The radiological state of the land and water areas constantly attracts public interest. Specially protected natural
reservations deserve special attention when it comes to studying radiological conditions. This study presents
findings of radioecological investigations conducted in the Kostomuksha State Nature Reserve in 2012 – 2015.
The Kostomuksha Mining Company, which is developing the Kostomuksha iron ore deposit was identified as a
potentially hazardous facility that might affect the radioecological situation in the naturel reserve, since production
of iron ores at the deposit involves extraction to the ground surface of acid rocks characterised by a naturally
high content of radioactive elements (granitic gneiss). Furthermore, several sources of radioactive radon gas
have been identified within the reserve boundaries. The study included investigation of natural and anthropogenic
radioactivity in the environmental components of the nature reserve and adjacent territories, including soil,
plants, bottom sediments, ambient air and natural waters. It was found that development of the Kostomuksha
iron ore deposit and operations of the mining and processing plant do not exert any considerable impact on the
radiological situation in the nature reserve. Data obtained during the study indicate that the overall radiological
situation in the reserve is acceptable and meets the relevant radiation safety standards. High levels of radiocesium
were found in the moss and bottom sediments of the nature reserve, which requires additional research to
determine a wider pattern of distribution of anthropogenic radioactivity across the adjacent territories and to
study the processes of buildup and migration of radionuclides in aquatic organisms of Kamennoye Lake.