Abstract
Photo-oxidized petroleum hydrocarbons are a unique class of water-soluble bioavailable compounds that have gained emerging recognition within toxic regulatory management bodies as an urgent and priority research need in high latitudes. In order to characterize the molecular signatures of photo-oxidized petroleum, bench-scale spills were irradiated over Alaskan seawater and freshwater at 5.5 °C. “Refined fuels” included heating oil, diesel, Jet-A, kerosene, and gasoline, with the Alaska North Slope (ANS) crude reference. An additional experiment assessed the photolytic aging of ANS crude “remediated” using a recently popularized strategy of in situ burning with and without herder application. A four-component fluorescence parallel factor model revealed a unique short-wavelength feature associated with photo-oxidized refined fuel that is not associated with traditional “microbial”- or “terrestrial-like” components. In contrast, crude oil photolytically decomposes into long-wavelength humic-like components (high humification index) and oxidized aliphatics. Fourier transform ion cyclotron resonance mass spectrometry data corroborated the optical data. Overall, on a per-volume basis, the refined fuels diesel, heating oil, kerosene, and Jet-A produce a significantly higher mass of photoproducts than crude oil and carry a unique chemical signature. This warrants new considerations regarding marine biota toxicity. This study also highlights new potential for tracking photo-modified water-soluble fractions of crude and refined fuels in high latitudes with fluorescence spectroscopy.
Published Version
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