Arsenic in Groundwater Wells in Quaternary Deposits in the Lower Fraser Valley of British Columbia

Wilson, Julie E.; Brown, Sandra; Schreier, Hans; Scovill, D.; Zubel, Marc

doi:10.4296/cwrj3304397

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…In the Lower Fraser Valley region of British Columbia, where this study was undertaken, the arsenic is of natural origin and is associated with marine and glaciomarine sediment deposits. It is predominantly found in deep wells, in aquifers which are classified as confined and of low vulnerability [7] .…”

Section: Sources and Distribution Of Groundwater Arsenicmentioning

confidence: 99%

Follow-up study of private well users affected by groundwater arsenic in the Surrey-Langley area

Gordon¹,

Sciences²,

Zubel³

et al. 2017

ephj

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Background: Arsenic is a potent toxicant and Group 1 human carcinogen which occurs naturally in certain sediments and can contaminate groundwater. In the Surrey-Langley area of British Columbia, a 2007 study of private wells found that 43% of wells tested contained arsenic concentrations above the maximum acceptable concentration (MAC) prescribed in Health Canada’s Guidelines for Canadian Drinking Water Quality. The well owners who participated in the 2007 study were informed of the results and of effective treatment methods that would remove the arsenic contamination. This is a follow-up study that surveyed affected well users approximately 10 years later in order to identify whether the well users had subsequently made any water treatment or behavioral changes to improve the quality of their drinking water, and also to determine whether knowledge translation of the arsenic risk had been effective. Methodology: This study contacted and enrolled private well users who were living at properties which had previously been included in the 2007 study and, in 2007, were found to have arsenic levels above the MAC in the groundwater. Respondents who agreed to participate completed a questionnaire designed to identify what treatment methods or behavioral methods they use to mitigate the risk posed by arsenic contamination. Pre-treatment and post-treatment samples of their drinking water were collected and the arsenic concentrations were analyzed. The effectiveness of treatment devices for arsenic removal was evaluated. The groundwater arsenic concentrations from approximately 10 years apart were compared to identify if arsenic levels had changed. Results: Of the 42 properties that participated in the 2007 study and had groundwater arsenic levels above the MAC, 17 participated in this follow-up study. 14 of the participants also took part in the 2007 study 10 years ago. 79% of participants had not known prior to taking part in the 2007 study that their drinking water contained arsenic levels above the MAC. All 79% then either installed reverse osmosis treatment devices to remove arsenic from their drinking water, or switched to using bottled water for drinking. This indicates that knowledge translation of the health risk was effective. Of the 8 properties using treatment devices rather than bottled water, to mitigate the arsenic risk, 2/8 (25%) were ineffective at reducing arsenic. In addition, arsenic groundwater concentrations were not found to have changed significantly in 10 years (p = 0.11). Conclusion: Participation in the 2007 study was viewed as useful and informative by participants. Knowledge translation of the health risk and the need for risk mitigation was effective, but 25% of treatment devices were found to be ineffective at removing arsenic from drinking water. These results suggests that further knowledge translation of the need for routine testing for arsenic in post-treated drinking water may be beneficial to affected private well users.

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Section: Sources and Distribution Of Groundwater Arsenicmentioning

confidence: 99%

Follow-up study of private well users affected by groundwater arsenic in the Surrey-Langley area

Gordon¹,

Sciences²,

Zubel³

et al. 2017

ephj

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“…Arsenic is a globally recognized geogenic and anthropogenic metalloid contaminant, − for which little information is available in a permafrost context. ,, Outside permafrost regions, it occurs in the oxidation states As(−I), As(III), and As(V) . Arsenite [As(III)] and arsenate [As(V)] are the dominant species encountered, although As(−I) sulfides and thiolated and methylated As(III) and As(V) species also occur under sulfidic and methanogenic redox conditions. ,− Iron-(oxyhydr)oxides are major solid-phase hosts of arsenite and arsenate in soils and sediments. ,, These phases are typically encountered at μg g –1 levels in alluvial materials because oxidizing conditions encountered during weathering and transport in surface water bodies favor their stability and transfer to depositional areas. ,, Iron-(oxyhydr)oxides exhibit high affinity toward As, forming stable inner and outer-sphere complexes with arsenite and arsenate. ,− However, their exposure to reducing conditions, encountered during rising subsurface water levels and/or exposure to labile organic C, triggers As mobilization via reductive dissolution. − This process is recognized worldwide as a driver of geogenic As release in aquifers composed of unconsolidated sediments across geologic environments and climatic conditions. ,,,− …”

Section: Introductionmentioning

confidence: 99%

Arsenic Mobilization from Thawing Permafrost

Skierszkan,

Schoepfer,

Fellwock

et al. 2024

ACS Earth Space Chem.

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Thawing permafrost releases labile organic carbon and alters groundwater geochemistry and hydrology with uncertain outcomes for the mobility of hazardous metal(loid)s. Managing water quality in thawing permafrost regions is predicated on a detailed understanding of the speciation and abundance of metal(loid)s in permafrost soils and porewaters produced during thaw, which remains limited at present. This study contributes new knowledge on the sources and fate of arsenic during the thaw of organic-rich permafrost using samples collected from a subarctic permafrost region associated with geogenic arsenic (Dawson Range, Yukon, Canada). Several permafrost cores and active-layer samples from this region were analyzed for their solid-phase and aqueous geochemical characteristics and their arsenic speciation. Porewaters were extracted from permafrost cores after thaw under anaerobic conditions for aqueous geochemical analyses. Bedrock samples from the field site were also analyzed for arsenic speciation and mineralogy. X-ray diffraction and X-ray near-edge spectroscopy (XANES) analyses of weathered bedrock upgradient of soil sampling locations contained arsenic(V) hosted in iron-(oxyhydr)oxides and scorodite. XANES and micro X-ray fluorescence analyses of permafrost soils indicated a mixture of arsenic(III) and arsenic(V), indicating redox recycling of arsenic. Soil-bound arsenic was colocated with iron, likely as arseniferous iron-(oxyhydr)oxides that have been encapsulated by aggrading permafrost over geologic time. However, permafrost thaw produced porewater containing elevated dissolved arsenic (median 40 μg L −1 , range 2−96 μg L −1 ). Thawed permafrost porewater also contained elevated dissolved iron (median 5.5 mg L −1 , range 0.5−40 mg L −1 ) and dissolved organic carbon (median 423 mg L −1 , range 72−3240 mg L −1 ), indicative of reducing conditions. This study highlights that arsenic can be found in reactive forms in permafrost soil, and that its thaw can release arsenic and iron to porewater and produce poor water quality.

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“…According to the data from private wells and source ground water, recently glaciated north-central areas of the state have the highest concentrations of arsenic in the ground water, followed by southwest area. As the soil of northern region consists of thicker glacial deposits, arsenic is detected predominantly in deeper wells Wilson et al 2008). In contrast, the eastern region (covers the broadest area from north to south) had the lowest arsenic concentrations.…”

Section: Occurrence Of Arsenic In Iowa Ground Watermentioning

confidence: 98%

Exposure to arsenic and atrazine from drinking water and risk of cancer

Roh¹

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Arsenic in Groundwater Wells in Quaternary Deposits in the Lower Fraser Valley of British Columbia

Cited by 7 publications

References 17 publications

Follow-up study of private well users affected by groundwater arsenic in the Surrey-Langley area

Follow-up study of private well users affected by groundwater arsenic in the Surrey-Langley area

Arsenic Mobilization from Thawing Permafrost

Exposure to arsenic and atrazine from drinking water and risk of cancer

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