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Biodegradability of Dispersant and Dispersed Oil at 5 and 25 °C

Zhang, Yu
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471347548

Abstract Details

2016, MS, University of Cincinnati, Engineering and Applied Science: Environmental Engineering.
Increasing the surface area to volume ratio of oil droplets, chemical dispersant agents reduce the interfacial tension between oil and water and thus facilitate the biodegradation of spilled oil. Prior to field application of dispersants, several factors should be taken into account such as the product effectiveness, environmental conditions (e.g., temperature, wind and pressure), toxicity to the marine organisms, and the fate and transport of the dispersed hydrocarbons and dispersants themselves. In this study, experiments were conducted with two crude oils (Alaskan North Slope, ANS and Endicott) and two dispersant products (Corexit 9500 and Finasol OSR 52) at 5 and 25 °C to determine the biodegradation of dispersants and dispersed oil at environmentally-relevant concentrations. Two oil degrading cultures, isolated from the surface (meso) and deep sea (cryo) waters of the Gulf of Mexico (GOM), were enriched on crude oil at 25 and 5 °C and were used as the inocula. The biodegradation experiments were performed at 5 °C for 56 d and at 25 °C for 48 (or 45) d in sterile GP2 artificial seawater as medium. The time series concentration of dioctyl sulfosuccinate (DOSS), the anionic surfactant in the dispersants, was monitored by liquid chromatography with tandem mass spectrometry (LC-MS/MS), in addition to alkanes and polycyclic aromatic hydrocarbons (PAHs), which were measured by gas chromatography-tandem mass spectrometry (GC-MS/MS). Although the initial concentration of DOSS in Finasol OSR 52 was 20% higher than in Corexit 9500, over 90% of the anionic surfactant fraction was metabolized for both types of dispersant products by the end of the experiment at 25 °C, while DOSS persisted at 5 °C for both products. Around 90% of the total alkanes degraded regardless of the temperature or treatment. PAH removal was favored in the presence of dispersant at 5 °C, while there was no significant degradation at 25 °C. The microbial community structures of the oil samples were also analyzed by polymerase chain reaction (PCR) analysis. Results indicated that the abundance of alcanivorax, pseudoidiomarina and thallassospira correlated well with hydrocarbon degradation trends. This study significantly expands on our understanding of biodegradation process of dispersants and oil components at environmentally-relevant conditions and also provides information regarding the bacterial community composition that is important to hydrocarbon degradation.
Pablo Campo, Ph.D. (Committee Chair)
Robyn N. Conmy, Ph.D. (Committee Member)
George Sorial, Ph.D. (Committee Member)
71 p.
Environmental Engineering
Biodegradation; Dispersant; Crude oil; Finasol OSR 52; Corexit 9500; surfactant

Recommended Citations

Citations

  • Zhang, Y. (2016). Biodegradability of Dispersant and Dispersed Oil at 5 and 25 °C [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471347548

    APA Style (7th edition)

  • Zhang, Yu. Biodegradability of Dispersant and Dispersed Oil at 5 and 25 °C. 2016. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471347548.

    MLA Style (8th edition)

  • Zhang, Yu. "Biodegradability of Dispersant and Dispersed Oil at 5 and 25 °C." Master's thesis, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471347548

    Chicago Manual of Style (17th edition)

ucin1471347548
214
© 2016, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.