Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Hydrogeochemical evaluation of groundwater along an E-W transect in the Meghna basin, Bangladesh
KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering. (KTH-International Groundwater Arsenic Research Group)
KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering. (KTH-International Groundwater Arsenic Research Group)ORCID iD: 0000-0003-4350-9950
Institute of Geological Sciences, Faculty of Science, Masaryk University.
Department of Geology, University of Dhaka.
Show others and affiliations
(English)Manuscript (Other academic)
Keyword [en]
groundwater composition, transect, lithofacies, Meghna basin, Bangladesh
National Category
Water Engineering
Identifiers
URN: urn:nbn:se:kth:diva-9347OAI: oai:DiVA.org:kth-9347DiVA: diva2:113542
Note
QC 20100809Available from: 2008-10-21 Created: 2008-10-21 Last updated: 2011-12-27Bibliographically approved
In thesis
1. Arsenic in Alluvial Aquifers in the Meghna Basin, Southeastern Bangladesh: Hydrogeological and Geochemical Characterisation
Open this publication in new window or tab >>Arsenic in Alluvial Aquifers in the Meghna Basin, Southeastern Bangladesh: Hydrogeological and Geochemical Characterisation
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

 Elevated levels of arsenic (As) in Bangladesh groundwater has emerged as a massive calamity exposing a large population to the risk of As toxicity from drinking water sources and agricultural products. Holocene alluvial aquifers in the delta- and flood-plains of the Ganges-Brahmaputra- Meghna (GBM) river systems are severely affected by high levels of As in groundwater. Groundwaters abstracted from Holocene alluvial aquifers of shallow depth (<150 m) contain As at concentrations mostly above WHO provisional drinking water guideline value of 10 μg/l whereas groundwater from the Holocene deeper aquifers (usually >150 m) and the Plio- Pleistocene aquifers contain low-As (<10 μg/l) water.The study reveals that the local and regional scale variations in groundwater composition, levels of As concentrations and the redox conditions are governed by the geological attributes of the aquifers. Groundwater in the grey to dark grey argillaceous sediments where organic matter and micas are abundant contain high concentration of dissolved As. Concentrations of As is generally low in the groundwater abstracted from the light grey to yellowish brown arenaceous sediments. A major proportion of As in the dark grey sediments is bound to poorly crystalline and amorphous metal-oxyhydroxides, particularly Fe-oxyhydroxides, that are readily mobile. On the other hand, As concentrations in the light grey to yellowish brown sediments are low and predominantly bound to less mobile stable crystalline phases. Redox reactions linked to the degradation of organic matter are the potential mechanism of As mobilisation through reductive dissolution of Fe-oxyhydroxides in grey to dark grey sediments in the Holocene shallow aquifers. This is reflected in groundwater compostion that is characterised by high concentrations of As, HCO3 -, Fe and dissolved organic carbon (DOC). However, concentration of dissolved Fe is probably controlled by the precipitation of secondary Fe-minerals like siderite (FeCO3), vivianite [Fe3(PO4)2 8H2O] and pyrite (FeS2). Weathering of biotite [K (Fe, Mg)3 AlSi3O10 (F, OH)2] is one of the major sources of Fe-oxyhydroxides in the sediment and thus plays a significant role in the processes of As mobilisation in groundwater.High concentrations of As and salinity are the major constraints for groundwater development in the Holocene alluvial aquifers of the Meghna basin. The Holocene shallow aquifers (<150 m) are high in dissolved As and salinity, while the Holocene deeper aquifers (>150 m) are low in As but contains pockets of saline groundwater. Molar ratios of Cl-/HCO3 - and Na+/Cl- indicate mixing of relict seawater with the freshly recharged water in these aquifers. Groundwater abstracted from the Pliocene Dupi Tila aquifer located at relatively higher elevations along the eastern part of the Meghna basin is not affected by As and salinity. Stable hydrogen (δ2H) and oxygen (δ18O) isotopes indicate relatively fast groundwater recharge rate with insignificant evaporation effect in the Meghna basin. The groundwater samples from shallow aquifers show relatively wider variations in isotopic composition than the deeper ones indicating multiple recharge regimes. Abstraction of groundwater from the Holocene deeper low-As aquifers for drinking purposes should thus be be properly guided to minimise the risk of cross-contamination and installation of high-capacity irrigation wells in the deeper aquifers must be avoided for sustainable drinking water supplies.

Place, publisher, year, edition, pages
Stockholm: KTH, 2008. xii, 26 p.
Series
Trita-LWR. PHD, ISSN 1650-8602 ; 1047
Keyword
Alluvial aquifer, groundwater, arsenic mobilisation, geology, Meghna basin, Bangladesh
National Category
Water Engineering
Identifiers
urn:nbn:se:kth:diva-9348 (URN)
Public defence
2008-11-05, F3, KTH, Lindstedtsvägen 26, Stockholm, 14:15 (English)
Opponent
Supervisors
Note
QC 20100809Available from: 2008-10-22 Created: 2008-10-21 Last updated: 2010-08-09Bibliographically approved
2. Hydrogeological and geochemical assessment of aquifer systems with geogenic arsenic in Southeastern Bangladesh: Targeting low arsenic aquifers for safe drinking water supplies in Matlab
Open this publication in new window or tab >>Hydrogeological and geochemical assessment of aquifer systems with geogenic arsenic in Southeastern Bangladesh: Targeting low arsenic aquifers for safe drinking water supplies in Matlab
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Naturally occurring arsenic (As) in Holocene aquifers in Bangladesh have undermined a long success of supplying the population with safe drinking water. Arsenic is mobilised in reducing environments through reductive dissolution of Fe(III)-oxyhydroxides. Several studies have shown that many of the tested mitigation options have not been well accepted by the people. Instead, local drillers target presumed safe groundwater on the basis of the colour of the sediments. The overall objective of the study has thus been focussed on assessing the potential for local drillers to target As safe groundwater. The specific objectives have been to validate the correlation between aquifer sediment colours and groundwater chemical composition, characterize aqueous and solid phase geochemistry and dynamics of As mobility and to assess the risk for cross-contamination of As between aquifers in Daudkandi and Matlab Upazilas in SE-Bangladesh. In Matlab, drillings to a depth of 60 m revealed two distinct hydrostratigraphic units, a strongly reducing aquifer unit with black to grey sediments overlies a patchy sequence of weathered and oxidised white, yellowish-grey to reddish-brown sediment. The aquifers are separated by an impervious clay unit. The reducing aquifer is characterized by high concentrations of dissolved As, DOC, Fe and PO43--tot. On the other hand, the off-white and red sediments contain relatively higher concentrations of Mn and SO42- and low As. Groundwater chemistry correlates well with the colours of the aquifer sediments. Geochemical investigations indicate that secondary mineral phases control dissolved concentrations of Mn, Fe and PO43--tot. Dissolved As is influenced by the amount of Hfo, pH and PO43--tot as a competing ion. Laboratory studies suggest that oxidised sediments have a higher capacity to absorb As. Monitored hydraulic heads and groundwater modelling illustrate a complex aquifer system with three aquifers to a depth of 250 m. Groundwater modelling illustrate two groundwater flowsystems: i) a deeper regional predominantly horizontal flow system, and ii) a number of shallow local flow systems. It was confirmed that groundwater irrigation, locally, affects the hydraulic heads at deeper depths. The aquifer system is however fully recharged during the monsoon. Groundwater abstraction for drinking water purposes in rural areas poses little threat for cross-contamination. Installing irrigation- or high capacity drinking water supply wells at deeper depths is however strongly discouraged and assessing sustainability of targeted low-As aquifers remain a main concern. The knowledge gained here can be used for developing guidelines for installing safe wells at similar environments in other areas of Bangladesh.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. xii, 46 p.
Series
Trita-LWR. PHD, ISSN 1650-8602 ; 1063
Keyword
Arsenic, Bangladesh, drinking water, groundwater, sustainability, geochemistry, hydrogeology, modelling
National Category
Oceanography, Hydrology, Water Resources Geochemistry Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-53300 (URN)978-91-7501-214-8 (ISBN)
Public defence
2012-01-20, F3, Lindstedtsvägen 26, KTH, Stockholm, 14:00 (English)
Opponent
Supervisors
Note
QC 20111227Available from: 2011-12-27 Created: 2011-12-27 Last updated: 2011-12-27Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Bhattacharya, Prosun

Search in DiVA

By author/editor
Hasan, Md. AzizBhattacharya, Prosunvon Brömssen, MattiasJacks, Gunnar
By organisation
Land and Water Resources Engineering
Water Engineering

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 116 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf