The long-term chemical fate of crude oil released in the Arctic during the Baffin Island Oil Spill (BIOS) project
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Date
2023-03-30
Authors
Hunnie, Blake
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Abstract
The risks of crude oil spills occurring within the Arctic heighten as ongoing impacts of climate change have given rise to ever increasing amounts of ship traffic. The Baffin Island Oil Spill (BIOS) project was designed in 1979 to further the collective understanding regarding the fate and behaviour of crude oil within the Arctic marine environment. A series of experimentally controlled oil releases occurred in Cape Hatt, Baffin Island, NU between 1980-1982 and were left subject to natural weathering processes. The sites of the BIOS project were revisited on numerous occasions to observe the long-term fate of crude oil spilled in an otherwise pristine, remote Arctic setting; most recently during the 2019 CCGS Amundsen expedition. Bulk surface (0-2cm) and subsurface (5-10cm) sediment samples were collected from oiled backshore plots from Crude Oil Point and Bay 106 within the Z-lagoon, and from the intertidal sediments of Bay 11 within the Ragged Channel, where a surface oil slick was left to encroach onto the beach. Collected samples were analyzed for a total of 99 petroleum hydrocarbons including Polycyclic Aromatic Hydrocarbons (PAHs), n-alkanes, branched alkanes, alkylcycloalkanes, hopane and sterane biomarkers, and alkylbenzenes using Gas Chromatography Mass Spectrometry. These hydrocarbon groups were detected in concentrations ranging from 0.0486 – 14.0, 1.15 - 1170, 0.224 – 51.7, 0.0643 – 16.9, 0.213 – 11.7, and 0.0171 – 8.60 mg/kg, respectively. The oiled sediments were generally observed to contain the highest concentrations of each hydrocarbon group at Crude Oil Point, followed by Bay 106, then finally Bay 11; suggesting that tidal and wave action were significant contributors to the removal of petroleum. Fourteen of the 16 US EPA priority PAHs were detected in concentrations exceeding the marine sediment quality guideline limits established by the Canadian Council of Ministers of the Environment, individually ranging from 7.00 – 640 ug/kg. The Toxic Equivalency Quotient values from these PAHs ranged from 1.40 – 270 and 1.70 – 350 ug/kg within the surface and subsurface sediments, respectively. Comparisons with available data from the 2001 BIOS revisitation indicate losses in dimethylphenanthrene and chrysene from 240000 – 1000 and 8500 – 640 ug/kg, respectively, suggesting extensive PAH weathering over the past 18 years.
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Keywords
The Arctic, Oil Spill, Weathering, Long-term Monitoring, BIOS Project, Hydrocarbons