Yearly monitoring in one of the most affected coastal zones by the
Prestige oil spill, namely Nemi?a and O Rostro beaches (NW Spain), has been carried out since 2004. Topographic data of beaches revealed seasonal altimetric changes up to 4 m that would prevent the on shore persistence of
oil. However, surficial and subsurficial
oil was detected in the intertidal area of both beaches in all campaigns. The hydrocarbon analysis confirmed that this
oil corresponded to the
Prestige oil, even nine years after the accident. Tar balls were highly biodegraded suggesting that the
oil was accumulated on the subtidal sediments for a long time and transported to the coast by the action of waves.
The present work provides new evidence of the long term persistence of deep oil spills from wrecks in marine areas where the hydrodynamic conditions play a twofold key role, in determining the exposed coastal area to recurrent contamination and in burying and resurfacing the oil in the intertidal zone.