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Photoenhanced toxicity of oil to larval fish - abstract
Citation:
Barron, M. Photoenhanced toxicity of oil to larval fish - abstract. Presented at 36th Annual Larval Fish Conference, Bergen, NORWAY, July 02 - 06, 2012.
Impact/Purpose:
Discuss photoxicity of oil to larval fish.
Description:
Photoenhanced toxicity is the increase in the toxicity of a chemical in the presence of ultraviolet light (UV), compared to toxicity elicited under conditions of minimal UV. A variety of oil products, weathered and chemically dispersed oils, and specific polycyclic aromatic compounds in oil have been demonstrated to be phototoxic. UV exposure to aquatic organisms can increase toxicity 2 to greater than 1000 times, depending on the intensity and spectrum of solar radiation, water clarity, and extent of petroleum exposure. The photoenhanced toxicity of petroleum appears to occur through activation of bioaccumulated residues (photosensitization) rather than photomodification of aqueous phase oil compounds. In photosensitization the bioaccumulated chemical absorbs light energy that is then transferred to cellular molecules, resulting in tissue damage through oxidative mechanisms. The phototoxic components of petroleum are three to five ring polycyclic aromatic hydrocarbons and heterocycles with specific ring conformations, including anthracenes, fluoranthenes, and dibenzothiophenes. Alkyl substitution does not appear to affect the degree of phototoxicity. Photoenhanced toxicity shows large differences in life stage and species sensitivity. The greatest risks are to the embryo and larval stages of aquatic organisms that are relatively translucent to UV and inhabit the upper water column water column and nearshore areas. Photoenhanced toxicity should be considered in assessing oil spill impacts and in determining spill response actions because estimates of the spatial and temporal extent of injury to aquatic organisms may be greater.