A team from the University of Plymouth (UK) and Environment Canada has identified, for the first time, individual soluble naphthenic acids (NA) in the process water resulting from the oil sands industry in Canada. A paper on their work is published in the ACS journal Environmental Science &,p; Technology.
The rapid growth of the oil sands industry has resulted in the concomitant accumulation of an estimated trillion liters (264 billion gallons) of oil sands process water (OSPW). Numerous concerns have been raised about the impacts of somewhat toxic, acid-extractable organic matter known as naphthenic acids (NA). So far, studies have focused on the toxicity of broad NA classes rather than on the toxicity of individual NA, Rowland et al. note in their paper.
To date, no individual NA have been identified, despite numerous attempts, and while the toxicity of broad classes of acids is of interest, toxicity is often structure-specific, so identification of individual acids may also be very important.
Here we describe the chromatographic resolution and mass spectral identification of some individual NA from oil sands process water. We conclude that the presence of tricyclic diamondoid
acids, never before even considered as NA, suggests an unprecedented degree of biodegradation of some of the oil in the oil sands.
The identifications reported should now be followed by quantitative studies, and these used to direct toxicity assays of relevant NA and the method used to identify further NAto establish which, or whether all NA, are toxic. The two-dimensional comprehensive gas
chromatography-mass spectrometry method described may also be important for helping to better focus reclamation/remediation strategies for NA as well as in facilitating the identification of the sources of NA in contaminated surface waters.—Rowland et al.
Resources
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Steven J. Rowland, Alan G. Scarlett, David Jones, Charles E. West, Richard A. Frank (2011) Diamonds in the Rough: Identification of Individual Naphthenic Acids in Oil Sands Process Water.
Environmental Science & Technology doi: 10.1021/es103721b