Preservation strategies for inorganic arsenic species in high iron, low-Eh groundwater from West Bengal, India

Gault, A. G.; Jana, Joydev; Chakraborty, Sudipto; Mukherjee, Partha; Sarkar, Mitali; Nath, Bibhash; Polya, David A.; Chatterjee, Debashis

doi:10.1007/s00216-004-2861-1

Cited by 75 publications

(32 citation statements)

References 40 publications

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“…Typically the highest concentrations of As III were reported from groundwater aquifer systems in Eduardo Castex (EC), with a range of 5 -1332 μg l -1 (Table 3), demonstrating the potential stability of these arsenic species in the environment prior to extraction and use by humans. Since the reporting of data from previous studies in Argentina, it has come to light that As III species in water are unstable in the presence of high concentrations of Fe III , causing oxidation of As III to As V (Gault et al 2005a;Gong et al 2002;Le et al 2000). This process can also occur from the photolytic reduction of nitrate to nitrite, which has been shown to convert up to 50 % of the As III to As V within 3 hours of collection (Hug et al 2001;Sharpless and Linden 2001).…”

Section: Discussionmentioning

confidence: 99%

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

O'Reilly

Watts

Shaw

et al. 2010

Environ Geochem Health

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Arsenic (As) speciation in surface and groundwater from two provinces in Argentina (San Juan and La Pampa) was investigated using solid phase extraction (SPE) cartridge methodology with comparison to total arsenic concentrations. A third province, Río Negro, was used as a control to the study. Strong cation exchange (SCX) and strong anion exchange (SAX) cartridges were utilised in series for the separation and preservation of arsenite (As ). Samples were collected from a range of water outlets (rivers/streams, wells, untreated domestic taps, well water treatment works) to assess the relationship between total arsenic and arsenic species, water type and water parameters (pH, conductivity and total dissolved solids, TDS). Analysis of the waters for arsenic (total and species) was performed by inductively coupled plasma mass spectrometry (ICP-MS) in collision cell mode. Total arsenic concentrations in the surface and groundwater from Encon and the San José de Jáchal region of San Juan (north-west Argentina within the Cuyo region) ranged from 9 -357 μg l -1As. Groundwater from Eduardo Castex (EC) and Ingeniero Luiggi (LU) in La Pampa (central Argentina within the Chaco-Pampean Plain) ranged from 3 -1326 μg l -1As. The pH range for the provinces of San Juan (7.2 -9.7) and La Pampa (7.0 -9.9) are in agreement with other published literature. The highest total arsenic concentrations were found in La Pampa well waters (both rural farms and pre-treated urban sources), particularly where there was high pH (typically > 8.2), conductivity (> 2600 μS cm As. Arsenic species for both provinces were predominantly As for groundwater, respectively. This translates to a relative As III abundance of 69 -100 % of the total arsenic in surface waters and 32 -100 % in groundwater. This is unexpected because it is typically thought that in oxidising conditions (surface waters), the dominant arsenic species is As V . However, data from the SPE methodology suggests that As III is the prevalent species in San Juan, indicating a greater influence from reductive processes. La Pampa groundwater had As (equating to up to 33 % of the total arsenic). Previously published literature has focused primarily on the inorganic arsenic species, however this study highlights the potentially significant concentrations of organoarsenicals present in natural waters. The potential for separating and preserving individual arsenic species in the field to avoid transformation during transport to the laboratory, enabling an accurate assessment of in-situ arsenic speciation in water supplies is discussed.

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Section: Discussionmentioning

confidence: 99%

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

O'Reilly

Watts

Shaw

et al. 2010

Environ Geochem Health

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“…Calibration blocks were placed at even intervals throughout each analytical run in order to correct the instrument drift. Samples (1 ml) for arsenic speciation were removed from the bottles in an anaerobic cabinet and passed through a 0.45-m filter prior to analysis by ion chromatography (IC)-ICP-mass spectrometry (MS) using the method of Gault et al (16). Standard reference materials were included in each analytical run; the arsenic concentrations determined were found to agree well with those certified.…”

Section: Methodsmentioning

confidence: 99%

Interactions between the Fe(III)-Reducing Bacterium Geobacter sulfurreducens and Arsenate, and Capture of the Metalloid by Biogenic Fe(II)

Islam

Pederick

Gault

et al. 2005

Appl Environ Microbiol

157

120

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Previous work has shown that microbial communities in As-mobilizing sediments from West Bengal were dominated by Geobacter species. Thus, the potential of Geobacter sulfurreducens to mobilize arsenic via direct enzymatic reduction and indirect mechanisms linked to Fe(III) reduction was analyzed. G. sulfurreducens was unable to conserve energy for growth via the dissimilatory reduction of As(V), although it was able to grow in medium containing fumarate as the terminal electron acceptor in the presence of 500 M As(V). There was also no evidence of As(III) in culture supernatants, suggesting that resistance to 500 M As(V) was not mediated by a classical arsenic resistance operon, which would rely on the intracellular reduction of As(V) and the efflux of As(III). When the cells were grown using soluble Fe(III) as an electron acceptor in the presence of As(V), the Fe(II)-bearing mineral vivianite was formed. This was accompanied by the removal of As, predominantly as As(V), from solution. Biogenic siderite (ferrous carbonate) was also able to remove As from solution. When the organism was grown using insoluble ferrihydrite as an electron acceptor, Fe(III) reduction resulted in the formation of magnetite, again accompanied by the nearly quantitative sorption of As(V). These results demonstrate that G. sulfurreducens, a model Fe(III)-reducing bacterium, did not reduce As(V) enzymatically, despite the apparent genetic potential to mediate this transformation. However, the reduction of Fe(III) led to the formation of Fe(II)-bearing phases that are able to capture arsenic species and could act as sinks for arsenic in sediments.The mobilization of arsenic from sediments to drinking water constitutes a major toxic hazard to millions in Bangladesh and West Bengal. A number of mechanisms have been proposed for the release of arsenic into the groundwater in Bengal shallow alluvial sedimentary aquifers (1,3,8,11,12,18,21,(33)(34)(35)39), including the oxidation of arsenic-rich pyrite in aquifer sediments, driven by lowering of the water level by abstraction, and then penetration of the aquifer by oxygen (8,11,12), or the reductive dissolution of arsenic-rich iron-oxyhydroxides, driven by the microbial consumption of sedimentary organic matter in anoxic groundwater (33,34,39). The latter mechanism has received recent support as the dominant mechanism for groundwater arsenic contamination (3,20,21,39).In a recent microcosm-based study (21), we provided the first direct evidence of the role of indigenous metal-reducing bacteria in the formation of toxic, mobile As(III) in sediment from the Ganges Delta. The study showed that addition of acetate to anaerobic sediments, as a proxy for organic matter and a potential electron donor for metal reduction, resulted in stimulation of the microbial reduction of Fe(III), followed by As(V) reduction and release of As(III). Culture-dependent techniques confirmed a role for Fe(III)-reducing bacteria in As release, while PCR studies showed that the microbial communities in these sediments were ...

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“…Immediately after sampling, the pH and reduction potential (E h ) in the slurry sample was measured, and the concentration of 0.5 M HCl extractable Fe II was determined using a ferrozine-based spectrophotometric assay. [50] In addition, arsenic speciation in the porewaters (filtered sub-samples through a 0.2-mm pore size filter) was determined by ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS) using the method developed in Gault et al [51] and described in Rowland et al [22] Nitrate and sulfate measurements were taken in filtered slurry samples (through a 0.2-mm pore size filter) using a Metrohm 761 compact ion exchange chromatograph (Metrohm AG, Herisau, Switzerland). All microcosms were kept frozen at the end of their incubation period (8 weeks) until further analyses.…”

Section: Sediment Characterisationmentioning

confidence: 99%

Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

et al. 2014

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Environmental context. The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters.Abstract. Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of As V to As III is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13 C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13 C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant Fe III reduction and As III mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13 C-hexadecane exhibited a similar extent of Fe III reduction to the non-amended microcosms, but marginally higher As III release. Moreover, gas chromatography-mass spectrometry analysis showed that 65 % of the added 13 C-hexadecane was degraded during the 8-week incubation. The degradation of 13 C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13 C-kerogen did not enhance Fe III reduction or As III mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13 C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including Fe III and As V reduction in the subsurface.

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Preservation strategies for inorganic arsenic species in high iron, low-Eh groundwater from West Bengal, India

Cited by 75 publications

References 40 publications

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

Interactions between the Fe(III)-Reducing Bacterium Geobacter sulfurreducens and Arsenate, and Capture of the Metalloid by Biogenic Fe(II)

Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

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