The modeling experiments show that DDT accumulates in trophic chain 

 quickly and effectively. Accumulation of DDT and its metabolites in fish 

 organs of vital importance was observed. These findings were distinctly 

 manifested in the fish brain tissue. 



Toxicological symptoms appear in parallel with increasing levels of DDT 

 in target organs, especially in the brain. Clinical and pathological-ana- 

 tomical intoxication may be reproduced by experimental modeling rather 

 quickly and synonymously, and the fish behavior and clinical symptoms are 

 similar to those of acute intoxication. 



When DDT and its metabolites (DDE and DDD) accumulate up to 3 ppm in 

 the brain tissue of fish (perch, pike), the fish die with obvious symptoms 

 of cumulative toxicosis. It should be noted that mammals and birds present 

 an analogous picture, i.e., convulsive phenomena as DDT accumulation ap- 

 proaches the lethal level, and death at definite accumulation levels (Hayden 

 1960; Dale, et al_ 1963; Ludwig and Ludwig 1969). 



Thus, these investigations enabled the development of principles of the 

 actions of DDT and its metabolites. Their distribution in organs and 

 tissues of freshwater fish, the development of a model of cumulative toxi- 

 cosis in fish under experimental conditions, and an understanding of the 

 basis of accumulation of DDT, along with its metabolism, depending upon the 

 functional role of the tissue and species of aquatic organism. 



REFERENCES 



Andryushchyenko, V.V. and Yu.K. Peshcholka. 1975. DDT in certain elemen- 

 tary biocoenosis of the Black Sea and the Delta of the Danube. In: 

 Studies of the Biological Production and Protection of Waters of the 

 Ukraine. Scientific Thought, Kiev, pp. 100-101. 



Braginskiy, L.P., F.Yah. Komarovsky, and Yu.K. Petsolka. 1976. Experi- 

 mental modeling of the mechanism of DDT intoxication in predatory fish. 

 In: Experimental Aquatic Toxicology. Zenatnyeh, Riga, pp. 204-215. 



Braginskiy, L.P., F.Yah. Komarovsky, and A.I, Myehryehzuko. 1979. Per- 

 sistent pesticides in the ecology of freshwater. Scientific Thought, 

 Kiev, 143 p. 



Calvin, M.M. 1969. Metabolism of pesticides. Special Scientific Report 

 Wildlife. Washington, No. 127, 293 p. 



Dale, W.E., T.B. Daines, and W.J. Hayer. 1963. Poisoning of DDT relation 

 between clinical signs and concentration in rat brain. Science, 142, 

 No. 3598, pp. 1474-1479. 



Hayden, R.E. 1960. Effects of DDT on birds. N.Z. Gardiner, 17, No. 1, pp. 

 66-73. 



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