TABLE 2 



Systematic numbering of Aroclor 1232 congeners (Ballschmitter 



and Zell, mSO), and congeners subjected to transformation by 



bacterioplankton of the Bering and the Chukchi Seas. 



PCB- 



100 



Congeners 



Numbers 



Structure 



5 

 8 



15 



Dichlorobiphenyls 

 2,3 

 2,4/ 



4,4/ 



18 

 22 

 28 

 31 



Trichlorobiphenyls 



2,2/,5 

 2,3.4/ 

 2.4,4/ 

 2.4/.3 



40 

 44 

 47 

 52 

 60 

 66 

 70 

 77 



Tetrachlorobiphenyls 

 2.3/3.3/ 

 2.2/.3.5/ 

 2,2/.4,4/ 

 2,2/5,5/ 

 2,3/.4,4/ 

 2,3/.4,4/ 

 2.3/.4/.5 

 3.3/.4.4/ 



87 

 97 

 101 



Pentachlorobiphenyls 



2.2/.3.4.5/ 

 2.2/.3/,4,5 

 2.2/.4.3.5/ 



153 



Hexachlorobiphenyls 

 2.2/.4.4/5.5/ 



21 days 



Fig. la. Most probable number of sapropliy tic bacteria (.SB, cells/ml) and PCB 

 transforming bacteria (PCBB, cells/ml) 



in the first day. The same trend also occurred with an initial 

 PCB concentration of 10 ng/l. In the first day, 70-73% of 

 dichlorobiphenyls were transfomied (Table 3). 



Over the next 10 days bacterial numbers increased 

 exponentially with both bacterial groups of SB and PCB 

 reaching 1.8 x 10^ cells/ml (confidence interval, 2.7 x 10' to 

 1.2 X 10^ cells/ml). The percentage of transformation of PCB 



days 



Fig. lb. Microbial transtormalion of individual Aroclor 1232 congeners (%) 

 in the experiments. In Experiment No. I. PCB initial concentration 

 was at lOOng/l. Numbers are coherent numbers, see Table 2. Samples 

 collected from the Bering Sea. East Polygon (Station 3). 



tV-ww»iv.5Ji.« 



Control, initial 

 composition of PCB 



Fig. 2. Microbial transformation of Aroclor 1232 (congeners numbers 5, 8, 

 15; see Table 2 ) in the central Bering Sea, Station 3 (East Polygon) in 

 July 1988. 



97 



