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MP3 Ecological Relevance of Photo-enhanced Toxicity
(114) Ecological Relevance of Petroleum Phototoxicity.
Barron, M1, 1 P.E.A.K. Research, Longmont, CO, USA
ABSTRACT- Oil and oil products are known to be phototoxic, exhibiting a 2 to greater than 100 fold increase in toxicity in the presence of ultraviolet radiation (UV). Fresh and weathered crude oils, middle distillates, and chemically dispersed oil exhibit photoenhanced toxicity when tested under natural sunlight or laboratory sources of UV that occur in aquatic habitats. In contrast, the majority of the oil toxicity databases have been derived from standard laboratory tests conducted under flourescent lighting systems that contain minimal UV. This presentation evaluates the ecological relevance of petroleum phototoxicty using two case studies: the Exxon Valdez oil spill and the Guadalupe oil field. Concentrations of petroleum hydrocarbons and heterocycles persisted in spill impacted aquatic habitats and exceeded concentrations causing phototoxicity in laboratory tests at both oil spill sites. Additionally, UV in the aquatic habitats exceed levels necessary to cause photoenhanced toxicity of petroleum. The results of this investigation show that petroleum phototoxicity is ecologically relevant and should be considered in oil impact assessment and spill response decisions. The risks of photoenhanced toxicity of spilled oil is greatest for embryo and larval stages of aquatic organisms that are relatively translucent to UV and inhabit the photic zone of the water column and intertidal areas.
Key words: PAH, phototoxicity, ultraviolet radiation, oil
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