DNA ADDUCTS AS A BIOMARKER OF POLLUTION: FIELD STUDY ON THE GENOTOXIC IMPACT EVOLUTION OF THE ERIKA OIL SPILL ON MUSSELS (MYTILUS EDULIS) OVER A PERIOD OF ELEVEN MONTHS

After the Erika oil spill in December 1999, several thousand tons of heavy fuel were released in marine environment and polluted the Atlantic French coast. DNA adducts were used as a biomarker of the Erika genotoxic impact on DNA of mussel digestive gland sampled at 15 locations from Finistère to Vendée county during a period of 11 months after the accident. Mussels collected in the impacted sites in December 1999 and January 2000 showed the highest total DNA adduct level (165 adducts/10⁸ nucleotides). The level decreased dramatically in February 2000 to a stable level through the rest of the year. The site considered as reference zone was also impacted just after the Erika oil spill. The DNA adduct patterns are similar at all locations, indicating a common genotoxic impact along the coast. Two adducts persisted and were used to characterize and follow the Erika genotoxic impact. The analysis revealed that mussels from three sites (respectively Finistére, Loire Atlantique, and Vendée counties) have been highly impacted by the Erika oil spill.