Survey of potential radon hazard in the territory of Krasnokamensk, Zabaykalsky krai

The study presents new data characterizing the potential radon hazard of territories adjacent to uranium ore mining areas, using the residential zone of Krasnokamensk as an example, located near the Streltsovsky uranium ore deposit (Zabaykalsky krai). It is revealed that the specific activity of 226Ra and 222Rn flux density (the decay product of 226Ra) obey the normal distribution law and vary in the range of 22.0-42.9 Bq/kg and 15-201 mBq/(m2·s), respectively. The radon flux density values for residential areas exceed the allowable level (80 mBq/m2·s according to clause 5.1.6 of OSPORB-99/2010) in 70% of cases but remain within the background values typical for this territory. The main reason for increased values of radon flux density is low humidification of the territory due to the small amount of precipitation during the year. The parameters of diffusive radon transfer, indicating high gas permeability of soils on this territory, are characterized. It is shown that the main source of radon entry into buildings is the infiltration of radon released from the soil beneath the building through enclosing structures. It is established that the greatest radon hazard is represented by the buildings of trade and public catering enterprises, built by individual projects in the late 1990s and after 2000s. Meanwhile, typical panel five-level residential buildings are characterized mainly by concentrations of radioactive gas in the air of premises, not exceeding the established hygienic standards. However, in the construction of new residential and public buildings it is advisable to assess the sufficiency of the radon-protective properties of the structures of the underground part of the project and, if necessary, provide a radon protection system to prevent potential health risks to the population and the environment.