Arsenic pollution of groundwater in parts of West Bengal; a case study

Saved in:
Authors:Mukhopadhyay, Dipak K.; Ghosh, Gautam
Author Affiliations:Primary:
Geological Survey of India, Monitoring Division, Kolkata, India
Volume Title:Arsenic pollution in groundwater of India
Volume Authors:Sarkar, Amitava, editor
Source:Arsenic pollution in groundwater of India, edited by Amitava Sarkar. Indian Journal of Geosciences, 64(1-4), p.41-48. Publisher: Geological Survey of India, Calcutta, India. ISSN: 2229-3574
Publication Date:2010
Note:In English. 9 refs.; illus., incl. 2 tables, sketch map
Summary:Abnormally high concentration of arsenic in groundwater above permissible limit of 50 ppb (Indian Standard) to a maximum of 3500 ppb have been reported from a 400-km- long and 60-km-wide belt within the upper and lower delta plain of Bengal basin, leading to a widespread health hazard. The long linear tract extends from north to south from Kaliachak in Malda district to Ramnagar area in Baruipur Block of 24-Parganas(S) district, West Bengal. Out of the three morphostratigraphic units, contamination of arsenic is restricted to the Katwa/Chinsurah Formation, both in the upper and lower delta regime of Bhagirathi/Hoogli, Jalangi-Churni-Jamuna-Padma distributaries system. The studies during 1989-94 revealed that arsenic occurs as dissolved pollutant within specific depth ranges in different locations and the overall depth of arsenic yielding aquifers range from 13.24 m to 109.2 m. In general, the shallow unconfined aquifers, dug wells, surface water and the deeper aquifers, are free from arsenic contamination. Arsenic in the aquifer sediment occurs as adsorbed arsenate ions on ferric hydroxide coating the sand grains. In general, the arsenic-infested groundwater is slightly alkaline, containing high concentration of Fe, Ca, Mg, bicarbonate and lower concentration of chloride, sulphate and fluorine. It is observed that arsenic-infested aquifer sediments are in general rich in Ti, Mn, B, Zr, Cr and Y. Speciation of arsenic has shown that more toxic trivalent arsenic is dominant over its pentavalent counter part. Several remedial measures have been recommended from the studies which include 1) sealing of offending tube wells and tapping of aquifers at safer zones delineated during the study of respective areas 2) alternative use of pre-treated surface water 3) issuance of early warning system to the users and 5) de-arsenification measures.
Subjects:Aquifers; Arsenic; Chemical fractionation; Concentration; Environmental analysis; Field studies; Geologic hazards; Ground water; Metals; Mineral composition; Natural hazards; Pollutants; Pollution; Remediation; Toxic materials; Asia; Bengal; India; Indian Peninsula; Ramnagar India; West Bengal India
Coordinates:N220000 N243000 E0890000 E0870000
Record ID:2012000602
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute.
Tags: Add Tag
No Tags, Be the first to tag this record!