BaP content, mg/kg dry weight 

 in biota 



10-n 



Chukchi Sea 



: I Polygon 

 '---■1® 1 



Fig. 4. Distribution ofthehighestconcentrationsofBaPmeasured in plankton 

 and neuston collected in the Bering and Chukchi Seas (August 1988). 



In the Chukchi Sea, the area of the highest BaP accumulation 

 by plankton was located along the highest latitudes, with the 

 maximum 12.6 |ig/kg occurring at Station 49. 



It should be especially noted that the maxima for BaP 

 accumulation in plankton were found at those stations (35,1 00, 

 and 49) that were also characterized by the maximum BaP 

 levels found in bottom sediments. This fact is most pronounced 

 at the northern section of the Chukchi Sea (Station 49): 12.6 

 and 4.5 )Jg/kg, respectively. These facts may indicate the 



primary role of biosedimentation processes in deposition of 

 pollutants to bottom sediments — in particular, in highly 

 productive shelf regions of the arctic seas. 



Plankton communities are particularly sensitive to changes 

 of the hydrochemical background. Due to some physical and 

 biochemical processes, PAH accumulation in plankton often 

 exceeds the concentration in their habitat by 15 to 165 times. 

 This process can be indicated by the coefficient of BaP 

 accumulation by plankton organisms or the biomagnification 

 coefficient ( ratio of BaP concentration in plankton to that in the 

 water, Cp:Cw). 



In 1988, the most significant BaP accumulation was 

 recorded at the East and North Polygons as well as in the 

 Chirikov basin (Station 100), where accumulation coefficients 

 were3.9x 10-,3.8x 10-,and2.0x 10-. In the other investigated 

 regions, these values were within 0.2 x 10' to 8.8 x 10' 

 (Table 1 ), which is comparable with the data obtained for these 

 regions in 1984. 



Note that in 1981 the accumulation coefficients were 

 higher than observed here with some as high as 1 0^ and 1 0\ A 

 reason for these differences could be that in 1981 there was a 

 higher BaP content in every element of the Bering Sea ecosystem 

 than was present during the 1988 cruise. 



Benzo(a)pyrene accumulation was also discovered in the 

 neuston community populating the surface layer of the seawater. 

 Benzo( a)pyrene accumulation in neuston was comparable with 

 that in plankton and had the values of 0.6 to 10.0 |ig/kg dry wt. 

 (Table 2 and Fig. 4). 



Eleven investigated samples show relatively high BaP 

 concentrations for neuston organisms from the Bering Sea — in 

 particular, in the Gulf of Anadyr and the East Polygon (Fig. 4). 

 These facts are evidence for a selective trend towards higher 

 PAH accumulation in the biotic component of these ecological 

 systems. 



Comprehensive investigations of PAH biogeochemical 

 cycles carried out in this region of the world's oceans showed 

 a widespread BaP distribution in the Bering and the Chukchi 

 Sea ecosystems. The general character of BaP distribution and 

 their accumulation in components of marine ecosystems testifies 

 to the fact that even though the degree of pollution of these 

 aquatic systems is not high, carcinogenic PAH's constitute a 

 constant and characteristic feature for most regions of the 

 Bering Sea and Chukchi Sea. 



312 



