(according to the Ameiican specialists) were revealed for the 

 first time in these arctic regions remote from human activities. 



Also, it was found that the concentration of HCH isomers 

 in the Chukchi Sea water was 20 to 25% higher compared with 

 the Bering Sea water (Table 1 ). These data can be explained 

 with the Henry's law for volatile compounds. Such compounds 

 as HCH isomers with relatively high volatility at low 

 temperatures are usually dissolved in the water, and when 

 temperatures rise they change into the gas phase. Since the 

 Bering Sea water is generally warmer than the Chukchi Sea 

 water, the Bering Sea water should retain less of these 

 compounds ( assuming they both have the same levels overlying 

 them in the air). 



The data on the study of the HCH isomeric composition 

 confirms (3 to 4 times excess of the alpha-isomer concentration 

 over the gamma-isomer concentration) that the main source of 

 the HCH discharge into these regions is atmospheric from 

 Southeast Asia where the hexachloran preparation with the 

 35% alpha-isomer concentration is mainly used. In the USSR 

 and the USA, whose shores are washed by the Bering and the 

 Chukchi Seas, only the lindane preparation with 98% of 

 gamma-isomer is used. 



A number of interesting conformities to natural laws can ' 

 be derived from a study of the distribution of the DDT group 

 compounds in this investigated-region water (Table 1). First of 

 all, DDT and its metabolites, DDD and DDE, are the only 

 group of chlorinated hydrocarbons whose concentration in the 

 Bering Sea has declined considerably since 1984 

 (from 0.8 ng/1 down to 0.01 ng/1 on average). In fact, the 

 concentration of the DDT group compounds in a number of 

 samples was at the level of minimum detection limit of the 

 method which was, respectively for each analyte reported in 

 Tables 1-4, the lowest value which could be reported for the 

 number of significant digits reported (e.g.. if the results were 

 presented as 2. 1 ng/g, then the detection limit for this column 

 of data was 0.1 ng/g). 



The contamination of marine ecosystems with polychloro- 

 biphenyls excites serious apprehension. These contaminants 

 are a mixture of 209 different components having multiple 



physical and chemical properties. Every congener undergoes 

 transformation processes at different rates and in 

 different directions depending on the environmental 

 conditions. 



As our investigation showed, the general PCB concentration 

 did not change significantly over the last 5 years (1984-1988) 

 remaining at the0.7to0.8ng/llevels(Tables 1,2). Furthermore, 

 in addition to looking at total PCB' s, individual PCB congeners 

 were also identified in all of the samples. Measuring the 

 individual congeners provides additional information about 

 the chemical and physical processes that interact to distribute 

 the separate components of the PCB mixtures within each of 

 the environmental compartments that were investigated. The 

 comments that follow are some of the preliminary conclusions 

 that resulted from these data. Of the total mix of possible hexa- 

 through monochlorobiphenyls, di- and trichlorobiphenyls were 

 the most abundant in the water samples. These data demonstrate, 

 firstly, the primary accumulation of the more soluble 

 components of the PCB's were appearing in the water and, 

 secondly, the intensity of photochemical process in this 

 geographic region appeared to be causing the formation of 

 many low-chlorinated components. 



The results of the study relating to the general mix of 

 CHC s identified, also allowed identification of new compounds 

 that were not found earlier in these regions — viz. , cis-chlordane, 

 trans-chlordane, cis-nonachlor, trans-nonachlor, and 

 oxychlordane. These compounds are mainly used in temperate 

 latitudes of the globe for control of termites and other insects. 

 Their appearance in this arctic region, therefore, appears to 

 occur as a result of long-distance atmospheric transfer processes. 

 Their concentration in the water reaches the 0.02 ng/1 level 

 (Table 1 ), with cis-chlordane and trans-chlordane usually 

 making up most of the total; in many samples it exceeded the 

 concentration of even the widely-used pesticide DDT, and in a 

 number of cases it equaled the PCB concentrations. 



In the study of vertical distribution of chlorinated 

 hydrocarbons, it was found they all reached depths of a few 

 thousand meters (Table 2). The distribution of PCB's and 

 DDT's was uniform while the HCH isomer concentrations 



TABLE 2 



The vertical distribution of chlorinated hydrocarbons in the 

 Southern Bering Sea (South Polygon). 



Chlorinated Hydrocarbon Concentration 

 (ng/1) 



281 



