DETERMINATION OF THE NAPHTHALENE BIODEGRADATION POTENTIAL OF A DIESEL CONTAMINATED SITE ON PRUDENCE ISLAND, NARRAGANSETT BAY, RI Allison Hubbard, Sarah Pierce, Mary Penniman, Dan McNally, Department of Science and Technology, Bryant University, Smithfield, RI RI NSF EPSCoR Summer Undergraduate Research Fellowship Program The T-Dock on Prudence Island is considered to be the source of contamination even after the removal of the fuel lines from the Naval Refueling Depot. There is a layer of diesel several inches thick that is migrating into Narragansett Bay at the intertidal zone. Previous studies have shown when bacteria are exposed to diesel contamination they develop a unique ability to use compounds, such as aromatics, as a carbon and energy source. In many cases, the aromatic compounds were mineralized into CO2 and H2O. The goal of this study was to determine the presence of PAH degrading bacteria in the diesel contaminated sediment. Conditions at the site, which were in constant change, included a high water table, brackish water, tidal action, and hypoxic sediment. Specifically, the site conditions were as follows: ď „T 27.8ď‚°C, 7.72, conductivity 13.86 ms/cm, and NO3- 53.2 mg/L; TP2; pH 8.11, conductivity 5.46 ms/cm, D.O. 1.6 mg/L, and NO3- 127.2 mg/L. Nitrate levels this high have been shown to be toxic to typical marine organisms. The preliminary results of the contaminated layer for growth conditions: Total Petroleum Hydrocarbon (TPH) of 5400 ppm, (comparatively) Prudence Island diesel has weathered ~84%, and only high-molecular weight compounds remain, which can be highly toxic. The media (LB, Nutrient Broth, Pore Water, PTYG, BSM, and Marine Broth) were compared in growing and culturing bacteria to cultivate a naphthalene degrader. The bacteria were identified and enumerated using spread plate technique and streak plating techniques in order to obtain a pure sample. Each species of bacteria were put through naphthalene screening tests: naphthalene ether, naphthalene vapor, and verification/enrichment cultures. Additional work is needed on whether there is a specific naphthalene degrader, or if a consortium of bacteria is required to degrade naphthalene to determine the bioremediation potential of the site.
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