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Arsenic incorporation into authigenic pyrite, Bengal Basin sediment, Bangladesh

Geochimica et Cosmochimica Acta

By:
, , , , , ,
DOI: 10.1016/j.gca.2007.03.022

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Abstract

Sediment from two deep boreholes (???400 m) approximately 90 km apart in southern Bangladesh was analyzed by X-ray absorption spectroscopy (XAS), total chemical analyses, chemical extractions, and electron probe microanalysis to establish the importance of authigenic pyrite as a sink for arsenic in the Bengal Basin. Authigenic framboidal and massive pyrite (median values 1500 and 3200 ppm As, respectively), is the principal arsenic residence in sediment from both boreholes. Although pyrite is dominant, ferric oxyhydroxides and secondary iron phases contain a large fraction of the sediment-bound arsenic between approximately 20 and 100 m, which is the depth range of wells containing the greatest amount of dissolved arsenic. The lack of pyrite in this interval is attributed to rapid sediment deposition and a low sulfur flux from riverine and atmospheric sources. The ability of deeper aquifers (>150 m) to produce ground water with low dissolved arsenic in southern Bangladesh reflects adequate sulfur supplies and sufficient time to redistribute the arsenic into pyrite during diagenesis.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Arsenic incorporation into authigenic pyrite, Bengal Basin sediment, Bangladesh
Series title:
Geochimica et Cosmochimica Acta
DOI:
10.1016/j.gca.2007.03.022
Volume
71
Issue:
11
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geochimica et Cosmochimica Acta
First page:
2699
Last page:
2717
Number of Pages:
19