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(38-65) Toxicity of Photomodified Polycyclic Aromatic Hydrocarbon Mixtures in Contaminated Sediments. Lampi, Mark*,1, El-Alawi, Yousef1, Tripuranthakam, Sridevi1, Huang, Xiao-Dong1, Dixon, George1, Greenberg, Bruce1, 1 Department of Biology, Waterloo, Ontario ABSTRACT- Polycyclic aromatic hydrocarbons are ubiquitous environmental contaminants that readily undergo photolysis and photooxidation when exposed to environmental UV/blue light. There exists conclusive evidence that many photooxidized PAHs (oxyPAHs) exhibit greater toxicity than their respective parent PAH. PAHs and oxyPAHs readily bind to the organic phase of particulate matter, such as sediments, in the environment. We are investigating the toxicity of intact and oxyPAH mixtures present in contaminated sediments from two different sites using a variety of assays. Sediment samples taken from Hamilton Harbour (Hamilton, ON), and Mohawk Lake (Brantford, ON) were fractionated, and analyzed using a 2D HPLC method developed in our laboratory. All sediments contained intact and modified PAHs, although we note a marked change in the profile of compounds present in the samples. Fractions of sediment extract were assayed for toxicity using acute lethality of Daphnia magna, as well as inhibition of growth, luminescence and oxygen consumption of the marine bacterium Vibrio fischeri. In all of the assays, the toxicities of fractions containing modified PAHs were on par with fractions containing intact PAHs. Further elucidation of the nature of the mixtures present is warranted. Key words: sediments, HPLC, photomodification, PAHs |
