Publication Date:
2022-05-25
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2012
Description:
Driven by increasingly heavy oil reserves and more efficient refining technologies, use of
heavy fuel oils for power generation is rising. Unlike other refined products and crude
oils, a large portion of these heavy oils is undetectable using the traditional gas
chromatography-based techniques on which oil spill science has been based. In the
current study, samples collected after the 2007 M/V Cosco Busan heavy fuel oil spill
(San Francisco, CA) were analyzed using gas chromatography (GC)-based techniques,
numerical modeling and Fourier transform ion cyclotron resonance mass spectrometry
(FT-ICR MS) to examine natural weathering of the oil over a one and a half year period.
Traditional GC techniques detected variable evidence of evaporation/ dissolution,
biodegradation and photodegradation. Petroleum hydrocarbon compounds smaller than
~n-C16 were rapidly lost due to evaporation and dissolution. Significant biodegradation
was not detected until one month post spill while photodegradation was only observed at
one field site. To further examine the processes of evaporation and dissolution, samples
were analyzed with comprehensive two-dimensional GC (GC×GC) and a physiochemical
model developed to approximate quantitative apportionment of compounds lost to the
atmosphere and water. Model results suggest temperature is the primary control of
evaporation. Finally, to examine the prominent non-GC amenable component of the oil,
samples were analyzed with FT-ICR MS. Results showed expected clustering of samples,
with those samples collected sooner after the spill having the most compositional
similarity to the unweathered oil. Analysis of dominant heteroatom classes within the oil
showed losses of high molecular weight species and the formation of stable core
structures with time. These results highlight the susceptibility to weathering of these
higher molecular weight components, previously believed to be recalcitrant in the
environment. Research findings indicate that environmental weathering results in
removal or alteration of larger alkylated compounds as well as loss of lower molecular
weight species through evaporation/dissolution, biodegradation and photodegradation,
with a resultant fraction of stable compounds likely to remain in the environment years
after the spill. This research demonstrates the advantages of combining multiple
analytical and modeling approaches for a fuller understanding of oil spill chemistry.
Description:
Funding for this research was provided by National Science Foundation Grants, WHOI Academic
Program Funds, the WHOI Ocean Ventures Fund, the Coastal Ocean Institute, the Richard and
Rhoda Goldman Fund
Keywords:
Heavy oil
;
Oil spills
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
Format:
application/pdf
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