The goals of this project are to: 1) gain a fundamental understanding of the behavior of Deepwater Horizon crude oil components when exposed to sunlight at the marine surface under a range of relevant conditions, and 2) understand how the photochemical transformations impact toxicity and biodegradation. These goals, as well as educational impacts, will be achieved through the following objectives:
- Determine photoproducts and reaction mechanisms for simulated sunlight exposed oil compounds exposed on the surface of sea water;
- Determine the impact of dispersants on the photochemical rates, products, and mechanisms for simulated sunlight exposed oil compounds in or on sea water;
- Determine the effects of photocatalyst nanoparticles (e.g. TiO2, ZnO) on the rate, products, and mechanisms of oil compounds exposed to simulated sunlight in or on sea water;
- Determine how prior phototreatments (items 1-3 above) impact toxicity and biodegradation (aerobic and anaerobic) of the oil and its components;
- Provide research experiences for undergraduates and high school students and teachers.
While a number of previous studies have evaluated aspects of crude oil photochemistry, none of the previous studies has comprehensively assessed a range of key parameters. For example, many studies utilized UV radiation not representative of sunlight, and few if any studies have monitored the impacts of dispersants on oil photochemistry. Only a limited amount of mechanistic data is available regarding petroleum photochemistry in general, and little if any information is available on how individual petroleum compounds impact the photochemistry of other components. Furthermore, the impact of phototransformations on the bioavailability, toxicity, and biodegradability or petroleum compounds is not understood. This project will address all of these shortfalls in the literature by systematically studying photochemical transformations of Deepwater Horizon oil or oil components as a function of irradiation
time and dispersant loading. The study will utilize a wide range of tools, including gas chromatography, liquid chromatography, ion chromatography, fluorescence, mass spectrometry (including GC-MS and electrospray MS), and time resolved transient spectroscopy. In addition, biological assessment tools will include Microtox analysis, toxicity tests under defined terminal electron acceptor conditions, and biodegradation assays. The results of this project will be important for: 1) improving our understanding of the fate of oil from the Deepwater Horizon and other spills, 2) improving predictive models for use in preparing for future spills, and 3) providing greater overall insight into photochemical processes and the interplay between photochemistry and biodegradation.
In addition to providing environmental benefits from an improved understanding of oil photochemistry and biochemistry in marine systems, this project will also involve a range of graduate, undergraduate, and high school students and high school teachers in projects that will provide education for future science and energy sector workforce members. Graduate students will not only learn key scientific skills, but they will also improve their interpersonal and leadership skills by working with undergraduates and high school participants. Undergraduates will gain important research experience and insight to accelerate their careers in science and technology. High school students and high school teachers will participate in summer research experiences, broadening their perspectives and impacting
their career choices. Teacher participants will impact all of their students. High school participants will be drawn from schools with high minority enrollment and all-girls schools.