降低。3.利用太沙基固结理论计算的回填料渗透系数(ktheory)随回填料中凹凸棒土含量的增加而降低;在有效固结压力σ′<100 k Pa的情况下,只有凹凸棒土含量Ap≥30%,ktheory才会低于10-9 m/s;用刚性壁渗透试验测得的渗透系数kf与ktheory有相同的变化特征。4.基于试验数据提出了2种预测砂-凹凸棒土回填料渗透系数的方法,其中方法 2更好;由于这些方法都是经验公式,所以它们能否应用于原位场地或其它类型回填料仍需进一步的研究。

关键词：凹凸棒土砂-凹凸棒土回填料隔离墙压缩性渗透性

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