Editor's Spotlight

Phototoxic potential of undispersed and dispersed fresh and weathered Macondo crude oils to Gulf of Mexico Marine Organisms

Crude oils contain a mixture of hydrocarbons, including phototoxic polycyclic aromatic hydrocarbons (PAHs) that have the ability to absorb ultraviolet (UV) light. Absorption of UV light by PAHs can substantially increase their toxicity to marine organisms. A study in Environmental Toxicology and Chemistry examined the potential for phototoxicity of fresh and naturally weathered Macondo crude oils alone and in combination with the dispersant Corexit 9500 to mysid shrimp (Americamysis bahia), inland silverside (Menidia beryllina), sheepshead minnow (Cyprinodon variegatus), and Gulf killifish (Fundulus grandis). The study found that the addition of Corexit 9500 to crude oil increased toxicity compared with tests with crude oil alone and that Macondo crude oils had the potential to be phototoxic to Gulf of Mexico marine organisms if specific light conditions and PAH concentrations were present during the Deepwater Horizon oil spill.