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- Bhattacharya, Prosun, 1962-, et al.
(author)
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Natural Arsenic in Coastal Groundwaters in the Bengal Delta Region in West Bengal, India
- 2010
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In: Management and Sustainable Development of Coastal Zone Environments. - Dordrecht : Springer Netherlands. - 9789048130672 ; , s. 146-160
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Book chapter (peer-reviewed)abstract
- Bengal Delta region is currently confronted with largest groundwater arsenic calamity in history of human kind (BGS-DPHE, 2001; Mukherjee and Bhattacharya, 2001; Bhattacharya et al., 2002a; McArthur et al., 2001; Smedley and Kinniburgh, 2002; Mukherjee et al., 2006; Nath et al., 2005, 2007, 2008). Concentrations of arsenic in drinking water wells in the region often exceed the WHO drinking water guideline value (10 μg L-1) and the national safe limit of both India and Bangladesh for arsenic in drinking water (Smedley and Kinniburgh, 2002; RGNDWM, 2002; CGWB, 1999; Bhattacharya et al., 2002a). About one third (35 million) population inhabiting in this region (West Bengal and Bangladesh), currently at risk of long-term arsenic exposure (Bhattacharya et al., 2001; RGNDWM, 2002; Chakraborti et al., 2004; Kapaj et al., 2006), are being diagnosed with a wide spectrum of adverse health impacts including skin disorders such as hyper/hypo-pigmentation, keratosis and melanosis and are also in hot-spot areas of BDP which is reflected in a rise in the number of cancer cases (Guha Mazumdar et al., 1988). The distribution pattern of arsenic occurrence in BDP is patchy and there are numerous hotspots of arsenic contamination in the semi-confined shallow Holocene aquifer (Bhattacharya et al., 1997; Smedley and Kinniburgh, 2002). The scale of the problem is serious both in terms of hotspots and geographic area coverage (173 × 10 3 km2, eastern part of Hoogly-Bhagirathi/Western part of Ganga-Padma-lower Meghna flood plains).
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| 2. |
- Mahanta, C., et al.
(author)
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Geochemical evidences in the release processes of Arsenic into the groundwater in a part of Brahmaputra Floodplains
- 2012
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In: METALS AND RELATED SUBSTANCES IN DRINKING WATER. - : IWA PUBLISHING. ; , s. 268-271
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Conference paper (peer-reviewed)abstract
- To understand the sources and mobilization processes responsible for arsenic enrichment in groundwater in the Brahmaputra Basin where higher arsenic concentration have been reported, the geochemical features of the aquifer sediments were studied. Six boreholes were drilled near the tubewells (1 and 2) where aqueous arsenic concentration varies between 250 - 350 mu g/l. The soil sediment was collected at 3 m (10 ft) interval and it was drilled to the depth of 45 m (150 ft) which is the common depth of the tubewell installed in the study area. The bulk chemical studies on the sediments show that the pH of soils varies from 4.2 to 5.2 with a mean value of 4.75. The groundwater composition in the study area is of Na-HCO3-. The major anions HCO3- is likely from the decomposition of organic matter and originates from weathering of silicate and calcite minerals by atmospheric or respired CO2. Selective sequential extraction (SSE) method proposed by Wenzel et al., (2001) for extraction of arsenic from soil was used. Results of sequential extraction experiment show that solid-phase arsenic is present predominantly in the reducible fraction (Ext_5 and Ext_6), and residual fraction (Ext_7) contributes to highest fraction in many soil sediment. The major processes of arsenic mobilization probably linked to desorption of As from Fe oxides/oxyhydroxides and the reductive dissolution of Fe rich phases in the aquifers sediments under reducing and alkaline conditions.
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