The chromatogram of the saturated hydrocarbons shows that the 

 n-paraffins had disappeared (Fig. 22) . Although there are divergences 



FIGURE 22. Chromatogram of the saturated hydrocarbons taken 

 at the Brignogan station April 4, 1978. 



in such parameters as metal and sulfur contents, the infra-red spec- 

 trum definitely confirms that it is crude from the Amoco Cadiz. We 

 believe that these differences may be due to the fact that we were 

 dealing with oil sheets that had been treated to a greater or lesser 

 degree. These observations should be compared with those made by 

 Aminot et al. at the same time at a station just offshore from this 

 one, which showed an abnormal loss of dissolved oxygen. He explained 

 it as in-situ biodegradation of the hydrocarbons, which appears to be 

 the only logical explanation. 



Distillation of the 340+ fractions shows little in the way of 

 interpretable differences (Table 6) . The sulfur and metal (nickel and 

 vanadium) contents show, by their stability, how important these com- 

 pounds are as pollution markers (Table 7) . 



TABLE 6. Simulated distillations of 340+ residues. 



The breakdown by chemical family is shown in Table 8. It appears 

 that the evolution of the crude in all of the emulsions is a sLow 

 process. A slight decrease in the ratio of saturated to aromatic 



134 



