Contamination Density Research Articles

Monitoring of <sup>137</sup>Cs, <sup>90</sup>Sr and <sup>40</sup>K in Gray Forest Soils and Plants of Reference Sites of the Vladimir Region

The paper presents the results of radiation monitoring of gray forest soils of reference agricultural plots of the Vladimir region, conducted in 2011 and 2016. The study established background values of specific activities of the studied radionuclides in the soils of reference sites. According to the density of contamination of the arable horizon of soils 137Cs and 90Sr, the level of the ecological situation was determined, which made it possible to attribute the soils of all reference areas of the region to uncontaminated territories suitable without restrictions for agricultural use. The power of the exposure dose of gamma radiation of soils and the contribution of 40K and 137Cs to the formation of the gamma background of soils are established. Correlation ana-lysis determined the influence of individual physical and chemical properties of soils on the behavior and distribution of radionuclides in the soil and the relationship between the radionuclides themselves. Based on the values of the specific activity of 137Cs and 90Sr in plant products grown on the soils of reference sites in 2011 and 2016, rows of cultivated plants were constructed, with a decreasing ability to accumulate these radionuclides from the soil. All grown plant products for all types of crops fully met the sanitary and hygienic standards required to limit the content of 137Cs and 90Sr in plant feeds (green mass, straw and grain) and food products (apples). According to the transition coefficients, it was found that the process of transition of 90Sr from soil to plants of all kinds proceeded more intensively than the transition of 137Cs. The calculated coefficients of linear correlation between the values of the specific activity of 137Cs and 90Sr in soils and plants revealed the strength and nature of their dependencies.

Primary incidence of cervical cancer in the population living in ecologically disadvantaged areas (2000–2020)

Introduction. Thirty six years after the Chernobyl disaster about 5 million people live in the radioactively contaminated territories of Ukraine, Belarus and Russia, and the density of radioactive contamination, determined mainly by long-lived Cesium-137 and Strontium-90, will remain radiologically significant for several decades. Purpose of the study. Based on official statistics for 2000-2020, to analyze the trend in the incidence of cervical cancer in females living in conditions of radioactive, chemical, and combined environmental contamination in the Bryansk region. Materials and methods. Poisson regression, Shapiro-Wilk test, Mann-Whitney U-test, Spearman test. Data sources - Bryansk Regional Oncological Dispensary, Rospotrebnadzor, Rostekhnadzor, Bryanskstat. Results. There were no statistically significant differences in the incidence of the cervical cancer, regardless of the level of radioactive, chemical, and combined environmental contamination. Also, we have found no significant correlations between the frequency of primary morbidity of the cervical cancer with neither the density of 137Cs and 90Sr contamination, nor air pollution with gaseous pollutants (VOCs, SO2, CO and NOx). A statistically significant (p<0.00001) gain in the long-term trend in the incidence of the cervical cancer over 2000-2019 was revealed in all the studied groups, regardless of the environmental conditions of the residence. The forecast for the incidence of the cervical cancer on average in the Bryansk region during 2020 shows a decrease by 20.7% in real values compared to the forecast data. Limitations. Incidence of the cervical cancer without regard to age groups, distribution at the stage of the disease, histological, and immunohistochemical profile. Conclusion. The obtained results indicate to the need for further work to understand the trends in the presence/absence of independent and combined effects of pollutants on the growth of oncogynecological pathology from the standpoint of assessing distant and regional metastasis, the histological, and immunohistichemical profile of a specific cervical cancer with levels of radioactive, chemical, and combined environmental contamination.

Оценка мощности амбиентного эквивалента дозы на лесных участках в юго-западных районах Брянской области

The large areas of forests in the Bryansk region are still contaminated with radionuclides released due to the accident at the Chernobyl NPP in April, 1986. The recovery of the economic and ecosystems potentials in the contaminated areas is the need to create a favorable living conditions for the population. This involves a full range of remediation activities in the contaminated areas aimed at the forests protection and regeneration. The aim of the work is to assess the ambient dose equivalent rate (ADER) in forest sites located in the zone of radioactive contamination. More than 1 thousand forest sites in the south-western part of the Bryansk region were surveyed from 2019 to 2022. The ADER and the density of the soil contaminated by Cs-137 for every surveyed forest site are available. The relationship between the ADER and the density of the soil radioactive contamination in various sites was analyzed. The dose rates were normalized with respect to the density of soil contamination. The ADER rates in the Bryansk forest areas ranged from 0.07 to 3.15 mSv/h. No reliable difference between the ADER in the areas of coniferous and deciduous forests was observed. There was reliable linear relationship between ADER and the density of soil contaminated by Cs-137. During forestry operations in radioactive contaminated areas the maximum permissible external radiation effective dose was the dose accumulated for the whole period of work in the forest sites with the average density of soil contaminated by Cs-137 of 450 kBq/m2.

Миграция 137Cs в экосистеме поймы р. Унеча

Purpose: to study the ¹³⁷Cs migration and concentration in the alluvial soils profile and the radionuclide transfer to plants in the river Unecha floodplain ecosystem. Materials and methods. Field studies were carried out in 2019–2021 in Bryansk region (Klintsovsky district, the village of Lopatni, the right bank of the river Unecha, the current reclamation system). The density of ¹³⁷Cs contamination of the territory after the Chernobyl accident was 185–555 kBq/m². Conjugated soil and plant samples were taken in various sub-systems of the floodplain (near-channel, central, near-terrace). Agrochemical indicators of fer-tility and ¹³⁷Cs specific activity in soil and plants were determined using generally accepted laboratory methods. Results. A strong variability of the agrochemical parameters of alluvial soils in layers every 5 cm within 0–20 cm was determined. A high content of mobile phos-phorus and a low content of potassium, a strongly acid reaction of the environment, and a ten-dency to the growth in the organic carbon content from the near-channel to near-terraсе floodplain subsystem was found. The ¹³⁷Cs horizontal distribution in the river Unecha flood-plain soils was determined by soil genesis of the floodplain subsystems; the maximum specific activity of ¹³⁷Cs 3953 Bq/kg was found in the near-terrace part of the floodplain. The ¹³⁷Cs maximum concentration was found in the near-channel and central subsystem in the soil layer of 0–5 cm, and in the near-terrace subsystem in the layer of 5–10 cm. In the floodplain of the river Unecha, the ¹³⁷Cs coefficient transfer from soil to plants decreases from the central to the near-channel and near-terrace. Conclusions. The formation of agrochemical indicators of al-luvial soil fertility and the ¹³⁷Cs vertical distribution is determined by soil genesis in floodplain subsystems; it can be uniformly decreasing or concentrated in separate layers at biochemical barriers. In the floodplain ecosystem, the ¹³⁷Cs concentration in the 0–20 cm layer increases from the near-channel to near-terrace subsystem. Forage production under the conditions of radioactive contamination of the near-river and central parts of the floodplain is possible without the use of protective measures.

Оцінка радіоекологічної ситуації для території природного заповідника «Древлянський» станом на 2023 р.

Technological methods for preparing geospatial data for assessing the radioecological situation and visualizing the results using geographic information system (GIS) software packages are presented in the article. The current levels of soil l37Cs contamination density within the grid of forest quarters of the reserve are given. The article emphasizes that the current levels of radiation contamination in the reserve have an irregular distribution. In this work, the procedure for data preparation was developed and technological methods were tested to assess the current state of the radioactively contaminated territory by forest quarters. The interpolation method was used to eliminate unevenness in the mapping layer of the source data. Radioecological zoning of the territory based on the density of soil contamination with l37Cs for 2023 was carried out to determine the suitability of the territory for the implementation of forest protection measures. Critical areas that generate hazardous levels of dose load for the employees of the Reserve were identified on the maps. The spatial distribution of forest fallout density was calculated. The spatial distribution of radiation contamination of timber and flammable fuel material within the forest quarters of the reserve was estimated. The analysis of the current radioecological situation for the territory of the Drevlians Reserve showed the effectiveness of using modern ArcGIS and MapInfo software packages. Such software combines the following capabilities: preparation of information matrices for calculations and interpolation, in case of limited input data, grouping and classification by values, formation of thematic data sets for storage and further display of results on map schemes.

Particle contamination simulation of Einstein probe follow-up X-ray telescope focusing mirror

Particle contamination can greatly affect the performance of X-ray focusing mirror. In this paper, we analyze the influence of particle contamination on X-ray focusing mirror. The model of interaction between contaminant particles and incident light is established from Mie scattering theory in the wavelength range of X-ray. And the relationship between them is mainly influenced by the complex refractive index of the particles <inline-formula><tex-math id="M1">\begin{document}$m$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230301_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230301_M1.png"/></alternatives></inline-formula> and the scale factor <inline-formula><tex-math id="M2">\begin{document}$\alpha$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230301_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230301_M2.png"/></alternatives></inline-formula>. Therefore, the reaction cross section and scattering function of particle contamination are calculated. Then, in order to obtain the effect of particle contamination on Einstein probe follow-up X-ray telescope (EP-FXT) focusing mirror, we carry out Monte Carlo simulation based on the design parameters of EP-FXT focusing mirror. Finally, the relationships among effective area, HEW, W90 and particle contamination density are calculated to characterize the influence of particle contamination on the performance of the focusing mirror. In this paper, structural and thermal model (STM) and qualification model (QM) are simulated simultaneously to make full use of their test data. By comparing the simulation results of STM effective area with the measured results, we find that the simulation results of STM effective area are accurate. When the EP-FXT is in orbit (the contamination amount is limited to less than 1.1 × 10<sup>–3</sup>), the effective area and angle resolution (HEW) meet the development requirements of EP-FXT. For the simulation of HEW, both QM and STM are in good agreement with the test results. The simulation results of HEW and effective area can be used to quantitatively analyze the effect of particle contamination on the performance of the focusing mirror. These quantitative analysis results provide a theoretical basis for the contamination prevention requirements of EP-FXT.

Оценка загрязнения древесины и коры дуба 137Cs в зоне отчуждения Чернобыльской атомной электростанции

The results of studying the 137Cs contamination of English oak (Quercus robur L.) trunks in high-aged oak forests in the most radioactive polluted part of the Polesye State Radiation-Ecological Reserve territory located in the evacuation (exclusion) zone of the Chernobyl nuclear power plant are presented. The features of modern surface contamination soil by 137Cs in oak forest stands have been established, the factors that caused them have been identified: removal of research objects from the release site and conditions for deposition of radioactive fallout, as well as vertical redistribution of radionuclide in the soil over the time since the accident. The density of 137Cs soil contamination varies by types of oak forest. The current indicators of 137Cs accumulation in wood, bark and oak trunks, their changes by forest types, the relationship with the density of soil pollution and the distance to the disaster site are determined. A 2-3-fold excess of 137Cs oak bark contamination was found in comparison with wood, which is due to their morpho-physiological characteristics. Over the past 25 years, the wood and bark proportions of the relative contributions to the specific activity of 137Cs of the oak trunks have changed significantly. The decrease in the contribution of the bark to the specific activity of 137Cs in the trunk is due to a slowdown in the entry of radionuclide into it. The 137Cs distribution in oak wood by classes of growth and development of trees by Craft is shown. It was found that the average values of the radionuclide specific activity in standing and lying deadwood are 25-28 % lower than in the wood of living trees. The tendency of decreasing of 137Cs concentration in oak wood from the periphery to the center of the trunk has been confirmed. As of 2021, according to the sanitary standard of the Republic of Belarus for the content of 137Cs 1480 Bq kg-1, harvesting of oak wood could be allowed in 84 % of the surveyed stands, oak trunks with bark - in 72 %. The standard of 740 Bq kg-1 corresponded to oak wood in bark and without bark in 32 % of forest stands.

Дозы облучения населения Беларуси вследствие аварии на Чернобыльской атомной электростанции на 2021-2025 гг.

In accordance with the Laws of the Republic of Belarus «On the social protection of citizens affected by the accident at the Chernobyl NPP» dated January 6, 2009 and «On the legal regime of territories exposed to radioactive contamination due to the accident at the Chernobyl NPP» dated May 26, 2012, the value of the average annual effective dose of exposure to residents is one of the indicators of the radiation situation in settlements contaminated with radionuclides as a result of the Chernobyl accident. The objective: to update the method for assessing the exposure doses to the population in the situation of existing exposure after the Chernobyl accident and, on its basis, to assess the average annual effective exposure dose to residents of settlements of the Republic of Belarus due to the Chernobyl accident for the period 2021-2025. The method for estimating the average annual effective doses due to external and internal irradiation to residents of radioactively contaminated settlements of the Republic of Belarus has been improved taking into account international recommendations in the field of radiation protection, changes in the radiation situation in the long-time period after the Chernobyl accident and the new data on individual dosimetry of internal exposure to the population based on the results of whole-body counter (WBC) measurements. An assessment of the average annual effective exposure doses to the population of the Republic of Belarus residing in the territory of radioactive contamination was carried out, and based on its results, the Catalog of average annual effective exposure doses to residents of 2193 settlements for the period 2021-2025 was compiled. According to the compiled Catalog of average annual effective exposure doses to residents of settlements located on the territory of radioactive contamination of the Republic of Belarus, in 29 settlements out of 2193, the total effective exposure dose can exceed 1 mSv/year, in addition, it is about 1 mSv/year in 5 settlements. In none of the settlements, the average annual effective radiation dose can exceed 5 mSv/year. Valid for the period 2021-2025 Catalog of average annual effective exposure doses to the residents of settlements located on the territory of radioactive contamination of the Republic of Belarus, along with data on the density of contamination of the territories of the Republic of Belarus with long-lived radionuclides, was used to compile the List of settlements and objects located in the zones of radioactive contamination, and to adopt a Resolution of the Council of Ministers of the Republic Belarus on designation of settlements to the corresponding zones of radioactive contamination.

Радіоекологічні дослідження на осушених ділянках ложа водойми-охолоджувача ЧАЕС

The results of radioecological monitoring of the research sites located on the drained areas and the coastal of the ChNPP cooling pond are presented. The features of the spatial distribution of the exposure dose rate, the density of soil radionuclide contamination by the emergency radionuclides were determined. The content of incorporated radionuclides in representatives of the genera Myodes and Sylvaemus were studied, the individual and interspecies variability of 137Cs and 90Sr levels in animals within the limits of one research site was determined. Currently, the indicators of radioactive contamination of biota in the drained areas of the cooling pond are within the variation of those values that are characteristic of most areas of the Chornobyl exclusion zone.

Dynamics of 137Cs and 90Sr content in the soil cover of agricultural lands in Zhytomyr region

The article examines the results of monitoring radionuclide contamination the soils of Zhytomyr region with 137Cs and 90Sr. We summarized the results of agrochemical certification of agricultural land for the period of research in 2006–2020 years (IX–XI rounds). For field and laboratory research, methods of agrochemical certification of agricultural lands and gamma-surveying of the territory and determination of the specific activity of 137Cs and 90Sr in soil samples were used. It was established that during the 36 years that have passed since the accident, the radiation state of the territory of Zhytomyr region has currently stabilized and is formed mainly under the influence of long-lived radionuclides cesium-137 and strontium-90. During the time that passed after the accident, only due to natural radioactive decay, the activity of the isotopes 137Cs and 90Sr decreased approximately by half. This was facilitated by natural processes and the implementation of measures to prevent the removal of radionuclides beyond the exclusion zone. Turf-podzolic soils, which are most common in the Polissia zone, are characterized by high sorption capacity and weak migration along the 137Cs profile. It was established that the number of agricultural lands contaminated with 137Cs and 90Sr with a density <5.0 Ki/km2 and <0.15 Ki/km2 is 99.9% and 99.5%, respectively, the density of land soil contamination in the section of the surveyed areas with 137Cs pollution varied from 0.07 to 3.41 Ki/km2, and 90Sr from 0.013 to 0.164 Ki/km2, therefore, according to current legislation, the soils are considered conditionally clean. A direct correlation between the indicators of the reaction of the soil solution with 137Cs contamination (r=0.94) and a significant correlation with 90Sr contamination (r=0.69) was revealed. A moderate correlation (r=0.40) was found between the indicators of the density of contamination of agricultural land with radionuclides 137Cs and 90Sr. It is emphasized that the use of the land fund of Zhytomyr region requires constant monitoring of soil fertility and contamination with radionuclides. The implementation of the task is possible under the condition of permanent soil and agrochemical monitoring, which is conducted by carrying out agrochemical certification of agricultural lands.

Assessment of annual effective dose from external exposure in forests of the south-western districts of the Bryansk region of Russia: 2015–2021

During a stay in a radioactively contaminated forest, a person is inevitably exposed to ionizing radiation from the man-made radionuclides. The purpose of this study was to evaluate the external component of the annual effective dose due to exposure in the forests contaminated following the Chernobyl accident. The study was conducted in the south-western districts of the Bryansk region of Russia in the period 2015–2021. Field (in situ) gamma spectrometric measurements were carried out on 46 forest plots located in the areas of 27 settlements. As of 01.01.2017, the officially established values of soil contamination density with 137Cs in the territory of the settlements themselves were in the range from 33 to 2050 kBq/m2 . According to the field gamma spectrometry, the density of soil contamination with 137Cs on the forest plots varied from 21 to 1930 kBq/m2 . The density of soil contamination with 137Cs in forest was in good agreement with the officially established level of soil contamination with 137Cs in the nearby settlement: the ratio of one indicator to another ranged from 0.70 to 1.32 (mean = 0.94; median = 0.95). The scatter in the measured values of the ambient dose equivalent rate from 137Cs was quite significant: more than one order of magnitude, from 31 to 2700 nSv/h. The variability of the ambient dose equivalent rate from natural radionuclides was relatively small: from 13 to 29 nSv/h. Based on the obtained experimental data and on published values of the duration of human stay in forest, the annual effective dose to selected groups of population was estimated. The dose from natural radionuclides, even in the case of a prolonged stay in the forest (1400 hours per year for foresters), did not exceed 0.02 mSv/year. The estimated values of the effective dose from 137Cs varied very widely from 0.001 to 1.9 mSv/year, depending on the selected forest plot and population group. On the whole, the data obtained indicate that the officially established values of the density of soil contamination with 137Cs in a settlement can be directly used in dosimetric models to estimate the component of the effective dose to a person due to his/her staying in the forest which is located in the area of this settlement. The currently recommended conversion coefficient from the density of soil contamination with 137Cs in a settlement to the ambient dose equivalent rate from 137Cs in the nearby forest is 1.28 (nSv/h)/(kBq/m2 ). To estimate the effective dose from natural radionuclides, it is recommended to use the value of the ambient dose equivalent rate equal to 21 nSv/h.

Restoration of surface soil contamination density to radionuclides at according to aerial photography

The problems that arise in the surface layer of the soil during periodic emissions at nuclear power plants are considered. The necessity of constant monitoring of this soil layer at different times of the year is substantiated. Various methods of this control are considered. It has been established that it is extremely difficult to implement them in remote areas. A method has been developed for monitoring the surface layer of the soil using aerodynamic survey of the distribution of γ-radiation on the soil surface. This is extremely important during the preparation of agricultural fields for sowing crops in the spring. A new algorithm for restoring images obtained using aerodynamic imaging of γ-radiation is proposed. The results of a new algorithm for image processing and identification are presented.

Экологические особенности накопления радионуклидов компонентами наземных экосистем зоны отчуждения

The studies were carried out 30 years after the Chernobyl accident on the lands of the former land use subject to natural successional changes. The patterns of the lateral distribution of 137Cs, 90Sr, 241Am in the upper 20-cm soil layer of various biogeocenoses, including those depending on the height fluctuations of the relief, have been studied. The values of the coefficient of variation (V) of the content of radionuclides in the upper soil layer decrease with the time that has passed since the accident. The highest value of the coefficient of variation (75.2 %) was obtained for 90Sr in the soil in the pine forest. The influence of various soil conditions on the entry of radionuclides into birch sap, cap mushrooms, and meadow grasses was studied. Despite the significant excess of the density of soil contamination with 137Cs of all the studied communities (up to 9.1 times), its volumetric activity in the juice is significantly lower than 90Sr, which indicates a lower availability of 137Cs compared to 90Sr. Dynamic processes of accumulation of radionuclides during the entire period of the movement of sap are studied. With increase in extent of moistening of the soil, accumulation of radionuclides in mushrooms tends to decrease. At the same time differences between types is established that connected with feeding habits of mushroom and variability of microclimatic conditions. The effect of soil moisture content, the ratio of 137Cs mobility forms in the soil on the biological availability of the radionuclide by meadow grasses was studied. A decrease in the specific activity of radionuclides in the plant components of ecosystems was found as the phytocenoses moved away from the epicenter of the accident at an identical density of soil contamination. A relationship has been established between the accumulation of radionuclides and the agrochemical parameters of the soil: maintenance of humus, absorption capacity, cation exchange capacity, hydrolytic acidity, content of exchange phosphorus, concentration of mobile calcium, magnesium and potassium on post-agrogenic lands. The analysis of the soil-to-plant transfer factors (Cf) and aggregated transfer factors (Tag), the discrimination coefficient (DF) of 137Cs by a chemical analog element (potassium) was carried out. Species features of plants associated with the transport of K+ - Cs+ cations make significant adjustments to the mechanisms of 137Cs accumulation. Attention is drawn to the significant increase in the concentration of 90Sr in all components in recent years.

Вариация поглощенной дозы облучения дикого кабана, обитающего на территории радиоактивного загрязнения

The article presents the results of the assessment of the absorbed dose rate from incorporated radionuclides of 137Cs and 90Sr in the body of wild boar living in an area with different levels of radioactive contamination. The internal irradiation dose was evaluated for incorporated 137Cs in muscle and 90Sr in bone tissue of wild boar. During the assessment, it was assumed that radionuclides 137Cs uniformly distributed in the tissue and are in equilibrium conditions, and radionuclides are 90Sr concentrated in the bone tissue of the animal, during the year the concentration of radionuclides is assumed to be constant. In total, samples were obtained from 117 wild boar individuals, among which 87 animals were seized in the exclusion zone and 30 in the resettlement zone. From the animal carcass, spot samples of muscle tissue were taken according to 500 ± 50 g, the 137Cs content in the samples was determined for raw, natural mass. The activity of 90Sr in bone tissue was determined by radiochemical method. As a result of the studies, it was found that the average total exposure dose of wild boar seized in the exclusion zone is twice that of animals seized in the resettlement zone (p < 0,05) and amounted to 653,6 ± 73,5 mGy/day for animals harvested in the exclusion zone and 328,8 ± 31,4 mGy/day for wild boar living in the zone resettlement. Analysis of the coefficients of variation showed that the maximum variation is observed among the values of the absorbed dose of radiation from the incorporated 137Cs in animals that were seized in the exclusion zone. The minimum variation rate occurs with respect to the external exposure dose in animals harvested in the resettlement zone. There is no significant difference (p < 0,05) between the median absorbed dose of exposure of wild boars living in the exclusion zone and the resettlement zone. The result of our studies suggests that the density of contamination is not the main factor determining the formation of an animal’s radiation dose.

Зонування територій радіоактивного забруднення після Чорнобильської аварії

The radiological zoning of Chornobyl contaminated areas was one of the essential elements of social and radiation protection. The zoning was based on estimates of annual committed effective doses to members of the public and on the levels of radionuclide deposition density. In 1991, 86 settlements were classified as associated with the zone of unconditional (mandatory) resettlement, and 841 settlements were assigned to the zone of guaranteed voluntary resettlement. The status of these settlements has been preserved until now. The assessments showed that as of 2022, for all settlements located outside the Chornobyl Exclusion Zone the radiological conditions do not exceed the current legislative criteria for inclusion in the zone of unconditional (mandatory) resettlement. It is also shown that in 2022, the zone of guaranteed voluntary resettlement can be assigned for: only 38 settlements, according to the legislative criterion "90Sr density of contamination" and only 17 settlements, according to the legislative criterion "137Cs density of contamination". The work also indicates and analyses the provisions of current legislation that require clarification.

Cervical and Endometrial Cancer Incidence in the Female Population from the Bryansk Region Living in Conditions of Chemical, Radioactive and Combined Environmental Contamination (2000-2020).

At the end of 36 years after the Chernobyl disaster, about 5 million people still live in the radioactively contaminated territories of Russia, Ukraine, and Belarus, and the density of radioactive contamination by Cesium-137 and Strontium-90 will remain radiologically significant for decades. We assessed cervical and endometrial cancer primary incidence (new cases) in the female population from the Bryansk region living in conditions of chemical, radioactive, and combined environmental contamination for 2000–2020. We found a significant increase in the long-term trend in the primary incidence of cervical and endometrial cancer in all the studied groups, regardless of the environmental conditions of residence (p < 0.00001). We did not find statistically significant differences in the incidence of cervical and endometrial cancer in women, regardless of the level of chemical, radioactive, and combined environmental contamination. However, women living in environmentally unfavorable areas (in total, in the territories of chemical, radioactive, and combined contamination) are statistically significantly more likely to develop endometrial cancer in terms of relative risk compared to environmentally safe (control) areas (RR 1.17 (1.08–1.27)). No such pattern was found for cervix cancer. It should be noted, since environmentally safe (control) areas have a certain level of contamination (albeit low), RR is underestimated.

Сeftazidime/avibactam in the treatment of exacerbation of a chronic respiratory infection in patients with cystic fibrosis: dynamics of clinical, microbiological, and functional parameters

Multidrug resistance of pulmonary pathogens in patients with cystic fibrosis (CF) requires new therapeutic solutions.The aim. To assess the effect of ceftazidime/avibactam (cef/avi) on clinical outcomes of pulmonary exacerbation of cystic fibrosis.Methods. This open single-group observational prospective non-interventional study was conducted in the routine clinical practice settings. Patients over 18 years with a confirmed diagnosis of CF and an exacerbation of a pulmonary infection were included into the study after physician’s decision to prescribe cef/avi. The examinations were performed at baseline and on Days 5 to 7, 21, and 30.Results. The analysis included data from 32 patients, 12 (38%) males and 20 (63%) females. The mean age was 31.6 years. Symptoms of exacerbation persisted in 97 % of patients on Days 5 to 7 of therapy and only in 3% at Day 21. FEV1, FVC, SpO2 also improved by Day 21 of the study (all – p &lt; 0.001). By Day 21, proportion of patients with CRP above 10 mg/ml grew from 71 to 9%. The average density of sputum contamination decreased from 7.2 to 5.5 CFU/ml. Quality of life according to Cystic Fibrosis QuestionnaireRevised (CFQ-R) questionnaire also improved.Conclusion. In patients with CF, exacerbation of lung infection in most cases is caused by multidrug resistant strains of Pseudomonas aeruginosa sometimes in combination with Staphylococcus aureus. Infectious agents (P. aeruginosa) remain highly sensitive to cef/avi (up to 91%) in this population so this justifies the use of cef/avi in treatment of a CF exacerbation. cef/avi administration led to relief of the exacerbation symptoms in 97% CF patients, as well as to significant improvement in spirometry parameters, increase in the oxygenation index, decrease in CRP and density of sputum contamination, and improved the quality of life. cef/avi administration was not associated with lethal outcomes, ICU admission, or serious adverse drug reactions.

An Analytical Study of the Key Physical Factors that Affect the Health Status of the Home Isolated Residents under COVID-19

The indoor living environment has an important impact on human health, which is more obvious at home segregation under COVID-19. This paper discussed some key factors that affect the health status, including the physical and mental aspects, of people isolated at home during COVID-19. In particular, the indoor temperature, the mass concentration, including the humidity and density of contaminants, were thoroughly studied. The measurement methods and related factors under different situations were also presented. Moreover, the interaction among different factors, showing how the whole ventilation system works, was also illustrated in the paper. Those results show that temperature and concentration (humidity, CO2, and fungus) levels should be controlled in a suitable range. People could use different ventilation systems in different situations or open a proper area of windows to keep healthy. It is also important to keep distance between people.

Paving the way forEuclid and JWST via probabilistic selection of high-redshift quasars

ABSTRACT We introduce a probabilistic approach to select 6 ≤ $z$ ≤ 8 quasar candidates for spectroscopic follow-up, which is based on density estimation in the high-dimensional space inhabited by the optical and near-infrared photometry. Densities are modelled as Gaussian mixtures with principled accounting of errors using the extreme deconvolution (XD) technique, generalizing an approach successfully used to select lower redshift ($z$ ≤ 3) quasars. We train the probability density of contaminants on 1902 071 7-d flux measurements from the 1076 deg2 overlapping area from the Dark Energy Camera Legacy Survey (DECaLS) ($z$), VIKING (YJHKs), and unWISE (W1W2) imaging surveys, after requiring they dropout of DECaLS g and r, whereas the distribution of high-$z$ quasars are trained on synthetic model photometry. Extensive simulations based on these density distributions and current estimates of the quasar luminosity function indicate that this method achieves a completeness of $\ge 56{{\ \rm per\ cent}}$ and an efficiency of $\ge 5{{\ \rm per\ cent}}$ for selecting quasars at 6 &amp;lt; $z$ &amp;lt; 8 with JAB &amp;lt; 21.5. Among the classified sources are 8 known 6 &amp;lt; $z$ &amp;lt; 7 quasars, of which 2/8 are selected suggesting a completeness $\simeq 25{{\ \rm per\ cent}}$, whereas classifying the 6 known (JAB &amp;lt; 21.5) quasars at $z$ &amp;gt; 7 from the entire sky, we select 5/6 or a completeness of $\simeq 80{{\ \rm per\ cent}}$. The failure to select the majority of 6 &amp;lt; $z$ &amp;lt; 7 quasars arises because our quasar density model is based on an empirical quasar spectral energy distribution model that underestimates the scatter in the distribution of fluxes. This new approach to quasar selection paves the way for efficient spectroscopic follow-up of Euclid quasar candidates with ground-based telescopes and James Webb Space Telescope.

Ambient dose equivalent rate from &lt;sup&gt;137&lt;/sup&gt;Cs and natural radionuclides in one-story residential buildings in settlements of the Bryansk region in 2020–2021

Method of in situ gamma-ray spectrometry was used to discriminate contributions of 137Cs and natural radionuclides to ambient dose equivalent rate indoors in settlements located in the zones of radioactive contamination after the Chernobyl accident. The measurements using a portable scintillation gamma spectrometer-dosimeter were carried out in 115 individual one-story residential buildings in 46 settlements of the Bryansk region of Russia in the summer period of 2020–2021. According to official data, the average density of soil contamination with 137Cs in the settlements ranged from 27 to 533 kBq/m2. Based on the type of building materials that had been used to construct the walls, the surveyed houses were divided into three large groups: wooden (walls made of logs) – 51 buildings, stone (walls built of bricks and/or concrete panels) – 34 buildings, and frame-panel – 30 buildings. The latter had walls constructed of wooden panels with the inclusion of heat-insulating material. Outside, the walls of the frame-panel houses were lined with a layer of silicate (white) bricks. 70 houses were built before the accident and 37 – after the accident. In eight cases it was not possible to reliably estimate the period of construction. The total ambient dose equivalent rate ranged from 42 to 228 nSv/h (average = 77 nSv/h). The values of the ambient dose equivalent rate from natural radionuclides were in the range 27–122 nSv/h. The average values of the ambient dose equivalent rate from natural radionuclides in the groups of wooden, frame-panel, and stone houses were 42, 42 and 58 nSv/h, respectively. The difference between stone houses and panel houses was statistically significant (P &lt; 0.01). The same difference was found between stone houses and wooden houses (P &lt; 0.01). The average values of the ambient dose equivalent rate from 137Cs, normalized to the density of soil contamination with 137Cs, were 0.13, 0.16, and 0.05 (nSv/h)/(kBq/m2) in wooden, frame-panel, and stone houses, respectively. The normalized ambient dose equivalent rates from 137Cs in the group of stone houses were statistically significantly (P &lt; 0.01) lower compared to the corresponding values for the groups of wooden houses and frame-panel houses. The small differences between frame-panel and wooden houses turned out to be statistically significant (P &lt; 0.05). The median and mean values of the normalized ambient dose equivalent rate from 137Cs for houses built before the accident were lower compared to those for houses built after the accident. These differences were statistically significant (P &lt; 0.01) for all groups of houses. The mean values of the normalized ambient dose equivalent rate from 137Cs and the ambient dose equivalent rate from natural radionuclides obtained in this study can be used to estimate the external effective dose to a person staying inside a one-story residential building. In this case, one should take into account not only the type of building materials used to construct the house, but also the time period of the construction: before or after the Chernobyl accident.