ORCID ID
0000-0002-9828-2792
Date of Award
5-2024
Degree Type
Dissertation
Degree Name
Ph.D.
Degree Program
Chemistry
Department
Chemistry
Major Professor
Podgorski, David
Second Advisor
Tomco, Patrick
Third Advisor
Tarr, Matthew
Fourth Advisor
Trudell, Mark
Abstract
Oil spilled in aquatic environments undergoes abiotic and biotic oxidation processes that produce hydrocarbon oxidation products (HOPs). HOPs rapidly diffuse in the water column, persisting and readily bioavailable to aquatic organisms. Characterizing HOPs is challenging because most of the mixture resides in the unresolved complex mixture (UCM). Understanding of the formation, fate, and toxicity of HOPs in high latitude environments remains limited. This research addresses these gaps through a comprehensive experimental approach, utilizing various analytical techniques including nonvolatile dissolved organic carbon (NVDOC) analysis, ultrahigh-resolution mass spectrometry, tandem mass spectrometry, inductively coupled plasma mass spectrometry, and fluorescence excitation-emission matrix spectroscopy. Additionally, biological techniques such as embryonic fish bioassays and reverse transcriptase polymerase chain reaction were employed.
The formation and composition of HOPs were evaluated using laboratory-simulated crude oil and diesel spills in Cook Inlet, Alaska. Nontarget analyses revealed the composition of photoproduced HOPs from crude oil and diesel, consisting of relatively reduced, saturated, and unsaturated compounds, along with signatures of toxic naphthenic acids, and six unique optical signatures. Targeted mass spectrometry analyses quantified eleven polycyclic aromatic hydrocarbons (PAHs) and two oxygenated PAHs in HOPs.
The environmental fate of HOPs was investigated at an oiled ballast water treatment facility in Valdez, Alaska. The treatment process effectively removed volatile organic hydrocarbons but did not eliminate HOPs. Instead, molecular and optical analyses revealed the treatment process induced a compositional shift in HOPs toward more oxygenated and complex compounds. Additionally, several heavy metals were quantified throughout the process.
The toxicity of HOPs was examined through embryonic Pacific herring (Clupea pallasi) exposures to laboratory generated polar UCMs, including HOPs and the readily water-soluble fraction of crude oil. Both polar UCMs induced similar toxic effects, suggesting that photomodification-induced toxicity is not driven by compositional changes but by increased concentrations of HOPs. Importantly, toxicity was observed without detectable PAHs, indicating that polar UCM is a significant driver of crude oil toxicity.
Overall, the results of this dissertation provide crucial insights into the environmental relevance of HOPs in high latitude environments and emphasize the importance of considering them in environmental risk assessments, monitoring, and regulations.
Recommended Citation
Harsha, Maxwell Louis, "Chemical Composition, Fate, and Toxicity of Dissolved Hydrocarbon Oxidation Products in High Latitude Aquatic Environments" (2024). University of New Orleans Theses and Dissertations. 3180.
https://scholarworks.uno.edu/td/3180
Included in
Analytical Chemistry Commons, Environmental Chemistry Commons, Environmental Health Commons, Environmental Monitoring Commons, Oil, Gas, and Energy Commons, Toxicology Commons
Rights
The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.