Critères de pollution par hydrocarbures dans les sédiments marins. Étude appliquée à la pollution du "Bohlen"

In October 16, 1976, the tanker "Bohlen" was wrecked in the Mer d'Iroise, at about 35 miles of Brest, and lossed about 7 000 t of Boscan crude oil. The coast of Brittany was polluted by 3 000 t, and 4000 t were dispersed in the marine environment. In July 1977, 23 surface sediment samples were collected to look for the traces of oil spill in the sea bottom, 9 months after the shipwreck. Only one sediment was very iittle polluted by the Boscan crude oil. Elsewhere, two other kinds of oil pollution were observed in sorne sediment samples. Severa! quantitative and qualitative criteria were used to research sorne oil pollution in the marine sediments and to know the origin: hydrocarbon concentrations, ratios total organic extra ct 1 organic carbon, hydrocarbons 1 organic carbon, quantitative distribution of the 3 fractions of the organic ex tract: saturated hydrocarbons, aromatic hydrocarbons, polar compounds, chromatographie distributions of saturated hydrocarbons, aromatic hydrocarbons and their sulfur compounds (thiophenic compounds). The use of these criteria are discussed in this study.