Nature of radioactive contamination of components of ecosystems of streamflows from tunnels of Degelen massif

• Contamination of soil cover, surface water and groundwater from tunnels of Degelen nuclear test area.
• Radionuclides in associated components of the ecosystem showed disequilibrium.
• Forecast that 137Cs and 239+240Pu will not be distributed more than 1.5 km from tunnel exits.
• Forecast that 90Sr will not be distributed more than 2 km.

The paper provides data on environmental contamination due to radionuclides' migration with water. As a result of investigations there was obtained data on character of contamination of soil cover, surface water and underflow from tunnels of Degelen massif. Character of radionuclides' spatial distribution in environment was also shown. Mobility ranges of radionuclides' vertical and horizontal movements have been established in soils both across and along the stream flow. There was also shown a possibility to forecast radionuclides' concentration in soil by specific activity of these radionuclides in water. Different concentrations of radionuclides in associated components of the ecosystem (surface waters – ground waters – soils) have shown disequilibrium of their condition in this system. Generalization of investigation results for tunnel water streams' with water inflows, chosen as investigation objects in this work, allows to forecast radionuclides' behavior in meadow soils and other ecosystems of water streams from tunnels of Degelen test site. Based on analysis of curves, describing radionuclides' behavior in horizontal direction, we can forecast, that at this stage 137Cs and 239+240Pu would not be distributed more than 1.5 km from the access to the daylight surface, 90Sr – not more than 2 km.