Effect of redox potential and pH on arsenic speciation and solubility in a contaminated soil

Masscheleyn, Patrick H.; DeLaune, Ronald D.; Patrick, W. H.

doi:10.1021/es00020a008

Cited by 932 publications

(485 citation statements)

References 20 publications

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“…Acetate and sulfate concentrations decreased and sulfide concentrations increased with time. As a result of increasingly reducing conditions, the incubations were expected to be characterized by initially increasing and subsequently decreasing (37,38). Note that field conditions beneath the landfill are most analogous to the time point with maximum Fe, As, and Mn concentrations.…”

Section: Reactor and Microcosmsmentioning

confidence: 99%

Laboratory Investigations of Enhanced Sulfate Reduction as a Groundwater Arsenic Remediation Strategy

Keimowitz

Mailloux

Cole

et al. 2007

Environ. Sci. Technol.

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Landfills have the potential to mobilize arsenic via induction of reducing conditions in groundwater and subsequent desorption from or dissolution of arsenic-bearing iron phases. Laboratory incubation experiments were conducted with materials from a landfill where such processes are occurring. These experiments explored the potential for induced sulfate reduction to immobilize dissolved arsenic in situ. The native microbial community at this site reduced sulfate in the presence of added acetate. Acetate respiration and sulfate reduction were observed concurrent with dissolved iron concentrations initially increasing from 0.6 μM (0.03 mg L −1 ) to a maximum of 111 μM (6.1 mg L −1 ) and subsequently decreasing to 0.74 μM (0.04 mg L −1 ). Dissolved arsenic concentrations initially covaried with iron but subsequently increased again as sulfide accumulated, consistent with the formation of soluble thioarsenite complexes. Dissolved arsenic concentrations subsequently decreased again from a maximum of 2 μM (148 μg L −1 ) to 0.3 μM (22 μg L −1 ), consistent with formation of sulfide mineral phases or increased arsenic sorption at higher pH values. Disequilibrium processes may also explain this second arsenic peak. The maximum iron and arsenic concentrations observed in the lab represent conditions most equivalent to the in situ conditions. These findings indicate that enhanced sulfate reduction merits further study as a potential in situ groundwater arsenic remediation strategy at landfills and other sites with elevated arsenic in reducing groundwater.

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Section: Reactor and Microcosmsmentioning

confidence: 99%

Laboratory Investigations of Enhanced Sulfate Reduction as a Groundwater Arsenic Remediation Strategy

Keimowitz

Mailloux

Cole

et al. 2007

Environ. Sci. Technol.

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“…In view of the potential risk of bioaccumulation and toxicity of As (Bhumbla and Keefer, 1994;Bhattacharya et al, 1997Bhattacharya et al, , 2001), the geochemical behaviour of As in nature has generated much concern in environmental research in recent years. Under the range of Eh and pH in soil compartments, As normally occurs in qIII and qV oxidation states (Cullen and Reimer, 1989 under oxidising conditions (peqpH)8) (Sadiq et al, 1983;Masscheleyn et al, 1991). An increased As content has been noted with increasing clay content of the contaminated soils (Galba and Polacek, 1973).…”

Section: Chemistry Of Cca Metals In Soilsmentioning

confidence: 99%

Metal contamination at a wood preservation site: characterisation and experimental studies on remediation

Bhattacharya

Mukherjee

Jacks

et al. 2002

The Science of The Total Environment

110

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The aim of this investigation was to determine the occurrence of As, Cu, Cr and Zn in the soil at an abandoned wood preservation unit and to examine some possible extractants for the contaminants in the soil. The mean As content of the contaminated surface soils (0-10 cm) was 186 mg kg , where as the mean concentrations of Cu, Cr y1 and Zn in soils from the contaminated area were 26, 29 and 91 mg kg , respectively. The elevated As content in y1 the mineral soils is related to adsorption of inorganic As phases in the fine grained fractions, which are characterised by large surface area and high positive surface charge under the current acidic conditions. Cu and Cr were found to be rather mobile, which is reflected in their lower abundance in soils and significant accumulation in sediments in the drainage leaving the area. The fine fraction of the soil (-0.125 mm) has an average metal content increased by nearly 34% as compared to the -2-mm fraction conventionally used for the analysis and assessment of soil contamination. The -2-mm fraction constitutes approximately 65% of the total weight while the fine fraction (-0.125 mm) constitutes approximately 10%. These facts, taken together, are essential for the choice of remediation measures. Oxalate solutions have been tested as extractants for soil remediation. Dark acid oxalate extraction dissolves the amorphous Al-and Fe-oxides and hydroxides and mobilises the adsorbed inorganic As species. Oxalate also acts as a ligand for the cationic heavy metals, releasing them from exchangeable sites. With a three-step sequential leaching, up to 98-99% of the metals could be removed. At lower concentrations and higher pH, the leaching decreased to approximately 70%. ᮊ

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“…Thus, flooding during the growing season, especially during later stages of plant growth, can effectively reduce Cd concentrations in rice grains (Arao et al, 2009;Hu et al, 2013a). In contrast, anaerobic conditions in paddy soils usually lead to the reduction of arsenate (As(V)) to arsenite (As(III)) which enhances the bioavailability of As to the rice plants (Masscheleyn et al, 1991;Marin et al, 1993;Takahashi et al, 2004). Thus, growing rice aerobically results in a marked decline in As accumulation in the rice Li et al, 2009b;Hua et al, 2011;Somenahally et al, 2011;Spanu et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Effects of water management on arsenic and cadmium speciation and accumulation in an upland rice cultivar

Ouyang

et al. 2015

Journal of Environmental Sciences

127

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Pot and field experiments were conducted to investigate the effects of water regimes on the speciation and accumulation of arsenic (As) and cadmium (Cd) in Brazilian upland rice growing in soils polluted with both As and Cd. In the pot experiment constant and intermittent flooding treatments gave 3-16 times higher As concentrations in soil solution than did aerobic conditions but Cd showed the opposite trend. Compared to arsenate, there were more marked changes in the arsenite concentrations in the soil solution as water management shifted, and therefore arsenite concentrations dominated the As speciation and bioavailability in the soil. In the field experiment As concentrations in the rice grains increased from 0.14 to 0.21 mg/kg while Cd concentrations decreased from 0.21 to 0.02 mg/kg with increasing irrigation ranging from aerobic to constantly flooding conditions. Among the various water regimes the conventional irrigation treatment produced the highest rice grain yield of 6.29 tons/ha. The As speciation analysis reveals that the accumulation of dimethylarsinic acid (from 11.3% to 61.7%) made a greater contribution to the increase in total As in brown rice in the intermittent and constant flooding treatments compared to the intermittent-aerobic treatment. Thus, water management exerted opposite effects on Cd and As speciation and bioavailability in the soil and consequently on their accumulation in the upland rice. Special care is required when irrigation regime methods are employed to mitigate the accumulation of metal(loid)s in the grain of rice grown in soils polluted with both As and Cd.

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Effect of redox potential and pH on arsenic speciation and solubility in a contaminated soil

Cited by 932 publications

References 20 publications

Laboratory Investigations of Enhanced Sulfate Reduction as a Groundwater Arsenic Remediation Strategy

Laboratory Investigations of Enhanced Sulfate Reduction as a Groundwater Arsenic Remediation Strategy

Metal contamination at a wood preservation site: characterisation and experimental studies on remediation

Effects of water management on arsenic and cadmium speciation and accumulation in an upland rice cultivar

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