The aim of the study is to analyze the accumulated data on the study of forest territories of the border regions of the Bryansk region that have been exposed to radioactive contamination for their involvement in economic activity, as well as the possible transfer of radioactive materials in forest fires. The area of recorded and unaccounted forests was estimated according to the “Forest Plan of the Bryansk Region for the period 2019-2028” and the results of the analysis of remote sensing data of the earth, the assessment of radiation pollution – according to the radiation surveys of the forest fund and radioecological monitoring of forests, assessment of cesium-137 content – according to radiation monitoring. In the course of the work, the dynamics of the transition of forests from the range of a high level of radioactive contamination to lower ones from 1991 to 2018 slightly changes the total area of contaminated forests by regions was revealed. Top-level values of cesium-137 content in the main types of forest combustible materials, which a dangerous factor is contributing to a significant increase in the content of radiocesium in atmospheric air and the transfer of radionuclides beyond the limits of radioactive contamination zones in a forest fire. The most radiation-hazardous is the forest litter, which contains more than 70% of the total cesium-137 reserve in forest combustible materials, the values of which reach values of 224 kBq / kg in the Krasnogorsk district of the Bryansk region. The obtained forecast of cesium-137 content in the forest litter by the zones of radioactive contamination of forests in the most polluted areas of the Bryansk region for the period up to 2046 indicates the preservation of a high degree of radioactive contamination of forests in the Krasnogorsk and Novozybkovsky districts after more than 60 years after the Chernobyl accident power plants. Due to the high class of natural fire hazard of forests in the south-west of the Bryansk region and the high risk of fires in contaminated areas, it is necessary to assess the degree of danger in the prevention and suppression of radioactive forest fires, especially criterion of the absorbed dose for workers in order to avoid the deterministic effect.

The research presents the data of long-term observations of the impact of the Kursk Nuclear Power Plant operation on the radioecological situation in the region of its location. The dynamics of the content of natural and artificial radionuclides in the components of agricultural ecosystems was studied due to the data based on the information from the radioecological monitoring network developed in 2003. Samples of soils, agricultural products and animal feeds were taken at 11 control sites located on arable lands and grasslands in the vicinity of the Kursk Nuclear Power Plant, and, in settlements, locally produced food was sampled. It was shown that for the period of studies of 2003-2019, the average specific activity of ⁹⁰Sr in the soils of agroecosystems of the 10 km influence zone of the Kursk Nuclear Power Plant varied within 2.7-4.3 Bq/kg, and specific activity of ¹³⁷Cs was 14.6-40.8 Bq/kg. At the same time, there were found no trends of increase in the content of artificial radionuclides in soil over time and at different distances from the NPP, and the increased specific activity of ¹³⁷Cs in soil compared to the global background is explained by the Chernobyl fallout. The variability of the average content of natural radionuclides in the soil for ⁴⁰K was 481-625 Bq/kg, ²²⁶Ra – 20.6-29.5 Bq/ kg, ²³²Th – 28.2-39.2 Bq/kg, which corresponded to all-Russian data. The average specific activity of ⁹⁰Sr in grain was 0.24-0.43 Bq/kg, and ¹³⁷Cs – 0.19-0.37 Bq/kg. Even the maximum levels of artificial radionuclides in grain were 44 times for ⁹⁰Sr and 85 times for ¹³⁷Cs lower than the current SanPiN standards. The highest specific activity values of ¹³⁷Cs and ⁹⁰Sr in potatoes, vegetables, and gourds were 160 times lower than the SanPiN standards. It was noted that the maximum content of ⁹⁰Sr in milk was more than 540 times lower than the SanPin standard, and for ¹³⁷Cs this difference was 330 times. The maximum content of ¹³⁷Cs in beef turned out to be over 850 times lower than the SanPiN standard for this radionuclide. About 70 Bq/a of ⁹⁰Sr and 200 Bq/a of ¹³⁷Cs enter the population diet with locally produced food, which is almost 400 times for ¹³⁷Cs and 200 times for ⁹⁰Sr lower than the annual limit. Milk (46%), meat (31%), potatoes and vegetables (14%) make the main contribution to the formation of the internal dose from agricultural products containing ¹³⁷Cs, and contribution to dose from ⁹⁰Sr is made by milk (14%) and crop products (potatoes, vegetables, bread) – up to 78%. In general, we concluded that over the past 17 years, the operation of the Kursk Nuclear Power Plant did not lead to a deterioration of the radioecological situation in the region of its location, because during the survey period there was no significant increase in the content of artificial radionuclides in agricultural products, foods and environmental components.

The paper is devoted to the verification of the model of external exposure of the Japanese population from radioactive fallout after the accident at the “Fukushima-1” NPP published by UNSCEAR in 2014. The paper presents specific quantitative examples of the verification of the external exposure model of the Japanese population after the accident at the “Fukushima-1” nuclear power plant. As an independent set of experimental data for validation of the model estimates we used the results of measurements of individual doses of external radiation in various population groups in Japan in different time periods after fallout. In the case of the deterministic version of the model, it was shown that for the adult population working mainly outdoors (construction workers and agricultural workers), the differences between the average values of effective doses predicted by the model and those obtained on the basis of measurements were less than 20%. For office workers, this difference was larger, from 34 to 70%, depending on whether their office buildings are wooden or multi-story concrete. For children under 16 years of age and a longer period of time for measuring individual doses after radioactive fallout (2011 – 2015), the differences between the model average effective doses and those estimated on the basis of measurements ranged from –24% to +32% in different time periods. In the case of the stochastic version of the model, it was shown that for the three considered groups of the adult population the distributions of individual doses obey the logarithmically normal law and the differences in the values of the calculated and experimental geometric means ranged from –7% to +20%. The geometric standard deviation values obtained in the simulation were always slightly higher than the similar values estimated based on the measurement results.

At present, discharges of ²³⁸U to surface waters by nuclear industry enterprises are limited by radiation factor. Registration and control of ²³⁸U discharges to water bodies is performed in units of radioactivity (Bq/year) according to the current permit for the water discharge of radioactive substances. At the same time, uranium belongs to the 1st hazard class by its chemical toxicity (extremely dangerous chemicals), it has hygienic standard for content in surface waters. A comparison was made for the limitation of ²³⁸U intake to surface waters, taking into account radiation exposure and chemical toxicity. Activity concentration of ²³⁸U in water was calculated, at which the annual dose for a critical population group from water use would be 0,1 mSv/year (scenario 1 – the water object is used for drinking water supply) or 1 mSv/year (scenario 2 – the water object is not used for drinking water supply). The calculated activity concentrations were expressed in units of mass concentrations and compared with the maximum permissible concentration of uranium in water, established in Russia, 15 mkg/L. It is shown that compliance with the radiation safety norms does not automatically guarantee compliance with the current hygienic standards for limiting the toxic effects of uranium on population and the environment. The concentration of ²³⁸U in water producing the annual dose to population 0,1 mSv taking into account all exposure pathways, exceeds the maximum permissible concentration of uranium in water by 15 times. If water body is not used for drinking water supply, the calculated concentration of ²³⁸U in water producing the annual dose to population 1 mSv, is higher than the maximum permissible concentration of uranium in water by 1500 times. The restrictions imposed by the current hygienic standards for the chemical toxicity of uranium could reduce the permissible discharge levels of ²³⁸U to surface waters. It is necessary to develop environmental quality standards for ²³⁸U, taking into account its chemical toxicity, and include them to the system of establishment of permissible discharge limits of radioactive substances.

A comparative analysis of the radon concentrations in modern multi-storey residential buildings of high energy efficiency class and buildings typical for urban areas of the twentieth century was carried out. The study was conducted in Russian cities located in various climatic zones – Ekaterinburg, Krasnodar, St. Petersburg, Salekhard, Chelyabinsk. The radon concentration in samples of buildings was measured using integrated radon radiometers based on nuclear track detectors according to a single method. The surveyed sample included 498 apartments in multi-apartment buildings. Among all the examined building types, the highest average radon concentration is observed in modern energy-efficient houses – 43 Bq/m³. In other types of buildings, the following average radon concentrations were obtained: brick 2–5 floors – 35 Bq/m³; panel 5 floors – 32 Bq/m³; panel 7–12 floors 1970-1990 years of construction – 22 Bq/m³; brick> 5 floors 1970–1980 years of construction – 20 Bq m³; panel, built since 1990 – 24 Bq/m³. The results of the study confirm the assumption that radon concentration in modern multi-storey energy-efficient houses is on average higher than in typical residential buildings of the Soviet period. The increased accumulation of radon in energy-efficient buildings is associated with a decrease in the building envelope permeability and the contribution of fresh air to the general air exchange. Despite the fact that there were no cases of exceeding hygienic standards for the indoor radon concentration in the framework of this study, the higher radon concentration in buildings of increased energy efficiency requires attention from the point of view of implementing the principle of optimization of radiation protection. In the future, extensive construction of energy-efficient buildings may increase the average and collective doses to the urban population in the Russian Federation.

Radon and its daughter products create more than half dose from all natural radiation sources. The radon entering the buildings is emitted mainly from soils lying at the base of the foundation. Therefore, before carrying out construction work, the radon hazard of the construction area are determined. In the Russian Federation, the radon hazard of an area can be determined using radon flux density measured on the soil surface. To date, radon researchers came to the conclusion that the geology of the territory affects the amount of radon released from the soil surface. However, there are almost no studies devoted to the release of radon from the surface of various soil types. The paper presents the measuring results of the radon flux density on the surface of loess loams, porcelain clay, argillaceous slate, sand-and-gravel sediment, rocky limestone, clayey limestone, andesite-basalt porphyrite and quartzrock. The measurements were carried out by the accumulation chamber method using the Alfarad Plus measuring complex. Also, measuring radium activity concentration and soil moisture were carried out. The research demonstrates that, depending on the type of soil, the amount of radon emanating from its surface differs by more than an order of magnitude. The largest values of radon flux density of ~ 800 mBq∙m^-2s^-1 were recorded for andesite-basalt porphyrite and quartzrock. The smallest ones of ~ 40 mBq∙m^-2s^-1 were registered for loess loams and argillaceous slates. For soils consisting of small sand and clay grains, a rather strong dependence of the radon flux density on soil moisture was found. When measuring soils with low moisture (2-6%), a proportional dependence of the radium activity concentration on the amount of radon emanating from the soil surface is not observed. The types of soils that lie at the foundations of the buildings, and their physical properties can be used as the basis for classifying building sites according to the degree of radon hazard. Relevant information may be provided by organizations engaged in design and survey work at building plots. The approach proposed in the work for assessing radon hazard will allow avoiding labor-intensive measurements of radon and thereby reduce the financial, material and labor costs of building construction.

An article contents the review of the data on the content of polonium and lead content: ²¹⁰Po, ²¹⁰Pb in natural entities, obtained from literary sources. The review is given of the existing methods for ²¹⁰Po and ²¹⁰Pb content investigation in different entities as well as the analysis of the expedience of the applying of the given polonium and lead content investigation in the foodstuffs technique for the use in a method under development of the radiochemical laboratory of the Institute. More perfect and simple for realization than existing method is given for ²¹⁰Po and ²¹⁰Pb content investigation in the foodstuffs from a sample with not more than 1.0 kg weight with minimal detectable activity not more than 0.01 Bq. The results are given of the investigation of ²¹⁰Po and ²¹⁰Pb content in the certain types of the foodstuffs sampled in the kitchen gardens located in Leningrad region and bought in the trade network of Saint-Petersburg. Estimation of potential average annual population internal exposure dose (E_int) is carried out due to ²¹⁰Po and ²¹⁰Pb content in the investigated foodstuffs which are consumed by the local population. For the estimation of the internal exposure doses we used the data on the food rations of adult population of the settlement of the city type according to the data of Rosstat and Internet-resources. It is demonstrated that population internal exposure dose even from several natural radionuclides taking into account consumption of a limited set of foodstuffs could exceed the exposure dose from artificial radionuclide in tens times even for the territories radioactively contaminated after the Chernobyl NPP accident.

The results of a retrospective analysis of leukocytic indices and dynamics of peripheral blood values in relation to external gamma-exposure dose among the personnel of the first atomic production facility in Russia were presented. The study was performed on the basis of the database “Leukemia in the cohort of workers of the Mayak Production Association employed in 1948-1958”. The database contains hematological, clinical and dosimetry information on the two groups of workers: the study group includes individuals with leukemia as the cause of death (n=84); control group includes personnel without hematological cancer pathology (n=300). The control group was composed by selecting 3-4 internal control cases for each leukemia case taking into account gender, age of the start of the exposure and the same accumulated absorbed dose of gamma-exposure to red bone marrow. Based on 19592 analysis of peripheral blood we had described hematopoiesis shifts along cell lines, performed correlation analysis of interrelation between hemogram values and radiation dose, analyzed particular characteristics of blast cells’ appearance in peripheral blood flow in the period prior to leukemias. Comparative analysis of various leukocytic indices was performed among Mayak PA personnel for the first time. The diverse nature of the response of bone marrow hematopoiesis was noted; more pronounced hematological shifts were indicated regarding more intensive production exposure. A number of hematopoietic features were detected among people exposed to production radiation: 1) cytopenia in relation to minimum accumulated doses of radiation exposure in both studied groups; 2) more pronounced lability of hemograms in relation to increased accumulation dose of external gamma-exposure and period of radiation exposure among individuals who had developed leukemia in future in comparison to controls; 3) correlation between peripheral blood cells and accumulated doses of external gamma-exposure was characterized by the highest values of coefficients among individuals with future leukemias; 4) myeloblasts were most often registered among all the blast cells; proerythroblasts were characterized by the shortest average period from the start of the exposure and to the moment of their appearance in the peripheral blood flow (178 days in the study group); polychromatophile erythroblasts in peripheral blood were registered only among the workers with future leukemia; 5) when comparing leukocytic indices in proportion to the categories of accumulated doses of external gamma-exposure, a pronounced variability in the ratio of blood cells was observed among exposed individuals who were subsequently diagnosed with leukemia, especially in the range of 2.0-2.5 Gy. Thus, a comprehensive analysis of hematological parameters, including the assessment of leukocytic indices, is more informative than studying a standard hemogram. Particular features of the dynamics of the cellular composition of peripheral blood can be used as indicators of pathological hematopoiesis in exposed workers prior to clinical manifestation of leukemia.

The analysis of published data on the average annual effective doses to personnel of Russia, Germany, Switzerland, France and Canada in dynamics for 2013-2017 was performed. It was established that in the countries under consideration there are significant differences in the processing of primary measurement information, the calculation on its basis of individual effective doses, as well as ways of averaging the data obtained and their presentation. Factors that may lead to different interpretations of the results are considered: – taking into account background doses due to natural radiation; – use in processing the results of various (in different countries) values of the minimum level of registration; – dose averaging in the absence of activity periods (loss of a dosimeter / vacation), and when registering unexpectedly high doses. These differences exist between the data of foreign countries, but the data presented by the Russian Joint state system of control and accounting of the individual doses of the citizens are especially different. It is shown that the data on average annual effective doses to personnel presented in the Federal Data Base of personnel exposure doses within the framework of the Russian Joint state system of control and accounting of the individual doses is 3-4 times higher than in foreign countries. It is shown that such a difference is caused not by actually high doses, but by the method of processing primary information and averaging data during generalization. It should be noted that such differences occur only for extremely small doses of technogenic exposure to personnel, and do not lead to a significant impact on the overall assessment of the state of radiation safety in the country, but when comparing with other countries, it is necessary to understand the reasons for such differences. The purpose of this work was to identify the causes of these discrepancies and to develop a method for processing primary measurement information and averaging the data when summarizing the results, which allows them to be significantly reduced. Such a method should ensure that the effective doses of personnel closest to the conditionally true values are obtained in the entire range of values, and can be used to summarize the data contained in the Federal Data Base of personnel exposure doses. Since the conversion of the data contained in the Federal Data Base of personnel exposure doses was not the task of the authors of this article, in order to achieve this goal, an attempt was made to process and summarize the measurement results (total 23 204) of the quarterly values of the individual dose equivalent Hp (10) obtained in the Laboratory of Radiation Control of Saint-Petersburg Research Institute of the Radiation Hygiene after Professor P.V. Ramzaev. Such processing has been performed. The subsequent comparison showed that the average annual effective doses to the personnel of medical organizations of St.-Petersburg, in which individual dosimetric control was carried out in the Laboratory of Radiation Control, transformed according to the developed algorithm, are much better consistent with similar data from foreign countries.

The aim of the current study was to perform a comparative assessment of the radiation and non-radiation health risks for the sample of transgenders as well as the assessment of their perception of these risks. The study was performed on the sample of patients, undergoing the gender reassignment surgery from female to male. The structure of surgical procedures and the corresponding X-ray examinations was analyzed with the subsequent assessment of the radiation and non-radiation health risks. The level of patient knowledge on the risks and benefits of the medical procedures and perception of the ratio of radiation and non-radiation risks were evaluated based on the results of the sociological study. The study included the patients that underwent gender reassignment surgery in August 2012 – February 2018 on the base of I.M. Sechenov First Moscow State Medical University. Data collection and questioning were performed in August 2019 – March 2020. Data on the structure of the surgical procedures and X-ray examinations was collected for 99 patients; 86 patients agreed to participate in the questioning. The results indicate that the selected sample of patients, undergoing the gender reassignment surgery from female to male, is a high risk group both for radiation and non-radiation factors. For the whole multi-stage gender reassignment surgery, a patient could receive a total effective dose up to 250 mSv due to repeated computed tomography scans of chest, abdomen and head with contrast, corresponding to the lifetime attributive radiation risk of up to 1×10^-2. Comparison of radiation and non-radiation risks for that patient sample indicates the dominance of the risk of successful suicide attempts (5×10^-2). Radiation risks are equal to or even exceed (for the final stages of the gender reassignment surgery) the other risks of mortality from the non-radiation factors (anesthesia – 5,4×10^-5, thrombosis – 2×10^-5, post-surgical complications – 6×10^-2). The reduction of suicide risks, as a result of the treatment, outweighs all other risk factors and justifies the gender reassignment surgery. The results of a sociological study show a decrease from 77% to 23% of suicidal thoughts among the patients. The study indicates that risk-communication was performed on the unsatisfactory level: less than 40% of the patients were informed about the possible health risks during the treatment; less than 50% of respondents knew about the benefits of X-ray examinations. About 70% of the patients rate their current problems with health higher compared to the risks from diagnostics and surgery. It explains the lack of interest to the radiation risk.

In 2019 Technical regulations of the Eurasian economical Union “On the safety of the bottled water, including natural mineral water” TR EAES 044/201 entered into force. These regulations established strict requirements to the indicators of the radiation safety for the bottled water, including natural mineral water. Application of these requirements in practice of the sanitary service led to the ban of the use of the bottled medical-table natural mineral water from the Zheleznovodsk site (Stavropolskiy krai), exploited from the well 69-bis by the criteria of the radiation safety. This study proposes possible solutions to the problem of the regulation of the natural mineral water by the radiation factor, complying to the existing requirements on the radiation safety as well as the proposals of the Institute of Radiation Hygiene on the changes in the Technical regulation TR EAES 044/201 and introduction of the requirements on the radiation safety of the natural mineral water in the legislation of the Russian Federation.

The dose rate of gamma radiation in air at a height of 1 m above the surface of virgin (undisturbed) soil is the starting point in the basic model that is used to estimate the dose of external radiation to the population living in areas contaminated due to the Chernobyl accident. Today, i.e. more than 30 years after the fallout, the finding of truly virgin lands is a rather difficult task, because many meadows were repeatedly plowed and/or rehabilitated after the accident. The purpose of this study was to develop a quantitative criterion for the detection of virgin soil areas using a portable gamma-ray spectrometer-dosimeter. To achieve this, we have conducted a statistical analysis of published and new data on the use of in situ gamma-ray spectrometry in radioactively contaminated territories of the Bryansk region of Russia and the Gomel region of Belarus in 2015–2018. The sample contains results of decoding 60 gamma spectra recorded at a height of 1 m above the ground in virgin meadows, cultivated lands and forests. Based on the performed analysis, a quantitative dosimetric criterion is proposed for in situ identification of virgin soils using a portable gamma-spectrometer-dosimeter. The article presents an algorithm for searching a virgin plot.