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The palaeosol model of arsenic pollution of groundwater tested along a 32km traverse across West Bengal, India
- Source :
-
Science of the Total Environment . 8/1/2012, Vol. 431, p157-165. 9p. - Publication Year :
- 2012
-
Abstract
- Abstract: The distribution of As-pollution in groundwater of the deltaic aquifers of south-eastern Asia may be controlled by the subsurface distribution of palaeo-channel sediments (As-polluted groundwaters) and palaeo-interfluvial sediments (As-free groundwaters). To test this idea, termed the palaeosol model of As-pollution, we drilled 10 sites, analysed groundwater from 249 shallow wells (screened <107mbgl), field-tested another 149 for As, and used colour as a guide to the presence or absence of As-pollution in a further 531 wells. Our work was conducted along a 32-km traverse running W to E across southern West Bengal, India. At seven drill sites we logged a palaeo-interfluvial sequence, which occurs as three distinct units that together occupy 20km of the traverse. These palaeo-interfluvial sequences yield As-free groundwaters from brown sands at depth<100m. The palaeo-interfluvial sequences are separated by two deep palaeo-channels, which were logged at 3 sites. The palaeo-channel deposits host As-polluted groundwater in grey sands. Our findings confirm the predictions of the palaeosol model of As-pollution. We show again that well-colour can be used both to successfully predict the degree of As-pollution in groundwater, and to locate regions of buried palaeo-interfluve that will yield As-free groundwater for the foreseeable future. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 00489697
- Volume :
- 431
- Database :
- Academic Search Index
- Journal :
- Science of the Total Environment
- Publication Type :
- Academic Journal
- Accession number :
- 77460196
- Full Text :
- https://doi.org/10.1016/j.scitotenv.2012.05.038