time. Professor N.S. Stroganov suggested that the relative sensitivity of 

 test organisms be estimated on the basis of the ratio to that of Daphnia 

 magna ; this can be done in works in both countries, since this species is 

 used in experiments in both the USSR and the USA. In any case, the system 

 which we have proposed (Table 2) should be looked upon as simply a first ap- 

 proach to the problem and should be refined as data are accumulated. 



Thus, there is a firm basis for successful cooperation of both nations 

 in the development of specific means for protection of bodies of water from 

 pollution. 



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Carlson, A.R. 1972. Effects of long-term exposure to carbaryl (sevin) on 

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