Change search
ReferencesLink to record
Permanent link

Direct link
Controls of sedimentary facies on arsenic mobilization in shallow aquifers of the Matlab North Upazila, southeastern Bangladesh
Memorial University of Newfoundland, Canada.
University of Dhaka, Bangladesh.
University of Dhaka, Bangladesh.
KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology.
Show others and affiliations
2013 (English)Conference paper, Abstract (Other academic)
Abstract [en]

Groundwater extracted from shallow (<100 m bgl) Holocene alluvial aquifers, is the primary source of drinking water in Matlab North Upazila, Southeast Bangladesh. The distribution of lithofacies and its relation to hydrochemistry in such heterogeneous deposits are of fundamental importance for the analysis of groundwater quality. Aquifer sediment samples were collected from 48 locations throughout the study area. Lithofacies distribution was characterized using grain size and sediment colors. Channel fills (sandy) and over bank (silt-clay) deposits the two main lithofacies groups, were identified. These sandy deposits represent an active meandering river or channel fills sediment sequence, which are usually capped by silts and clays of an over bank sediment sequence. All the collected sediments samples were generalized and subdivided based on four distinct color variations, such as Black, White, Off-white, and Red according to Munsell color chart and water-well drillers’ perception.

Mineral compositions showed variability with the sediment color and grain size. Red and off-white sediments contain fewer amounts of metastable minerals (hornblende, actinolite, kyanite and pyroxenes etc.) than that of black sediments, whereas black sediments contain higher amount of biotite. The relatively high content of biotite and other dark colored ferromagnesian minerals are responsible for the black and grayish color of these sediments. Ferruginous coating on silicates, particularly on quartz grains, gives the red and off-white coloration. Based on the available information regarding sediment colors of aquifers in which tubewell screens were placed, 44 domestic hand pumped tubewells (HTWs) were selected for water sampling. The groundwater abstracted from black sediments of shallow aquifer showed higher concentrations in DOC (median: 5.81 mg/L), dissolved NH

4+ (median: 3.47 mg/L), PO43- (median: 1.36 mg/L), Fe (median: 4.87 mg/L), As (median: 252.53 μg/L) and relatively low Mn (median: 0.54 mg/L) and SO42-(median: 0.59 mg/L) concentrations, whereas groundwater abstracted from off-white and red sediments of shallow aquifer showed lower concentrations in DOC (median: 1.95 and 1.71 mg/L, respectively), dissolved NH4+ (median: 0), PO43- (median: 0.14 and 0.04 mg/L, respectively), Fe (median: 2.25 and 0.63 mg/L, respectively), As (median: 17.36 and 15.05 μg/L, respectively) and relatively high Mn+2 (median: 1.12 and 1.15 mg/L, respectively) and SO42- (median: 0.79 and 0.78 mg/L, respectively) concentrations. The water samples collected from black sediments (median Eh: 211 mV) indicated most reducing environment, followed by white (median Eh: 227 mV), whereas off-white and red sediments (median Eh: 268 and 274 mV) signified less reducing environment. The study supports that the sediment colors in shallow aquifer can be a reliable indicator of high and low-As concentrations and can be a useful tool for local drillers to target arsenic safe aquifers.

Place, publisher, year, edition, pages
Athens, Georgia, 2013.
National Category
URN: urn:nbn:se:kth:diva-124506OAI: diva2:635901
12th International Conference on the Biogeochemistry of Trace Elements (ICOBTE), June 16-20, Athens, USA
Sida - Swedish International Development Cooperation Agency

QC 20150204

Available from: 2013-07-07 Created: 2013-07-07 Last updated: 2015-02-04Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Hossain, MuhammedBhattacharya, Prosun
By organisation
Environmental Geochemistry and Ecotechnology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 92 hits
ReferencesLink to record
Permanent link

Direct link