Oxidative dissolution of amorphous FeS and speciation of secondary Fe minerals: Effects of pH and As(III) concentration

An, Xue-Liang; Huang, Fu-Gen; Ren, Haitao; Wang, Yanfang; Chen, Yao; Liu, Zhongmin; Zhang, Hongwei; Han, Xu

doi:10.1016/j.chemgeo.2017.04.025

Cited by 41 publications

(12 citation statements)

References 43 publications

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“…This indicates that the binding of As to these minerals is relevant to understand As reactivity as reported in other studies (Deng et al, 2018; Johnston et al, 2012; Asta et al, 2009). As reported in the literature (An et al, 2017; Zhang et al, 2016; Troyer et al, 2014b), Fe and S are present in subsurface environments as iron-sulfide minerals such as pyrite and mackinawite. After these solids have been exposed to the surface because of mining activities, Fe and S can oxidize, resulting in the formation of Fe(III) oxides and sulfate.…”

Section: Resultsmentioning

confidence: 57%

Reactivity of As and U co-occurring in Mine Wastes in northeastern Arizona

et al. 2019

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The reactivity of co-occurring arsenic (As) and uranium (U) in mine wastes was investigated using batch reactors, microscopy, spectroscopy, and aqueous chemistry. Analyses of field samples collected in proximity to mine wastes in northeastern Arizona confirm the presence of As and U in soils and surrounding waters, as reported in a previous study from our research group. In this study, we measured As (< 0.500 to 7.77 μg/L) and U (0.950 to 165 μg/L) in waters, as well as mine wastes (< 20.0 to 40.0 mg/kg As and < 60.0 to 110 mg/kg U) and background solids (< 20.0 mg/kg As and < 60.0 mg/kg U). Analysis with X-ray fluorescence (XRF) and electron microprobe show the co-occurrence of As and U with iron (Fe) and vanadium (V). These field conditions served as a foundation for additional laboratory experiments to assess the reactivity of metals in these mine wastes. Results from laboratory experiments indicate that labile and exchangeable As(V) was released to solution when solids were sequentially reacted with water and magnesium chloride (MgCl2), while limited U was released to solution with the same reactants. The predominance of As(V) in mine waste solids was confirmed by X-ray absorption near edge (XANES) analysis. Both As and U were released to solution after reaction of solids in batch experiments with HCO3−. Both X-ray photoelectron spectroscopy (XPS) and XANES analysis determined the predominance of Fe(III) in the solids. Mössbauer spectroscopy detected the presence of nano-crystalline goethite, Fe(II) and Fe(III) in (phyllo)silicates, and an unidentified mineral with parameters consistent with arsenopyrite or jarosite in the mine waste solids. Our results suggest that As and U can be released under environmentally relevant conditions in mine waste, which is applicable to risk and exposure assessment.

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Section: Resultsmentioning

confidence: 57%

Reactivity of As and U co-occurring in Mine Wastes in northeastern Arizona

et al. 2019

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“…The development of reducing conditions is progressive with depth, and results in an oxic-to-anoxic transition zone in the upper sediment column, in the hypolimnion of seasonally stratified lakes or, in some cases, under prolonged ice cover (e.g., Palmer et al 2019 ). At this redox interface, decreasing concentrations of available O 2 result in the release of As through reductive dissolution of Fe- and Mn-(oxy)hydroxides (Wolthers et al 2005 ; Bennett et al 2012 ; An et al 2017 ). Under changing redox conditions, the formation of organo-mineral aggregates (OMAs) and/or Fe monosulfides (FeS; e.g., mackinawite) may promote the sequestration of metal(loid)s (e.g., As, Cu, Cd, Ni, Pb, and Zn) through co-precipitation with, or sorption to, these authigenic phases (Coles et al 2000 ; Farquhar et al 2002 ; Gallegos et al 2007 ; Du et al 2018 ; Zhou et al 2021 ).…”

Section: Introductionmentioning

confidence: 99%

“…Under changing redox conditions, the formation of organo-mineral aggregates (OMAs) and/or Fe monosulfides (FeS; e.g., mackinawite) may promote the sequestration of metal(loid)s (e.g., As, Cu, Cd, Ni, Pb, and Zn) through co-precipitation with, or sorption to, these authigenic phases (Coles et al 2000 ; Farquhar et al 2002 ; Gallegos et al 2007 ; Du et al 2018 ; Zhou et al 2021 ). However, the effectiveness of these mechanisms in sequestering elements from bottom waters to sediments in natural environments is difficult to predict (Moon and Peacock 2012 ; Chen et al 2014 ; Kleber et al 2015 ; An et al 2017 ; Vega et al 2017 ; Qu et al 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Mediation of arsenic mobility by organic matter in mining-impacted sediment from sub‐Arctic lakes: implications for environmental monitoring in a warming climate

et al. 2022

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Arsenic (As) is commonly sequestered at the sediment–water interface (SWI) in mining-impacted lakes through adsorption and/or co-precipitation with authigenic iron (Fe)-(oxy)hydroxides or sulfides. The results of this study demonstrate that the accumulation of organic matter (OM) in near-surface sediments also influences the mobility and fate of As in sub-Arctic lakes. Sediment gravity cores, sediment grab samples, and porewaters were collected from three lakes downstream of the former Tundra gold mine, Northwest Territories, Canada. Analysis of sediment using combined micro-X-ray fluorescence/diffraction, K-edge X-ray Absorption Near-Edge Structure (XANES), and organic petrography shows that As is associated with both aquatic (benthic and planktonic alginate) and terrestrially derived OM (e.g., cutinite, funginite). Most As is hosted by fine-grained Fe-(oxy)hydroxides or sulfide minerals (e.g., goethite, orpiment, lepidocrocite, and mackinawite); however, grain-scale synchrotron-based analysis shows that As is also associated with amorphous OM. Mixed As oxidation states in porewater (median = 62% As (V), 18% As (III); n = 20) and sediment (median = 80% As (-I) and (III), 20% As (V); n = 9) indicate the presence of variable redox conditions in the near-surface sediment and suggest that post-depositional remobilization of As has occurred. Detailed characterization of As-bearing OM at and below the SWI suggests that OM plays an important role in stabilizing redox-sensitive authigenic minerals and associated As. Based on these findings, it is expected that increased concentrations of labile OM will drive post-depositional surface enrichment of As in mining-impacted lakes and may increase or decrease As flux from sediments to overlying surface waters.

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“…The development of reducing conditions in sediments is progressive with depth, and results in an oxic-to-anoxic transition zone in the upper sediment column, in the hypolimnion of seasonally stratified lakes or, in some cases, under prolonged ice cover (e.g., Palmer et al, 2019). At this redox interface, decreasing concentrations of available O2 result in the release of As through reductive dissolution of Fe-and Mn-(oxy)hydroxides (Wolthers et al, 2005;Bennett et al, 2012;An et al, 2017). Under changing redox conditions, the formation of organo-mineral aggregates (OMAs) and/or Fe monosulphides (FeS; e.g., mackinawite) may promote the sequestration of metal(loid)s (e.g., As, Cu, Cd, Ni, Pb, Zn) through co-precipitation with, or sorption to, these authigenic phases.…”

Section: Introductionmentioning

confidence: 99%

“…However, the effectiveness of these mechanisms in sequestering elements from bottom waters to sediments in natural environments is difficult to predict (Moon and Peacock, 2012;Chen et al, 2014;Kleber et al, 2015;An et al, 2017;Vega et al, 2017;Du et al, 2018;Qu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Grain-Scale Analysis of Solid-Phase Organic Matter and Arsenic Mobility in Mining-Impacted 1 Sediment from Sub‐Arctic Lakes, Northwest Territories, Canada

Miller

Parsons

Jamieson

et al. 2021

Preprint

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Arsenic (As) is commonly sequestered at the sediment-water interface (SWI) in mining-impacted lakes through adsorption and/or co-precipitation with authigenic iron (Fe)-(oxy)hydroxides or sulphides. The results of this study demonstrate that the accumulation of solid-phase organic matter (OM) in near-surface sediments also influences the mobility and fate of As in sub-Arctic lakes. Sediment gravity cores, sediment grab samples, and porewaters were collected from three lakes downstream of the former Tundra gold mine, Northwest Territories. Analysis of sediment using combined micro-X-ray fluorescence/diffraction, K-edge X-ray Absorption Near-Edge Structure (XANES), and organic petrography shows that As is associated with both aquatic (benthic and planktonic alginate) and terrestrially-derived OM (cutinite; funginite). Most As is hosted by fine-grained Fe-(oxy)hydroxides or sulphide minerals ( e.g., goethite, orpiment, lepidocrocite, mackinawite); however, grain-scale synchrotron-based analysis shows that As is also associated with amorphous OM. Mixed As oxidation states in porewater (median = 62 % As (V), 18 % As (III); n = 20) and sediment (median = 80 % As (-I) and (III), 19 % As (V); n = 9) indicate the presence of variable redox conditions in the near-surface sediment and suggest that post-depositional remobilization of As has occurred . Detailed characterization of As-bearing OM at and below the SWI suggests that OM plays an important role in stabilizing redox-sensitive authigenic minerals and associated As. Based on these findings, it is expected that increased concentrations of labile OM will drive post-depositional surface-enrichment of As in mining-impacted lakes and may increase or decrease As flux from sediments to overlying surface waters.

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Oxidative dissolution of amorphous FeS and speciation of secondary Fe minerals: Effects of pH and As(III) concentration

Cited by 41 publications

References 43 publications

Reactivity of As and U co-occurring in Mine Wastes in northeastern Arizona

Reactivity of As and U co-occurring in Mine Wastes in northeastern Arizona

Mediation of arsenic mobility by organic matter in mining-impacted sediment from sub‐Arctic lakes: implications for environmental monitoring in a warming climate

Grain-Scale Analysis of Solid-Phase Organic Matter and Arsenic Mobility in Mining-Impacted 1 Sediment from Sub‐Arctic Lakes, Northwest Territories, Canada

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