The analysis of instrumental data of “Prague” and “Warsaw” scenarios on the dynamics of ¹³¹I specific activities in the grass is carried out. Reconstruction of the ¹³¹I the specific activities dynamics in the grass in the Mazovia and Bohemia localities is performed in three models: direct calculation the input data of the “Prague” and “Warsaw” scenarios, homogeneous cloud, heterogeneous rain and heterogeneous cloudhomogeneousrain. The actual ¹³⁷Cs fallout densities in the grass sampling sites in average more than 2.9 times for Prague and 2 times for Warsaw. Effective rain during the main fallout at the grass sampling sites, reconstructed on the model of a homogeneous cloud is 3–4 times more than at the nearest weather stations during this time. A realistic scenario of the input data leading to the optimal agreement of the calculated and instrumental data is revealed. It is shown that direct calculations and the homogeneous cloud model give almost identical results and lead to a significantly better agreement with the instrumental data than the an inhomogeneous cloud model. The calculated and instrumental data show a significant decrease in the ¹³¹I specific activity in the grass after the end of the main fallout due to its flushing from the grass surface by strong prolonged rain 13 and 19 days after the accident in Mazovia and 30 and 35 days in Bohemia. Uncertainties in the results of reconstruction of the dynamics of ¹³¹I and ¹³⁷Cs activities in vegetation are estimated. The meangeometric values and standard mean-geometric deviations of the calculation/ 8instrumental data ratios are: 0.8–1.1 and 1.8–1.9 for grass.

Results of development of the database “Leukemia in the cohort of workers of the Mayak Production Association employed in 1948-1958” that was developed in the Laboratory of Radiation Epidemiology of Southern Urals Biophysics Institute were presented. The database contains hematological, clinical and dosimetric information for the workers of main plants of the first production facility of Soviet atomic industry employed in the period of production development – 1948-1958. The computer database contains information for two groups of Mayak Production Association workers: main group of workers with leukemia as the main cause of death (n=84) and group of personnel without hematological cancer pathology for comparison (n=300). The comparison group was composed in such a way to allow 3-4 controls of corresponding gender, age of exposure start, accumulated dose of external gamma-exposure to red bone marrow for each leukemia case. Methods of data collection and sources of medical data were described. Characteristics of software developed for the database was presented. The database containing a total of 19593 results of blood tests reflects dynamics of hematological values in atomic facility personnel due to prolonged radiation exposure. The range of accumulated absorbed doses of external gamma-exposure to red bone marrow in the group of personnel with leukemia diagnoses was 0.001-4.96 Gy; average dose for males was 1.24 Gy and 0.61 Gy – for females. Similar range is observed in the group of personnel without leukemia outcomes. Alongside differences in accumulation rates of external radiation exposure doses is evident: in the group of workers with hematological cancer pathology the average period of radiation exposure at production facility was 14.3 years for males and 12.1 years for females; in the comparison group – 20.4 and 13.9 years, respectively. Most leukemia cases were diagnosed in the workers of radiochemical facility (54.8%). Myeloid leukemia prevailed (47.6%) in the leukemia structure; among them acute myeloid leukemia made more than a half of the cases; lymphoid leukemia was diagnosed in 14.3% cases with prevailing role of chronic lymphoid leukemia. Acute and chronic monocytic leukemia were the rarest types of malignant neoplasms of hematopoietic tissue. Possible correlation between hematological values with individual doses of external gamma- and internal alpha-exposure (incorporated Pu-239) distributed over time was stated. The database allows calculating integrated leukocytic indices reflecting response of hemopoietic system to radiation exposure, tracking changes in hemopoiesis in proportion to accumulated dose to red bone marrow, analyzing specific characteristics of rehabilitation of hematological alterations after occupational contact to ionizing radiation is terminated. Information on acute and chronic diseases available for the workers in the database allows excluding non-specific response of hemopoietic system caused by associated pathology. A revision of leukemia risk estimated in the relation to dose rate for personnel exposed to chronic radiation could be regarded as one of perspective trends in using the database.

Results of individual monitoring for personnel of X-ray surgical teams in several clinics of St. Petersburg are presented and analyzed. Measurements of the operational quantities – individual dose equivalents H_p (3) and H_p (10) were performed by thermoluminescent dosimetry method. Dosimeters designed to measure H_p (3) were located in the operators forehead area, and to determine H_p (10) both above the operator ‘s individual protective apron in the collar or chest area and under the protective apron in the chest area. The results of 34 measurements of the annual values of H_p (3) and H_p (10) measured above the apron and 24 values of H_p (10) measured below the apron were processed and analyzed. The results after the statistical treatment show that the probability of exceeding the annual values of H_p (3) in the personnel of X-ray surgical teams of the new dose limit 20 mSv is small, less than 1%. Exceeding the current dose limit of the equivalent exposure dose of the lens of the eye (150 mSv) is hardly possible at all under normal conditions. The best solution for evaluating the radiation dose of the lens of the eye is to measure the individual equivalent of the dose H_p (3), using a suitably calibrated TL-dosimeter (thermoluminescent dosimeter) located near the worker’s eyes. However, this additional dosimeter is only necessary when the values of eye lens equivalent dose can approach the new value of dose limit of 20 mSv. According to the results of the study, it is possible to introduce such an additional dosimeter if the annual value of H_p (10) recorded by the dosimeter located above the protective apron is more than 10 mSv.

In 2015–2016, 13 forest and 7 virgin grassland plots located in the south-western districts of the Bryansk region were surveyed. The aim of the work was to experimentally test the possibility of using a method for calculating the dose rate of gamma radiation in air in radioactively contaminated forests in a remote period after the Chernobyl accident. According to the results of gamma-spectrometric analysis of soil samples obtained at the sites in another study, the values of inventory and vertical distribution of ¹³⁷Cs in the upper 20 cm layer were established. In this paper, these data were used to calculate the air kerma rate using a method taken from literature. In addition, at the sites of soil sampling, ambient dose equivalent rate in air was measured, and the contribution of ¹³⁷Cs to the total gamma dose rate was determined with a field gamma spectrometer-dosemeter. The measured values of the ambient dose equivalent rate from ¹³⁷Cs correlated positively and statistically significantly with the calculated values of the air kerma rate. The Spearman correlation coefficient was 0.989 (P < 0.01) for the location “forest” and 0.893 (P < 0.05) for the location “grassland”. There was no statistically significant difference between the “forest” and “grassland” locations when analyzing the ratio of the measured dose rate values to the calculated dose rate values (the Mann-Whitney U test, P > 0.05). Results of this work show that, when calculating gamma radiation dose rate in air in forests at a remote stage after the Chernobyl accident, it is enough to know the ¹³⁷Cs inventory in the upper 20 cm soil layer and a detailed picture of vertical distribution of the radionuclide in this layer. The presence of woody biomass can be neglected. This dose rate estimate is conservative. However, a degree of overestimation of the dose rate in air is small, within +10%, which is quite acceptable for determining the external effective dose rate for an individual in the radioactively contaminated forest.

When analyzing the results of radon surveys, there could be an issue with measurements that are below the limit of detection (LOD) of the measurement technique used. This issue is usually referred to as the management of left-censored data. The paper presents the results of the practical application of one the most accurate and easy to calculate methods for analyzing censored data – the β-substitution method – to the analysis of an indoor radon concentrations dataset. The results of the radon survey conducted in the framework of the regional program “Radon” in Krasnoselskiy district of St. Petersburg in 2000 have been used as the test dataset. It is shown that inappropriate approaches to the management of the censored data, such as discarding the censored values or substituting them with the LOD value, can lead to considerably biased estimates of parameters or statistics of the resulting distributions. Further, this could result in an overestimation of doses and risk estimates which are based on the median values. The visual and quantitative analysis of Q-Q plots leads to conclusion that the estimated parameters of the distribution after the application of the β-substitution method are characterized by a minimum bias. The applied β-substitution method could be recommended for use as an element in the procedure of analyzing the results of radon surveys to minimize the bias of the estimates of the parameters of the radon concentration distributions alongside with Q-Q plots used to verify the conformity of radon concentrations with a lognormal distribution.

The paper presents an overview of the international scientific and technical publications on a problem of radon accumulation in new energy efficient buildings and in houses reconstructed according to requirements of energy saving. Energy efficiency is an important requirement of the environmentally sustainable development. Housing and communal services have significant potential for energy saving. In Russia, the construction of highest energy efficiency classes buildings occurs at an accelerated rate and reached 75% of all multiapartment houses built in 2017. The applying of modern technologies that reduce heat loss is accompanied by a decrease in the air exchange rate, which leads to deterioration of indoor air quality, in particular, the accumulation of radon. In the international literature, there are examples of the several times growth of radon concentration after the reconstruction of the building, the average radon concentration in retrofitted buildings increased by 22–120%. In new houses built to meet energy saving requirements, there can also be a significant increase in radon concentration compared to low-energy efficiency classes houses. Excess of sanitary and hygienic norms was found in some countries, including Russia. Radon exposure of dwellers of energy-efficient buildings is largely determined by the living habits. Based on the review data, it can be assumed that the average level of Russian population exposure to radon can increase under conditions of intensive construction of energy-efficient buildings.

The aim of the study was to identify patterns of distribution of the magnitude of the the equivalent dose rate of gamma radiation in an open area of urban space, depending on the functional purpose of the inner-city territory and the type of artificial coating. Materials and methods. Measurements of the equivalent dose rate of gamma radiation (gamma background) in the city of Voronezh were carried out at 70 points, conventionally classified by functional use (industrial area, transport area, residential area, recreational area), as well as the type of coverage in open areas (granite stone blocks , asphalt pavement, paving slabs, open ground) For carrying out radiation monitoring, a highly sensitive portable search device was used – a search measuring gauge microprocessor ICP-PM1401MA. To assess the reliability of differences in the average values of the indicator by functional inner-city zones and types of artificial turf, the methods of parametric statistics (Student’s criterion) are used. Parametric methods of statistics in comparison with nonparametric methods allow statistically unambiguous interpretation of the results. There is no need to use other statistical tools in this regard. Results. The results of the evaluation of the radiation background show that the equivalent dose rate of gamma radiation (gamma background) in the city of Voronezh is from 0.06 to 0.14 µSv / h and it does not exceed the permissible value (0.3 µSv / h). Significant differences in the average values of indicators in the industrial, transport, residential functional areas in relation to the recreational area were not found (t_calc. < _ttabl., P < 0.05). The maximum levels of gamma background (0.09-0.14 µSv / h) in the territory of the city of Voronezh were found in those places where processed natural stones (granite) were used for the improvement of the territory. When solving the problem of identifying the dependence of the indicator of the equivalent dose rate of gamma radiation in an open area of an inner-city space on the type of coating, in order to reduce uncertainties in the future, it is necessary to take into account the formulation of materials, especially the fraction of granite chips.

The article discusses the features inherent in the language of communication of specialists in radiation safety among themselves and with the public. Despite the confidence expressed by the population to specialists, their communication is difficult not only for organizational reasons, but also for their languages of communication. The population best understands the language not of the source of information on radiation safety issues (specialists), but of the transmitter of this information – journalists. It is necessary to take into account the difference in the tasks of specialists and journalists in conveying information to the population on the urgent problems of radiation safety, in particular, projects of the nuclear industry. It is shown that taking into account the peculiarities of the language characteristic of the population (or any of its groups) helps in a large degree to optimize information support for risk communication of the population on radiation safety issues. This is necessary for the development of an adequate attitude to the work of the nuclear industry. The article also considers the stages of risk- communication and the factors contributing to its optimization.

The work provides a comparative analysis of average annual individual radiation doses based on the obtained values of individual dose equivalent Hp (10), which had been obtained during 5 years of investigations (2014-2018) by using the thermo-luminescent dosimetry method of 70 employees working computed tomography, radioscopy, fluorography and radiography from 15 medical institutions in Dushanbe city. The ratio of medical personnel of the different professional groups showed that 63% of them were engaged in radiography, 19% x-ray, 10% computed tomography and 8% radioscopy. Analysis of the average annual radiation doses of every occupational group showed that the specialists in charge of fluorography have a high dose (max 1.74 mSv) and the personal of computed tomography have the lowest dose (max 1.34 mSv), and over time there is a tendency to equalize the values of average annual doses for all professional groups in the area close to the value of 1.5 mSv. The obtained data of the effective annual dose for all occupational categories had not exceeded the permissible dose limits values required by the «Radiation Safety Standards» (NRB-06 SP 2.6.1.001-06). Calculations are given without subtracting background values. The analysis data allows to identify the most exposed professional groups and to address the issues of ensuring radiation safety in a targeted manner.

The aim of the current study was to evaluate the effectiveness of cooking (washing, soaking and boiling) of the mushrooms to reduce the ¹³⁷Cs concentration. The following tubular dried mushrooms were selected for the study: Boletus edilus (cepe), porcini lurid boletus, annulated boletus, orange-cup boletus, variegated boletus and bay bolete. The mushrooms were collected in 2016 in the Bryansk region areas (Gordeevsky, Klintzovsky and Krasnogorskiy districts) with the maximum contamination after the Chernobyl NPP accident. The activity concentration of ¹³⁷Cs was determined by gamma-spectrometry. Effectiveness of cooking was assessed by calculating the coefficient of cooking reduction equal to the ratio of the activity of ¹³⁷Cs in water fraction to the activity in the initial dried mushroom sample. The results of the study indicated that the most effective way of cooking the mushrooms was washing, allowing reducing the concentration of ¹³⁷Cs by 49%. The major part of ¹³⁷Cs was transferred to the water fraction with the first decanting – 32%; with the consecutive two decantings – 11% and 6%, respectively. During the soaking of mushrooms, 26% of ¹³⁷Cs is transferred into the water fraction within the first 3 hours: 14% – during the first hour, 9% – in the second and 3% – in the third. Increase in the soaking time had low effect on the reduction of the concentration of ¹³⁷Cs and reduced the taste characteristics of the meal. The complex use of all three stages of cooking (washing, soaking and boiling) allows reducing the concentration of ¹³⁷Cs up to 75% in the mushroom broth.

This work is devoted to the assessment of the absorbed dose in the skin of patients undergoing interventional radiological examinations. There is a probability of deterministic effects in the skin of patients due to high doses of radiation during this type of medical examinations. The aim of this work was to conduct direct measurements of the absorbed dose in the skin of patients undergoing interventional radiological procedures using special dosimetric radiochromic films Gafchromic XR-RV3 to visualize the distribution of radiation over the patient’s skin surface and to study the possibility of exceeding the threshold values for the deterministic effects in the skin. The paper discusses the features of measurements with GafchromiC XR-RV3 films. The method of film digitization on conventional flatbed scanner and image processing with the ImageJ program was tested. The obtained calibration curve for this type of film was presented. The skin dose distributions for several interventional studies obtained with radiochromic films were presented. The measured value of the maximum absorbed dose in the skin for four of the fourteen analyzed procedures exceeded the threshold value of the absorbed dose for the occurrence of skin erythema in 2 Gy. The highest values of the maximum absorbed dose in the skin were obtained for the coronary angioplasty – 3.2 Gy and for the procedure of embolization of the uterine arteries – 2.9 Gy.

In the last years radiation-hygienic passportization and Joint state system of control and accounting of the individual doses of the citizens have become a trusted source of the validated data on the state of the radiation safety in the Russian Federation and have become the basis of the Russian system of the information provision of the radiation safety. Annual analysis of that data is presented in the annual information bulletin “Doses of the population of the Russian Federation”. The current study is focused on the analysis of the data from the information bulletins to evaluate the trends in the doses of the Russian population from main sources of ionizing exposure in 2003–2018. It is indicated that the mean annual doses from man-made exposure of the group A staff in that period varies from 1,0–1,4 mSv per year, group B – 0,65–0,8 mSv per year. The number of exceedances of the annual dose limits from group A staff varied from 5 to 52 per year; for group B – 0–22 per year. For the whole investigated period there were only three cases of the exceedance of the 50 mSv annual individual dose for group A staff and four cases of the exceedance of the 12,5 mSv annual effective dose for group B staff. Mean effective dose per X-ray examination in 2006–2013 was decreasing from 0,56 mSv to 0,26 mSv and started to slowly increase leading to 0,29 mSv in 2018. The same trends were identified for the mean dose from medical exposure per citizen: reduction in 2003-2013 from 0,86 mSv to 0,45 mSv with the subsequent increase up to 0,56 mSv. The biggest contributor for the dose from medical exposure is computed tomography: the number of CT examinations increased from 1,3 mln in 2003 to 11,7 mln in 2018; contribution to the collective dose – from 5,7% to 54%. Mean annual effective doses from natural exposure of the population of the Russian regions varied from 1,6 to 15,1 mSv per year with the mean value for Russia of 3,11 – 3,79 mSv/year. The highest mean annual doses exceeding 5 mSv in each year were observed in Republic of Altay, Jewish Independent Region, Stavropol and Zabaikalskiy Krai, Republic of Tyva and Irkutsk region. Total effective doses exceeding 10 mSv/year were observed in Republic of Altay and Jewish Independent Region. For ten subjects of the Russain Federation (Republics of Buryatia, Altay, Tyva, Stavropol and Zabaikalskiy Krai, Irkutsk and Chita regions, Jewish Independent Region, Aginsko-Buryatskiy and Ust’-Ordinskiy independent districts) they exceed 5 mSv/year for the whole assessed period.