The liver, unlike other organs, was notable for greater stability in 

 content of DDT metabolites. This was conditioner^ by rapid transformation of 

 DDT in this organ. During the second phase of intoxication, o,p' - DDT, 

 p,p' - DDT, and p,p' - DDD were predominant. 



Thus, the accumulation of DDT and its metabolites in organs and tissues 

 of fish is conditioned by their specific peculiarities, functional purpose, 

 and time of development of intoxication. 



With the intent of studying accumulation of persistent pesticides, the 

 level of transformation in aquatic organisms, and their distribution and 

 transmission in trophic chains, experiments in aerated aquaria and pools 

 were carried out. In the process of studying the transformation of DDT and 

 its metabolites in the food chain, forage organism ( Tubifex tubifex and 

 Daphnia magna ), consumer fish ( Cyprinus carpio ), and predatory fish ( Perca 

 f luviatilis and Esox lucius) were modeled. 



Food organisms poisoned by chemically pure p,p' - DDT (1.1 to 3 ppm) 



Con- 

 ac- 

 . ..v.,, — ,„^ >,..„„, ,^„, ^^ ^^...^.^^ ....v.,^ w. ...^ ^.^f....^ ■ were con- 

 trolled, and the complex of morphlogical and functional indices charac- 

 terizing the development of intoxication were studied (Braginskiy, et al . 

 1976). 



Food organisms poisoned by chemically pure p,p' - DDT (1.1 to 3 pf 

 were fed to yearling carp, which in turn were eaten by predatory fish, 

 trol fishes were given food without DDT. During the experiments, DDT 

 cumulation and metabolism at selected levels of the trophic chain were 



Investigations have shown that the DDT residue from water was taken into 

 the tissues of the Daphnia and tubificids in a very short time period, prac- 

 tically within the first day. When these organisms were fed to fish, con- 

 siderable concentrations of DDT residues were found in organs and tissues, 

 especially in fatty layers and in brain tissues, as early as the first 3 

 days, with a constant increase throughout the experiments. In the forage 

 species, ( Daphnia and the tubificids), DDT metabolizes primarily to DDD, 

 while DDE is formed Mery slowly. In carp, the general accumulation of 

 pesticides with high specific weights of the DDE metabolite greatly in- 

 crease. An analogous picture is characteristic of perch and pike. When 

 these species are fed for an extended time with food containing DDT, the ac- 

 cumulation of this substance in their lipid containing tissues increases, 

 with a prevalence of the metabolites DDE and DDD. 



Tubificids metabolize DDT only to DDD; Daphnia to DDD and DDE, carp to 

 DDD and DDE, and perch and pike to DDD and DDE, but with different percent- 

 age ratio. 



Experimental research has shown that in parallel with fatty tissue, DDT 

 accumulates extensively in fish brain tissue, reaching critical values 

 (Braginskiy, et a_l_. 1979). It was found that using poisoned natural food, 

 the developing of intoxication in fish was, in fact, connected with accumu- 

 lation of DDT and its metabolites. It was stated that the fish died from 

 toxicosis at critical levels of DDT accumulation in the brain (3 ppm and 

 greater). These findings correspond to the results obtained during the in- 

 vestigation of analogous phenomena in warm-blooded animals (Dale, et al . 

 1963). 



115 



