Field-collected crude oil, weathered oil and dispersants differentially affect the early life stages of freshwater and saltwater fishes.

The Deepwater Horizon (DWH) oil spill was the biggest in US history and released 3.19 million barrels of light crude oil into the Gulf of Mexico. In this study, we compared the toxicity of water accommodated fractions (WAFs) of naturally weathered crude oils, source oil, and source oil with dispersant mixtures and their effects on developing sheepshead minnow and zebrafish.

Comparison of Diluted Bitumen (Dilbit) and Conventional Crude Oil Toxicity to Developing Zebrafish.

To facilitate pipeline transport of bitumen, it is diluted with natural gas condensate, and the resulting mixture, "dilbit", differs greatly in chemical composition to conventional crude oil. Despite the risk of accidental dilbit release, the effects of dilbit on aquatic animals are largely unknown. In this study, we compared the toxicity of water accommodated fractions (WAFs) of dilbit and two conventional crude oils, medium sour composite and mixed sweet blend, to developing zebrafish.