Ganzha C. The role of hydrobionts in transformation of physical and chemical forms of radionuclides in aquatic ecosystems

This research focuses on the distribution characteristics of physical and chemical forms of 90Sr and 137Cs in shoreline soils, bottom sediments, aquatic plants and bivalve molluscs in the Chornobyl Exclusion Zone (CEZ). During 2008-2014 we studied the forms of distribution of radionuclides in the components of the most contaminated water bodies within the CEZ - Glyboke and Daleke lakes that are located within the left-bank floodplain of the Pripyat River as well as Chornobyl NPP cooling pond. We analysed the ability of radionuclide migration in the main components of aquatic ecosystems, calculated internal absorbed dose rate, as well as inventory and balance 90Sr and 137Cs in the ecosystem of Glyboke Lake into account the dynamics of the physical and chemical forms of radionuclides. During the research in the ecosystem of Glyboke Lake in a state of dynamic equilibrium were about 5 TBq of 90Sr, which accounted for 40% soluble and exchange, 53% - temporarily bound form and 7% were in the mineral residue. The content of 137Cs was about 15 TBq, among which 14% were in water-soluble and exchange forms, 31% - in the temporarily bound forms and 55% - in the mineral residue.