The monitoring programme of the ecological and ecotoxicological consequences of the "Erika" oil spill
Résumé
On December 11, 1999, Erika, an oil tanker flying the Maltese flag and loaded with 31 000 t of heavy fuel oil, was making its way from Dunkirk to Livorno when it encountered difficult weather conditions Southwest of the Brittany coast (gale force winds 8 to 9 and 6 m waves). On the morning of the 12th December, the captain broadcast an SOS; his vessel was breaking in two, approximately 30 nautical miles to the south of Penmarc'h Point (Finistère, France). The fore section of the vessel sank during the night of the 12-13 December and the aft section was taken in tow on the morning of December 13, but subsequently sank in the early afternoon. Both parts lay in 120 m of water and were located 10 km apart. Approximately, 19 000 t of heavy fuel oil were spilled into the sea. The first of the fuel oil came ashore on December 23 and the major strandings took place between December 24 and 27. The Loire Atlantique and Vendée coasts were severely contaminated and the départements of Finistère, Morbihan, and Charente Maritime in the South, were in no way spared. Violent winds blowing at right angles to the coast accompanied by extremely high tides washed the pollution high up the beach strand, reaching the tops of cliffs more than 10 m high. The struggle at sea against the pollution began on December 15 and 1 200 t of fuel were recovered within the next fortnight. Between mid May and late summer 2000, a little more than 10 000 t of heavy fuel oil were fluidised by adding colza methyl ester and pumped from the tanks of the sunken vessel, while an additional 1 200 t were pumped out during final cleaning. A total of 12 400 t of the originally transported 31 000 t were retrieved from both the sea and the wreck and a little less than 19 000 t were released into the environment. In addition, the cleaning of the contaminated coasts that took a Corresponding author: Morgan.Le.Moigne@ifremer.fr place throughout 2000 and 2001 removed a total of 240 000 to 280 000 t of polluted material (according to sources) containing 30 000 to 40 000 t of emulsion (with 30-50 % seawater) and therefore more or less equalling the amount of oil spilled.