Repository logo

Photodegradation of bitumen-derived organics in oil sands process-affected water

dc.contributor.authorChallis, Jonathan K.
dc.contributor.authorParajas, Angelique
dc.contributor.authorAnderson, Julie C.
dc.contributor.authorAsiedu, Evelyn
dc.contributor.authorMartin, Jonathan W.
dc.contributor.authorWong, Charles S.
dc.contributor.authorRoss, Matthew S.
dc.description.abstractThe chemical composition of water-soluble organics in oil sands process-affected water (OSPW) is primarily composed of natural constituents of bitumen that are solubilized and concentrated during aqueous extraction of oil sands. OSPW organics are persistent and acutely toxic, and a leading remediation strategy is long-term ageing in end-pit lakes, despite limited data available on its photochemical fate. Here, direct photolysis of whole OSPW, or of its constituent fractions, was examined at environmentally relevant wavelengths (>290 nm) in bench-top studies. Changes in the chemical profiles of whole OSPW, acid- (AEO), and base-extractable organics (BEO) were characterized by liquid chromatography with ultra-high resolution mass spectrometry in negative (−) and positive (+) ionization modes. Following 18 d of irradiation, photolysis reduced the total ion intensity in all samples in both modes. The most photo-labile species included the O2−, O3−, O4−, O2S−, and O4S− chemical classes, which were depleted in whole OSPW by 93–100% after only 5 d. In positive mode, detected species were more recalcitrant than those detected in negative mode, with an average reduction across all heteroatomic classes of 75 ± 11.0% after 18 d. Estimated environmental half-lives for heteroatomic classes ranged from 57 d (O4S−) to 545 d (O3N+), with a greater recalcitrance for classes detected in positive mode compared to negative mode. Under field conditions in end-pit lakes, natural photolysis may be an important mechanism for effective OSPW remediation, and we suggest that future end-pit lakes be shallow to maximize light penetration and natural photolysis in ageing OSPW.
dc.identifier.citationChallis et al. (2020). Photodegradation of bitumen-derived organics in oil sands process-affected water. Environmental Science: Processes and Impacts, 22, 1243-1255.
dc.rightsAll Rights Reserved
dc.subjectoil and gas fields
dc.subjectwater pollutants
dc.titlePhotodegradation of bitumen-derived organics in oil sands process-affected wateren
dc.typeArticle Post-Print


Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
2.02 MB
Adobe Portable Document Format