ST. PETERSBURG, FL – Scientists completed the first time-series study (2007-2016) of Gulf of Mexico deep-sea fishes and their exposure to polycyclic aromatic hydrocarbons (PAHs) following Deepwater Horizon. There was a 7- to 10-fold increase in PAH concentrations in fish muscle tissue in 2010−2011 compared to 2007, followed by a decrease in 2015-2016 to near levels measured in 2007. Water samples from summer 2010 measured at the depth of the subsurface oil plume (900−1300 m) had PAH concentrations up to 60.4 μg/L (compared to 0.1 μg/L background levels). Water samples from summer 2011 showed a reduction in PAHs concentrations, but they were still high (up to 48.2 μg/L) and at deeper depths (1200−2000 m) than 2010. Water samples from 2015 showed undetectable amounts of PAHs, indicating recovery after the oil spill. These results suggest an episodic contamination event in 2010 that continued through 2011 and a longer-term exposure to deep pelagic organisms than their shallower counterparts.
Petrocarbon evolution: Ramped pyrolysis/oxidation and isotopic studies of contaminated oil sediments from the Deepwater Horizon oil spill in the Gulf of Mexico