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(16-07) Evaluating the efficiency of oil spill countermeasures by monitoring changes in the bioavailability and toxicity to fish of PAH from wetland sediments. Kiparissis, Yiannis*,1,2, Hodson, Peter1, Zambon, Sylvia1, Ewert, Andrew1, Ibrahim, Ismail1, Ramachandran, Shakunthala1, Lee, Ken3, Venosa, Allan4, 1 School of Environmental Studies, Queen's University, Kingston, ON2 Environmental and Resource Studies, Trent University, Peterborough, ON3 Fisheries and Oceans, Mont-Joli, PQ4 USEPA, Cincinnati, OH ABSTRACT- The effectiveness of wetland bioremediation strategies was assessed by monitoring the bioavailability and toxicity of oil-derived PAH to early life stages of fish. Weathered medium MESA oil was applied to experimental plots on vegetated beaches with different combinations of fertilizer, plant removal, and sediment aeration. Sediments sampled over 1.5 years were tested by bioassays of mixed function oxygenase (CYP1A) enzyme activity in livers of trout as an index of PAH exposure and bioavailability. To assess the toxic potential of the same sediments, Japanese medaka (Oryzias latipes) were exposed during embryonic development (for 17 days) or during sexual maturation (for 3 months). Oiled sediments from the experimental plots all caused CYP1A induction relative to un-oiled controls, indicating the presence and bioavailability of PAH. Oiled sediments were embryotoxic as evident by the development of "blue-sac" disease (BSD) syndrome. Maturing medaka exposed to oiled sediments experienced a high mortality rate, reduced growth and increased prevalence of severe fin defects, hepatic lesions and intersex gonads. Overall, CYP1A induction and toxicity did not vary markedly among treatments, but declined slowly with time. These observations were supported by chemical analysis, suggesting that PAH were depleted primarily by weathering or sediment dispersion rather than by bioremediation treatments. Key words: oil-derived PAH, bioavailability, toxicity, bioremedation |
