96 
5.4.2.4 PCA formula and congener group profiles 
Figure 10 compares the formula and congener group patterns of s- and mPCA for 
selected samples. C14 compounds are dominant (mean 69 %, range 59-100 %) in the 
mPCA-patterns of all samples as also typical for technical mixtures. No differences 
between regions were observed. 
The picture is more complex for sPCA-patterns. Cn and C12 congeners were most 
abundant in the biota from the Baltic and North Sea. The distribution resembled 
those in technical sPCA, but showed a larger variability. To facilitate a comparison of 
the sPCA patterns, the sums of all congeners of each chain length is given in Figure 11 
for cod from the Baltic Sea and compared to technical sPCA mixtures. The C-chain 
patterns were quite similar. 
However, cod livers from the northern North Atlantic showed a change. Here, C10 
and C12 congeners were most intense with exception of one sample from northern 
Iceland as the C-chain profiles in Figure 12 demonstrate. Moreover, the isomer groups 
C12H20CI6 and C12H19CI7 had a high fraction. C12H19CI7 contributed about 20 % to the 
sPCA sum. The change of C10 congeners from a minor to a major fraction of sPCA was 
also observed by Tomy et al. (2000) in marine mammals from the Northern North 
Atlantic such as beluga, walrus and seals. 
Table 29 summarises the relative contribution of C10 and C12 congeners to total 
sPCA as well as the C10/C12 ratio for cod liver from the Baltic Sea, the northern North 
Atlantic and biota liver from bear Island. The C10 fraction and C10/C12 ratio increased 
to 28.4 % and 0.76, respectively, in cod liver from the northern North Atlantic 
compared to 13.6 % and 0.43 in technical mixtures or 16.8 % and 0.53 in cod liver from 
the Baltic Sea. A corresponding or even higher increase could also be observed for 
biota liver from Bear Island. The change indicates a fractionation and enrichment of 
the more volatile C10 congeners during long range transport to this remote region.