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Redox-sensitive mobilization of arsenic from Fe- and Mn-oxihydroxides: a main driver for high As-levels in groundwater of the Bengal Delta Plain

Wagner, Frank; Berner, Zsolt; Stüben, Doris

Abstract:
The groundwater of the Bengal Delta Plain, the only source of drinking water for many millions of people has As concentrations which exceed by up to two order of magnitudes the threshold value of 10 µg/l recommended by the WHO [1, 2].
This study focuses on characterisation of the hydrogeochemical environment of the As contamination and on the availability and mineralogical speciation of As in the aquifer sediments of an area of about 35 km2 (Malda District, West Bengal, India), where hot-spots with As enriched groundwater occur in close vicinity of low As zones. Evidences have been found for the occurrence of distinct redox zones with high As concentrations, in which conditions for selective reduction of Mn, Fe or SO4 occur. This implies that under specific local conditions Mn- and Fe-oxihydroxides represent important As-bearing phases in the aquifer.
The comparison of the results of two field campaigns carried out in 2002 and 12 month later indicates a shift towards slightly stronger reducing conditions, along with local increases of arsenic concentrations in groundwater. High As concentrations in the shallow groundwater appare ... mehr


Zugehörige Institution(en) am KIT Institut für Mineralogie und Geochemie (IMG)
Publikationstyp Zeitschriftenaufsatz
Jahr 2004
Sprache Englisch
Identifikator ISSN: 0935-1221
KITopen-ID: 1000009750
Erschienen in European journal of mineralogy / Beiheft
Band 16
Seiten 154
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