The GC traces for the impacted oysters are consistent throughout 

 the study. The aromatic hydrocarbons (Figs. 3.66, 3.67) are dominated 

 by the alkylated dibenzothiophenes and alkylated phenanthrenes through- 

 out. The alkyl naphthalenes and fluorenes, significant in December of 

 1978, are removed from the tissues by June 1980. Aromatic hydrocarbons 

 in the control oysters (Fig. 3.67), while less concentrated, are 

 dominated by the same compound series, though the compositions in the 

 controls remain consistent with time (i.e. no loss of fluorenes or 

 naphthalenes) . GC/MS traces of the oysters confirm the importance of 

 the dibenzothiophene series (Fig. 3.68). 



Saturated hydrocarbon GC traces are illustrated in Figures 3.69 

 and 3.70 for impacted and control oysters respectively. The saturates 

 of the L'Aber Wrac'h samples are dominated by branched alkanes (e.g. 

 isoprenoids) and a large low boiling UCM (Cn - C20) • Tne U ^M in the 

 controls is less pronounced yet significant, and while the isoprenoids 

 are abundant indicating some weathered petroleum, a higher boiling 

 smooth n-alkane distribution (i.e. paraffins, n-C2o ~ n ~C3o) is of 

 equal importance. Figures 3.71 to 3.76 show some representative aroma- 

 tic and saturated fraction data from oyster samples taken from L'Aber 

 Wrac'h and the control station. 



The results of the plaice analyses are summarized in Table 19. 

 The absolute concentration data does not address the source of the 

 observed levels which for the most part are not linked to AMOCO CADIZ 

 oil. The muscle tissues exhibit some petroleum-like GC traces includ- 

 ing some UCM material and smooth n-alkane distributions with the 

 presence of UCM material primarily responsible for the higher levels 

 shown in Table 19. Liver tissue in all samples is much higher in 

 absolute hydrocarbon content (Figs. 3.77 and 3.78). The f^ (saturated) 

 traces are characterized by a high molecular weight UCM (cycloalkanes) , 

 and an n-alkane distribution in the C22 to C23 region, while the 

 f2 traces are characterized by polyolefinic material, including 

 the biosynthesized compound squalene. These f± and f2 distributions 

 are characteristic of fish livers from many geographic regions (Boehm, 

 1980; Boehm and Hirtzer, 1981) and are probably not related to any 

 particular spill event. 



82 



