A Review and Evaluation of the Impacts of Climate Change on Geogenic Arsenic in Groundwater from Fractured Bedrock Aquifers

Bondu, Raphaël; Cloutier, Vincent; Rosa, Éric; Benzaazoua, Mostafa

doi:10.1007/s11270-016-2936-6

Cited by 53 publications

(25 citation statements)

References 80 publications

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“…These wells are 27.5 m apart which illustrate that arsenic concentrations can vary over small spatial scales (Ravenscroft et al 2009;Smedley and Kinniburgh 2013;Ayotte et al 2017). In these fractured aquifers, this large spatial variability is mainly governed by groundwater flow through influencing the dilution process and hydrochemistry with previous studies illustrating a similar process (Peters 2008;Smedley et al 2007;Bondu et al 2016). Groundwater samples had low Ca/Na ratios with boreholes containing elevated arsenic concentrations having lower ratios (Fig.…”

Section: Arsenic Geochemistry and Speciationsupporting

confidence: 53%

Occurrence, Geochemistry and Speciation of Elevated Arsenic Concentrations in a Fractured Bedrock Aquifer System

McGrory

Henry

Conroy

et al. 2021

Arch Environ Contam Toxicol

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The presence of elevated arsenic concentrations (≥ 10 µg L−1) in groundwaters has been widely reported in areas of South-East Asia with recent studies showing its detection in fractured bedrock aquifers is occurring mainly in regions of north-eastern USA. However, data within Europe remain limited; therefore, the objective of this work was to understand the geochemical mobilisation mechanism of arsenic in this geologic setting using a study site in Ireland as a case study. Physicochemical (pH, Eh, d-O2), trace metals, major ion and arsenic speciation samples were collected and analysed using a variety of field and laboratory-based techniques and evaluated using statistical analysis. Groundwaters containing elevated dissolved arsenic concentrations (up to 73.95 µg L−1) were characterised as oxic-alkali groundwaters with the co-occurrence of other oxyanions (including Mo, Se, Sb and U), low dissolved concentrations of Fe and Mn, and low Na/Ca ratios indicated that arsenic was mobilised through alkali desorption of Fe oxyhydroxides. Arsenic speciation using a solid-phase extraction methodology (n = 20) showed that the dominant species of arsenic was arsenate, with pH being a major controlling factor. The expected source of arsenic is sulphide minerals within fractures of the bedrock aquifer with transportation of arsenic and other oxyanion forming elements facilitated by secondary Fe mineral phases. However, the presence of methylarsenical compounds detected in groundwaters illustrates that microbially mediated mobilisation processes may also be (co)-occurring. This study gives insight into the geochemistry of arsenic mobilisation that can be used to further guide research needs in this area for the protection of groundwater resources.

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Section: Arsenic Geochemistry and Speciationsupporting

confidence: 53%

Occurrence, Geochemistry and Speciation of Elevated Arsenic Concentrations in a Fractured Bedrock Aquifer System

McGrory

Henry

Conroy

et al. 2021

Arch Environ Contam Toxicol

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“…Changes in near‐surface and deep groundwater dynamics will also modify the variation of solute concentrations across headwater subcomponents. For example, water quality is likely to degrade (e.g., increasing sulfate and metals) with deeper water tables (Manning et al, ), geochemical evolution along longer flow paths (Bondu et al, ) and stream waters becoming more dependent on solute‐rich ground water.…”

Section: Discussionmentioning

confidence: 99%

The Importance of Interflow to Groundwater Recharge in a Snowmelt‐Dominated Headwater Basin

Carroll

Deems

Niswonger

et al. 2019

Geophysical Research Letters

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Understanding the sensitivity of groundwater generation to climate in a mountain system is complicated by the tight coupling of snow dynamics to vegetation and topography. To address these feedbacks, we combine light detection and ranging (LiDAR)‐derived snow observations with an integrated hydrologic model to quantify spatially and temporally distributed water fluxes across varying climate conditions in a Colorado River headwater basin. Results indicate that annual groundwater flow is an important and stable source of stream water. However, interflow decreases during drought as a function increased plant water use and the relative fraction of groundwater to streams increases. Seasonal snowmelt and vegetation water use regulate small recharge rates in the lower portions of the basin, but snowmelt transported via interflow from high mountain ridges toward convergent topographic zones defines preferential recharge in the upper subalpine. Recharge in this zone appears decoupled from annual climate variability and resilient to drought.

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“…In comparison, less geochemically evolved groundwater (younger groundwater) contains low dissolved arsenic, i.e. higher Ca/Na ratios (Ryan et al 2013;Bondu et al 2016). As the geochemical signature of groundwater evolves along the ow path arsenic concentrations increase with depth (Fig.…”

Section: Arsenic Geochemistrymentioning

confidence: 99%

“…As the geochemical signature of groundwater evolves along the ow path arsenic concentrations increase with depth (Fig. 3a) (Smedley et al 2007;Bondu et al 2016). Ca/Na ratios calculated in this present study are mixed which suggests a mixing of younger and older groundwaters along the ow path presumably at fracture points which is supported given that a signi cant portion of groundwater is recharge water (Fig S4a-b).…”

Section: Arsenic Geochemistrymentioning

confidence: 99%

Occurrence, Geochemistry and Speciation of Elevated Arsenic Concentrations in a Fractured Bedrock Aquifer System

McGrory

Henry

Conroy

et al. 2021

Preprint

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The presence of elevated arsenic concentrations (≥10 µg L-1) in groundwaters has been widely reported in areas of south east Asia with recent studies showing its detection in fractured bedrock aquifers mainly in regions of north-eastern United States. Data within Europe remains limited; therefore, the objective of this work was to understand the geochemical mobilisation mechanism of arsenic in this geologic setting. Physiochemical (pH, Eh, d-O2), trace metals, major ion and arsenic speciation samples were collected and analysed using a variety of field and laboratory-based techniques and evaluated using statistical analysis including multivariate analysis. Elevated dissolved arsenic concentrations (up to 73.95 µg L-1) were observed in oxic-alkali groundwaters with the co-occurrence of other oxyanions (e.g. Mo, Se, Sb and U), low dissolved concentrations of Fe and Mn and low Na/Ca ratios indicating that arsenic was mobilised through alkali desorption of Fe oxyhydroxides. Arsenic speciation using a solid-phase extraction methodology (n=20) showed that the dominant species of arsenic present in groundwater was arsenate, with pH being a major controlling factor. The expected source of arsenic is sulfide minerals within fractures of the bedrock aquifer with transportation of arsenic and other oxyanion-forming elements facilitated by secondary Fe mineral phases. However, the presence of methylarsenical compounds detected in the groundwaters illustrates that microbially mediated mobilisation processes were also (co)-occurring. This study demonstrates how field speciation of arsenic can be utilised to overcome analytical limitations of conventional laboratory speciation and to facilitate in the interpretation of the environmental mobility of arsenic within groundwaters.

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A Review and Evaluation of the Impacts of Climate Change on Geogenic Arsenic in Groundwater from Fractured Bedrock Aquifers

Cited by 53 publications

References 80 publications

Occurrence, Geochemistry and Speciation of Elevated Arsenic Concentrations in a Fractured Bedrock Aquifer System

Occurrence, Geochemistry and Speciation of Elevated Arsenic Concentrations in a Fractured Bedrock Aquifer System

The Importance of Interflow to Groundwater Recharge in a Snowmelt‐Dominated Headwater Basin

Occurrence, Geochemistry and Speciation of Elevated Arsenic Concentrations in a Fractured Bedrock Aquifer System

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