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Photoenhanced toxicity of weathered crude oil in sediment and water to larval zebrafish
Citation:
Barron, M., J. Kryzwa, C. Lilavois, AND Sandy Raimondo. Photoenhanced toxicity of weathered crude oil in sediment and water to larval zebrafish. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. Springer, New York, NY, 100(1):49-53, (2018).
Impact/Purpose:
Sunlight is known to increase the toxicity of crude oil and other petroleum products, a phenomenon known as photoenhanced toxicity, but this phototoxicity is typically not considered in oil spill assessments. This research is important because it demonstrates that petroleum similar to the oil spilled during Deepwater Horizon was phototoxic in both sediment and water. The research adds to the growing literature that phototoxicity should be incorporated into oil spill assessments, and that for the first time, this work demonstrates the importance of sediment as a pathway to the increased toxicity of oil through the interaction with natural sunlight.
Description:
Solar radiation exposure can increase the toxicity of bioaccumulated oil compounds in a diversity of aquatic species. We investigated the photoenhanced toxicity of weathered South Louisiana crude oil in sediment and water accommodated fractions (WAF) to larval zebrafish. Larvae were first exposed for 24 h to one of six treatments: no oil (sediment or water), 7.5 g oil/kg sediment, oil-only WAF, oil WAF plus the dispersant Corexit 9500A, or dispersant alone. Larvae were then exposed to high or low levels of sunlight in control water for 3 or 3.5 h. Hydrocarbon concentrations were measured in exposure media, including alkanes, polycyclic aromatic compounds and total petroleum hydrocarbons. Significant phototoxicity was observed in larvae exposed to oiled sediment, oil-only WAF, and oil plus dispersant WAF. The results indicated that petroleum from the northern Gulf of Mexico can be phototoxic to larval fish exposed to oil in either the water column or sediment.
