Master of Science (MS)


Environmental Sciences

Document Type



In April 2010, large quantities of crude oil were released into the Gulf of Mexico (GoM) raising questions about the possible contamination of marine organisms with constituents of concern known as Polycyclic Aromatic Hydrocarbons (PAHs). In order to determine the impact of the Deepwater Horizon (DWH) crude oil spill, Gulf menhaden (Brevoortia patronus) were harvested from two coastal regions of Louisiana. Tissue analysis to determine total PAH concentration was conducted using an adapted matrix solid phase dispersion (MSPD) method; a Soxhlet extraction process was used to determine fish oil to mass ratios for “small” (fork length < 16 cm) and “large” (fork length > 16 cm) menhaden. Menhaden oil and meal, harvested prior to the DWH spill, was used to create menhaden facsimiles for baseline total PAH concentrations. Gulf menhaden were harvested off of the coast of Louisiana from July 2011 through October 2011. Sampling occurred at sites around Vermilion Bay (VB) as well as Grand Isle (GI) and the menhaden were analyzed by region as well as size to determine if the concentrations of PAHs varied based on these factors. PAH concentrations were quantified along with total Benzo[a]pyrene mutagenic (B[a]P-MEQ) and Benzo[a]pyrene toxic equivalencies (B[a]P-TEQ) and all analysis was completed using Gas Chromatography/Mass Spectroscopy (GC/MS). Results were reported in ng of total PAH/g of dry weight tissue and the detection limits of the GC/MS method were between 0.4 ng/g dry weight and 4.4 ng/g dry weight. In conclusion, the two Louisiana coastal regions were not statistically different and therefore cannot be used to identify the impact of the DWH spill in a one-year sampling event. However, PAH concentrations were statistically different based on month with a significant interaction based on size. Mean concentrations for “small” and “large” menhaden were not statistically different; the B[a]p-TEQs were highly significant suggesting the larger menhaden were exposed to more carcinogenic PAHs throughout their life due to variations in feeding patterns. Continuing the study for a second year will provide further elucidation on species life cycle exposure to PAHs and possible impacts to fisheries.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Portier, Ralph J.