of Chukthi (Station 59) — than in the other areas that were 

 sampled. For the Bering Strait, in this shallow-water area, the 

 copper concentration in bottom sediments only reached a 

 maximum of 3.56 Hg/g. 



Cadmium showed a similar heterogeneity of distribution. 

 In general, cadmium concentration in water varied from 0.0 1 to 

 0. 1 3 |ig/l in the Chukchi Sea. Cadmium concentration in the 

 Bering Strait water was below the level of detection. The 

 highest cadmium concentration (3.69 (ig/1 ) was found at Station 

 24 in the surface water layer, which is probably related to local 

 geographic conditions. 



Cadmium distribution in bottom sediment showed little 

 variation in its concentration and was generally low and of little 

 significance, with average concentrations being 

 0.6 ng/g dry mass in the Bering Sea, 0.4 |ig/g in the Chukchi 

 Sea, and 0.2 |ig/g in the Bering Strait. 



TABLE 1 



Metal concentrations in the water of the Bering Sea 

 and the Chukchi Sea. 



Station Horizon Concentration, |a g/1 



(meters) Cu Cd Mn Zn Pb 



TABLE 2 



Metal concentration in the bottom sediments of the Bering Sea 

 and the Chukchi Sea (|J.g/g dry weight). 



Note: Metal concentration is below sensitivity of method. 

 (0.3) - depth of bottom sediment sampling, m. 



Metal concentration is below sensitivity of the method. 



The study of manganese distribution in the investigated 

 ecological systems showed an extremely low concentration in 

 seawater, except for Station 109. The concentration of 

 manganese did not exceed 0.04 |ig/l ( see Table 1 ) . The average 

 manganese concentration in bottom sediments was 

 220 |ig/g dry wt. These data are consistent with the results of 

 Loring (1984) obtained for bottom sediment samples 

 (340 |4g/g) taken near the Arctic coast. 



The high concentration of manganese (5,996.4 |ig/g) 

 observed at Station 29 is, probably, related to manganese 

 remobilization processes in this region of the bottom. 



Concentrations of zinc and lead were determined only in 

 samples of seawater. The concentration of zinc in the Bering 

 Sea varied from 0.15 |ag/l (central part) to 3.67 |ig/l (eastern 

 part), and the concentration of lead varied from 

 0.02 |ig/l (eastern part) to 1.03 |ig/l (central part). 



The concentration of zinc and lead ranged from 0.01 to 

 2.13 |ig/l and 0.07 to 2.34 |ig/l, respectively. 



In conclusion, it should be noted that our results for metal 

 concentrations in water and bottom sediments of the Bering 

 Sea and the Chukchi Sea are close to the values obtained by 

 other investigators (Hegge, 1982: Maeda, 1986; Hegge etai. 

 1987). 



Thus, studies from the Third US-USSR Joint Bering & 

 Chukchi Seas Expedition verify that metal concentrations in 

 water and bottom sediments of the Bering Sea and the Chukchi 

 Sea are still at background levels. 



318 



