The control of organic matter on microbially mediated iron reduction and arsenic release in shallow alluvial aquifers, Cambodia

Rowland, Helen; Pederick, R. L.; Polya, David A.; Pancost, Richard D.; Dongen, Bart E. van; Gault, A. G.; Vaughan, David J.; Bryant, Charlotte; Anderson, Bruce; Lloyd, Jonathan R.

doi:10.1111/j.1472-4669.2007.00100.x

Cited by 182 publications

(153 citation statements)

References 69 publications

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“…Reducing conditions with low redox potentials can facilitate As release in groundwater (Bhattacharya et al, 1997;McArthur et al, 2001;Rowland et al, 2007;Mladenov et al, 2010). The elevated As concentrations in the groundwater of the Datong and Hetao Basins were influenced very strongly by ORP values (Fig.…”

Section: Impact Of Redox Potential On Groundwater As Occurrencementioning

confidence: 99%

Comparison of arsenic geochemical evolution in the Datong Basin (Shanxi) and Hetao Basin (Inner Mongolia), China

Luo

Cui

et al. 2012

Applied Geochemistry

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a b s t r a c tInsightful knowledge of geochemical processes controlling As mobility is fundamental to understanding the occurrence of elevated As in groundwater. A comparative study of As geochemistry was conducted in the Datong Basin (Shanxi) and Hetao Basin (Inner Mongolia), two strongly As-enriched areas in China.The results show that As concentrations ranged from <1-1160 lg L À1 (n = 37) in the Datong Basin and <1-804 lg L À1 (n = 62) in the Hetao Basin. The groundwater is of the Na-HCO 3 type in the Datong Basin and Na-Cl-HCO 3 type in the Hetao Basin. Silicate mineral weathering and cation exchange processes dominated the groundwater geochemistry in the two study areas. Principal component analysis of 99 groundwater samples using 12 geochemical parameters indicated positive correlations between concentrations of As and Fe/Mn in the Datong Basin, but no correlation of As and Fe/Mn in the Hetao Basin. Phosphate correlated well with As in the Datong Basin and Hetao Basin, suggesting phosphate competition might be another process affecting As concentrations in groundwater. High concentrations of As, Fe, and Mn occurred in the pe range À2 to À4. The results of this study further understanding of the similarities and differences of As occurrence and mobility at various locations in China.

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Section: Impact Of Redox Potential On Groundwater As Occurrencementioning

confidence: 99%

Comparison of arsenic geochemical evolution in the Datong Basin (Shanxi) and Hetao Basin (Inner Mongolia), China

Luo

Cui

et al. 2012

Applied Geochemistry

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“…This topographic index, combines local upslope contributing area and slope and seems to be a key to understand much of the hydrological processes and soil properties (Sørensen et al, 2006;Yimer et al, 2006). It is reported that TWI was positively correlated with soil organic matter (Pei et al, 2010), which indirectly supports the central role of organic matter in the mobilization of As in groundwater Fendorf et al, 2010;Rowland et al, 2007). As expected from Fig.…”

Section: Logistic Regression Modelmentioning

confidence: 54%

Predicting the risk of arsenic contaminated groundwater in Shanxi Province, Northern China

Zhang

Rodríguez‐Lado

Johnson

et al. 2012

Environmental Pollution

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a b s t r a c tShanxi Province is one of the regions in northern China where endemic arsenicosis occurs. In this study, stepwise logistic regression was applied to analyze the statistical relationships of a dataset of arsenic (As) concentrations in groundwaters with some environmental explanatory parameters. Finally, a 2D spatial model showing the potential As-affected areas in this province was created. We identified topography, gravity, hydrologic parameters and remote sensing information as explanatory variables with high potential to predict high As risk areas. The model identifies correctly the already known endemic areas of arsenism. We estimate that the area at risk exceeding 10 mg L À1 As occupies approximately 8100 km 2 in 30 counties in the province.

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“…with less than 1 % organic matter (OM) [33][34][35] and they contain different types of OM. Recent studies in sediments from arsenic hot spots in West Bengal, [27,36] Cambodia, [22,37] and Taiwan [38] have shown that extractable OM, including long chain n-alkanes and other hydrocarbons of immature (e.g. petroleum) origin are present.…”

Section: Introductionmentioning

confidence: 99%

“…[20,24] As V reduction was shown repeatedly in a series of microcosm studies set up with sediments from arsenic affected aquifers, where simple organic proxies such as acetate or lactate were used to stimulate microbial mobilisation of arsenic. [15,19,20,22,25,26] Molecular studies in some of these systems revealed the presence of known Fe III and As V respiring bacteria, as well as arsenate respiratory reductase gene sequences. [19,[25][26][27] Nevertheless, the identification of the active members of the microbial communities in these complex sedimentary environments is challenging, especially when investigating specific microbe-substrate interactions.…”

Section: Introductionmentioning

confidence: 99%

“…[11][12][13][14][15][16][17][18] One of these processes, microbial reduction of As V , is widely accepted as being an important mechanism of As III release in shallow reducing aquifers. [19][20][21][22][23] Bioavailable organic carbon serves both as a carbon source and electron donor for the microbial respiratory reduction of sedimentary As V , which serves as an electron acceptor, resulting in the release of As III , which is more mobile, to the aqueous phase. [20,24] As V reduction was shown repeatedly in a series of microcosm studies set up with sediments from arsenic affected aquifers, where simple organic proxies such as acetate or lactate were used to stimulate microbial mobilisation of arsenic.…”

Section: Introductionmentioning

confidence: 99%

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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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The control of organic matter on microbially mediated iron reduction and arsenic release in shallow alluvial aquifers, Cambodia

Cited by 182 publications

References 69 publications

Comparison of arsenic geochemical evolution in the Datong Basin (Shanxi) and Hetao Basin (Inner Mongolia), China

Comparison of arsenic geochemical evolution in the Datong Basin (Shanxi) and Hetao Basin (Inner Mongolia), China

Predicting the risk of arsenic contaminated groundwater in Shanxi Province, Northern China

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

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