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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”.

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.

During the acute phase of the Chornobyl accident the biota of the contaminated area was exposed to high doses of ionising radiation. Although these doses decreased significantly over the years, the exposure persisted over a prolonged period. This long-term exposure can be considered as a direct cause of genetic modifications occurring in organisms, and the search for correlative changes in the state of biota under the impact of radioactive contamination is an extremely urgent task. The aquatic macrophyte Glyceria maxima is the most common coenosis-forming plant of the littoral vegetation of the floodplain water bodies in the Chornobyl Exclusion Zone, and is capable of concentrating radionuclides in significant quantities. In this study, we aim to determine whether long-term radiation exposure has affected organs of reproductive structure (flower, pollen, seed) and, consequently, the viability of local populations of this species. All the traits analysed showed an inverse relationship with the absorbed dose rate of the maternal plants. It was determined that with an increase in the absorbed dose rate, the pollen size decreases, and the range of individual grains in the sample begins to vary more: small, heterogeneous in shape and size pollen grains are formed. Additionally, a decrease in pollen grain size correlates with a decrease in the proportion of fertile pollen. Pollen grains viability (fertility) decreases by 20–40% with increasing radiation dose rate. The response of reproductive structures to radiation exposure is non-linear: already at low doses (>2 μGy/h), negative changes in functional and morphological traits are observed, while at higher doses (9–13 μGy/h), the changes slow down. It is assumed that the radiation exposure mainly affects the early reproductive stages (pollen grains and partially flowers), while the main nutrients in water, that determine the trophic status of the reservoir, affects the late stages (seeds).

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.

The article demonstrates the results of a study of the landscape structure of the Chornobyl Radiation and Ecological Biosphere Reserve (Ukr.: Chornobylskyi radiatsiino-ekolohichnyi biosfernyi zapovidnyk – ChREBR). Because of radioactive pollution, a sharp drop in human activity, and the granting of the territory the status of a protected object, the process of area rewilding took on certain characteristics and led to the return of ecosystems’ natural processes. The studies cover a 7-year period from 2016 to 2022, i.e., from the moment this territory was granted protected status. That territory was abandoned by people more than 37 years ago and the former rural and urban landscapes have either already been transformed or are in the process of being transformed into natural ones. The scale of forest massifs has changed during the previous seven years, which has caused increased pasture overgrowth. huge forest massifs have been lost because of enormous forest fires and floods, particularly along the Pripet and Uzh rivers. Semi-natural successions occur in the gardens, and wooden homes are almost extinct. From orbit, a number of communities no longer resemble settlements. They are cloaked in bushes and trees instead. For places that have been ploughed, the same holds true. The last seven years show that change is happening more slowly than in the decades before. The pattern of natural processes in ecosystems, including periodic fires, the blocking of reclamation channels, and other factors, is the primary driver of changes in the composition of the land cover.

The release of the television series Chernobyl (HBO, Sky Atlantic 2019) drew renewed attention to the tragedy, its locations, and the affected population, generating new productions in Russia, such as the film Chernobyl: Abyss (Danila Kozlovskij, 2021), explicitly made in response to the Western series, signalling a desire to re-appropriate the narrative of the disaster and its territories. Indeed, a recurrent characteristic of the film and television productions of the countries most affected by the 1986 nuclear disaster (Ukraine, Belarus, and Russia) has been the representation of the land and the inhabitants’ relationship with it (Lindbladh 2019). This is also a central theme in Svetlana Alexievich’s renowned 1997 work Voices from Chernobyl: Chronicle of the future, whose stories inspired some episodes of the Anglo-American series. This article analyzes the representation of the relationship between the inhabitants of the Chornobyl/Chernobyl Exclusion Zone and their homeland in film and television productions dedicated to the nuclear disaster, beginning with Eastern European films made in the early 1990s, moving on to the representation in the Western series, and culminating with an analysis of Kozlovskij’s Chernobyl: Abyss. Features considered include the development of romantic narratives within the contaminated zone, the visual representation of radiation, and the depiction of the local institutions’ response to the disaster.

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 Key message We propose a framework to derive the direct loss of aboveground carbon stocks after the 2020 wildfire in forests of the Chornobyl Exclusion Zone using optical and radar Sentinel satellite data. Carbon stocks were adequately predicted using stand-wise inventory data and local combustion factors where new field observations are impossible. Both the standalone Sentinel-1 backscatter delta (before and after fire) indicator and radar-based change model reliably predicted the associated carbon loss. Context The Chornobyl Exclusion Zone (CEZ) is a mosaic forest landscape undergoing dynamic natural disturbances. Local forests are mostly planted and have low ecosystem resilience against the negative impact of global climate and land use change. Carbon stock fluxes after wildfires in the area have not yet been quantified. However, the assessment of this and other ecosystem service flows is crucial in contaminated (both radioactively and by unexploded ordnance) landscapes of the CEZ. Aims The aim of this study was to estimate carbon stock losses resulting from the catastrophic 2020 fires in the CEZ using satellite data, as field visitations or aerial surveys are impossible due to the ongoing war. Methods The aboveground carbon stock was predicted in a wall-to-wall manner using random forest modelling based on Sentinel data (both optical and synthetic aperture radar or SAR). We modelled the carbon stock loss using the change in Sentinel-1 backscatter before and after the fire events and local combustion factors. Results Random forest models performed well (root-mean-square error (RMSE) of 22.6 MgC·ha−1 or 37% of the mean) to predict the pre-fire carbon stock. The modelled carbon loss was estimated to be 156.3 Gg C (9.8% of the carbon stock in burned forests or 1.5% at the CEZ level). The standalone SAR backscatter delta showed a higher RMSE than the modelled estimate but better systematic agreement (0.90 vs. 0.73). Scots pine (Pinus sylvestris L.)-dominated stands contributed the most to carbon stock loss, with 74% of forests burned in 2020. Conclusion The change in SAR backscatter before and after a fire event can be used as a rough proxy indicator of aboveground carbon stock loss for timely carbon map updating. The model using SAR backscatter change and backscatter values prior to wildfire is able to reliably estimate carbon emissions when on-ground monitoring is impossible.

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

The article presents data from the study of vegetation dynamics in the Chornobyl Exclusion Zone 30 years after the nuclear disaster and the resettlement of its local people. The 1993 prognostic data on the further development of grass and forest community groups in this area was only partially correct. The new prognosis for demutation successions reflects deviations from the linear development with a possible horizontal "shift", depending on climatic conditions, bio-ecological features of plants, as well as the impact of fires. Based on the analysis of recent data from geobotanical studies of the vegetation, the values of ecofactors that determine the course of demutation of communities were calculated. In particular, the classic course of succession is now inherent in the former settlements of the exclusion zone where the formation of forests takes place. In the old fallow lands, the previously prevailing Elytrigia repens has lost its dominant position, and has been replaced by Calamagrostis epigejos, which we associate with a certain deficiency of nitrogen compounds in the soil. The allelopathic properties of cereals inhibit the process of replacing grass communities with forest ones, which affects the course of succession. The issues of demutation of residential areas of the Exclusion Zone are considered and the sequence of changes in different habitats is described. Post-pyrogenic changes in the forest vegetation are noted and the capacity of invasive plant species to invade natural ecosystems are characterized. It is emphasized that frequent and large-scale fires cause a significant imbalance in forest ecosystems, and result in the appearance of a largenumber of alien species.

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.

This study investigated the content of 137Cs (a long-lived radioactive isotope of caesium) in various parts of Pinus sylvestris L. (Scotch pine) and Dicranum polysetum Sw. (rugose fork-moss) at three different sites within the exclusion zone of the Chornobyl nuclear power plant over two years. The Leliv site is located within the 10 km zone, while the Paryshiv and Dytiatky sampling sites are within the 30 km zone. Samples of different P. sylvestris organs were collected, including 1- and 2-year-old branches and needles and wood and outer bark, and the entire D. polysetum. Sampling was conducted every two weeks throughout the year during 2014 and 2015. The specific activity levels of 137Cs in the samples were measured using gamma spectrometry with a CANBERRA gamma spectrometer unit and a coaxial high-purity HPGe semiconductor detector. The study found that at the Leliv and Paryshiv sites, the highest content of 137Cs in living organs of P. sylvestris was found in the wood. At the Dytiatky site, the needles and branches of the first and second years had anomalously high concentrations of radiocaesium (137Cs). This could be due to a thin layer of forest litter (1.5 cm) at that site. The study also found significant changes in the specific activity levels of 137Cs in living pine organs throughout the year. The highest concentration was observed in pine branches and needles in summer, and the maximum values in wood were observed in winter. The study suggests that a constant circulation of 137Cs in the soil–plant system can cause seasonal changes in the content of 137Cs in living pine organs. Symbiotic mycorrhizal fungi can play an important role in the circulation of radiocaesium in forest ecosystems. The outer bark of P. sylvestris did not show any seasonal changes in the content of 137Cs. It may not be involved in radiocaesium redistribution inside the plant but can serve as a long-term source of this radionuclide entering the forest litter. The study found no seasonal changes in the accumulation of 137Cs by D. polysetum, which might be due to the physiological characteristics of this plant species. Based on the analysis of the conducted studies, the recommendation is to consider the seasonal changes in the content of 137Cs during monitoring activities and when using Scots pine in areas potentially contaminated with this radionuclide.

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]

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.

his 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.

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 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.

Camera traps (CT) were used in 2018 to assess the current state of the Przewalski’s horse (PH) population. Przewalski’s horses were introduced into the Ukrainian Chornobyl exclusion zone (CEZ) in 1998. Up to 720 km2 (of the 2600 km2 total CEZ area) were investigated between February and November 2018, however the assessment reported here was made between May–July when PH are more settled with regards to the territory used. Totally 137 PH were recorded in the Ukrainian part of the CEZ: 47 stallions, 66 mares (adult & fillies) and 24 foals (10 males, 4 females and 10 of unidentified gender). At least four more PH (stallion, 2 mares, 1 foal) are noted at a remote site in the Belarus CEZ (V. Dombrovsky, or. rep.). All foals were born April-July 2018. There were 13 harem herds with foals (3–16 individuals in total in each), four small non-breeding groups (2-3 individuals), ca. 6 stallion groups (2–6 individuals), and at least one solitary stallion. Harem and non-breeding herds generally kept to ca. 18 sites, stallion groups normally roamed. Two-three groups lived on territories which including both Ukrainian and Belorussian parts of the CEZ. During 2007–2010 PH crossed the river Prypiat and finally founded a local reproducing sub-population. Almost all PH are from the 2nd and higher generations, only two mares had a brand mark which identified the original introduced population. One herd (Ilintsy) includes a domesticate breed mare (in autumn she moved to a neighbouring group, in Stechanka, where in 2019 gave birth to a hybrid foal sired by the Ilintsy stallion). At least, two males (solitary stallion and colt) had signs of hybridization (i.e. PH and domesticated horse). Underestimation of the total PH population in our study is likely as not all appropriate sites were investigated. The total herd, as identified here, of PH grew seven-fold between 1998 and 2018. However, the rate of population increase between 2009–2018 was in 1.5 times less than that 1998–2008 previously reported. This reduced population growth rate was likely due to the changing age structure of the herd, the initial herd contained only older (more productive) mature mares, over time numbers of younger (less productive) mares increased. The present demographic indices and reproductive potential do not indicate any negative tendencies in the population development, and evidence the further fitness to the local conditions. PH are native to open steppe landscapes and our study confirms their preference to meadows in the CEZ. However, we observed that PH do not avoid forests. Reforestation of meadows and predominance of woodlands in the CEZ are obstacles for comprehensive monitoring of PH, and may contribute to an underestimation of the population size as direct visual observations do not work well in the woodlands. CT studies offer a solution to this problem.

The study reports the first estimation of the Eurasian lynx population inhabiting the Ukrainian Chornobyl Exclusion Zone (CEZ, 2600 km2) in 2013–2018. Although lynx were once common in this region, anthropogenic impacts reduced their numbers substantially by the 19th century, leaving lynx as only occasional visitors to the area. In 1986 after an accident on the Chornobyl NPP the human population was removed from the areas affected by radioactive contamination, and regular economic activity was stopped there. As a result, a gradual recovery of the lynx population was observed. Assessments of the given study are based on camera trap data obtained from wildlife studies conducted in 2013–2018 over nearly 30% of total CEZ area. The number of locations where the camera traps worked simultaneously ranged from 5 to 89. Lynx was recorded 302 times, including 125 observations of 50 identifiable individuals. The total size of the lynx population was estimated to be approximately 53 to 68 individuals of all sex and age groups. For the identified lynx, sex was defined for 22 individuals: 6 females and 16 males. Eleven of 50 identified individuals were cubs. Over the whole period 6 family groups were recorded, 5 of which were females which had 2 cubs, and one a female with a single cub. Most of the identified lynx (33 of 50) were each recorded in one location only. In those cases when the individuals were repeatedly observed in 2 or more locations (up to 6) the maximum distance between locations ranged 1–23 km (mean distance = 1.9 km). The density of animals was approximately 2.2–2.7 individuals per 100 km2, which is comparable to other areas of Europe where conditions are favourable for this species. Whilst only a preliminary estimate, our results indicate that 32 years after the Chornobyl NPP accident, the CEZ has one of the highest lynx populations in Ukraine. Conditions for lynx are favourable in the CEZ because it has abundant prey species (roe deer and red deer), high forest cover (more than 63%), absence of a residential human population, no agricultural activity, a low level of disturbance from other human activity, and the area has protected status. The recovery of lynx in the CEZ demonstrates the conservation benefits that even unmanaged rewilding can achieve.

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-sursface facilities at “Vector” site.

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.

In 2012–2016 a European bison adult bull was observed (by camera traps) in the Chornobyl Exclusion Zone (CEZ, Ukraine), west of Tovstyi Lis village. This is the first record of wild bison in Kyiv Polissya for over 300 years. The animal must have come from the Paliessie State Radioecological Reserve (PSRER, Belarus), having crossed the Pripyat river. The site where he was observed is 30–40 km from the locality where bison were introduced into the PSRER in 1996. The total area over which the bull has been observed is ca. 30–50 km2, and includes deciduous (oak, hornbeam, aspen) and mixed woodlands, and former grassy meadows now overgrown with birch, alder, aspen, pine. This constitutes the most favourable habitat type for bison available in the CEZ. The animal was only observed in February–March and August–October. Currently we are not able to judge how permanently the animal stays on this territory. Taking into account the amount of appropriate habitat in the region, size of the CEZ, protection regime and the fact that bison was a native species in the past, the CEZ could be the best area in Ukraine where a large free population of the European bison could be established.

The full-scale invasion of Ukraine by Russian military forces on 24 February 2022 put the radiological well-being of the people in Ukraine under unprecedented threat. Apart from the risks linked to operating nuclear power plants, there was substantial evidence of looting of facilities of all kinds, including those holding radioactive materials, as well as the scope for physical disturbance of radioactively contaminated areas and waste storage facilities. The actions of Russian military personnel invading Ukraine through the territory of the Chornobyl Exclusion Zone (the ChEZ) were of serious concern. Before its shutdown a few days after the beginning of the occupation, the automated radiation monitoring system of the ChEZ recorded sharp increases in the gamma-background in several areas which indicated some non-typical processes taking place on its territory. The State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) and its technical support organisation, the Scientific and Technical Centre for Nuclear and Radiation Safety (SSTC NRS), as well as the rest of the professional nuclear community in Ukraine and worldwide, recognised the potential for movement of the radioactive contamination (reaching 10 1 -10 4 kBq m -2 Cs-137 in the most of the territory) by the Russian military machinery and personnel to areas outside the ChEZ, creating locally contaminated spots along the routes taken by the invaders towards Kyiv. Certain apprehensions were caused by the inventory carried out after the liberation of the ChEZ which revealed the theft of calibration sources and radioactive samples from laboratories located in Chornobyl. As soon as this information became available to the public, it caused a wide response and anxiety, as a result of which SNRIU made a decision to conduct a radiation survey of the liberated territories in the Kyiv region. The survey was conducted between June and December 2022 by SSTC NRS specialists with the support of DSA. The scope of the survey was limited by available time and resources; however, the total route of the survey was about 840 km, and covered more than 50 settlements and a limited part of the ChEZ. The radiation survey combined the continuous gamma-dose rate measurements by the detectors installed in the laboratory vehicle and additional manual measurements at specified points. As a result of the radiation survey, no deterioration of the radiation situation was observed in the liberated territories. No contaminated objects, radiation sources, or other radioactive material removed from the ChEZ were found either. Measurements of the Cs-137 soil contamination in the ChEZ, although limited, corresponded to the results which had been obtained before the war. It can be concluded that in the surveyed territories, the direct impact on the public in the form of additional radioactive contamination removed from the ChEZ in February-March 2022 was negligible. The same applies to the radiation consequences of forest fires that occurred in the ChEZ during its occupation. However, due to the damage of the radiation monitoring system, explosive hazard, and destruction of transport infrastructure, the consequences of the occupation of the ChEZ by Russian troops will be long-term., (Creative Commons Attribution license.)

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]

A study in 2012–2016 using camera traps confirmed the presence of brown bear in the Chornobyl exclusion zone (Ukraine). The presence of ca. 2–3 individuals was established in an area of up to 80 km2 near the village of Tovstyi Lis. Bears were observed on 17 occasions in all seasons except winter. Confirmed sightings were also recorded near the villages of Paryshiv and Ladyzhychi, though number of the animals in this area is unknown. Both locations include vast broadleaved woodlands with moist soil and abundant food reserves. The evidence collected (photographs, video, footprints, markings on trees, oral reports of a female bear with cubs) suggest the development of a resident breeding group and the revival of the species in Kyiv Polissia after centuries of its absence. This is facilitated by the size of the exclusion zone (2,600 km2), abundant resources and the absence of humans. A similar revival of bear has been reported in the neighbouring Poliskyi Radioecological Reserve in Belarus. Together both territories (4,750 km2) promise to be a new large reservation for brown bear in Eastern Europe.

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 137Cs and 241Am 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 (137Cs) and 0.43 Bq/g (241Am) were found. 137Cs contents were significantly higher at the cooling pond, where 241Am 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, 137Cs 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, 137Cs still remains solved and accessible in the cooling pond. However, 241Am remained adsorbed to the topsoil, thus accessible to terrestrial mosses, but precipitated in the sapropel of the cooling pond.

The article is aimed at theoretical substantiating and analyzing of the international cooperation, development of practical proposals on improvement of the international cooperation and influence on the status and socio-economic development of the Chornobyl exclusion zone. As a result of the research, the international projects concerning the economic development and status of the Chornobyl zone are indicated and the dynamics of indicators of socio-economic development are analyzed. Further potential prospects of development are determined. The basic directions of optimization of development together with attraction of investments in the region are proposed. The necessity of sanation and return of agricultural lands to production use and continuation of socio-economic rehabilitation of the region is the conclusion drawn. Prospect for further researches in this direction is substantiation of possible variants of activation of the investment attractiveness of the ecologically depressed region.

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 se-lected 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.