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
Geochemical characterisation of shallow aquifer sediments of Matlab Upazila, Southeastern Bangladesh - Implications for targeting low-As aquifers
KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology. (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)
KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology. (KTH-International Groundwater Arsenic Research Group)ORCID iD: 0000-0003-4350-9950
KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering. (KTH-International Groundwater Arsenic Research Group)
Show others and affiliations
2008 (English)In: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009, Vol. 99, no 1-4, 137-149 p.Article in journal (Refereed) Published
Abstract [en]

High arsenic (As) concentrations in groundwater pose a serious threat to the health of millions of people in Bangladesh. Reductive dissolution of Fe(Ill)-oxyhydroxides and release of its adsorbed As is considered to be the principal mechanism responsible for mobilisation ofAs. The distribution ofAs is extremely heterogeneous both laterally and vertically. Groundwater abstracted from oxidised reddish sediments, in contrast to greyish reducing sediments, contains significantly lower amount of dissolved arsenic and can be a source of safe water. In order to study the sustainability of that mitigation option, this study describes the lithofacies and genesis of the sediments within 60 m depth and establishes a relationship between aqueous and solid phase geochemistry. Oxalate extractable Fe and Mn contents are higher in the reduced unit than in the oxidised unit, where Fe and Mn are present in more crystalline mineral phases. Equilibrium modelling of saturation indices suggest that the concentrations of dissolved Fe, Mn and PO43--tot in groundwater is influenced by 4 secondary mineral phases in addition to redox processes. Simulating As-[I] adsorption on hydroferric oxides using the Diffuse Layer Model and analytical data gave realistic concentrations of dissolved and adsorbed As-[I] for the reducing aquifer and we speculate that the presence of high PO43--tot in combination with reductive dissolution results in the high-As groundwater. The study confirms high mobility of As in reducing aquifers with typically dark colour of sediments found in previous studies and thus validates the approach for location of wells used by local drillers based on sediment colour. A more systematic and standardised colour description and similar studies at more locations are necessary for wider application of the approach.

Place, publisher, year, edition, pages
2008. Vol. 99, no 1-4, 137-149 p.
Keyword [en]
arsenic, groundwater, Bangladesh, redox, hydrogeochemistry, shallow, sedimentary aquifer, arsenic enrichment, west-bengal, reducing conditions, alluvial, aquifers, groundwater, extraction, mobility, delta, environments, mitigation
National Category
Environmental Sciences
Identifiers
URN: urn:nbn:se:kth:diva-17811DOI: 10.1016/j.jconhyd.2008.05.005ISI: 000259055100010Scopus ID: 2-s2.0-48549085236OAI: oai:DiVA.org:kth-17811DiVA: diva2:335856
Note
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2012-03-22Bibliographically approved
In thesis
1. 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

Other links

Publisher's full textScopus

Authority records BETA

Bhattacharya, Prosun

Search in DiVA

By author/editor
von Brömssen, MattiasHäller Larsson, SaraBhattacharya, ProsunHasan, Md. AzizBivén, AnnelieThunvik, RogerJacks, Gunnar
By organisation
Environmental Geochemistry and EcotechnologyLand and Water Resources EngineeringEnvironmental Management and Assessment
In the same journal
Journal of Contaminant Hydrology
Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 88 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