The monograph represents the theoretically summarization of the experimental results obtained during 35-year studies of artificial radionuclides hydrogeomigration in geological and conjugated environment. Modern problems of radioecological monitoring are actualized. The processes of groundwater self-cleaning from radionuclides have been investigated and parameterized. A number of radio-ecological factors of artificial radionuclides biogeomigration in sub aquatic landscapes within the Ukrainian Polissia (Woodlands) have been identified, which determine the barrier functions of forestry-marsh biogeocenoses. Methodological and methodical approaches to the analysis of long-term monitoring observations within the catchment areas contaminated with radionuclides are considered. The main task of such studies is to establish the degree of barrier stability of the landscape complex of the catchment for water intake. The level of generalizations, local (close to the object), regional or global is substantiated by studies of the appropriate level, which should be started with the establishment of the share of secondary contamination of surface waters with radionuclides that is related to the implementation of the balance method. The methods of scientific analysis also include a variety of statistical methods aimed at identifying landscape and geochemical factors responsible for the deposition, migration, and assimilation of radionuclides within watersheds. The described factor selection procedure is the basis for predicting the concentrations and aqueous removal of radionuclides. On this basis, a forecast of radionuclide water migration for local and regional levels has been developed. Examples of the analysis of efficiency of the executed and substantiation of possible water protection and fire-prevention measures in the Chernobyl exclusion zone are presented. The monograph is designed for experts in the fields of radiogeochemistry, biogeochemistry, hydrology and hydrogeology, radioecology, agro-ecology, technogenic-ecological safety and security, conducting monitoring studies, as well as for students of natural specialties of higher education institutions.

Tritium is a radioisotope that is extremely mobile in the biosphere and that can be transferred to the environment and to humans mainly via tritium oxide or tritiated water. Moreover, as is widely known, it is extremely difficult to detect in the environment. In the last decade, many studies and research activities have been performed to fill the knowledge gap on this radionuclide, the amount of which is expected to be increasingly released into the environment from nuclear installations in the near future. Considering this and the fact that the biological and environmental effects produced by tritium have been examined mainly from a medical and detection monitoring point of view, it is considered important to propose in this study a review of the critical aspects of tritium from the environmental, engineering, and waste management points of view. Identifying sources and effects of tritium, tritium materials and wastes containing tritium in the environment is also fundamental for planning the specific and necessary actions required for an effective waste management approach under, e.g., disposal conditions. The critical analysis of the published recent studies has allowed to evaluate, for example, that the expected rate of tritium generation in a fusion reactor is four orders of magnitude higher than that of LWRs, and the environmental release from a fusion reactor is 1.4–2.2‱, which is twice as much as from a heavy water reactor and more than two orders of magnitude higher than from a LWRs. Furthermore, with reference to the waste management strategy, it is emphasized, e.g., that the condensation of moisture inside vaults and the interaction of H₂O with the disposal body determine the formation of tritiated water, which is filtered through the concrete and eventually released into the environment. Consequently, in the selection of engineered barrier materials for repositories/disposal facilities, the use of a mixture of a framework and layered silicates is proposed to improve its absorption and filtering properties.