Interaction of Tritium with Elodea canadensis and Lemna minor.

Tritium is the least toxic radionuclide. The main contribution into the total tritium content in ecosystems is made by technogenic tritium, which is due to the operation of nuclear fuel cycle enterprises. The tritium content in the ecosystem of the River Yenisei is connected with its background values as well as with tritium entering the water ecosystem as a result of the operation of the Mining and Chemical Combine, MCC Rosatom. Presented here are the investigations of the possible transformation of tritium interacting with certain species of aqueous plants - submerged rnacrophyte Elodea canadensis and an aqueous plant floating on the surface of water reservoirs Lemna minor. Elodea sampling was made in a real water reservoir - the River Yenisei, while lemna was grown in the laboratory conditions. The experiments show that with the chronic exposure of young elodea shoots to tritium, the latter transforms from HTO to OBT. Optimal conditions were also obtained for the maximum transformation of tritium ≈35% from the total content: at 25°C and the light period 6/18 (day/night). In the experiments with duckweed, observed a significant increase in area of fronds in introducing tritium into the system.