lized instantly, or they manifest clear symptoms of insectides poisoning: 

 tremor of limbs and wings, disturbances of coordination, convulsions, and 

 death in 20-30 min. after exposure. To check corresponding symptoms of 

 intoxication and the rate of their development relative to the DDT content 

 in tissues, the material was analyzed by the gas chromatographic method 

 and scale of conventional values of the level of accumulation of DDT in 

 tissues of fish is proposed (Table 4). 



This test has a dignostic value when analyzing the causes of mass 

 mortality of fish. Accumulation of DDT i.e. the vital organs of fish, es- 

 pecially in the brain, may be the cause of sudden catastrophic death in 

 stress situations, e.g., after a sharp increase in water temperature, 

 during spawning, and as a consequence of mobilization of fat reserves and 

 resultant appearance of DDT dissolved in lipids in the blood streams. 

 Detection of insecticides in the brain tissue of long preserved, or even 

 petrified fish, enables identification of the role of DDT as one of the 

 causes of death, while the chemical analysis of such tissue is very com- 

 plicated, and requires equipment for gas chromatography. 



The oligochaet Tubifcex tubifae.x in non-toxic media normally maintains 

 a vertical body attitude, swaying evenly like a wheat field in the wind. 

 On the bottom, they form tangles. In toxic media the bodies of the worms 

 stretch convulsively, the movements become disordered, and under deep in- 

 toxication, the worms lie immobile, unentangled on the bottom, and the 

 reddish coloration of the body disappears (evidently as a result of hemo- 

 globin degradation as in chironomid larvae). 



TABLE 4. TESTS ON DDT CONTENT IN STORAGE TISSUES OF FISH 



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