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Issue 11, 2011
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An examination of the toxic properties of water extracts in the vicinity of an oil sand extraction site

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Abstract

The industrial extraction of oil sands (OS) in northern Alberta, Canada, has raised concerns about the quality of the Athabasca River. The purpose of this study was to examine the toxic properties of various water extracts on Oncorhynchus mykiss trout hepatocytes. The water samples were fractionated on a reverse-phase C18 cartridge and the levels of light-, medium- and heavy-weight polycyclic aromatic hydrocarbons (PAHs) were determined by fluorescence spectroscopy. Primary cultures of trout hepatocytes were exposed for 48 h at 15 °C to increasing concentrations of the C18 extract corresponding to 0.02, 0.1, 0.5 and 2.5X concentrations from upstream/downstream sites in the Athabasca River, lake and groundwater samples, OS tailings and interceptor well-water samples. Changes in cell viability, phase I and phase II biotransformation enzymes (cytochrome P4501A and glutathione S-transferase activities), oxidative damage (lipid peroxidation LPO) and genotoxicity (single and double DNA strand breaks) were monitored in post-exposure cells. The water samples decreased cell viability and increased all the above endpoints at thresholds of between 0.02 and 0.1X the water concentration. The most responsive biomarker was DNA damage but it also offered the least discrimination among sites. LPO was higher at sites downstream of the industrial operations compared to upstream sites. A decision tree analysis was performed to formulate a set of rules by which to identify the distinctive properties of each type of water samples. The analysis revealed that OS tailings and interceptor waters were characterized by an increased concentration in light PAHs (>42 μg L−1) and this fraction represented more than 85% of the total PAHs. These samples also inhibited GST activity, which could compromise the elimination of genotoxic PAHs present in the system. An analysis of groundwater samples revealed a contamination pattern similar to that for OS tailings. There is a need for more research into specific biomarkers of toxicity from OS tailings compounds such as naphthenic acids, light PAHs among others, which are a characteristic fingerprint of OS extraction activities.

Graphical abstract: An examination of the toxic properties of water extracts in the vicinity of an oil sand extraction site

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Publication details

The article was received on 22 Jul 2011, accepted on 09 Aug 2011 and first published on 14 Sep 2011


Article type: Paper
DOI: 10.1039/C1EM10591D
Citation: J. Environ. Monit., 2011,13, 3075-3086
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    An examination of the toxic properties of water extracts in the vicinity of an oil sand extraction site

    F. Gagné, C. André, M. Douville, A. Talbot, J. Parrott, M. McMaster and M. Hewitt, J. Environ. Monit., 2011, 13, 3075
    DOI: 10.1039/C1EM10591D

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