Long-Term Persistence of Dispersants following the Deepwater Horizon Oil Spill

During the 2010 Deepwater Horizon (DWH) oil spill, 1.84 M gallons of chemical dispersant was applied to oil released in the subsurface and to oil slicks at the surface. We used liquid chromatography with tandem mass spectrometry to quantify the anionic surfactant DOSS (dioctyl sodium sulfosuccinate) in samples collected from environments known to contain oil persisting from the DWH oil spill. DOSS was found to persist in variable quantities in deep-sea coral communities (6–9000 ng/g) 6 months after the spill and on Gulf of Mexico beaches (1–260 ng/g) 26–45 months after the spill. These results indicate that the applied dispersant, which was thought to undergo rapid degradation in the water column, remains associated with oil in the environment and can persist for ∼4 years.