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To investigate the effects of chronic exposure to low-dose radiation on bone marrow (BM) hematopoiesis of bank voles inhabiting the radioactively contaminated territory of the Chornobyl exclusion zone. Animals were collected within the highly radioactive area of the so-called Red Forest located close to the destroyed 4th reactor of the Chornobyl Nuclear Power Plant. Radioecological investigations included evaluation of radiocontamination of soil samples by 90Sr and 137Cs, levels of incorporated radionuclides in animals' bodies and organs, as well as the absorbed dose rates. The study of peripheral blood and BM parameters combined with cytogenetic analysis of BM micronucleated polychromatic erythrocytes (MNPCEs) and standard metaphase test was carried out. The blood system of the exposed animals manifested significant changes in peripheral blood parameters (anemia and leucocyte formula left shift), ineffective differentiation, and maturation of BM cells, particularly relevant to the erythroid and granulocyte pools. Increased yields of BM MNPCEs and chromosomal aberrations, including dicentrics (dics) and Robertsonian fusion-like configurations (Rbts), were revealed. Observed disturbances in the BM and peripheral blood suggest functional instability and inefficient compensatory and recovery reactions of the blood system of the bank voles from the contaminated areas of the Chornobyl exclusion zone. We assume that they are the consequences both of direct radiation exposure and hereditary pathological changes that have formed in a number of generations inhabiting radioactively contaminated areas. [ABSTRACT FROM AUTHOR]

A feature of the conducted research is the study of a topical issue - the influence of external and internal factors on the prevalence of pathogens of blood-parasitic diseases. One of the most important external factors of influence is the exposure dose of γ-radiation, since the catching of mouse-like rodents was carried out at the landfills of the drained bed of the cooling reservoir of the Chernobyl Nuclear Power Plant. Therefore, the aim of the work was to study mouse-like rodents for the presence of causative agents of blood-parasitic diseases in natural populations under the influence of radioecological conditions of man-made transformation of the cooling reservoir of the Chernobyl Nuclear Power Plant. Mouse-like rodents of the genera Apodemus and Myodes were studied from three different locations of the cooling pond using parasitological methods. Radiological methods were used to determine the level of contamination of the specified three places where mouse-like rodents were caught using the γ- and β-dosimeter Pripyat RKS 20.3. Examination of blood smears of mouse-like rodents from three experimental polygons of the cooling reservoir of the Chernobyl Nuclear Power Plant revealed the presence of pathogens of blood-parasitic diseases in 93.8% of animals. In particular, such pathogens as Rickettsia spp., Ehrlichia spp., Bartonella spp., Babesia spp., Hepatozoon spp., Haemobartonella (Mycoplasma) spp., were identified. and spirochetes. The prevalence of zoonotic agents among mouse-like rodents of the Chernobyl Zone of radioactive contamination, as well as its dependence on the level of radioecological pollution of the respective landfills, was established. Therefore, according to the results of the conducted research, the presence of causative agents of blood-parasitic diseases among mouse-like rodents, which are both intermediate and their definitive hosts, including those from dangerous zoonoses, which, subject to the application of timely and complex preventive measures, will prevent human infection. [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 "Chernobyl nuclear disaster" released huge amounts of radionuclides, which are still detectable in plants and sediments today. Bryophytes (mosses) are primitive land plants lacking roots and protective cuticles and therefore readily accumulate multiple contaminants, including metals and radionuclides. This study quantifies 137 Cs and 241 Am in moss samples from the cooling pond of the power plant, the surrounding woodland and the city of Prypiat. Activity concentrations of up to 297 Bq/g ( 137 Cs) and 0.43 Bq/g ( 241 Am) were found. 137 Cs contents were significantly higher at the cooling pond, where 241 Am was not detectable. Distance to the damaged reactor, amount of original fallout, presence of vascular tissue in the stem or taxonomy were of little importance. Mosses seem to absorb radionuclides rather indiscriminately, if available. More than 30 years after the disaster, 137 Cs was washed out from the very top layer of the soil, where it is no more accessible for rootless mosses but possibly for higher plants. On the other hand, 137 Cs still remains solved and accessible in the cooling pond. However, 241 Am remained adsorbed to the topsoil, thus accessible to terrestrial mosses, but precipitated in the sapropel of the cooling pond.

Points of temporary localization of radioactive waste (PTLRW) are areas adjacent to the Chоrnobyl NPP where trenches and burrows for radioactive waste localization were created during the priority measures to eliminate the accident. The aim of the presented work was to compare the structure of the microbial community on PTLRW and areas contaminated with radionuclides. The largest number of sequences (relative abundance > 1%) in samples from both PTLRV and radionuclide-contaminated ecosystems was observed of the Phylum: Proteobacteria, Actinobacteria, Acidobacteria, Planctomycetes, Verrucomicrobia, Gemmatimonadetes, Chloroflexi and Bacteroidetes. The dominant Order (relative abundance > 5%) were: Rhizobiales, Rhodospirillales, Actinomycetales, Solirubrobacterales, Acidimicrobiales Acidobacteriales, Solibacterales and Ellin6513. According to Shannon and Simpson, the soil with the highest biodiversity was in the soil taken from the surface of the trench in the «Red Forest». The lowest Chao1 index Shannon and Simpson Index had soil from outside of the trench in the «Red Forest». Comparing the two presented ecotypes, a significant difference was observed in the amount of the Proteobacteria Phylum, towards Actinobacteria, and Acidobacteria. Also, samples from the territory of the trench “Red Forest” had the largest number of identified Species. Therefore, we can conclude that there are processes of ecosystem formation. Namely, they are affected by high absorbed doses and additional nutrition, represented by radionuclide contamination and wood residues.

The results of studies of radioactive contamination of fishes’ organs and tissues of different ecological groups in water basins within the Chоrnobyl exclusion zone and other water basins of Kyiv region & Pokuttya have presented. During last years a continuing decrease of 90Sr specific activity in ichthyofauna representatives of all Ukrainian water basins was registered. The exception are the pray fish species of closed water basins of the Chоrnobyl exclusion zone where the 90Sr content remains at a certain high level. It is shown, that 90Sr for present time is the main dose-formed radionuclide for fish of the majority of water bodies within the Chornobyl exclusion zone.

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 μGy/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 μGy/h by 38 and 48 %, respectively, compared to this parameter value under the external dose rate of 0.45 μGy/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 μGy/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.

Following the 1986 Chornobyl accident, an area approaching 5000 km 2 surrounding the nuclear plant was abandoned, creating the Chornobyl exclusion zone (CEZ). Although this area likely contains the most radioactive terrestrial ecosystem on earth, the absence of humans and associated activities for nearly 35 years since the accident has resulted in increases in wildlife numbers. Both the Belarussian and Ukrainian components of the CEZ are now designated as nature reserves; together they form one of Europe's largest protected areas and have been described as an iconic example of rewilding. Forests and former agricultural land (now scrub) dominate the CEZ and wildfires are an annual event. In April 2020, the CEZ suffered its most widespread fires to date when greater than 800 km 2 of the 2600 km 2 Ukrainian portion of the CEZ was burnt. Large-scale fires in the CEZ have implications for wildlife, as they do elsewhere, but they also pose additional radioecological and radiological protection questions. We discuss the implications of wildfires in the CEZ, considering effects on wildlife and changes in radionuclide mobility. We also demonstrate that the risk to firefighters and the wider public from the inhalation of radionuclides in smoke resulting from fires in the CEZ is likely to be low. However, further experimental and modeling work to evaluate potential doses to firefighters from inhaled radioactive particles would be valuable, not least for reassurance purposes. Integr Environ Assess Manag 2021;17:1141-1150 © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)., (© 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).)

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]

Assessment is given 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 μSv in case of external exposure and 0.37 μSv in case of internal exposure. It is shown that the expected effective dose of internal exposure of firefighters during suppression of wildfires in ChEZ was below the dose from external exposure. At the moment exposures of 90Sr and 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.

Changes of faunal composition of insects-hortobionts and long-term dynamics of species diversity in the Chernobyl exclusion zone biotopes is studied. It is shown that 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 – natural, 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.

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 contami-nated after the Chornobyl NPS accident, are studied.

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]

Background: Radiation accidents at the Chornobyl Nuclear Power Plant (USSR, 1986) and Fukushima-1 (Japan,2011) have shown that global environmental contamination is an intervention in normal human life making nega-tive effect on population health. These accidents highlighted a number of statutory and regulatory both with me-dical and social problems for individuals, who returned voluntarily for permanent residence in the ChornobylExclusion Zone i.e. a radiation-hazardous area (they are named the «self-settlers»)., Objective: generalization of experience in the settlement of normative-legal, ecological-dosimetric and medico-social life issues of population living in the Chornobyl NPP (ChNPP) Exclusion Zone («self-settlers»)., Object and Methods: The chosen problem is complex, necessitating the generalization of radiation-hygienic, med-ical-biological, socio-economic, demographic and sociological research results obtained by the national and foreignauthors. A set of theoretical research and analysis of empirical data methods on the principles of interdisciplinaryinteraction was used; the systematic, legal, economic, medical-biological, demographic and retrospective-dosimet-ric approaches of research were applied., Results: It was shown that a part of population refused to evacuate or had returned for permanent residence to theradiation-hazardous lands after the ChNPP accident. In 1986-2009 the number of «self-settlers» ranged from 150to 2,000 in different years. In 2021 - the 101 people. Those were mainly people of working age, mostly females, single people or widows/widowers. Рrevious medical and dosimetric studies have shown that long-term residence inthe Exclusion Zone affects physical and mental health of «self-settlers» and causes atypical aging, includinginvolvement of the central nervous system. According to calculations, the average effective total radiation doseaccumulated by «self-settlers» for the first 3 years was 30 % of dose for the entire post-accident period, and thedose accumulated over 20 years was 54 % of the dose accumulated over 35 years. But the effective radiation dosesaccumulated in different periods after the accident differ significantly in residents of different Exclusion Zone settlements. This information needs further study in terms of the «radiation dose - health status» dependence., Conclusions: The effective radiation doses accumulated in different periods after the accident differ significantlyin the residents of different Exclusion Zone settlements. Тhe average effective total radiation dose accumulated by«self-settlers» for the first 3 years was 30 % of the dose for the entire post-accident period, and the dose accumulated over 20 years was 54 % of the dose accumulated over 35 years., (N. V. Gunko, O. M. Ivanova, K. M. Loganovsky, N. V. Korotkova, S. V. Masiuk.)

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

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]