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PHOTOACTIVATED TOXICITY IN AQUATIC ENVIRONMENTS
Citation:
Diamond, S A. PHOTOACTIVATED TOXICITY IN AQUATIC ENVIRONMENTS. Chapter 7, Hader, D., G. Jori (ed.), UV Effects in Aquatic Organisms and Ecosystems. John Wiley & Sons Incorporated, New York, NY, , 219-250, (2003).
Description:
Most aquatic organisms have evolved mechanisms to minimize damage by ultraviolet (UV) radiation. Many terrestrial species have additionally had to adapt to plant compounds (e.g. furanocoumarins) that are extremely toxic when activated by UV radiation. Over evolutionary time, it is unlikely that these compounds have been present in aquatic systems at concentrations sufficient to trigger adaptive responses. Within the last century however, release of anthropogenic contaminants, particularly PAHs (polycyclic aromatic hydrocarbons), has greatly increased the potential for photoactivated toxicity in aquatic environments. Most phototoxic compounds exert toxicity in aquatic environments. Most phototoxic compounds exert toxicity via a photosensitizing process that produces (within tissues), has greatly increased the potential for photoactivated toxicity in aquatic environments. Most phototoxic compounds exert toxicity via a photosensitizing process that produces (within tissues) reactive oxygen species that ultimately damage biomacromolecules. Some phototoxic compounds, under certain conditions, may exert toxicity after they have been photochemically modified in the external environment. Both mechanisms require sufficient doses of chemical and UV radiation, particularly UV-A (-320 to 400 nm). Assessment of the potential for phototoxic damage in aquatic systems requires thorough analysis of both of these elements, as well as species and lifestage-specific vulnerabilities. Because photoactivated contaminants are present in high concentrations at fairly isolated areas that may function as sinks, and are presently still being introduced into aquatic systems, consideration of phototoxicity will continue to be significant ecological concern.