rings (aromatic and nonaromatic) . The structure of these complex mixtures was 

 not elucidated at this time, but could be studied in the future. 



RESULTS 



Results are presented in Tables 1, 2, and 3. The weight of the compounds 

 AVSP (before saponification) and APSP (after saponification) are indicated. 

 The value of the ratio AVSP/APSP is characteristic of the capacity of the 

 medium to be biodegraded. A value close to 1 shows poor bacterial activity. 

 As the value increases, better biodegradation is indicated. This fact is due 

 to the functionalized intermediate compounds made by the bacteria and extract 

 in basic medium. 



The fraction FB is constituted by unsaponif iable compounds. Comparison 

 of FA and FB is not interesting. Only the comparison of FB values for 

 different sampling times is relevant. When biodegradation increases (less 

 linear hydrocarbons) , the FB fraction decreases. At Al and A2 station (in 

 very polluted zones) , the concentrations of hydrocarbons (linear or 

 substituted) were about null in 1980, but complex organic compounds of heavy 

 molecular weight, which are extractable with hexane (since present in the FA 

 fraction) , remain in the sediment. The molecular structure of these compounds 

 has not been established (the pet role urn- type asphaltenes are not extracted at 

 the very beginning by pentane) . 



CONCLUSIONS 



Station C. 



In 1980, in spite of the presence of 0.54 g in the FA fraction, its 

 chromatogram was no longer characteristic of a petroleum-polluted zone (C17, 

 C18, C19 predominant). However, light petroleum pollution is indicated at 20 

 cm below the surface. 



Station B_ 



In 1980, various deposits did not allow correct sampling; therefore, only 

 1978 and 1979 values were determined. In 1979, there seemed to an indication 

 of return to normal state, especially at the rhizome level (bottom) . 



Station A. 



In 1980, half of the hydrocarbons of 1979 remained. This fraction did 

 not show the presence (by chromatogram) of linear or substituted hydrocarbons; 

 however, its weight cannot be explained only by the unbiodegradable cyclanes 

 or aromatics (33 g) . 



104 



