Crude oils spilled into aquatic environments will undergo oxidative transformation processes due to microbial degradation and photodegradation (Griffiths et al., 2014). Such oxidative processes increase the water solubility and subsequent bioavailability of these petroleum compounds within the water column (Barron, 2017; Bekins et al., 2020). These oxidized petroleum products can induce acute and sublethal toxicity to receiving aquatic organisms, with their characterization and potential impacts in aquatic environments having been identified as a significant research priority (Aeppli et al., 2018; Lee et al., 2015; Ward et al., 2018). Furthermore, the majority of standardized analytical techniques used to characterize the risk of petroleum contamination to aquatic systems, such as total petroleum hydrocarbon or aromatic hydrocarbon analyses, cannot detect the more polar and water-soluble fractions that contain these oxidized petroleum toxicants (Mohler et al., 2020; Zito et al., 2019). The knowledge gaps pertaining to production, transport and risks associated with oxidized crude oil products following accidental spill events impair the accuracy of environmental detection, contaminant behaviour and fate predictions, subsequently hindering adequate preparation for environmental emergency response.
With the recent completion of the expanded Trans Mountain Pipeline in Canada, higher volumes of shipping traffic carrying diluted bitumen from the oil sands region of Western Canada are anticipated within coastal regions, increasing the likelihood of spill accidents. Once contaminated, coastal systems are often difficult to remediate and subsequently pose risk to sensitive ecologic and socioeconomic areas (Feng et al., 2021; Mehvar et al., 2018) As UV light can penetrate to the shallow depths of coastal environments (Barron et al., 2008), freshly spilled crude and sunken weathered oils can oxidise to generate more bioavailable petroleum toxicants within the water column. Recent studies have demonstrated that diluted bitumen contains higher proportions of the oxidized compounds which induce significant acute and sublethal toxicity to aquatic organisms in freshwater (Hepditch et al., 2024a, 2024b). Currently, it is not known if such oxidized compounds within diluted bitumen would present a similar risk to coastal dwelling organisms nor has there been many studies to investigate the potential production of oxidized compounds resultant of microbial and photooxidative processes in saltwater.
Figure 1: As background to the topic of the oil sands industry, an Athabasca oil sands processing facility is shown here, located north of Fort McMurray (Alberta, Canada) and adjacent to Athabasca River.
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To address these knowledge gaps, we propose to characterize the oxidised petroleum constituents of diluted bitumen in the water accommodated fractions (WAFs) following controlled photooxidation weathering experiments. The WAFs of diluted bitumen oil will be produced according to the methods described by Bérubé et al. (2023), with the addition of a solar radiance lamp to generate solar irradiation. Briefly, low-energy WAFs will be created by gently mixing oil and water with stir-plates for 18-hour periods. The oxidised constituents in the WAFs will be analysed using both high resolution (Orbitrap) and ultrahigh resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. This chemical profiling will be done in conjunction with acute and chronic toxicity studies carried out by other researchers based in Canada using the Eastern oyster (Crassostrea virginica) as a receptor model organism of coastal shoreline environments relevant to crude oil spills in Canada.
DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.
The student will gain training and expertise in the field of environmental analysis, including sample collection and preparation. The student will have the option to work in-house in Canada with the research team of Dr Headley or Dr Ahad. This international exposure will provide hands-on training in oil sands environmental chemistry. At the University of Warwick, the student will gain expertise from one of the world’s leading FTICR laboratories, learning FTICR mass spectrometry and including use of different ionization, dissociation, and data analysis techniques.
Dr. Barrow has approximately 25 years of experience of working with FTICR mass spectrometry, petroleum-related and environmental samples, and data analysis of complex mixtures, collaborating with industry and with environmental organizations. Prof. Bending provides expertise on microbial profiling, metagenomics, and soil microcosm type systems. Dr. Headley has approximately 40 years of research experience (more than 27 years of working at Environment and Climate Change Canada) and is amongst the world’s leading experts on the oil sands industry. Dr. Ahad has conducted his research in Canada and the UK, and has been working with GSC-Quebec for more than 14 years.
Year 1: Introduction to FTICR mass spectrometry, training on the 12 T solariX and 15 T solariX XR, introduction to data analysis methods, analysis of initial samples. Develop protocols to analyze photo-oxidized petroleum constituents.
Year 2: Analyse samples from photodegradation experiments using GC-Orbitrap MS (GSC-Québec), negative-ion ESI Orbitrap-MS (ECCC) and FTICR-MS (Warwick).
Year 3: Complete analysis of samples from photodegradation experiments. Work on several manuscripts in collaboration with colleagues.
Aeppli, C., Swarthout, R. F., O’Neil, G. W., Katz, S. D., Nabi, D., Ward, C. P., Nelson, R. K., Sharpless, C. M., & Reddy, C. M. (2018). How Persistent and Bioavailable Are Oxygenated Deepwater Horizon Oil Transformation Products? Environmental Science & Technology, 52(13), 7250–7258. https://doi.org/10.1021/acs.est.8b01001.
Barron, M. G., Vivian, D., Yee, S. H., & Diamond, S. A. (2008). Temporal and spatial variation in solar radiation and photo-enhanced toxicity risks of spilled oil in Prince William Sound, Alaska, USA. Environmental Toxicology and Chemistry, 27(3), 727–736. https://doi.org/10.1897/07-317.1.
Barron, M. G. (2017). Photoenhanced Toxicity of Petroleum to Aquatic Invertebrates and Fish. Archives of Environmental Contamination and Toxicology, 73(1), 40–46. https://doi.org/10.1007/s00244-016-0360-y.
Bekins, B. A., Brennan, J. C., Tillitt, D. E., Cozzarelli, I. M., Illig, J. M. G., & Martinović-Weigelt, D. (2020). Biological Effects of Hydrocarbon Degradation Intermediates: Is the Total Petroleum Hydrocarbon Analytical Method Adequate for Risk Assessment? Environmental Science and Technology, 54(18), 11396–11404. https://doi.org/10.1021/acs.est.0c02220.
Bérubé, R., Garnier, C., Lefebvre-Raine, M., Gauthier, C., Bergeron, N., Triffault-Bouchet, G., Langlois, V. S., & Couture, P. (2023). Early developmental toxicity of Atlantic salmon exposed to conventional and unconventional oils. Ecotoxicology and Environmental Safety, 250, 114487. https://doi.org/10.1016/j.ecoenv.2022.114487.
Feng, Q., An, C., Chen, Z., Owens, E., Niu, H., & Wang, Z. (2021). Assessing the coastal sensitivity to oil spills from the perspective of ecosystem services: A case study for Canada’s pacific coast. Journal of Environmental Management, 296, 113240. https://doi.org/10.1016/J.JENVMAN.2021.113240.
Griffiths, M.T., Da Campo, R., O’Connor, P.B. & Barrow, M.P. (2014) Throwing light on petroleum: simulated exposure of crude oil to sunlight and characterization using atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry. Analytical Chemistry, 86(1), pp. 527-534. https://doi.org/10.1021/ac4025335
Hepditch, S. L. J., Ahad, J. M. E., Martel, R., To, T. A., Gutierrez-Villagomez, J. M., Larocque, È., Vander Meulen, I. J., Headley, J. V., Xin, Q., & Langlois, V. (2024). Behavior and Fate of Spilled Diluted Bitumen and Conventional Heavy Crude Oil in Shallow Groundwater Systems. Available at SSRN: Https://Ssrn.Com/Abstract=4726089 or Http://Dx.Doi.Org/10.2139/Ssrn.4726089. https://doi.org/10.2139/SSRN.4726089.
Hepditch, S. L. J., Gutierrez-Villagomez, J. M., To, T. A., Larocque, E., Xin, Q., Heshka, N. E., Headley, J. V., Vander Meulen, I. J., Dettman, H. D., Triffault-Bouchet, G., Ahad, J. M. E., & Langlois, V. (2024). Aquatic Toxicity and Chemical Fate of Diluted Bitumen Spills in Freshwater Under Natural Weathering. Available at SSRN: Https://Ssrn.Com/Abstract=4799040 or Http://Dx.Doi.Org/10.2139/Ssrn.4799040. https://doi.org/10.2139/SSRN.4799040.
Mehvar, S., Filatova, T., Dastgheib, A., de Ruyter van Steveninck, E., & Ranasinghe, R. (2018). Quantifying Economic Value of Coastal Ecosystem Services: A Review. Journal of Marine Science and Engineering 2018, Vol. 6, Page 5, 6(1), 5. https://doi.org/10.3390/JMSE6010005.
Mohler, R. E., Ahn, S., O’Reilly, K., Zemo, D. A., Espino Devine, C., Magaw, R., & Sihota, N. (2020). Towards comprehensive analysis of oxygen containing organic compounds in groundwater at a crude oil spill site using GC×GC-TOFMS and Orbitrap ESI-MS. Chemosphere, 244. https://doi.org/10.1016/j.chemosphere.2019.125504.
Lee, K., Boufadel, M., Chen, B., Foght, J., Hodson, P., Swanson, S., & Venosa, A. (2015). Expert Panel Report on the Behaviour and Environmental Impacts of Crude Oil Released into Aqueous Environments (Issue November). Royal Society of Canada.
Ward, C. P., Sharpless, C. M., Valentine, D. L., French-McCay, D. P., Aeppli, C., White, H. K., Rodgers, R. P., Gosselin, K. M., Nelson, R. K., & Reddy, C. M. (2018). Partial Photochemical Oxidation Was a Dominant Fate of Deepwater Horizon Surface Oil. Environmental Science and Technology, 52(4), 1797–1805. https://doi.org/10.1021/acs.est.7b05948
Zito, P., Podgorski, D. C., Johnson, J., Chen, H., Rodgers, R. P., Guillemette, F., Kellerman, A. M., Spencer, R. G. M., & Tarr, M. A. (2019). Molecular-level composition and acute toxicity of photosolubilized petrogenic carbon. Environmental Science and Technology, 53(14), 8235–8243. https://doi.org/10.1021/acs.est.9b01894
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