Distribution of the residual tritium content in organs of Carassius gibelio (Prussian carp) freshwater ray-finned fish

The distribution of residual tritium in organs of Carassius gibelio (Prussian carp) freshwater rayfinned fish as a representative of the Carassius phytophagous genus of Cyprinidae family was studied for determining the 3 Н accumulation in the aquatic plants–fishes food chain in water bodies contaminated with radionuclides. In the first step, tritium was accumulated by 3000 g (wet weight) of the aquatic plant biomass in aquaria of 100 L volume with the specific water activity of 100 kBq L –1 . The aquatic plants were shown to actively take up the introduced tritium, accumulating up to 70% of the radionuclide. The content of tritium bound to organics in the biomass increased to 21% of the whole accumulated tritium. After that, the plants ( Ceratophyllum, Lemna ) were dried and mixed with dry fish fodder (1: 1), and the mixture was pressed in granules. The activity of each granule was up to 50 Bq. These granules were used for forced feeding of fishes, so that each individual took up in the course of the 550-day experiment up to 330 kBq of tritium. According to the analysis results, about 75% of the whole amount of the accumulated tritium was present in muscle tissues. Determination of the tritium content of proteins and lipids in the experimental systems revealed no differences in the use of Ceratophyllum and Lemna as fodder.