Diamondoid diacids (’O4’ species) in oil sands process-affected water
MetadataShow full item record
RATIONALE: As a by-product of oil sands extraction, large volumes of oil sands process water (OSPW) are generated, which are contaminated with a large range of water-soluble organic compounds. The acids are thought to be derived from hydrocarbons via natural biodegradation pathways such as a- and ß-oxidation of alkyl substituents, which could produce mono- and diacids, for example. However, while several monoacids (‘O2’ species) have been identified, the presence of diacids (i.e. ’O4’ species) has only been deduced from results obtained via Fourier transform infrared (FTIR) spectroscopy, Fourier transform ion cyclotron resonance high-resolution mass spectrometry (FTICR-HRMS) and nuclear magnetic resonance (1H-NMR) spectroscopy and the structures have never been confirmed.METHODS: An extract of an OSPW from a Canadian tailings pond was analysed and the retention times and the electron ionization mass spectra of some analytes were compared with those of bis-methyl esters of authentic diacids by gas chromatography × gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS) in nominal and accurate mass configurations.RESULTS: Two diamondoid diacids (3-carboxymethyladamantane-1-carboxylic acid and damantane-1,3-dicarboxylic acid) were firmly identified as their bis-methyl esters by retention time and mass spectral matching and several other structural isomers were more tentatively assigned. Diacids have substantially increased polarity over the hydrocarbon and monoacid species from which they probably derive: as late members of biodegradation processes they may be useful indicators of weathering and ageing, not only of OSPW, but potentially of crude oil residues more generally. CONCLUSIONS: Structures of O4 species in OSPW have been identified. This confirms pathways of microbial biodegradation, which were only postulated previously, and may be a further indication that remediation of OSPW toxicity can occur by natural microbial action. The presence and abundance of these diacids might therefore be useful as a measure of biodegradation and weathering.
Showing items related by title, author, creator and subject.
Steroidal aromatic Naphthenic Acids in oil sands process-affected water: Structural comparisons with environmental estrogensRowland, S.; West, C.; Jones, D.; Scarlett, Alan; Frank, R.; Hewitt, L. (2011)The large volumes, acute toxicity, estrogenicity, and antiandrogenicity of process-affected waters accruing in tailings ponds from the operations of the Alberta oil sands industries pose a significant task for environmental ...
Identification of individual tetra- and pentacyclic naphthenic acids in oil sands process water by comprehensive two-dimensional gas chromatography/mass spectrometryRowland, S.; West, C.; Scarlett, Alan; Jones, D.; Frank, R. (2011)The oils sands industry of Canada produces large volumes of process water (OSPW) which is stored in large lagoons. The OSPW contains complex mixtures of somewhat toxic, water-soluble, acid-extractable organic matter ...
Fisher, Steven J. (2002)Two case studies are described where partially biodegraded petroleum residues were collected from the marine environment and analysed to investigate the changes in aromatic hydrocarbons with increasing biodegradation.The ...