CHEMICAL FATE OF BUNKER C FUEL OIL IN A SUBTROPICAL MARINE ENVIRONMENT FOLLOWING A SPILL IN TAMPA BAY, FLORIDA

A hydrocarbon chemistry study was performed on sediments, oil masses and mangrove prop roots of a mangrove island in Boca Ciega Bay, Florida following a spill of Bunker C fuel oil in Tampa Bay. Normal alkane (n-alkane) and polycylic aromatic hydrocarbon (PAH) profiles were monitored for effects of degradation and weathering in these mediums for a period of one year. Initial findings indicated a loss of lower molecular weight n-alkanes and PAH\u27s in sediments and prop roots. There was little or no loss of these low molecular weight components in the oil mass samples. Hydrocarbon profiles at the end of the year long study indicated a loss of many of the n-alkanes with a corresponding increase in the unresolved complex mixture, and a shift in the profile towards higher molecular weight compounds. One and two ring PAH\u27s were also lost during the year, while three and four ring PAH\u27s (phenanthrene, pyrene and chrysene) showed little evidence of degradation and/or weathering. Increased exposure to physical processes appeared to enhance the weathering of the petroleum hydrocarbons. Mangrove prop roots, exposed to such additional processes, clearly degraded more rapidly than sediments or oil masses. Sediments exhibited more weathering than did oil mass samples which were protected from these natural weathering processes and showed little change from the original Bunker C composition throughout the year. The lack of significant weathering effects on the PAH\u27s indicates probable long term residual toxicity for biological communities in and around Eleanor Island