SECTION 14 

 REVERSIBILITY OF INTOXICATION AND FACTORS GOVERNING IT 

 I.V. Pomozovskaya^ 



Criteria characterizing the poor state of the aquatic environment and 

 its inhabitants, their degradation and pathology when affected by various 

 kinds of pollutants have been developed intensively during recent years. 

 One of the industries with the largest water requirement is the pulp and 

 paper industry. Wastes coming from this type of enterprise are among the 

 most complicated and multi-factorial toxic complexes. In this connection, 

 the attention given to the study of the effects exerted by wastes from these 

 enterprises on bodies of water and aquatic organisms is quite natural. 



Aquatic toxicological experimentation conducted in the zone of action 

 of such mills have provided valuable data on the real danger of waste 

 waters, the effects of their separate components, and their complexes upon 

 aquatic organisms of varying organisation and taxonomic ranking. These 

 studies have enabled a comparison of biological effects, related to the 

 functioning of various waste treatment plants, and have provided recommenda- 

 tions for their most economic and rational reconstruction and exploitation. 



In this type of work carried out for a few years in Karelia, the main 

 criteria of toxicity chosen were the survival time of organisms, symptoms of 

 intoxication, changes in growth development and reproduction (fecundity, 

 quality of progeny, rate of maturation and spawning, etc), and alterations 

 in indices of the functional state; such as gas exchange, hematology, and 

 the degree and pattern of reversibility of intoxication. 



The problem of reversibility of intoxication of organisms occupies a 

 special position in the whole complex of methodical approaches. Intoxica- 

 tion of fish and other organisms is highly probable, even in the presence 

 of a space limited point-sources pollution, since such sources may be on the 

 direct route of migration of the organism. 



An inquiry into the problem of the possible reversibility of intoxica- 

 tion may assist in predicting results for organisms that undergo short 

 duration exposure in the polluted zone during crises, and in the case of 

 salvo discharges. This index should be considered when the remote conse- 

 quences of prolonged low-dose intoxication are in question, in assessing 



^Karelian Branch of the Academy of Sciences of the USSR, Division of Water 

 Problems, Prospect Uritskogo, 68, KASSR, Petrozavodsk, USSR. 



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