Accumulation and distribution of radionuclides in higher aquatic plants during the vegetation period

The long-term observations of the dynamics of Sr-90 and Cs-137 concentration, as well as the physicochemical forms of these radionuclides in 10 species of higher aquatic plants during the vegetation period of Glyboke Lake in the Chornobyl Exclusion Zone were presented. The accumulation of radionuclides depends on the influence of environmental factors and species characteristics of the studied plants. It has been shown that the accumulation of Sr-90 and Cs-137 by plants mainly occurs in accordance with the physiological stages of their development. Under conditions of intensive growth and accumulation of biomass in the juvenile period, plants disproportionately uptake Cs-137 from the environment; during the seed ripening period at the stage of aging, plants mainly accumulate Sr-90, as evidenced by the non-correlation of this radionuclide concentration in water and plants in the considered periods. The specific features of the accumulation of radionuclides by plants were studied by the method of analysis of physicochemical forms, which consists in the sequential extraction of radionuclides from plant preparations and makes it possible to quantitatively investigate potentially exchange and fixed forms. The analysis of physicochemical forms confirmed the patterns of seasonal distribution of radionuclides, as well as their accumulation in cells, tissues and in the whole plant obtained from long-term observations.