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Photoenhanced Toxicity of Petroleum to Aquatic Invertebrates and Fish
Citation:
Barron, M. Photoenhanced Toxicity of Petroleum to Aquatic Invertebrates and Fish. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. Springer, New York, NY, 73(1):40-46, (2017).
Impact/Purpose:
Accidental oil spills can result in significant mortality of a diversity of species in areas where they occur. While many studies demonstrate toxicity of petroleum products to aquatic organisms, oil toxicity may be greater in the environment than measured in laboratory studies due to photoenhanced toxicity. This paper is a mini review of how solar radiation can increase the toxicity of oil. The work is important because: 1) it is part of an invited group of papers providing concise summaries of aspects of petroleum toxicology and chemistry, thus it will be a well read contribution, 2) it establishes EPA's expertise in oil ecotoxicology, which will be useful to the Agency in future spills and oil related regulation.
Description:
Photoenhanced toxicity is a distinct mechanism of petroleum toxicity that is mediated by the interaction of solar radiation with specific polycyclic aromatic compounds in oil. Phototoxicity is observed as a twofold to greater than 1000-fold increase in chemical toxicity to aquatic organisms that also have been exposed to light sources containing sufficient quantity and quality of ultraviolet radiation (UV). When tested under natural sunlight or laboratory sources of UV, fresh, and weathered middle distillates, crudes and heavy oils can exhibit photoenhanced toxicity. These same products do not exhibit phototoxicity in standard test protocols because of low UV irradiance in laboratory lighting. Fresh, estuarine, and marine waters have been shown to have sufficient solar radiation exposure to elicit photoenhanced toxicity, and a diversity of aquatic invertebrate and fish species can exhibit photoenhanced toxicity when exposed to combinations of oil and UV. Risks of photoenhanced toxicity will be greatest to early life stages of aquatic organisms that are translucent to UV and that inhabit the photic zone of the water column and intertidal areas exposed to oil.
