Long-term Monitoring: Lingering Oil Evaluating Chronic Exposure of Harlequin Ducks and Sea Otters to Lingering Exxon Valdez Oil in Western Prince William Sound: Exxon Valdez Oil Spill, Restoration Project 12120114-Q.

摘要

For the first time since the 1989 Exxon Valdez Oil Spill, we found that average cytochrome P4501A induction (as measured by EROD activity) during March 2013 was not elevated in wintering harlequin ducks captured in areas of Prince William Sound oiled by the spill, relative to those captured in unoiled areas. Another metric of oil exposure (the incidence of individuals with elevated cytochrome P4501A induction) was consistent with this result, as it also showed similar values between oiled and unoiled areas. We interpret these findings to indicate that exposure of harlequin ducks to residual Exxon Valdez oil abated within 24 years after the original spill. These findings follow results from 2011, which showed reductions since 2009 in these metrics on oiled areas relative to unoiled and hence progress towards abatement of exposure, despite continued differences between areas in 2011,. The data presented in this report add to a growing body of literature indicating that persistence of oil in the environment, and exposure of wildlife to that oil, can occur over much longer time frames than previously assumed. These data may be used to define the duration of exposure (nearly two and a half decades) for one of the wildlife species most likely to suffer extended exposure.