Natural Background Radiation in Residential and Public Buildings Located in the Vicinity of Mining Operations in the Arctic

Natural background radiation (NBR) largely contributes to the human inhalation of radionuclides originating from the decay of U-238, U-235 and Th-232 isotopes. This problem is of particular importance for public health in the areas with high seismicity induced by mining operations. The purpose of this article was to assess the impact of mining activities on NBR in the residential and public buildings located in the immediate vicinity of the apatite-nepheline ore mining operations in the Arctic. Materials and methods. The measurements were taken in residential and public buildings of Kirovsk (Murmansk Region) adjacent to open-pit and underground mines. The following were measured: total radioactivity dose of samples of raw ores and their concentrates, their spectral characteristics, as well as the aerosol concentration of radon decay products, and volumetric radon concentration in the basements of residential and public buildings located within 3 km from the mining area. Results. The radioactivity of open-pit ore was significantly (7.3 times) higher than that from underground mines (107,300 ± 9823 and 14,615 ± 1980 Bq/kg, respectively). However, the radioactivity of the final product (apatite concentrate) did not depend on the extraction technique (59,792 ± 865 and 61,827 ± 1022 Bq/kg, respectively). Indoor air concentrations of radon in the basements of buildings located up to 3 km from the mines, increased linearly by an average of 0.15 Bq/m3 for each ton of explosives used in ore breaking. The levels of radon and its decay products in residential and public buildings in areas adjacent to the mining operations did not exceed 100 Bq/m3. Thus, mining and blasting operations in the stress-strain state of ore-bearing rocks might have an important impact on the intensity of radionuclide emissions and changes in NBR inside residential and public buildings located in Arctic settlements adjacent to the areas of apatite-nepheline ore mining.