content of DDT and its metabolites in tissues is comparatively low. The 

 greatest accumulation of DDT residues is found in the inner fat and brain 

 tissue of fish. Internal organs (liver, stomach and intestine) contain a 

 considerable quantity of the metabolites (DDE and DDD), but comparatively 

 little DDT. An even lesser amount of residual DDT is found in gonads and 

 spawn, while the lowest levels of residues of this pesticide are found in 

 muscular tissue (Komarovskiy, et al_. 1975). 



Thus, residual quantities of DDT and its metabolites are mainly accumu- 

 lated in fatty and brain tissues. Having been taken into the fish, DDT 

 undergoes substantial metabolic changes. This fact is indicated by pre- 

 dominance of the metabolites DDE and DDD in storage organs. 



It should also be noted that the results did not demonstrate the pre- 

 sence of polychlorinated biphenyls in organs and tissues of fish from the 

 study sites. However, corresponding analysis of fish specimens from the 

 Black Sea and the Barents Sea were positive for the presence of PCB (chro- 

 matograms showed saw-tooth peaks, analogous to those of the Baltic fish 

 that were convincingly shown by Swedish scientists to be associated with 

 PCB's). Chromatograms of the freshwater fish associated with the present 

 investigation showed only peaks typical for DDT and its metabolites. 



The experimental research associated with this study provided the op- 

 portunity to confirm data on specific differences in accumulation and dis- 

 tribution of DDT residues in fish tissue, and to demonstrate differences 

 conditioned by the functional role of tissues, and the metabolic rate of 

 DDT during intoxication. Pesticide accumulation depends upon metabolic ac- 

 tivity. For example, DDT accumulation is much greater in tissues of preda- 

 tory fish, notable for their elevated level of metabolism. Total DDT con- 

 tent in the liver of fish from the experimental water-bodies was as follows: 

 pike - 1.400 ppm, zander - 0.220 ppm, silver carp - 0.115 ppm, and carp - 

 0.047 ppm. Crucian carp, subjected to the effect of high concentrations 

 (40 ppm) of this pesticide had DDT accumulation in intestine 0.850 ppm by 

 the end of the exposure, while pike perch had 1.430 ppm. 



Pesticides accumulation was conditioned by the functional role of 

 tissues. It was the greatest in the tissues playing an important role in 

 the detoxification of pesticides (liver), and those having a comparatively 

 high content of lipid (liver, inner fat, and intestine). For example, 

 total DDT uptake under experimental intoxication for pike perch was as fol- 

 lows: liver - 0.220 ppm, intestine - 3.175 ppm, inner fat - 5.635 ppm, 

 muscles - 0.057 ppm. 



The clinical picture of fish intoxication as a result of acute DDT expo- 

 sure was characterized by a marked behavioral change. Intensive locomotor 

 activity gave way to deceleration and a disturbance of coordinative move- 

 ments, loss of balance, adynamia and death. Dissection of the fish re- 

 vealed marked hemorrhaging of the brain and other vital organs (gills, 

 liver, heart, kidneys, etc.), as well as necrotic changes, especially in the 

 liver. 



113 



