Comparative Toxicity of Louisiana Sweet Crude Oil (LSC) and Chemically Dispersed LSC to Two Gulf of Mexico Aquatic Test Species [open pdf - 120KB]
"Large quantities of Louisiana sweet crude (LSC) oil have been released into the Gulf of Mexico since the explosion of the Deepwater Horizon oil exploration platform on April 20, 2010. The use of dispersants in oil spill response involves tradeoffs between effects to the shoreline and effects to pelagic and deep sea environments. In an effort to mitigate the impact of floating oil on sensitive shoreline habitats the decision was made to use dispersants listed on the U.S. Environmental Protection Agency's (EPA) National Contingency Plan (NCP) Product Schedule (EPA 2010a). Dispersants have been applied offshore on the surface as well as underwater at the source of the leak. In an effort to assess options to address this unprecedented event, the EPA conducted independent studies with eight dispersants on the NCP Product Schedule to assess the relative acute toxicity of each dispersant alone, LSC oil alone and dispersant-LSC oil mixtures. Toxicity testing to determine the hazards of eight dispersant products has been performed in two phases. Phase one included acute toxicity tests with two Gulf of Mexico aquatic species, and in vitro cytotoxicity and endocrine screening assays using human cell lines. These tests were performed with each of the dispersants in the absence of oil. The results of the aquatic toxicity tests generally classified the dispersants as ranging from slightly toxic to practically non-toxic to both test species with the exception of one dispersant found to be moderately toxic to fish (Hemmer et al. 2010)."
United States. Environmental Protection Agency: http://www.epa.gov/