Identifier

etd-11172014-134851

Degree

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

Document Type

Dissertation

Abstract

Many of the organic components of oil have the capacity to persist in the environment, bioaccumulate in tissues, and are toxic to surrounding organisms. Since the early 1970s, environmental assessment programs have utilized bivalves as monitoring tools of chemical contaminants in the marine environment. Because of their sedentary and filter-feeding habit (bioaccumulation), mussels and oysters been employed as sentinel organisms in environmental quality monitoring studies in coastal ecosystems. The use of indigenous (diploid) bivalves for biomonitoring water quality is limited during the summer months due to high stress and changes in biochemical composition induced by reproductive development. In this work caged diploid and triploid oysters were compared to one another to determine if seasonal variations in total polycyclic aromatic hydrocarbon (PAH) bioaccumulation exist between the ploidy. Variations in bioaccumulation between the two ploidy were tested using a static laboratory exposure study and a real-time field monitoring (15 months) study in Barataria Bay, Louisiana. A modified QuEChERS and dispersive solid phase extraction (dSPE) method were developed and validated for determination of PAHs in oyster tissue. Laboratory oil exposure results showed there was a significant increase of 40.0%, 45.3%, and 48.9% in total PAH content between the summer diploid and triploid oysters with the 500, 5000, and 25000 ppm exposure treatments, respectively. There was a 31.3% to 58.2% increase in total PAH content between the summer diploid oysters and remaining seasonal treatments (winter diploid and triploid) over the exposed oil treatment range (500, 5000, and 25000 ppm). Significant increases (17.2% to 33.4%) in total PAH content within the triploid oysters were observed at the Bay Jimmy field sites for the months coinciding with the spawning season (June-September) and elevated lipids levels in the diploid oysters. In contrast, triploid oysters only displayed a 4.81% to 5.43% increase in PAH content within their tissue during the winter and early spring months (November-early May). The use of triploid oysters as a biomonitoring tool is feasible for assessing environmental impacts following chemical or oil spills. A caged triploid oyster monitoring system is a viable alternative to indigenous diploid bivalves throughout the year.

Date

2014

Document Availability at the Time of Submission

Student has submitted appropriate documentation to restrict access to LSU for 365 days after which the document will be released for worldwide access.

Committee Chair

Malone, Ronald F.

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