Geostatistical modelling of arsenic in drinking water wells and related toenail arsenic concentrations across Nova Scotia, Canada

Dummer, Trevor J.B.; Yu, Zhijie; Nauta, Laura; Murimboh, John; Parker, Louise

doi:10.1016/j.scitotenv.2014.02.055

Cited by 55 publications

(34 citation statements)

References 43 publications

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“…The four wells in the Meguma Supergroup with groundwater As concentrations ranging from 18 to 365 µg/L have pH values greater than 7 and tend to be low in dissolved oxygen, with > 90% of the As present as As(III) (Bottomley, 1984). In this special issue, a study of spatial patterns of well water As in Nova Scotia has led to the development of a statistical model based on arsenic concentrations in 10,498 private wells that predicted not only concentrations of arsenic in well water from a set of geological and environmental factors but also concentrations of arsenic in toenail samples from study subjects (Dummer et al, this issue). The maximum As concentration from the 10,498 private wells in Nova Scotia was 3,900 µg/L, with 17% of the wells containing more than 10 µg/L of As (Table 2).…”

Section: Risks From Arsenic In Private Well Water Of Northeast Unitmentioning

confidence: 99%

At the crossroads: Hazard assessment and reduction of health risks from arsenic in private well waters of the northeastern United States and Atlantic Canada

Zheng

Ayotte

2015

Science of The Total Environment

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This special issue contains 12 papers that report on new understanding of arsenic hydrogeochemistry, performance of household well water treatment systems, and testing and treatment behaviors of well users in several states of the northeastern region of the United States and Nova Scotia, Canada. The responsibility to ensure water safety of private wells falls on well owners. In the U.S., 43 million Americans, mostly from rural areas, use private wells. In order to reduce As exposure in rural populations that rely on private wells for drinking water, risk assessment, which includes estimation of population at risk of exposure to As above the EPA Maximum Contaminant Level, is helpful but insufficient because it does not identify individual households at risk. Persistent optimism bias among well owners against testing and barriers such as cost of treatment mean that a large percentage of the population will not act to reduce their exposure to harmful substances such as As. If households are in areas with known As occurrence, a potentially large percentage of well owners will remain unaware of their exposure. To ensure that everyone, including vulnerable populations such as low income families with children and pregnant women, is not exposed to arsenic in their drinking water, alternative action will be required and warrants further research.

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Section: Risks From Arsenic In Private Well Water Of Northeast Unitmentioning

confidence: 99%

At the crossroads: Hazard assessment and reduction of health risks from arsenic in private well waters of the northeastern United States and Atlantic Canada

Zheng

Ayotte

2015

Science of The Total Environment

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“…Randall et al (1988) noted that for the Northeastern Appalachian groundwater region, flow is generally most rapid in the uppermost 15 to 35 m below the bedrock surface, with fractures much less abundant below 75 m depth, but with localized productive zones at depths of 100 to 650 m. Diggins (2014) investigated fracturing in granite, schist, and amphibolite in the Appalachian belt in Massachusetts, noting minimal flow below 170 m and the majority of flow constrained to the upper 100 m. Dummer et al (2015) recorded that most of Nova Scotia's 117 000 domestic wells in bedrock aquifers are less than 155 m deep. Baechler and Boehner (2014) suggested that active karst solution of saline evaporite rocks on Cape Breton Island can occur locally at depths exceeding 400 m. Farvolden et al (1988) in an assessment of crystalline rocks in the Canadian Precambrian Shield stated that while a case can be made for a log-linear decrease in hydraulic conductivity with depth in the upper 100 to 400 m, fracture zones associated with steep fault zones have been encountered down to at least 1000 m.…”

Section: Present-day Hydrological Settingmentioning

confidence: 99%

Geology and Hydrogeology of Faults on Cape Breton Island, Nova Scotia, Canada: an overview

Baechler¹

2015

atgeol

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Cape Breton Island provides a hydrogeological view into the roots of an ancient mountain range, now exhumed, glaciated, and tectonically inactive. It exhibits deep crustal faults and magma chambers associated with formation of the Appalachian mountain belt and the Maritimes Basin during the Paleozoic, as well as Mesozoic rifting relating to the opening of the Atlantic Ocean. Cenozoic exhumation brought these features near surface and into the active groundwater flow field where they were impacted by glaciation and fluctuating sea level. The faults have been important from a societal viewpoint in development of municipal groundwater supplies, controlling inflows to excavations, hydrocarbon exploration, quarry development, and geotechnical investigations. Conceptual models presented here outline fault control on groundwater flow based on seven case studies. Future research should focus on basin-bounding faults in support of managing their role in aquifer development and protection, mountain-front recharge, controlling large-magnitude springs, groundwater-stream interaction, and channel morphology. The hydrogeological importance of these faults has historically been underappreciated. rÉSUMÉ L'île du Cap Breton procure un aperçu hydrogéologique des racines d'une ancienne chaîne de montagnes, maintenant exhumée, érodée par la glaciation et tectoniquement inactive. Elle présente des chambres magmatiques et des failles crustales profondes associées à la formation de la ceinture montagneuse des Appalaches et du bassin des Maritimes au cours du Paléozoïque, ainsi qu'au rifting du Mésozoïque lié à l' ouverture de l' océan Atlantique. L' exhumation survenue durant le Cénozoïque a rapproché ces particularités de la surface à l'intérieur du champ d' écoulement des eaux souterraines actif, où elles ont été touchées par la glaciation et les fluctuations du niveau de la mer. Les failles se sont avérées importantes sur le plan sociétal pour l' établissement de réserves municipales d'approvisionnement en eau souterraine, le contrôle des infiltrations d' eau dans les excavations, la prospection des gisements d'hydrocarbures, l'aménagement des carrières et les études géotechniques. Les modèles conceptuels présentés illustrent le contrôle par les failles de l' écoulement des eaux souterraines d'après sept études de cas. Les recherches futures devraient porter sur les failles délimitant des bassins aux fins de la gestion de leur rôle dans le développement et la protection des aquifères, l'alimentation du front des secteurs montagneux, le contrôle des sources de forte magnitude, l'interaction entre les eaux souterraines et les cours d' eau et la morphologie des canaux. L'importance hydrogéologique de ces failles a été sousestimée par le passé. [Traduit par la redaction]

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“…Although atmospheric deposition (Weiss et al 2002;Sullyman 2003;O'Driscoll et al 2005), lead shot (Schwab and Daury 1989), and till (Dummer et al 2015) have been recognized as possible sources of these elements in lakebed sediments in the CMR, their relative importance is unknown, and other unrecognized sources may exist.…”

Section: Introductionmentioning

confidence: 99%

A paleolimnological archive of metal sequestration and release in the Cumberland Basin Marshes, Atlantic Canada

Dunnington

White

Spooner

et al. 2017

FACETS

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We used a paleolimnological approach at Long Lake, Nova Scotia, to construct a 10 500-year record of metal deposition in lakebed sediments and elucidate the influence of both natural and anthropogenic environmental changes. Aquatic sediment concentrations of mercury (Hg), arsenic (As), and chromium (Cr) in Long Lake fluctuated substantially and, during some periods, exceeded guidelines for the protection of aquatic life. Increases in lead (Pb), Hg, Cr, trace metals, and nitrogen stable isotopes (δ 15 N) were broadly coincident with a period of widespread drying from ca. 8000 to 4000 cal BP and were likely a consequence of regional fires. From ca. 4000 cal BP until 1700 AD, metal levels in general were low due to decreased erosion, increased precipitation, and reduced fire activity. Water level lowering and forced sediment aggradation (tiding) in the 1800s led to increases in minerogenic Pb and Cr, though fossil fuel combustion also likely contributed to total Pb concentrations. Stratigraphic proxies indicated increased inorganic sedimentation rates, and reduced autochthonous productivity were coincident with lower Hg and As concentrations in the Long Lake sediment. Our data indicate that natural phenomena (fire) can result in sediment contaminant exceedances, that most metals have multiple sources, and that both human-induced disturbance and emissions have contributed to Pb contamination in the last 200 years. In addition, wetter and generally cooler climate appeared to favour lower concentrations of contaminants in lake sediments. Although wetland sediments in the Cumberland Basin Marshes are not heavily polluted with metals, the development of constructed wetlands and the disruption of aquatic sediments have the potential to concentrate, mobilize, and increase the bioavailability of metals.

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Geostatistical modelling of arsenic in drinking water wells and related toenail arsenic concentrations across Nova Scotia, Canada

Cited by 55 publications

References 43 publications

At the crossroads: Hazard assessment and reduction of health risks from arsenic in private well waters of the northeastern United States and Atlantic Canada

At the crossroads: Hazard assessment and reduction of health risks from arsenic in private well waters of the northeastern United States and Atlantic Canada

Geology and Hydrogeology of Faults on Cape Breton Island, Nova Scotia, Canada: an overview

A paleolimnological archive of metal sequestration and release in the Cumberland Basin Marshes, Atlantic Canada

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