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EARLY LIFESTAGE EFFECTS OF PAH PHOTOACTIVATED TOXICITY IN MEDAKA (ORYZIAS LATIPES)
Citation:
Diamond, S A., D. R. Mount, V R. Mattson, L J. Heinis, AND T L. Highland. EARLY LIFESTAGE EFFECTS OF PAH PHOTOACTIVATED TOXICITY IN MEDAKA (ORYZIAS LATIPES). Presented at 21st SETAC Annual Meeting, Nashville, TN, November 12-16, 2000.
Description:
Two critical questions have yet to be sufficiently addressed for risk assessments of photoactived PAH toxicity to be completed. These include standrdized methods for quantifying the dose of activating radiation received by target organisms, and the potential for early lifestage effects, particularly for species that are likely to have UV doses in sensitive embryo/larval stages. We addressed this latter question by exposing adult medaka continuously to four concentrations of fluoranthene (0.0, 0.7, 1.8, and 5.7 ug fluoranthene/1) in filtered Lake Superior water, collecting eggs each day, allowing embryos to mature for 24 hr (in the adult exposure tanks), and then irradiating eggs under UV-A lamps for various periods of time. Irradiation was conducted at 900 uW/cm-2, UV-A. No effects of UV radiation in the absence of fluoranthene, or fluoranthene in the absence of UV radiation were detected. In high fluoranthene treatments (1.8 and 5.7 ug/1) effects of irradiation were observed after 90 m of UV exposure. These treatments were characterized by at least 50% mortality after 48 h (post-UV exposure). Mortality corresponded with dramatic shrinkage of the yolk sac and concomitant abnormal development of the embryo. In embryos surviving longer than 48 hr abnormalities were apparent, in approximately 10% of the embryos surviving to 48 h post hatch. Additional mortality occurred at hatching (approximately 5%). These preliminary results suggest that, at fluoranthene levels representative of PAH exposure at many contaminated sites, embryos of some fish species may be at significant risk for photoactived toxicity, even after fairly brief, and environmentally-realistic UV exposures.