Medical Radiology and Radiation Safety. 2026. Vol. 71. № 4
DOI:10.33266/1024-6177-2026-71-4-47-55
P.S. Miklyaev1, T.B. Petrova2, D.V. Shchitov3, P.A. Sidyakin3, M.A. Murzabekov3, D.N. Tsebro3, E.I. Kaygorodov1, 4
PATTERNS OF SPATIAL DISTRIBUTION OF RADIUM-226 SPECIFIC ACTIVITY IN SOILS AND RADON EXHALATION RATE FROM THE SOIL SURFACE IN THE TERRITORY OF PYATIGORSK
1 E.M. Sergeev Institute of Environmental Geoscience, Moscow, Russia
2 M.V. Lomonosov Moscow State University, Moscow, Russia
3 North Caucasus Federal University, Stavropol, Russia
4 Federal State Unitary Enterprise Research and Technical Center of Radiation-Chemical Safety and Hygiene, Moscow, Russia
Contact person: P.S. Miklyaev, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
ABSTRACT
Purpose: To identify spatial distribution patterns of ²²⁶Ra specific activity in soils and radon flux density (RFD) from the soil surface within the territory of Pyatigorsk, and to determine the correlation between these parameters and indoor radon concentrations (IRC) for the purpose of developing medium- and large-scale mapping of areas by potential radon hazard levels.
Material and methods: RFD measurements were primarily conducted during the dry season using the open-chamber method with activated charcoal, employing equipment from the “Kamera-01” measuring complex. Measurements of dose rate were performed using DRG-01T and DKg-07D “Drozd” gamma dosimeters at a height of 1 m above the ground surface. Measurements of specific activity of natural radionuclides in soil samples were carried out using a gamma spectrometric system equipped with a NaI(Tl) 63×63 mm scintillation detector and “Progress-2000” software in a 1-liter Marinelli beaker geometry. The samples were preliminarily stored for two weeks in hermetically sealed Marinelli containers to achieve radioactive equilibrium between radium and radon. In total, the study included 224 measurements of RFD from the ground surface, 47 determinations of specific activity of natural radionuclides in samples of bedrock and unconsolidated deposits, and approximately 200 measurements of dose rate.
Results: Radium specific activity values within the city ranged from 15–195 Bq/kg, and the RFD ranged from 10–567 MBq/m2∙s. The lowest values of radiation parameters are typical for the floodplain and the I-II upper floodplain terraces of the Podkumok River, the highest values are for territories composed of Maikop clays. In most of the city’s territory, except for the floodplain of terraces I–II, the average RFD values exceed the level of 80 mBq/m2∙s, and the proportion of private values exceeding this level is more than 50%, which makes it possible to classify this territory as a potentially radon-hazardous category. Extremely high 226Ra concentrations (477–868 Bq/kg) and RFD (679–2760 mBq/m2∙s) were recorded in the distribution sites of fresh travertines precipitating from hot hydrogen sulfide-carbon dioxide waters in the Goryachaya Mountain area. Several local radon anomalies have also been detected in the Pyatigorsk (RFD values reach 5260 mBq/m2∙s), which appear at separate points and do not repeat over time, which are apparently associated with local convective radon transport in the soil. The paper presents the results of radon monitoring at anomalous points in different seasons of the year.
Keywords: radon exhalation rate, soil radium specific activity, mapping, zoning, geological data
For citation: Miklyaev PS, Petrova TB, Shchitov DV, Sidyakin PA, Murzabekov MA, Tsebro DN, Kaygorodov EI. Patterns of Spatial Distribution of Radium-226 Specific Activity in Soils and Radon Exhalation Rate from the Soil Surface in the Territory of Pyatigorsk. Medical Radiology and Radiation Safety. 2026;71(4):47–55. DOI:10.33266/1024-6177-2026-71-4-47-55
References
1. Ting D.S. WHO Handbook on Indoor Radon: a Public Health Perspective. International Journal of Environmental Studies. 2010;67;1:100–102. Doi: 10.1080/00207230903556771.
2. Marennyy A.M., Tsapalov A.A., Miklyayev P.S., Petrova T.B. Zakonomernosti Formirovaniya Radonovogo Polya v Geologicheskoy Srede = Patterns of Radon Field Formation in the Geological Environment. Moscow, Pero Publ., 2016. 394 p. (In Russ.).
3. Gulabyants L.A. A New Approach to Solving the Problem of Protecting Buildings from Radon. Vestnik MGSU = Bulletin of Moscow State University of Civil Engineering. 2011;3-2:3-8. (In Russ.).
4. Petermann E., Bossew P., Kemski J., Gruber V., Suhr N., Hoffmann B. Development of a High-Resolution Indoor Radon Map Using a New Machine Learning-Based Probabilistic Model and German Radon Survey Data. Environmental Health Perspectives. 2024;132;9:97009. Doi: 10.1289/EHP14171.
5. Miklyayev P.S., Petrova T.B., Sidyakin P.A., Marennyy A.M., Tekeyev R.A., Tsapalov A.A., Shchitov D.V., Tsebro D.N., Murzabekov M.A., Karl L.Ye., Gavril’yev S.G. Formation of Radon Environment in Buildings of Educational Institutions of the City of Lermontov. Meditsinskaya Radiologiya i Radiatsionnaya Bezopasnost’ = Medical Radiology and Radiation Safety.2025;70;2:40–48 (In Russ.). Doi: 10.33266/1024-6177-2025 70-2-40-48.
6. Bossew P., Cinelli G., Ciotoli G., Crowley Q.G., De Cort M., Elío Medina J., Gruber V., Petermann E., Tollefsen T. Development of a Geogenic Radon Hazard Index - Concept, History, Experiences. International Journal of Environmental Research and Public Health. 2020;17;11:4134. Doi: 10.3390/ijerph17114134.
7. Baumann S., Petermann E., Cinelli G., et al. Radon Hazard Mapping: Usability of Environmental Predictors Including Atmospheric Radon and Radon Flux and Knowledge Transfer between Regions (Belgium and Germany). Environmental Earth Sciences. 2025;83:196. Doi: 10.1007/s12665-025-12126-2.
8. Sidyakin P.A., Yanukyan E.G., Fomenko N.A., Vakhilevich N.V. Formation of Population Exposure Levels in the Caucasian Mineral Waters Region due to Radioactivity of Rocks. Izvestiya Vysshikh Uchebnykh Zavedeniy. Geologiya i Razvedka = Proceedings of Higher Educational Establishments. Geology and Exploration. 2016;1:66-70 (In Russ.).
9. Sidyakin P.A., Shchitov D.V., Fomenko N.A., Lebedeva S.A. On the Radiation and Ecological Situation in the Urbanized Areas of the Resort Towns of the Caucasian Mineral Waters. Inzhenernyy Vestnik Dona = Ingineering Journal of Don. 2015;1-1:16 (In Russ.).
10. O Sanitarno-Epidemiologicheskoy Obstanovke v Stavropol’skom Kraye v 2011 Godu = On the Sanitary and Epidemiological Situation in Stavropol Krai in 2011. State Report. Stavropol Publ., 2012 (In Russ.). URL: https://26.rospotrebnadzor.ru/doc/gd/doklad11.pdf (Date of Access: 15.10.2025).
11. O Sostoyanii Sanitarno-Epidemiologicheskogo Blagopoluchiya Naseleniya v Stavropol’skom Kraye v 2014 Godu = On the State of Sanitary and Epidemiological Well-Being of the Population in Stavropol Krai in 2014. State Report. Stavropol Publ., 2015 (In Russ.). URL: https://26.rospotrebnadzor.ru/doc/gd/doklad14.pdf (Date of Access: 15.10.2025).
12. O sostoyanii Sanitarno-Epidemiologicheskogo Blagopoluchiya Naseleniya v Stavropol’skom Kraye v 2024 Godu = On the State of Sanitary and Epidemiological Well-Being of the Population in Stavropol Krai in 2024. State Report. Stavropol Publ., 2025 (In Russ.). URL: https://26.rospotrebnadzor.ru/doc/gd/doklad24.pdf (Date of Access: 10.15.2025).
13. Miklyayev P.S., Petrova T.B., Klimshin A.V., Marennyy A.M., Tekeyev R.A., Fin’kovskaya N.S., Shchitov D.V., Sidyakin P.A., Murzabekov M.A., Tsebro D.N. Radiation Situation in the Beshtau Mountain Range. Radiatsiya i Risk (Byulleten’ Natsional’nogo Radiatsionno-Epidemiologicheskogo Registra) = Radiation and Risk. 2024;33;2:65-78 (In Russ.).
14. Miklyayev P.S., Petrova T.B., Marennyy A.M., Nefedov N.A., Ostapchuk T.V., Shchitov D.V., Sidyakin P.A., Murzabekov M.A. Levels of Radon Exhalation on the Western Slope of Mount Beshtau, Caucasian Mineral Waters. Geoekologiya. Inzhenernaya Geologiya, Gidrogeologiya, Geokriologiya = Geoecology. Engineering Geology, Hydrogeology, Geocryology. 2018;5:20-30 (In Russ.).
15. Karpenko Ye.I., Sanzharova N.I., Spiridonov S.I., Serebryakov I.S. Radioecological Situation in the Area of the Former Uranium Mining Enterprise LPO Almaz. Radiatsiya i Risk (Byulleten’ Natsional’nogo Radiatsionno-Epidemiologicheskogo Registra) = Radiation and Risk. 2009;18;4:73-81 (In Russ.).
16. Shandala N.K., Titov A.V., Isayev D.V., Semenova M.P., Seregin V.A., Ostapchuk T.V., Shlygin V.V., Starinskiy V.G., Starinskaya R.A. Assessment of the Impact of Heavy Rains on the Radiation Situation in the Area of Adit No.16 of the Former Almaz Plant. Meditsina Ekstremal’nykh Situatsiy = Medicine of Extreme Situations. 2017;60;2:202-207 (In Russ.).
17. Bel’skikh Yu.S., Titov A.V., Shandala N.K., Isayev D.V., Semenova M.P., Doron’yeva T.A., Seregin V.A., Krotkova Yu.V., Filonova A.A. Radiological Hazards on the Territory of Mine No.1 of the Lermontov Production Association Almaz. Gigiyena i Sanitariya = Sanitation, Russian Journal. 2025;104;1:6-12 (In Russ.).
18. Krupkin A.B., Gusev A.V. Radiation and Hygienic Assessment of the Impact of Negative Natural Factors, as Well as the Consequences of the Activities of JSC Hydrometallurgical Plant on the Population of the City of Lermontov. ANRI = ANRY. 2023;4:64-76 (In Russ.).
19. Pakholkina O.A., Zhukovskiy M.V., Yarmoshenko I.V., Vereyko S.P. Assessment of Average Annual and Average Long-Term Values of EEVA of Radon in Premises. ANRI = ANRY. 2010;2:50-55 (In Russ.).
20. Petoyan I.M., Shandala N.K., Titov A.V., Zinov’yeva N.V. Morbidity of the Adult Population Living in the Area of the Uranium Legacy under the Influence of Radon. Gigiyena i Sanitariya = Sanitation. Russian Journal. 2022;101;3:281-287 (In Russ.).
21. Miklyayev P.S., Kaygorodov Ye.I., Petrova T.B., Marennyy A.M., Karl L.E., Shchitov D.V., Sidyakin P.A., Murzabekov M.A., Tsebro D.N., Gubanova Yu.K., Mnatsakanyan M.R., Gertsen G.P. Mapping the Potential Radon Hazard of the Territory of Pyatigorsk Taking into Account Geological Data. Meditsinskaya Radiologiya i Radiatsionnaya Bezopasnost’ = Medical Radiology and Radiation Safety. 2025;70;1:45-52 (In Russ.).
22. Ivanova I.K. On the Age of Travertines of Mount Mashuk and their Relationships with the Podkumok Terraces. Byulleten’ Komissii po Izucheniyu Chetvertichnogo Perioda = Bulletin of the Commission for the Study of the Quaternary Period. 1947;9:36-47 (In Russ.).
23. Otsenka Potentsial’noy Radonoopasnosti Zemel’nykh Uchastkov pod Stroitel’stvo Zhilykh, Obshchestvennykh i Proizvodstvennykh Zdaniy = Assessment of Potential Radon Hazard of Land Plots for the Construction of Residential, Public and Industrial Buildings. Methodological Guidelines 2.6.1.038-2015. Moscow, FMBA Rossii Publ., 2015. 36 p. (In Russ.).
24. Lyashenko S.I., Danilov S.R., Potapov Ye.G., Shchelkunov A.V., Denisenko Z.P. Radioactive Indicators of Mineral Waters from the Main Deposits of the Caucasian Mineral Waters Region. Kurortnaya Meditsina = Resort Medicine. 2020;1:18-26 (In Russ.).
25. Miklyayev P.S., Petrova T.B., Marennyy M.A., Marennyy A.M., Dorozhko A.L., Makeyev V.M. Map of Radon Flux Density in Moscow. ANRI = ANRY. 2012;3:15-24 (In Russ.).
PDF (RUS) Full-text article (in Russian)
Conflict of interest.The authors declare no conflict of interest.
Financing. The work was supported by the Russian Science Foundation, grant No. 24-17-00217.
Contribution. Article was prepared with equal participation of the authors.
Article received: 20.03.2026. Accepted for publication: 25.04.2026.