Abstract
<jats:p>Using chamber models of the dynamics of 90Sr, 103,106Ru, 134,137Cs, 141,144Се in water masses and plants, the efficiency of extraction of aboveground organs of HELOPHYTES after a single emergency entry of radioactive fallout into fishery reservoirs with varying degrees of overgrowth was assessed. Calculations were performed for 5 hypothetical precipitation time points, which were selected taking into account the routes of radionuclides entering plants and the stage of phytomass development. The most effective method for decontamination of water bodies will be the removal of aboveground plant organs within 1-3 days after the fallout (up to 40 % of each radionuclide that entered the ecosystem) under conditions of ecosystem contamination from July 1 to September 1, i.e., during the period of formation of maximum aboveground phytomass. Over time, the activity of radionuclides concentrated in aboveground organs will rapidly decrease and the removal of plants 10 days after the fallout will allow the removal from the ecosystem of no more than 17 % of 103,106Ru, about 20 % of 90Sr and 134,137Cs, and 27 % of 141,144Сe, after 30 days - no more than 7, 10 and 24 % of the total amount of these radionuclides, respectively.</jats:p>