Public exposure in the Orenburg region due to natural sources of ionizing radiation. Part 3: Approaches to radon survey planning

Abstract

A comprehensive radiation survey of settlements in six districts of the eastern part of the Orenburg region in terms of exposure to natural sources of ionizing radiation, carried out in 2019, revealed numerous exceedances of the hygienic norm (action level) for indoor radon concentration in residential and public buildings. It was found that among other studied factors, exhalation of radon from the ground under the buildings is the main source of high levels of public exposure. Due to the lack of funding for the continuation of the survey in 2020, specialists of St. Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev, Directorate of Rospotrebnadzor in the Orenburg region and the Center of Hygiene and Epidemiology in the Orenburg region needed to develop new approaches to survey planning. These new approaches should provide maximum amount of measurement information necessary to ensure radiation safety of the region’s population, with minimal financial investments and labor costs. Indoor radon concentration in residential and public buildings was undoubtedly chosen as the studied factor, and the integrated measurement method using SSNTDs was chosen as the most suitable method for the objectives of the survey due to its scalability and ease of detectors deployment. Since exposure to radon and its progeny is the second leading cause of lung cancer after smoking, the selection of priority districts of the region for the radon survey was based on average standardized trachea, bronchi, and lung cancer morbidity rates in the districts of the Orenburg region for 2009-2018. The survey conducted in 2020-2023 revealed exceedances of the hygienic norm (action level) for indoor radon concentration in five of seven surveyed districts. By 2025 it is planned to conduct radon surveys in three more districts of the Orenburg region with increased respiratory systems cancer morbidity rates.