Arsenic mobilization and attenuation by mineral–water interactions: implications for managed aquifer recharge

Neil, Chelsea W.; Yang, Yu-Jun; Jun, Young‐Shin

doi:10.1039/c2em30323j

Cited by 41 publications

(35 citation statements)

References 141 publications

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“…One of the most concerning geochemical risks to receiving aquifers is the potential for arsenic mobilization from aquifer sediments (Neil et al, 2012). The release of arsenic has been observed at numerous managed aquifer recharge sites around the world due to several different geochemical mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Multiscale Characterization and Quantification of Arsenic Mobilization and Attenuation During Injection of Treated Coal Seam Gas Coproduced Water into Deep Aquifers

Rathi

Siade

Donn

et al. 2017

Water Resources Research

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Coal seam gas production involves generation and management of large amounts of co‐produced water. One of the most suitable methods of management is injection into deep aquifers. Field injection trials may be used to support the predictions of anticipated hydrological and geochemical impacts of injection. The present work employs reactive transport modeling (RTM) for a comprehensive analysis of data collected from a trial where arsenic mobilization was observed. Arsenic sorption behavior was studied through laboratory experiments, accompanied by the development of a surface complexation model (SCM). A field‐scale RTM that incorporated the laboratory‐derived SCM was used to simulate the data collected during the field injection trial and then to predict the long‐term fate of arsenic. We propose a new practical procedure which integrates laboratory and field‐scale models using a Monte Carlo type uncertainty analysis and alleviates a significant proportion of the computational effort required for predictive uncertainty quantification. The results illustrate that both arsenic desorption under alkaline conditions and pyrite oxidation have likely contributed to the arsenic mobilization that was observed during the field trial. The predictive simulations show that arsenic concentrations would likely remain very low if the potential for pyrite oxidation is minimized through complete deoxygenation of the injectant. The proposed modeling and predictive uncertainty quantification method can be implemented for a wide range of groundwater studies that investigate the risks of metal(loid) or radionuclide contamination.

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Section: Introductionmentioning

confidence: 99%

Multiscale Characterization and Quantification of Arsenic Mobilization and Attenuation During Injection of Treated Coal Seam Gas Coproduced Water into Deep Aquifers

Rathi

Siade

Donn

et al. 2017

Water Resources Research

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“…15 These electrostatic forces can also promote ironĲIII) (hydr)oxide interactions with other negatively charged water components such as natural organic matter (NOM). 4 In regions where arsenic contamination of ground and surface waters is a concern, such as Bangladesh, 9 NOM is also ubiquitously present at concentrations ranging from 0-10 mg C (carbon) per L in surface water and 0-2 mg C per L in groundwater. 16 Therefore, it is important to fully understand how the presence of arsenic, together with NOM, will impact ironĲIII) (hydr)oxide precipitation.…”

Section: Introductionmentioning

confidence: 99%

Fractal aggregation and disaggregation of newly formed iron(iii) (hydr)oxide nanoparticles in the presence of natural organic matter and arsenic

Neil

Ray

Lee

et al. 2016

Environ. Sci.: Nano

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Water chemistry affects the nucleation kinetics, precipitate morphology, and quantity of ironĲIII) (hydr)oxide nanoparticles, directly impacting the reactive surface area of geomedia and fate of associated waterborne contaminants. In this study, we utilized in situ grazing-incidence small angle X-ray scattering (GISAXS) and complementary ex situ techniques to investigate heterogeneous ironĲIII) (hydr)oxide nucleation on quartz in the presence of natural organic matter (NOM) and arsenate. Results indicate unique fractal aggregation behavior in the systems containing NOM and precipitating ironĲIII) (hydr)oxide nanoparticles. Furthermore, the coexistence of arsenic and NOM lead to the formation of two distinct particle size ranges: larger particles dominated by arsenic effects, and smaller particles dominated by NOM effects. These new findings provide important implications for understanding the nucleation, growth, and aggregation of ironĲIII) (hydr)oxides in aqueous systems where NOM is present, such as natural surface waters and water and wastewater treatment plants. This study also offers new insight into how NOM-associated ironĲIII) (hydr)oxides can interact with aqueous contaminants such as arsenate.A better understanding of the fate and transport of ironĲIII) (hydr)oxide nanoparticles is crucial for controlling trace toxic contaminants in natural and engineered aquatic systems. Despite this, their nucleation, growth, and aggregation are not well understood. We studied the impacts of natural organic matter and arsenate on newly-forming ironĲIII) (hydr)oxide in situ and found that these constituents altered the nanoparticle size and aggregation state. Our findings allow us to elucidate how contaminants affect the aggregation or disaggregation of ironĲIII) (hydr)oxide nanoparticles in aqueous environments, where organic matter will be nearly ubiquitously present. Outcomes can also be informative in developing reactive transport models that better predict the ability of ironĲIII) (hydr)oxides to attenuate aqueous contaminants.

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“…Lately, however, the release of arsenic was noted as a serious concern during MAR. − Arsenic concentrations in recovered water from MAR sites, such as southwest central Florida (10–130 μg/L) and South Australia (14–25 μg/L), were much higher than the injected water (3 μg/L for both sites), also surpassing the 10 μg/L arsenic maximum level set by the U.S. EPA. ,, First, the oxidative dissolution of arsenic-bearing minerals, such as arsenian pyrite (FeAs x S 2– x , < 0.5–10 wt % As) and arsenopyrite (FeAsS), is a dominant mechanism for arsenic mobilization during MAR. ,− In addition, non-redox-related arsenic mobilization mechanisms can exist. For instance, competitive ligand interactions and pH changes of groundwater induced by recharged water injection can increase arsenic mobility.…”

Section: Introductionmentioning

confidence: 99%

“…During the oxidative dissolution of arsenopyrite induced by dissolved oxygen (O 2 ) or nitrate (eq and ), arsenic and iron are released and oxidized from arsenic(I) to arsenic(III) and arsenic(IV) and from iron(II) to iron(III) . Iron(III) further forms secondary mineral phases, such as iron(III) (hydr)oxides, which can, in turn, adsorb aqueous arsenic species and decrease their mobility. ,, Changes in local water chemistry induced by MAR can impact the oxidative dissolution of arsenopyrite, secondary iron(III) (hydr)oxides formation and their physicochemical properties, and the adsorption of arsenic onto iron(III) (hydr)oxides . In particular, different water components in the recharged water may have varied impacts on arsenopyrite dissolution and secondary iron(III) (hydr)oxide precipitation.…”

Section: Introductionmentioning

confidence: 99%

Effects of Phosphate, Silicate, and Bicarbonate on Arsenopyrite Dissolution and Secondary Mineral Precipitation

Burnell

Neil

et al. 2020

ACS Earth Space Chem.

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Managed aquifer recharge (MAR) has been applied to meet quickly growing water demands. However, during MAR operations, the injected water can induce dissolution of local minerals and result in the release of toxic metalloids, such as arsenic. To alleviate this concern, it is pivotal to understand the effects of injected water chemistry on arsenic mobilization during MAR. In this bench-scale study with geochemical conditions relevant to MAR operations, we investigated the impacts of three environmentally abundant oxyanions (i.e., phosphate, silicate, and bicarbonate) on arsenic mobilization from arsenopyrite (FeAsS) and secondary mineral precipitation. Phosphate showed time-dependent reversed effects on arsenic mobility. In short term (6 h), phosphate promoted the dissolution of FeAsS through monodentate mononuclear surface complexation. However, over a longer experimental time (7 days), the enhanced formation of secondary minerals, such as iron(III) (hydr)oxide (maghemite, γ-Fe2O3) and iron(III) phosphate (phosphosiderite, FePO4·2H2O), helped to decrease arsenic mobility through readsorption. Silicate increased arsenic mobility and bicarbonate decreased arsenic mobility during the entire 7 day reaction. The phosphate system showed the highest amount and largest sizes of secondary precipitates among the three oxyanions. These new observations provide a useful mechanistic understanding of the impacts of different oxyanions on arsenic mobilization and secondary mineral formation during the geochemical transformation of arsenic-containing sulfide minerals in MAR and also offer useful insight into water chemistry factors during pretreatment for MAR source water.

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Arsenic mobilization and attenuation by mineral–water interactions: implications for managed aquifer recharge

Cited by 41 publications

References 141 publications

Multiscale Characterization and Quantification of Arsenic Mobilization and Attenuation During Injection of Treated Coal Seam Gas Coproduced Water into Deep Aquifers

Multiscale Characterization and Quantification of Arsenic Mobilization and Attenuation During Injection of Treated Coal Seam Gas Coproduced Water into Deep Aquifers

Fractal aggregation and disaggregation of newly formed iron(iii) (hydr)oxide nanoparticles in the presence of natural organic matter and arsenic

Effects of Phosphate, Silicate, and Bicarbonate on Arsenopyrite Dissolution and Secondary Mineral Precipitation

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