Monitoring follow up of two areas affected by the Prestige oil four years after the spillage.

The sinking of the oil tanker Prestige in November 2002 resulted in the spill of more than 63,000 tonnes of crude oil, and polluted more than 1,000 km of coastline, especially affecting Galicia (northwestern Spain). Four years after the accident, a new biological monitoring study was undertaken of two Galician areas intensely affected by the spill, Lira and Ancoradoiro, previously evaluated in the months following the accident ( Laffon et al. 2006 ). The mussel Mytilus galloprovincialis was employed as bioindicator organism to determine both polycyclic aromatic hydrocarbons (PAH) levels and genotoxic effects. PAH were determined chromatographically in seawater samples and mussel tissues collected from November 2006 to January 2008. The results obtained showed that PAH pollution was still present in these areas, but bioaccumulation of these compounds in mussels was low, compared to reference mussels, and lower than in our previous study. DNA damage assessment was also performed in gills and hemolymph cells by means of the alkaline comet assay. DNA damage levels were higher in mussels from the exposed areas than in reference mussels. DNA damage decreased after a 7-d recovery period in the laboratory, but prolonging the recovery period up to 14 d did not contribute to less DNA damage in gill cells. Hemolymph cells were more sensitive than gill cells to the induction of DNA damage.