Arsenic Chemistry in Soils and Sediments

Fendorf, S. E.; Nico, Peter; Kocar, Benjamin D.; Masue, Yoko; Tufano, Katharine J.

doi:10.1016/s0166-2481(10)34012-8

Cited by 65 publications

(62 citation statements)

References 106 publications

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“…Wetlands are often regarded as sources of As for groundwater and/or rivers Polizzotto et al, 2008;Fendorf, 2010;Neubauer, Köhler, et al, 2013;Neubauer, v.d. Kammer, et al, 2013).…”

Section: Implications For As Dynamics In Wetlandsmentioning

confidence: 99%

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Highlighting the wide variability in arsenic speciation in wetlands: A new insight into the control of the behavior of arsenic

Guénet

Davranche

Vantelon

et al. 2017

Geochimica et Cosmochimica Acta

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Highlighting the wide variability in arsenic speciation in wetlands: a new insight into the control of the behavior of arsenic. Geochimica et Cosmochimica Acta, Elsevier, 2017, 203, pp.284-302 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1Highlighting the wide variability in arsenic speciation in wetlands: AbstractAlthough the behavior of Arsenic (As) under reducing conditions in periods of high water levels in wetlands is well understood and documented, there is a lack of information under oxidizing conditions when the water level decreases. In this study, we were interested in the first stage of the oxidizing period, when oxidation products are still in suspension. A soil sample from the Naizin Kervidy wetland (France) was incubated in the laboratory to produce a reduced soil solution. The reduced solution was subsequently oxidized, filtered and ultrafiltered using decreasing pore size membranes (5 µm, 3 µm, 0.2 µm, 30 kDa and 5 kDa). The distribution of As and Fe was investigated in each size fraction of the oxidized solution and their speciations were studied using XAS, HPLC and SEC-ICP-MS. Organic matter was characterized using thermally assisted hydrolysis and methylation gas chromatography-mass spectrometry (THM-GC-MS) and fluorescence spectroscopy. The majority of the As was present as As(V) but a small amount of As(III) still remained despite the advanced oxidized conditions. In the > 0.2 µm fractions, the XAS analyses showed that As was associated, in the second shell, with Fe (As-Fe = 3.35 Å) as bidentate binuclear complexes and C (As-C = 2.90 Å), suggesting the integration of As in biological objects. In the < 30 kDa fraction, As was directly bound to C (As-C = 1.96 Å) in the first shell indicating the presence of organic As species. In the second shell, an As-Fe distance of 3.35 Å was found showing that 2 part of the As was still complexed with Fe. The 0.2 µm-30 kDa fraction was a transitional fraction in terms of the Fe species and OM composition. In this fraction, organic matter exhibited a more humic character (aromatic molecules) inducing an increasing cation binding capacity. As a consequence, in this fraction and in the smallest one, As, Fe and OM seemed to form ternary complexes in which the Fe or nano-oxides in the > 30 kDa fraction and as monomer, or cluster in < 30 kDa fraction acted as a bridge. In all of the fractions, a proportion of As(V) was present as organic methylated species. These organic species might be produced by several organisms (animal or plant) via a detoxification process. They seemed to be bound to the particulate and colloidal Fe/OM phases as well as integ...

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“…Wetlands are often regarded as sources of As for groundwater and/or rivers Polizzotto et al, 2008;Fendorf, 2010;Neubauer, Köhler, et al, 2013;Neubauer, v.d. Kammer, et al, 2013).…”

Section: Implications For As Dynamics In Wetlandsmentioning

confidence: 99%

“…Several mechanisms have been proposed to explain the As contamination of aquifers. Among them, riparian wetlands and floodplains appeared to play a potential role in the As solubilization process Fendorf, 2010). Arsenic enrichment has been identified in many wetland soils (e.g.…”

Section: Introductionmentioning

confidence: 99%

Highlighting the wide variability in arsenic speciation in wetlands: A new insight into the control of the behavior of arsenic

Guénet

Davranche

Vantelon

et al. 2017

Geochimica et Cosmochimica Acta

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“…Because As III is more readily desorbed from Fe oxides than As V , release of As may also occur upon microbial reduction of As V to As III under the reducing conditions of the pond. [18,33,35] Larson et al [4] found the As in pore water at the sedimentation pond to be 55-93 % As III during summer sampling, supporting that microbial reduction and release from sediment is taking place. [4] arsenic determined by the method described in Salome et al [14] Bars indicate concentration of uranium and arsenic associated with each fraction.…”

Section: Geochemical Controls On U Transportmentioning

confidence: 95%

“…[33] Downstream of the tailings pile by 2 km, the Pete's Creek wetland site has an As concentration of 87 mg kg À1 , suggesting that transport is limited past the pond. Surface water As concentrations are also lower at the Pete's Creek wetland site than at the pond (577 mg L À1 ).…”

Section: Geochemical Controls On U Transportmentioning

confidence: 99%

“…[31] In addition, As V can be reduced by dissimilatory metal reducing bacteria or by bacteria as a detoxification mechanism to form less toxic methylated As III . [32][33][34] Thermodynamically, As V reduction is favoured over Fe III and sulfate reduction. [35] Uranium and As may also control the solubility of each other in the environment.…”

Section: Introductionmentioning

confidence: 99%

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Effect of biogeochemical redox processes on the fate and transport of As and U at an abandoned uranium mine site: an X-ray absorption spectroscopy study

Troyer

Stone

2014

Environ. Chem.

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Environmental context. Uranium and arsenic, two elements of human health concern, are commonly found at sites of uranium mining, but little is known about processes influencing their environmental behaviour. Here we focus on understanding the chemical and physical processes controlling uranium and arsenic transport at an abandoned uranium mine. We find that the use of sedimentation ponds limits the mobility of uranium; however, pond conditions at our site resulted in arsenic mobilisation. Our findings will help optimise restoration strategies for mine tailings.Abstract. Although As can occur in U ore at concentrations up to 10 wt-%, the fate and transport of both U and As at U mine tailings have not been previously investigated at a watershed scale. The major objective of this study was to determine primary chemical and physical processes contributing to transport of both U and As to a down gradient watershed at an abandoned U mine site in South Dakota. Uranium is primarily transported by erosion at the site, based on decreasing concentrations in sediment with distance from the tailings. Sequential extractions and U X-ray absorption near-edge fine structure (XANES) fitting indicate that U is immobilised in a near-source sedimentation pond both by prevention of sediment transport and by reduction of U VI to U IV . In contrast to U, subsequent release of As to the watershed takes place from the pond partially due to reductive dissolution of Fe oxy(hydr)oxides. However, As is immobilised by adsorption to clays and Fe oxy(hydr)oxides in oxic zones and by formation of As-sulfide mineral phases in anoxic zones down gradient, indicated by sequential extractions and As XANES fitting. This study indicates that As should be considered during restoration of uranium mine sites in order to prevent transport.

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