Arsenic Incorporation Into Authigenic Pyrite, Bengal Basin Sediment, Bangladesh

Journal Article · Tue Jul 10 04:00:00 EDT 2007 · Geochim.Cosmochim.Acta 71:2699-2717,2007

DOI:https://doi.org/10.1016/j.gca.2007.03.022· OSTI ID:909780

Lowers, H A; Breit, G N; Foster, A L; Whitney, J; Yount, J; Uddin, Md N; Muneem, Ad A

Sediment from two deep boreholes ({approx}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.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 909780
• Report Number(s): SLAC-REPRINT-2007-114
• Journal Information: Geochim.Cosmochim.Acta 71:2699-2717,2007, Journal Name: Geochim.Cosmochim.Acta 71:2699-2717,2007 Vol. 71; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ABSORPTION SPECTROSCOPY
AQUIFERS
ARSENIC
BANGLADESH
BOREHOLES
DEPOSITION
DIAGENESIS
ELECTRON PROBES
GROUND WATER
IRON
MICROANALYSIS
Other
OTHER
PYRITE
SEDIMENTS
SULFUR