• The primary types of lateral and vertical migration of natural and technogenic radionuclides were identified and studied in each of the types of geochemical landscapes studied.

• The main natural and technogenic geochemical barriers hindering the spread of technogenic contamination were determined.

• An evaluation was made of the degree to which radioactive and stable contaminants arising in the course of operations by nuclear and radiation enterprises affect the environment in the areas where these enterprises are located.

• Methods were developed for small-, medium-, and large-scale radio-ecological mapping applicable to various landscape-geochemical and geological-geomorphological situations.

By analyzing the results obtained, it is possible to draw the general conclusion that the radiation ecology situation in the regions where the Nerpa Ship Repair Plant and the Smolensk and Balakovo nuclear power plants operate meets current safety requirements. Meanwhile, in the regions where the PMCPA and the Mayak Production Association are located, there are areas where the natural landscapes have been subjected to radiation and chemical contamination. In the area around the Priargunsk facility, the greatest radioecological danger is presented by the repository for the liquid and solid wastes produced by the operations of the molybdenum-uranium ore processing plant and the sulfuric acid production plant. The toxic substances included in these wastes have contaminated the soils, subsoil rock, surface water, and groundwater in the zone affected by the repository. Migration of the water threatens the radiation and chemical contamination of underground sources from which drinking water is drawn.

The wide-ranging plumes of intensive radioactive contamination of the soil cover in the Mayak area (the East Urals Radioactive Trace and the Techa River Valley) were formed in the early stage of activities at the enterprise. During the existence of the East Urals Trace, the contours of this radioactive anomaly have undergone substantial changes. At the same time, lateral migration of radionuclides has been observed in the Techa River Valley caused by the washing out of contaminants from the soil and bottom sediments by flood waters, which have carried the toxic substances into the transitory river systems.