Characterizing sediment sources and natural hydrocarbon inputs in the lower Athabasca River, Canada

For over a decade, the contribution of oil sands mining and processing to the pollution of the Athabasca River has been controversial. We show that the oil sands development is a greater source of contamination than previously realized. In 2008, within 50 km of oil sands upgrading facilities, the loading to the snowpack of airborne particulates was 11,400 T over 4 months and included 391 kg of polycyclic aromatic compounds (PAC), equivalent to 600 T of bitumen, while 168 kg of dissolved PAC was also deposited. . In the Athabasca and its tributaries, development within the past 2 years was related to elevated dissolved PAC concentrations that were likely toxic to fish embryos. In melted snow, dissolved PAC concentrations were up to 4.8 g/L, thus, spring snowmelt and washout during rain events are important unknowns. These results indicate that major changes are needed to the way that environmental impacts of oil sands development are monitored and managed.airborne deposition ͉ oil sands processing ͉ water contamination ͉ hydrocarbons ͉ oil sands mining

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“…1). The Athabasca River is exposed to the McMF 50 km upstream of Fort McMurray and is present within its banks to Eymundson Creek (38).…”

Section: Methodsmentioning

confidence: 99%

Oil sands development contributes polycyclic aromatic compounds to the Athabasca River and its tributaries

Kelly

Short²,

Schindler

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

347

345

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“…3). Previous reports indicated that differences in water quality along tributaries of the Athabasca River were due to the influence of incisement of the rich bitumen beds in the McMurray Formation (e.g., Conly et al 2002Conly et al , 2007Headley et al 2001Headley et al , 2005Alberta Government 2010). However, prior studies were substantially shorter in duration and spatial extent than the 38 year study described here.…”

Section: Establishing Reference In the Oil Sands Regionmentioning

confidence: 99%

“…Bitumen, a form of heavy crude oil, contains particulate organic material, hydrocarbons, associated metals, and sulfur compounds (WHO 2004). Earlier assessments (2001)(2002)(2003)(2004)(2005)(2006)(2007) attributed the presence of contaminants and heavy metals in the Athabasca River and its tributaries to natural erosion of the geological strata that contain bitumen (e.g., Conly et al 2002Conly et al , 2007Hedley et al 2001Hedley et al , 2005. The Alberta Government (2010) concluded, "there has been no increase in concentrations of contaminants as oil sands development has progressed."…”

Section: Introductionmentioning

confidence: 99%

Assessment of seven Canadian rivers in relation to stages in oil sands industrial development, 1972–2010

Alexander

Chambers

2016

Environ. Rev.

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Abstract:We compiled a 38 year dataset (1972 to 2010) to evaluate changes in water chemistry over time in relation to oil sands mining activities. We examined patterns in three focal elements (dissolved selenium, dissolved arsenic, total vanadium) at 96 sites along seven tributaries of the Athabasca and Clearwater Rivers. Concentrations of the three focal elements did not differ between sites sampled upstream versus downstream of future development, between sites upstream versus downstream of the primary bitumen-bearing geologic formation, or at an upstream site over a 33 year period on the Muskeg River . Hence, longitudinal patterns observed in water chemistry following mine development cannot be attributed to natural background variation. In contrast, concentrations and loads of the three focal elements were greater post-development compared to reference values (p ≤ 0.01), and were typically greatest during the early exploration and land clearing stage of mine development (p < 0.01). Positive correlations between our three focal elements and 17 other variables either associated with bitumen or considered priority pollutants (r ≥ 0.13, p ≤ 0.04) suggest that the historical impacts of oil sands development on water quality extend beyond our three focal parameters. These results indicate that erosion and subsequent runoff associated with land clearing, construction, and early operational activities have affected water quality in the oil sands region. Key words:McMurray Formation, Alberta oil sands, oil sands mining, oil sands processing, trace metals, water quality.Résumé : Afin d'évaluer les changements dans les propriétés chimiques de l'eau au fil du temps en lien avec les activités minières des sables bitumineux, nous avons compilé un ensemble de données sur 38 ans (1972 à 2010) et l'avons utilisé pour examiner les tendances de trois éléments ciblés (le sélénium dissous, l'arsenic dissous, vanadium total) à 96 sites le long de sept affluents des rivières Athabasca et Clearwater. Les concentrations des trois éléments ciblés ne différaient pas entre les sites échantillonnés en amont par rapport à ceux en aval du développement futur, entre les sites en amont par rapport à ceux en aval de la formation géologique primaire de bitume, ou à un site en amont sur une période de 33 ans sur la rivière Muskeg (1976Muskeg ( -2009. Par conséquent, les tendances longitudinales observées dans la chimie de l'eau à la suite du développement minier ne peuvent pas être attribuées à la variation naturelle du milieu. Les concentrations et les charges des trois éléments ciblés, en revanche, étaient plus grandes (p ≤ 0,01) après le développement comparées aux valeurs de référence et étaient typiquement les plus grandes (p < 0,01) pendant la première étape du développement minier, soit l'exploration et le dégagement du terrain. Des corrélations positives (r ≥ 0,13, p ≤ 0,04) entre nos trois éléments ciblés et 17 autres variables liées au bitume ou considérées des polluants en priorité suggèrent que les impacts historiques du développe...

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“…1), oil-sand material can be found within 75 m of the surface and portions of the oil and deposits are exposed, especially along the banks of the Athabasca River, as well as the lower portions of several tributaries, where rivers have incised into the McMurray Formation. [6] The erosion of the exposed oil sands deposits has distributed hydrocarbons throughout the region's river system and these hydrocarbons arising from natural processes may be referred to as naturally derived hydrocarbons. [7] Heavy metals and major ions co-occur with elevated levels of naturally occurring petroleum hydrocarbons and complex mixtures of naphthenic acids.…”

Section: Introductionmentioning

confidence: 99%

The Characterization and Distribution of Inorganic Chemicals in Tributary Waters of the Lower Athabasca River, Oilsands Region, Canada

Headley¹,

Crosley²,

Conly³

et al. 2005

Journal of Environmental Science and Health, Part A

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Brazilian off-season maize production is characterized by low yield due to several factors, such as climate variability and inadequate management practices, specifically weed management. Thus, the goal of this study was to determinate the critical period of weed competition in off-season maize (Zea mays L.) crop using thermal units or growing degree days (GDD) approach to characterize crop growth and development. The study was carried out in experimental area of the University of São Paulo, Brazil, with weed control (C), as well as seven coexistence periods, 2, 4, 6, 8, and 12 leaves, flowering, and all crop cycle; fourteen treatments were done. Climate data were obtained from a weather station located close to the experimental area. To determine the critical period for weed control (CPWC) logistic models were fitted to yield data obtained in both W and C, as a function of GDD. For an arbitrary maximum yield loss fixed in 2.5%, the CPWC was found between 301 and 484 GDD (7-8 leaves). Also, when the arbitrary loss yield was fixed in 5 and 10%, the period before interference (PBI) was higher than the critical weed-free period (CWFP), suggesting that the weeds control can be done with only one application, between 144 and 410 GDD and 131 and 444 GDD (3-8 leaves), respectively. The GDD approach to characterize crop growth and development was successfully used to determine the critical period of weeds control in maize sown off-season. Further works will be necessary to better characterize the interaction and complexity of maize sown off-season with weeds. However, these results are encouraging because the possibility of the results to be extrapolated and because the potential of the method on providing important results to researchers, specifically crop modelers.

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Characterizing sediment sources and natural hydrocarbon inputs in the lower Athabasca River, Canada

Cited by 71 publications

References 16 publications

Oil sands development contributes polycyclic aromatic compounds to the Athabasca River and its tributaries

Oil sands development contributes polycyclic aromatic compounds to the Athabasca River and its tributaries

Assessment of seven Canadian rivers in relation to stages in oil sands industrial development, 1972–2010

The Characterization and Distribution of Inorganic Chemicals in Tributary Waters of the Lower Athabasca River, Oilsands Region, Canada

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