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The limits of the average value of the average annual external radiation dose rate of fishes from four lakes (with different degrees of radionuclide pollution of ichthyofauna representatives) of the Chornobyl Exclusion Zone as of 2021 are given, namely: Azbuchyn Lake (4 - 33 μGy/h), Vershyna Lake (3 - 26 μGy/h), Glyboke Lake (2 - 15 μGy/h) and Plyutovyshche Lake (0.02 - 0.16 μGy/h). Bottom-dwelling fish species such as tench and Prussian carp receive the highest external radiation dose, and rudd and surface fish species receive the lowest. It has been proven that the radionuclide 137Cs forms from 62.8 to 98.7 % of the absorbed dose of external irradiation of fishes from the studied water bodies. It is clearly shown that the current levels of the average annual absorbed external dose rate for many of the studied fishes of the lakes exceed the screening dose of 2 μGy/h and in 6 cases out of 22 exceed the safe level of 10 μGy/h recommended by the European Commission project “PROTECT”. [ABSTRACT FROM AUTHOR]

Methods for dose estimation of 137Cs in mouse-like rodents, specifically bank voles (Myodes glareolus), commonly found within the research sites in the Chornobyl Exclusion Zone, are being proposed. The International Commission on Radiological Protection recommends using the specially developed “BiotaDC” software, but it needs to be adapted to solve specific applied issues. It is shown that the “BiotaDC” approach adequately describes dose accumulation of 137Cs for external exposure inside nest chambers if the mean integral value of soil activity concentration at a depth of 0.5 m is used, for external exposure above soil – if the mean integral value of soil activity concentration at a depth of 0.2 m is used. However, the authors propose a method considering the age of animals at the time of capture and the age-related dynamics of changes in such parameters as excretion and accumulation of radioisotopes for internal dose estimation using the “BiotaDC” software. A detailed dose estimation algorithm is being proposed. Dose estimates for internal irradiation according to the authors’ method and the method of the International Commission on Radiological Protection are being compared. [ABSTRACT FROM AUTHOR]

The structure of signals from detectors for monitoring the gamma-background around the Chornobyl NPP was considered. It is shown that they are not random, they contain certain regular components. A comparison of the signals obtained on several detectors at the same time undeniably demonstrates that the patterns obtained are not occasional and not erroneous effects. [ABSTRACT FROM AUTHOR]

The results of cytogenetic studies of bank voles (Myodes glareolus) carried out during 2009 - 2016 in the areas of the Chornobyl Exclusion Zone with different levels of radionuclide contamination are presented. In the remote period after the Chornobyl accident features of chromosomal instability in somatic cells of examined animals, manifested as elevated levels of bone marrow cells with micronuclei, are observed. Probably, they can be caused by transgenerational radiation-induced chromosomal instability and changes in the ecological characteristics of the population under the combined impact of chronic low-intensity radiation and negative environmental factors. [ABSTRACT FROM AUTHOR]

The results of the assessment of levels of radionuclide contamination of fish during 2013 - 2019 in the reservoirs of the Chornobyl Exclusion Zone (lakes Azbuchyn, Vershyna, Hlyboke, Daleke, Yanivsky Backwater, Chornobyl NPP cooling pond) are presented. It was found that the concentration of 137Cs in representatives of ichthyofauna of water bodies during the study period continued to decrease, while the concentration of 90Sr, with some exceptions, remained unchanged or increased. The concentration of radionuclides in fish of the studied reservoirs was about 60 - 5000 times for 90Sr and in 3 - 200 times for 137Cs higher than the permissible levels for fish products accepted in Ukraine. [ABSTRACT FROM AUTHOR]

Morphophysiological and hematological parameters of different species and ontogenesis types of mice rodents from the drained areas of the Chornobyl cooling pond were studied for the first time; comparative analysis, including data of control and stable populations of the Chornobyl exclusion zone, was performed. Radioecological characterization of the research sites was carried out; the contents of the main dose-forming radionuclides were determined; animals’ exposure doses were estimated. In all experimental groups, similar changes in the hematopoietic system were observed, however, pathological features were less pronounced in individuals from the drained areas of the cooling pond. It was revealed that in the animal body under the chronic low dose exposure activation of compensatory and recovery processes occurs along with the destructive processes. It has been shown that the lifetime increase in radiation exposure of mature animals causes the imbalance of bone marrow hematopoiesis with the gradual exhaustion of blood system potential. [ABSTRACT FROM AUTHOR]

The paper provides an overview of radioactive waste temporary storage sites (RWTSS) located at the Chornobyl exclusion zone. The screening, investigation, and other activities currently undertaken at RWTSS in order to ensure their safety, as well as associated obstacles, are outlined. Possible ways of the management of radioactive waste stored in RWTSS are determined, and the necessity of taking the relevant decisions is highlighted. [ABSTRACT FROM AUTHOR]

Under natural conditions, in one of the most radioactively contaminated water bodies of the Chornobyl exclusion zone, lake Glyboke in 2020, experimental studies were carried out to assess the effectiveness of the use of additional “clean” feeding to reduce the levels of radioactive contamination of 90Sr and 137Cs in fish. The radiological efficiency of decreasing the 137Cs intake into the muscle tissue of fish with the use of additional “clean” feeding, mainly due to biological dilution, was 2.9 ± 0.4 times. The biological half-life of 137Cs in the muscle tissue of radioactively contaminated fish was 115 ± 25 days with the consumption of natural and additional “clean” food, which is approximately 2 times longer compared to the case when the fish consumes only clean food. In contrast to 137Cs, using additional “clean” feeding led to an increase of 90Sr content in the fish organism as compared to the control (up to 5 times) in proportion to the relative increase in the mass of fishbone tissue, which contains the bulk of strontium. [ABSTRACT FROM AUTHOR]

This paper describes the testing of titanium dioxide, chemically modified by arsenate groups, as an adsorbent of 90Sr from the component of aquatic ecosystems of the Chornobyl exclusion zone. It is shown, that the chemical composition of the aquatic environment impacts 90Sr adsorption. The 4As-TiO2 adsorbent reduces the activity of some samples by almost 100 %, which indicates selectivity and high adsorption capacity of the adsorbent in relation to 90Sr. In some experiments, this value reached 100 %, and the activity was reduced to the level of the maximum permissible 90Sr concentration. [ABSTRACT FROM AUTHOR]

Results of purposeful groundwater monitoring and modelling studies are presented, which were carried out in order to better understand groundwater flow patterns from the “Vector” site for near-surface radioactive waste disposal and storage in the Chornobyl exclusion zone towards river network. Both data of observations at local-scale monitoring well network at “Vector” site carried out in 2015 - 2016 and modelling analyses using the regional groundwater flow model of Chornobyl exclusion zone suggest that the groundwater discharge contour for water originating from “Vector” site is Sakhan River, which is the tributary to Pripyat River. The respective groundwater travel time is estimated at 210 - 340 years. The travel times in subsurface for 90Sr, 137Cs, and transuranium radionuclides (Pu isotopes, 241Am) are estimated respectively at thousands, tenths of thousands, hundreds of thousands - million of years. These results, as well as presented data of analyses of lithological properties of the geological deposits of the unsaturated zone at “Vector” site, provide evidence for good protection of surface water resources from radioactivity sources (e.g., radioactive wastes) to be disposed in the near-surface facilities at “Vector” site. [ABSTRACT FROM AUTHOR]

Changes of the 137Cs and 40K content during a year in the plants of forest ecosystems were investigated on the territory of the “Paryshev” sampling area (the Chornobyl NPP exclusion zone). One- and two-year-old needles and branches of P. sylvestris were used as objects of study. Samples were selected at intervals of 1 time every two weeks during 2014 and 2015. As a result of the research, it was found that the magnitude of the specific activity of 137Cs and 40K in the needles and branches of P. sylvestris is not constant, but leaped during the year. It has been suggested that fluctuations in the concentrations of activity of these radionuclides in the studied organs of P. sylvestris are associated with their circulation in the chain “soil - fungus-symbiotroph - plant”. The correlation coefficients R within 0.5 - 0.68 indicate the existence of direct and moderate relationship between fluctuations in the concentration of 40K and 137Cs activity in the needles and branches of P. sylvestris throughout the year. Probably, the mechanisms of absorption and escape of these radionuclides in P. sylvestris are similar. The content of 40K in the researched organs is higher than the content of 137Cs. It can be connected to the ability of the mycorrhiza to hold radiocaesium (to be a barrier) and to the selective accumulation of potassium by the plant. [ABSTRACT FROM AUTHOR]

The functional state of the cellular antioxidant defence system of shoots of Arabidopsis thaliana plants that grow in natural conditions in the areas of the Chornobyl Exclusion Zone with the values of the external dose rate of 0.45, 0.61, 1.05, 4.81 and 6.80 pGy/h was evaluated. The decrease of the content of thiobarbituric acid reactive compounds in the shoots of Arabidopsis thaliana was revealed under the external dose rate of 4.81 and 6.80 pGy/h by 38 and 48 %, respectively, compared to this parameter value under the external dose rate of 0.45 pGy/h. In the investigated samples the capacity of guaiacol peroxidase increases, catalase and ascorbate peroxidase decreases significantly with the increase of the external dose rate from 0.45 to 6.80 pGy/h. Probably, revealed changes in the functional state of the cellular antioxidant defence system of the shoots of Arabidopsis thaliana in the conditions of radioactive contamination are adaptive in nature. [ABSTRACT FROM AUTHOR]

Assessment of area and behavior of large wildfire in the Chornobyl Exclusion Zone (ChEZ) which has been burning during April 27 - 29, 2015. Levels of radionuclide contamination of combustible material show that expected effective dose of firefighters during one fire-line hour did not exceed 0.64 pSv in case of external exposure and 0.37 pSv in case of internal exposure. It is shown that the expected effective dose of internal exposure of firefighters during suppression of wildfires in ChEZ were below the dose from external exposure. At the moment exposure of 90Sr ad 241Pu (along with 238-240Pu and 241Am) make the most significant contribution to the internal dose of firefighters during forest and grassland fires suppression in the ChEZ. [ABSTRACT FROM AUTHOR]

Changes of faunal composition of insects-hortobionts and longterm dynamics of species diversity in the Chernobyl exclusion zone biotopes is studied. It is shown that on despite of the continuing fluctuations in species diversity, which may be associated with the process of long-term dynamics of the number of species, there was a clear trend to increasing abundance of species of insects. In evolutionary terms the settlement of harmful populations in natural habitats should be considered as the primary groupings as opposed to the secondary - on agricultural crops. For these groupings there are different vectors of selection: in the first case - naturally, in the second - artificial under the influence of anthropogenic factors. Different types of selection lead to the formation of different structures of phenotypic groupings and, accordingly, of their physiological characteristics. With the competitive process, biological regulation, nutrition by plants with natural resistance, the primary groupings acquire the genetic diversity, generalized type of nutrition and high viability. In secondary groupings, the vector of selection is aimed at high reproductive potential, due to the specialized type of nutrition by cultural plants that have much higher energy value than natural. [ABSTRACT FROM AUTHOR]

The questions of specific craniometric features variability of background species of murine rodents (common voles and house mice), which arises as the result of permanent habitation of the animals in ecosystems contaminated after the Chornobyl NPS accident, are studied. [ABSTRACT FROM AUTHOR]

Based on field researches conducted in the exclusion zone of the Chernobyl nuclear power plant in the years after the accident, identified the peculiarities of formation absorbed doses in animals of different taxonomic and ecological groups that live in conditions of radioactive contamination of ecosystems. Was shown importance of consideration of radiation features on wild animals according to their life cycle, conditions and ways of life. Was displayed data about the importance of different types of irradiation according to the period of stay the animals in the ground, in burrows and nests. Was reviewed the questions about value of external and internal radiation in absorbed dose of different types of wildlife. Was shown the results of the calculation of the absorbed dose of bird embryos from egg shell. [ABSTRACT FROM AUTHOR]

This paper describes the testing of titanium dioxide, chemically modified by arsenate groups, as an adsorbent of 90Sr from the component of aquatic ecosystems of the Chornobyl exclusion zone. It is shown, that the chemical composition of the aquatic environment impacts 90Sr adsorption. The 4As-TiO2 adsorbent reduces the activity of some samples by almost 100 %, which indicates selectivity and high adsorption capacity of the adsorbent in relation to 90Sr. In some experiments, this value reached 100 %, and the activity was reduced to the level of the maximum permissible 90Sr concentration. [ABSTRACT FROM AUTHOR]

Results of comparative cytogenetical examination of two groups are presented. First group is staff from two workshops (RAW management and RAW deactivation) of SJE "Complex" in Chornobyl exclusion zone. Second group consists of the persons who had no mutagenic factors influence during their professional activity (conditional control). Classical chromosome analysis method was used. It was found chromosome damages frequency in staff is significantly higher than spontaneous level in conditional control group. Professional experience duration and external exposure integral doses of both workshops staff do not differ. Staff of RAW deactivation workshop, who is additionally influenced by chemical and physical factors, has significantly higher chromosome aberration frequency, particularly due to specific cytogenetical markers of exposure. Correlation between external exposure integral doses and total chromosome aberration frequency, chromosome type aberration frequency, stabile interchromosomal exchanges frequency was found. [ABSTRACT FROM AUTHOR]

Studies of the 137Cs content in fruit bodies of Suillus luteus in the territory of the Chornobyl exclusion zone and Kyiv region outside the zone were carried out during the period 1986 - 2020. It was found that the dynamics of 137Cs activity in the mushroom can be described as a two-stage process. The first stage since 1986 was characterized by the annual increase in levels of specific activity of 137Cs for the following 10 - 12 yrs. During the second stage, there has been a gradual decrease in concentrations of 137Cs. The ecological half-life of 137Cs in the mushroom at the second stage differs for different sampling sites. Its minimum values were noted at Yaniv and Novo-Shepelychy sampling sites inside the exclusion zone. The maximum of 137Cs ecological half-life in Suillus luteus was observed on the Rzhyshchiv sampling site, which is the most remote from the Chornobyl Nuclear Power Plant outside the exclusion zone. [ABSTRACT FROM AUTHOR]

Based on modeling the dynamics of the Chornobyl emission radionuclide content in the components of the most polluted reservoirs of the Chornobyl Exclusion Zone, the absorbed dose for helophytes was reconstructed. During the growing season of 1986, the absorbed dose of plants of Glyboke Lake was 78 Gy, Daleke Lake 39 Gy. The absorbed dose rate of plant roots was 2.4 times higher than that of aboveground organs. According to actual data, in the period 2016 - 2019 in the Glyboke Lake average dose of external and internal plant irradiation was about 7.5 mGy/year, and in the Daleke Lake 5.6 mGy/year. On abnormally contaminated sections of the Glyboke Lake, the external dose reaches 0.5 - 1.0 Gy/year. During the period 1986 - 2020, the maximum cumulative (biological) dose of helophytes of Glyboke Lake can be 190 Gy, Daleke Lake 80 - 85 Gy. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Predictive assessment of radiation impacts on the air environment, soil cover, staff, which is located in a residential area, staff of an adjacent to the CSSNF enterprises as a result of work to prepare the site for construction of CSSNF at the Chornobyl Exclusion Zone is presented. It is shown that radiation effects on components of the environment will not result in exceeding the reference levels of radiation safety. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A spectroscopic method has been developed based on measuring of beta-spectra, which takes into account the physico-chemical state of the investigated objects and the instability of electronic systems in field conditions. This method allows for the investigation of the 90Sr and 137Cs concentration in various objects with a change in the 137Cs/90Sr ratio from 1 to 100 with an error of better than 20 %. A methodology has been developed that takes into account the change in the density of the inanimate objects and is based on shifting of the peak position of the conversion electrons from the 137Cs decay. The verification of the methodology compared to radiochemical measurements of 90Sr in soil samples showed complete agreement within 10 - 15 %, with a change of the activity in the samples by four orders of magnitude. [ABSTRACT FROM AUTHOR]

Results of radioecological and cytogenetic studies are presented. The soil contamination on the testing experimental sites of Chornobyl exclusion zone was studied. The correlation between the concentrations of 137Cs and 90Sr in the carcasses of animals and the level of soil contamination was revealed. The chronic exposure to radioecological conditions of the exclusion zone is shown to increase the pathological changes in bone marrow cells, which is determinates micronucleus test using. [ABSTRACT FROM AUTHOR]

The problem of identifying the sensitivity of living organisms to ionizing irradiation remains relevant, considering the spread of anthropogenic environmental pollution. The study on the effect of single X-ray irradiation (1,5 Gy) on peripheral blood of bank voles (Myodes glareolus (Schreber, 1780)) captured within territories with background radiation level was conducted. Hematological indicators, characterizing the overall condition of performance of the body, were determined dynamically on the first and seventh days after exposure to detect both early changes and the rate of recovery processes. The patterns and features of the main components of leukocyte formula found in peripheral blood of irradiated animals are being discussed. Differences between irradiated and control mouse-like rodents are shown, using parameters of erythrocytes and leukocytes. The analysis of changes in the peripheral blood of irradiated bank voles indicates the high reserve capacity of the body, according to its ability to restore homeostasis. [ABSTRACT FROM AUTHOR]

The paper presents a brief description of the Nuclear Safety Monitoring System (NSMS), which is a part of the Integrated Automated Monitoring System of the “Shelter” object (a facility that covers the destroyed Unit No. 4 of the Chornobyl NPP). Further development of the NSMS is proposed by introducing algorithms for automatic identification of neutron anomalies with a help of fuzzy logic and statistical methods; digital filtering of specific irregular impulse interferences leading to metrological system failures; algorithms for predicting changes in neutron flux density and assessing changes in the nuclear hazard of fuel containing materials accumulations. [ABSTRACT FROM AUTHOR]

The data on the state of radioactive contamination of leaves of plants growing directly on the territory of the drained part of the cooling pond of the Chernobyl NPP are presented. It was shown that the main source of contamination is the root intake of radionuclides (137Cs and 90Sr). This contamination is larger in previously drained areas compared to recently exposed ones. Hot particles were found on the leaf surface by autoradiography. Their total β-activity is a few percent of the total pollution. Possible sources of hot particles – resuspension in the air in the region of the northern part of the cooling pond are discussed. [ABSTRACT FROM AUTHOR]

The paper reports results of the study of depots and biogenic fluxes of 90Sr and 137Cs in the typical coniferous (Scots pine) and deciduous (Silver birch) forest ecosystems of the Chernobyl Exclusion Zone during 2016 - 2018. Data on activity concentrations and shares of the total activity of the studied radionuclides in the components of aboveground and underground biomass and their vertical distributions by 10 cm layers of the soil profile up to a depth of 1 m are presented. The downward and upward fluxes of 90Sr and 137Cs activity (including the processes of their deposition as a result of growth and formation biomass) are calculated in annual terms. Significantly higher 90Sr mobility in elements of forest ecosystems than 137Cs is confirmed. The estimated flux values for the investigated forest areas indicate a gradual further increase in the share of these radionuclides in the aboveground biomass components (up to 0.9 %·year-1 from the total activity in forest ecosystems) owing to the increase of organic matter stocks. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)