Probing the biogeochemistry of arsenic: response of two contrasting aquifer sediments from Cambodia to stimulation by arsenate and ferric iron.

Pederick, R L; Gault, A G; Charnock, J M; Polya, D A; Lloyd, J R

Pederick, R L; Gault, A G; Charnock, J M; Polya, D A; Lloyd, J R.

Afiliación

Pederick RL; School of Earth, Atmospheric and Environmental Sciences & Williamson Research Centre for Molecular Environmental Science, University of Manchester, UK.

J Environ Sci Health A Tox Hazard Subst Environ Eng ; 42(12): 1763-74, 2007 Oct.

Article en En | MEDLINE | ID: mdl-17952777

RESUMEN

Many millions of people worldwide are at risk of severe poisoning through exposure to groundwater contaminated with sediment-derived arsenic. An ever-increasing body of work is reinforcing the link between microbially-mediated redox cycling in aquifer sediments and the mobilisation of sorbed As(V) into groundwaters as the potentially more mobile and toxic As(III) anion. However, to date, few studies have examined the biogeochemical cycling of Fe and As species by microbes indigenous to Cambodian sediments. In this study two contrasting sediments, taken from a shallow As-rich reducing aquifer in the Kien Svay district of Cambodia, were used in a laboratory microcosm study. We present evidence to show that microbes present in these sediments are able to reduce Fe(III) and As(V) when provided with an electron donor, and that the two sediments respond differently to stimulation with Fe(III) and As(V). Shifts in the community composition of the two sediments after stimulation with As(V) suggest a potential role for members of the beta-Proteobacteria in As(V) reduction, a phylogenetic grouping known to contain microorganisms capable of As(III) oxidation, but not previously implicated in As(V) reduction. PCR-based analysis of the sediment microbial DNA using primers specific to the arrA gene, (a gene essential for microbial As(V) respiration), indicates the presence of microorganisms capable of dissimilatory As(V) reduction.

Asunto(s)

Arseniatos/metabolismo; Arsénico/metabolismo; Compuestos Férricos/metabolismo; Abastecimiento de Agua/análisis; Absorciometría de Fotón; Arseniatos/química; Arsénico/química; Bacterias/clasificación; Bacterias/genética; Bacterias/metabolismo; Biodegradación Ambiental; Cambodia; Compuestos Férricos/química; Sedimentos Geológicos/microbiología; Oxidación-Reducción; Reacción en Cadena de la Polimerasa; ARN Ribosómico 16S/genética; Microbiología del Agua; Contaminantes Químicos del Agua/química; Contaminantes Químicos del Agua/metabolismo

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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Arseniatos / Arsénico / Abastecimiento de Agua / Compuestos Férricos País/Región como asunto: Asia Idioma: En Revista: J Environ Sci Health A Tox Hazard Subst Environ Eng Asunto de la revista: TOXICOLOGIA Año: 2007 Tipo del documento: Article Pais de publicación: Reino Unido

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