Current studies show that the lingering oil is no longer bioavailable and key injured resources are no longer being affected by the lingering oil: Injured populations met the recovery criteria established by the EVOS Trustee Council for sea otters (between 2009 and 2014, 20 to 25 years post-Spill) and harlequin ducks (by 2013, 24 years post-Spill) (Ballachey et al., 2014; Esler 2015b). Recovery, as defined by the EVOS Trustee Council, generally requires a return to conditions that would have been present had the Spill not occurred, as well as cessation of exposure of animals to oil lingering since the Spill. Lacking pre-Spill baseline studies, researchers contrasted a number of metrics between oiled and unoiled areas, including abundance, survival, habitat use, physiology, biomarkers of oil exposure, and population trajectories based on models.
Studies published in 2013 indicate that PAH concentrations in mussel tissue from both oiled and unoiled sites in PWS are below even trace levels and are therefore a safe food source for both subsistence users and wildlife (Payne, J.R., W.B. Driskell, M.G. Carls, M.L. Larsen, and L.G. Holland. 2013. Long-term environmental monitoring program: Results and interpretations from sampling, 2008-2012. PWS Regional Citizens’ Advisory Council contract no. 951.10.01.)