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Fate and Impacts of Vegetable Oil Spills in Aquatic Environments

Salam, Darine
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321367790

Abstract Details

2011, PhD, University of Cincinnati, Engineering and Applied Science: Environmental Science.
The kinetics and ecological impacts of the aerobic biodegradation of vegetable oils in contaminated aquatic environments were studied in respirometric microcosms at different oil loadings (100, 333, and 1,000 gal acre-1) and mixing regimes (fully, moderately, and non-mixed microcosms). No significant difference in the extent of oil biodegradation was observed between the fully and moderately mixed microcosms at 100 and 333 gal acre-1 loadings, indicating minimal influence of enhanced mixing in these cases. Furthermore, comparable oxygen uptake rates were measured initially in the moderately and non-mixed microcosms at the 100 and 333 gal acre-1 loadings, suggesting an initial dependence of the microbial activity on the oil surface available for emulsification rather than on the oil concentration. Regardless of the mixing condition, reduced initial oxygen uptake rates were measured at 1,000 gal acre-1 loading and were associated with an initial oxygen mass transfer limitation. The results of the Microtox® assay showed no major toxicity at the 100 gal acre-1 loading. Furthermore, oxygen was not completely depleted from the water column at this oil coverage. At higher oil loadings, oxygen was fully depleted from the mixed and non-mixed water columns. A transient toxicity in the aqueous phase was observed in the case of the moderately mixed microcosms at 333 gal acre-1 and was maintained at moderate levels (EC50 ~30%) in the non-mixed microcosms. A substantial increase in toxicity (EC50 ~10 %) was observed in both mixing conditions when the initial oil loading was increased to 1,000 gal acre-1. Furthermore, the effect of antioxidants on the fate and impacts of vegetable oils in contaminated aquatic media was investigated. Respirometric experiments on the effect of increasing concentrations of butylated-hydroxytoluene (BHT) (0, 50, 100, 200, 400, and 800 ppm) on the biodegradability of glyceryl trilinoleate (333 gal acre-1), revealed the formation of intractable rigid polymers unavailable for bacterial degradation in all BHT treatments and particularly in the microcosms not supplemented with the antioxidant. In this case, limited oil mineralization was observed after 19 weeks of incubation (41%) compared to the microcosms supplemented with BHT (> 67 %). In these microcosms, no significant difference in the achieved oil mineralization was observed with increasing BHT concentrations, suggesting minimal additional protective effect of BHT above 50 and up to 800 ppm. In addition, the effect of BHT on the biodegradability and toxicity of purified canola oil (333 gal acre-1) was investigated in the absence and presence (200 ppm) of the antioxidant. Substantial oil mineralization was achieved after 16 weeks of incubation (> 77%) and was not significantly different between the two BHT treatments. Furthermore, for both treatments, a transient toxicity was observed and was attributed to the combined effect of toxic biodegradation intermediates and autoxidation products. Autoxidation in the microcosms initially supplemented with the BHT, was supported by the disappearance of the antioxidant after only 2 weeks of incubation. Intractable solid polymers were formed in all biotic microcosms and were attributed to an interaction between the oil autoxidation products and the degrading biomass rather than to oil polymerization.
Makram Suidan, PhD (Committee Chair)
Albert Venosa, PhD (Committee Member)
Margaret Kupferle, PhDPE (Committee Member)
George Sorial, PhD (Committee Member)
164 p.
Sanitation
Vegetable Oil Spills; Aerobic Biodegradation; Autoxidation; Polymerization

Recommended Citations

Citations

  • Salam, D. (2011). Fate and Impacts of Vegetable Oil Spills in Aquatic Environments [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321367790

    APA Style (7th edition)

  • Salam, Darine. Fate and Impacts of Vegetable Oil Spills in Aquatic Environments. 2011. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321367790.

    MLA Style (8th edition)

  • Salam, Darine. "Fate and Impacts of Vegetable Oil Spills in Aquatic Environments." Doctoral dissertation, University of Cincinnati, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321367790

    Chicago Manual of Style (17th edition)

ucin1321367790
565
© 2011, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.