BaP transfiirmalion in perceni 

 fnim the onginal tonteniralion 





urtacc liiver 1984 

 .urfafc layer 1*^88 

 1988 



Fig. 1 . BaP microbial transformation m experiments iii ,v;7h in the Bering and 

 Cliuckchi Seas water (August, 1988). 



Chukchi Sea, maximum activity of microbial populations was 

 found at Stations 45 and 50, where 25—45% of the BaP was 

 transformed. 



The e.xperiments showed little differences in the amount 

 of PAH's degraded by bacterioplankton in the surface 

 microlayer and 0.5 m level (Table 1 ). In certain areas of the 

 World Ocean, these processes are more pronounced in the 

 surface microlayer. the zone of air-sea interaction (Tsyban, 

 1985). However, there is no direct correlation between the BaP 

 content in sea waters and amount transformed. For example, 

 low rates of BaP transfomiation occurred in waters with the 

 highest concentration of BaP, 63 |lg/l at Station 29. 



To study the degradation of PAH' s at in situ concentrations 

 ( 1 and 10 |ig/l), long in situ experiments were conducted up to 

 2 1 days. The results show that 54-57% of the initial BaP mass 

 was transformed with the first 5-7 days (Table 2 ); after 2 1 days 

 the process declined considerably. Maximum degradation was 

 67-85% of the initial concentrations. Similar results were 

 found for concentrations of 1 and 10 |ig/l. The results from 

 Stations 36 and 50 showed that despite local features of the BaP 

 transfomiation (Table 1 ), bacterioplankton of the Bering and 

 Chukchi Seas possess similar biodegradation potential. 

 Transformation and removal of BaP in the surface layer occurred 

 at a rate of 7 |ag/l over a period of 3 weeks. 



In summary, from the investigations performed in 1981. 

 1984, and 1988 in the Bering and Chukchi Seas, heterotrophic 

 microflora exist in the waters, and the heterotrophic microflora 

 show a pronounced biodegradation potential in relation to 



TABLE 1 



Microflora transformation of BaP in the Bering and Chukchi Seas 

 Water in in situ experiments of 10 days. August 1988. 



PAH's (Izrael ct a!., 1987). In addition, the rate of BaP 

 transformation in the Bering Sea microflora is sufficiently high 

 and similar to rates measured in the Baltic Sea (Tsyban et ai, 

 1985). Thus, the metabolism of PAH's by microflora should 

 be considered as an essentially important process in the 

 detoxication and remov al of pollutants from the ecosystems of 

 the World Ocean. 



94 



