Chernobyl Exclusion Zone Research Articles

Combining clinostating and proton irradiation for modeling the space environment: a case study with a Chernobyl accession of Arabidopsis thaliana

Purpose The study of mechanisms of plant responses to extreme conditions, particularly, microgravity and ionizing radiation, is crucial for space exploration. Modern space biology of plants focuses on increasing plant tolerance to harsh conditions of space environment. Given the limited access to the International Space Station, we designed and assembled the 3D clinostat for mimicking microgravity, which, in combination with proton irradiation, allows simulating space conditions. As a case study for testing the device, we studied the effect of clinostating on Arabidopsis thaliana accession originating from the Chernobyl exclusion zone. Materials and Methods Using the combined clinostating and proton irradiation, we simulated the conditions of long-term space flight for Arabidopsis thaliana plants of the Chernobyl accession – progeny of chronically irradiated plants, grown from field-collected (Masa-0) and laboratory-cultivated (Masa-0-1) seeds, and for wild-type Col-8. The clinostating and irradiation of plants were also carried out separately. Plant responses were studied as photosynthetic and phenotypic endpoints of seedlings. Results and Conclusions Parameters of chlorophyll fluorescence estimated immediately after exposure showed that Masa-0-1 plants were resistant to the simulated space conditions, while Masa-0 demonstrated modulation of non-photochemical fluorescence quenching. Proton irradiation generally inhibited photosynthesis of Masa-0, Masa-0-1, and Col-8 seedlings. The combined effect of irradiation and clinostating modulated the photosynthetic activity of Col-8 seedlings. The leaf area of seedlings did not change after exposure to simulated conditions. The 3D clinostat model and software are published along with this article for researchers interested in the field of space biology.

The effects of long-term radiation exposure on the reproductive structures of Glyceria maxima (Hartm.) Holmb.: A case study in the Chornobyl exclusion zone

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).

Risk factors for delayed bone union in opening wedge high tibial osteotomy.

The purpose of this study was to investigate the relationship between patient demographics and potential intraoperative factors and delayed bone union in opening wedge high tibial osteotomy (OWHTO). A retrospective review of 65 patients (37 females, 28 males; mean age: 60.1±10.1 years; range, 44 to 77 years) who underwent OWHTO using an angle-stable implant with beta-tricalcium phosphate gap filling between September 2016 and October 2019 was conducted. The osteotomy site was divided into five zones from the lateral hinge on anteroposterior radiographs, and we defined the zone in which bone healing was observed. The bone union area was assessed according to this definition at three, six, nine, and 12 months after surgery, and bone union was defined as union at the fourth zone or greater. A generalized estimating equations approach was employed to investigate longitudinal data pertaining to bone union area as a dependent variable. In addition, the association of bone union at six months postoperatively and predictors were evaluated using cross-sectional statistical methods. The categorical predictors included in the models were smoking, diabetes, hinge fracture, and autologous osteophyte grafting. The continuous variables included in the models were age, body mass index, opening gap width, and plate position. Smoking (odds ratio [OR]=0.478, p<0.01), large opening gap width (OR=0.941, p=0.014), and anterior plate placement (OR=0.971, p<0.01) were significantly associated with decreased bone union area. Union rate at six months in smokers was significantly lower compared to nonsmokers (16.6% and 67.8%, respectively; OR=0.10, p=0.023). Area under the curve in the receiver operating characteristic analysis for bone union at six months was 0.60 for gap width and 0.63 for plate placement. Smoking, large opening gap width, and anterior plate placement are risk factors for delayed bone union after OWHTO. Surgeons should avoid anterior placement of the plate and carefully consider other options for smokers and those who require a large correction.

Identification of drought-induced forest damage in 2022 and of its key site condition drivers through satellite imagery

Abstract An extensive discoloration (yellowing, browning), and defoliation (leaf loss) were observed in Slovak forests during the summer of 2022. These phenomena are attributed to the combination of very low atmospheric precipitation and extremely high air temperatures from June to early August. In this study, the deterioration of forest health was analysed by comparing the image classification of Sentinel-2 satellite data from the year of intense drought occur-rence, 2022, with that from a referenced year without drought occurrence, 2020. The results indicated that in 2022, the proportion of heavily damaged stands with defoliation exceeding 50% doubled, reaching 19.3% (417,000 ha), and an area of 223,000 ha experienced an increase in defoliation by 30% or more. The damage exhibited an uneven spatial distribution, with the most significant impact observed in the western and southern parts of central Slovakia, as well as partially in the southern part of eastern Slovakia. Further GIS analyses revealed that forests growing on slopes with southern aspects suffered more severe damage than with northern exposures. However, the difference between the most damaged forests with south-southeast exposure (12.2%) and the least damaged ones with north-northwest exposure (8.2%) was only 4%. The level of damage gradually decreased with increasing altitude. Nevertheless, compared to previous studies, the damage was significantly manifested even in the fourth forest vegetation zone, up to an elevation of approximately 800 m. Regarding soil texture, which influences the water regime, the damage gradually decreased with decreasing sand content, ranging from sandy soils (17.5%) to clayey soils (6.6%).

Beyond an Environmental “Hermeneutics of Suspicion”

This essay engages debates about hopeful critical scholarship in the environmental humanities via an analysis of the figure of the Babushka of Chornobyl in literature, film, and photography. The argument for hazardous hope unfolds in two steps. First, the article discusses how contaminated environments like the Chornobyl Exclusion Zone, where the Babushkas live, invite an interpretative move that models what Paul Ricoeur and, more recently, Rita Felski have problematized as the hermeneutics of suspicion. Such a move involves a mistrust of what is at the surface, calling for the exposure of hidden material agencies beyond what can be sensorily perceived. This suspicious disposition is also the critical stance of much environmental humanities scholarship, even when it attempts to be hopeful. Second, the article proposes that the cultural texts it examines not only model a suspicious gaze but can also easily be read suspiciously—as glossing over the harrowing realities of a precarious life in a sacrifice zone. Yet they also show us pockets of beauty, joy, and community and hint toward reformulations of environmental futurity that cannot easily be accounted for via such suspicious criticism. In that, they invite us to leave behind, if only temporarily, the hermeneutics of suspicion and to explore hazardous hope in a contaminated environment.

Захворюваність на непухлинні хвороби системи кровообігу в осіб, евакуйованих з 30-кілометрової Чорнобильської зони відчуження, у післяаварійний період: ефект малих доз радіації

Захворюваність на непухлинні хвороби системи кровообігу в осіб, евакуйованих з 30-кілометрової Чорнобильської зони відчуження, у післяаварійний період: ефект малих доз радіації

Оцінка доз опромінення нориці рудої 137Cs на дослідних полігонах Чорнобильської зони відчуження з урахуванням вік-залежної динаміки зміни фізіологічних параметрів

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.

Потужність поглиненої дози зовнішнього опромінення представників іхтіофауни озер у Чорнобильській зоні відчуження

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”.

Magnesium Potassium Phosphate Cement for Encapsulation of Ash from Burning Radioactively Contaminated Wood

When wood from Chornobyl radioactively contaminated forests is burned in the Incinerator created in the Chornobyl zone under support of the European Commission, ash with a high content of Cs radionuclides is formed. Recently, magnesium potassium phosphate cements (MKPC) have been proposed as an effective alternative to Portland cement-based protective matrices. In this work, MKPC compositions were optimized for laboratory-scale encapsulation of inactive model ash, used as surrogate of the radioactive ash. The influence of the MgO/KH2PO4 ratio and the amount of added model ash on the temperature and setting time of the MKPC paste were determined. The compressive strength after 28 days of MKPC curing without ash was 22.7 MPa. After adding 20 wt.% model ash, the compressive strength of the MKPC matrix was 34.5 MPa, 40 % model ash was 23.4 MPa and 60 % model ash was 8.3 MPa. Thus, the accepted amount of the added ash that does not initiate the essential strength decrease of the MKPC matrix is 40 %. X-ray diffraction analysis of the MKPC matrix with 40 % model ash shows the presence of the main phase – K-struvite MgKPO4·6H2O. In addition to K-struvite, there are peaks of unreacted MgO and compounds such as calcite CaCO3, quartz SiO2 and potassium chloride KCl, which are parts of the model ash. It has been shown that ash components such as hydroxyapatite Ca5(PO4)3(OH) and calcium oxyphosphate Ca4(PO4)2O are involved in the formation reaction of phosphate cement and it contributes to increasing of the permissible amount of ash encapsulated into the MKPC matrix. SEM images of MKPC samples demonstrate a dense structure with well-connected ash particles. The leaching behavior of the MKPC matrices and their thermal stability were also assessed using immersion tests and thermogravimetric analysis, respectively. The Cs leaching rate of 1.2×10-4 g/cm2·day from the MKPC matrix containing 40 % MA is lower than the rates typical for cement waste forms. The obtained results demonstrate the possibility of using new magnesium-potassium phosphate cement as a matrix for the encapsulation of ash from the combustion of radioactively contaminated wood in the Chornobyl zone.

LEGAL ASPECTS OF THE ORGANIZATION OF TOURIST ACTIVITIES IN THE TERRITORY OF THE CHERNOBYL RADIATION-ENVIRONMENTAL BIOSPHERE RESERVE

The publication highlights the main organizational and legal principles of the creation and operation of the Chornobyl Radiation-Ecological Biosphere Reserve. The key normative legal acts that determine the legal regime of the territory that suffered radiation contamination as a result of the accident at the Chornobyl NPP are analysed to characterize the legal status of the Chornobyl Radiation and Ecological Biosphere Reserve and the peculiarities of carrying out nature-reserve business within its boundaries, as well as establish requirements for the implementation of tourism activities in this area. It is noted that the legal regime of the territory of the Chornobyl radiation and ecological biosphere reserve is mainly determined by the particular Law of Ukraine "On the legal regime of the territory exposed to radioactive contamination as a result of the Chernobyl disaster", which introduced the division into categories of zones of radioactively contaminated territories. Special attention is focused on the normative basis of the activities of the Chornobyl Radiation-Ecological Biosphere Reserve itself, the legal status of which is formed by: the Decree of the President of Ukraine "On the Creation of the Chernobyl Radiation-Ecological Biosphere Reserve", the Regulation on the Chornobyl Radiation-Ecological Biosphere Reserve and the Project for the Organization of the Territory of the Chornobyl Radiation-Ecological Biosphere Reserve and the protection of its natural complexes, which are approved by the relevant orders of the Ministry of Environmental Protection and Natural Resources of Ukraine. Peculiarities of environmental protection activities within the Chornobyl radiation-ecological biosphere reserve are regulated by the Law of Ukraine "On the Nature Reserve Fund of Ukraine" and the Land and Water Codes of Ukraine. It is emphasized that the peculiarities of conducting tourist activities on the territory of the Chornobyl Radiation and Ecological Biosphere Reserve are regulated based on the Law of Ukraine "On Tourism" and the Instructions on the conditions and requirements for conducting certain types of activities on the territory of the exclusion zone and the zone of unconditional (mandatory) resettlement and control over their observance. It was concluded that the tourist resources of the territory of the Chornobyl radiation-ecological biosphere reserve have a significant attractive potential due to the unique combination of artificial and ecological destinations within this reserve, and the State Agency of Ukraine provides the management of this territory for the Management of the Exclusion Zone. Keywords: Chornobyl exclusion zone; biosphere reserve; nature reserve fund; tourist resources; tourist activity.

Uptake from water and depuration of 137Cs and 90Sr by silver Prussian carp (Carassius gibelio)

To follow up field observations in the Chornobyl Exclusion Zone (ChEZ), a series of controlled model aquarium experiments were conducted to determine the uptake and depuration rates of 137Cs and 90Sr in silver Prussian carp (Carassius gibelio) in fresh water, varying in temperature from 5 to 27 °C, with daily feeding rates of 0–1.5 % fish weight day−1.In the present study, the 137Cs uptake rates in muscle tissues directly from water, 0.05–0.09 day−1 at temperatures of 5–27 °C, were significantly lower than previously reported for fish fed under natural conditions in contaminated lakes within the ChEZ. The rate of 90Sr uptake in bone tissues of silver Prussian carp varied from 0.055 day−1 at a water temperature of 5 °C and feeding rates ≤0.15 % fish weight day−1 to 1.5 ± 0.2 day−1 at a temperature of 27 ± 1 °С and at the highest tested feeding rate of 1.5 % day−1.The rate of decrease of 137Cs concentration in muscle tissues was kb = 0.0028 ± 0.0004 day−1 (T1/2 = 248 ± 35 days) at the lowest water temperature tested (5 °С). At water temperatures between 13 and 26 °С and a feeding rate of 0.15 % day−1, the rate increased to kb = 0.0071–0.0092 day−1 (T1/2 = 75–99 days).The rates of decrease of 90Sr activity concentration in bone tissues at water temperatures between 22 and 25 °С and a feeding rate of 0.5 % day−1 were kb=0.004–0.0014 day−1, and the associated biological half-life T1/2 ranged 50–160 days, respectively. The present work supported conclusions related to the main pathways of 137Cs and 90Sr uptake by silver Prussian carp, and demonstrated the usefulness of combining field and laboratory uptake and depuration experiments.

Uptake of technetium-99 by food crops under field conditions

Long-term field experiments have been carried out in the Chornobyl Exclusion zone to determine parameters describing technetium (99Tc) transfer into five food plants (Lettuce, Radish, Wheat, Bean, and Potato) from four types of soil, namely Podzoluvisol, Greyzem, Phaeozem, and Chernozem. Technetium was added to the soils under field conditions in a pertechnetate form. In the first two years, soil type had little effect on Tc uptake by plants. In the first and second years after contamination, the concentration ratios (CR), defined as 99Tc activity concentration in the crop (dry weight) divided by that in the soil (dry weight), for radish roots and lettuce leaves ranged from 60 to 210. For potato tubers, the CR was d 0.4–2.3, i.e., two orders of magnitude lower than for radish and lettuce, and for summer wheat grain it was lower at 0.6 ± 0.1. After 8–9 years, root uptake of 99Tc by wheat decreased by 3–7 fold (CR from 0.016 ± 0.005 to 0.12 ± 0.034) and only 13–22 % of the total 99Tc added remained in the upper 20 cm soil layers. The time taken for half of the added 99Tc to be removed from the 20-cm arable soil layer due to vertical migration and transfer to plants was short at c. 2–3 years.

Chromosomal disorders in Triticum aestivum subject to prolonged radionuclide pollution of soil from the Exclusion Zone of the Chornobyl Nuclear Power Plant

Due to the large number of nuclear power plants around the globe and the growing threat of radioactive accidents, a complex assessment of the biological consequences of the Chornobyl disaster is a relevant issue. Study of mutagenic activity of prolonged and chronic action of radionuclide pollution of soil in the Chornobyl Exclusion Zone long after the accident will allow us to identify the current level of threat they pose to the human genome and can reveal specific cytogenic markers of radionuclide environmental pollution. For this purpose, we germinated seeds of wheat of soft winter varieties Smuhlianka and Bohdana in soil samples from the Chornobyl Exclusion Zone 35 years after the disaster. Specific activity of Cs-137 and Sr-90 accounted for 4.5–28.2 kBq/kg. To determine the frequency and range of chromosomal aberrations, we used the anaphase-telophase method. In aberrant cells, we studied extracellular distribution of chromosomal disorders. The frequency of aberrant cells was 3.53–7.55 times above the spontaneous level. High mutagenic activity remained in the conditions of the lowest density of radionuclide pollution of soil. The range of chromosomal disorders mostly included paired fragments and bridges and containd chromosomal acentric rings, binding of chromosomes, myocardium, and lagging and leading chromosomes. Radionuclide pollution in the Chornobyl Exclusion Zone induced multiple cellular aberrations in the rhizome meristem, the share of which was the highest in case of low specific radionuclide pollution of soil, and exhibited a tendency towards decrease against the background of the highest density of radionuclides. Pollution of the environment with radionuclides as a result of disasters at nuclear energy objects poses a threat to the human genome and is a global problem, requiring state support to solve through systematic genetic monitoring in readionuclide-polluted territories and areas adjacent to them.

A tuning-free moderate-scale burned area detection algorithm — a case study in chornobyl-contaminated region

ABSTRACT The predefined threshold is one of the main fundamental and methodological challenges underlying the uncertainty and delayed release of existing burned area (BA) products. To improve the accuracy and timeliness of BA mapping, a tuning-free moderate-scale BA detection algorithm (AT&RF algorithm) was proposed to carry out rapid BA mapping for the immediate post-fire assessment. A case study was carried out at the Chornobyl Exclusion Zone (ChEZ) to assess the performance of the algorithm. The evaluation results indicated that the algorithm successfully detected the BA in 2015 and 2020 in ChEZ, which outperforms the existing BA products by significantly decreasing the omission error by 18.6% and 15.1% and improving the Kappa coefficient and critical success index by 9.4% and 4.0% on average for MCD64A1 and FireCCI51 products, respectively. It is also possible to transfer the algorithm quickly to other regions without complicated adjustments and significantly improve the timeliness and accuracy compared to the existing global BA products for assessing environmental impact and scope.

INFLUENCE OF рН AND Ca&lt;sup&gt;2+&lt;/sup&gt; IONS ON CHEMICAL COMPOSITION AND SORPTION OF &lt;sup&gt;137&lt;/sup&gt;Cs BY CHERKASY BENTONITES (UKRAINE)

The safety of near-surface and deep radioactive waste storage facilities is based on a system of engineered and natural barriers. Significant degradation of the engineered barrier system composed of cemented waste matrixes covered by cement mixture, concrete compartments, and structures at the basement of the storage facility may cause radionuclide transfer from the facility to groundwater. Mixing of the cement and concrete with water leads to the formation of several various hydration products with subsequent leaching of Ca2+ ions and formation of hydroxyl ions (OH-), which affects the alkalinity of the water environment and the sorption properties of bentonite, as a component of the engineered barrier at the basement of near-surface facilities. The article presents the results of an experimental study of the influence of Ca2+ ion concentration and pH of the model solution (similar to groundwater composition at Vector Site in Chornobyl Exclusion Zone) on the elemental composition and sorption properties of natural (NB) and Na-modified (PBA-20) bentonites from the Cherkasy deposit concerning 137Cs at the Solid : Solution ratio of 1 : 100. Geochemical modeling suggests that addition of CaCl2 to test solution and resulting alkaline pH leads to precipitation of solids, mainly oxides, hydroxides, Fe oxyhydroxides (hematite, goethite, limonite), and Ca carbonates (calcite, aragonite, dolomite). Their role in Cs adsorption was evaluated. The concentration of structural elements (Si, Al) in bentonites practically does not change with Ca2+ ion concentration increase in the model solution, demonstrating the bentonite structure’s stability under these conditions. At the same time, an increase in the Ca concentration and a decrease in the Na concentration was found in the ion exchange complex of the bentonites if compared to the initial natural bentonite. This results in the transformation of Na-modified bentonite from Na, Ca-form to Ca, Na-form. The total sorption capacity of NB and PBA-20 bentonite concerning Cs+ ions at increased concentrations of Ca2+ ions and pH of the solution slightly decreases, though retaining high values of the degree of absorption (&gt; 90 %). The total adsorption of Cs+ ions on NB and PBA-20 bentonites from model groundwater with the addition of CaCl2 from 16 to 960 mg/dm3 and increase of рН from 7.4 to 11.8 decreases with the increase in ionic strength, in particular, due to competition with Са2+ and Na+ ions. NB and PBA-20 bentonites of the Cherkasy deposit remain a reliable component of the liner at the repository basement owing to their main functional property – high absorption capacity for 137Cs, which is an important dose-forming radionuclide of short-lived low- and medium-level waste.

Abstract 7322: Polygenic adaptation and co-regulatory dynamics in Chernobyl wolves: Unveiling immune and oncogenic stress interactions with implications for human cancer resilience

Abstract Wolves living in the Chernobyl Exclusion Zone (CEZ) for at least six generations have adapted to high radiation exposure and are a unique model for studying genetic selection under extreme conditions of oncogenic stress. The objective of this study was to build off previously described signatures of adaptation in CEZ wolves, identify networks of genes associated with immune adaptation in CEZ wolves, and determine prognostic significance of these genes in human cancer datasets to provide insight into immune adaptation and cancer immunity. RNA from blood samples of wolves in CEZ, Belarus (BLR), and Yellowstone (YLS) were sequenced previously. Here we analyzed these data by mapping wolf transcripts to human orthologs. Radiation exposure (in CEZ and BLR) was quantified by intramuscular Cesium-137. Differential gene expression (DESeq2), network co-expression analysis (lmQCM), and gene set variation analysis (GSVA) assessed transcriptomic changes between populations. Germline single nucleotide polymorphism (SNP) for all three populations were inferred from RNA-seq data. Genes differentially regulated between populations, including gene modules showing signatures of polygenic selection through increased rates of genetic divergence (p&amp;lt; 0.05) in CEZ wolf populations, were deemed as outlier genes. Those n=3,180 CEZ outlier genes were then investigated in human cancer data from The Cancer Genome Atlas (TCGA) to determine prognostic impact in 10 tumor types highly conserved between human and canines. GSVA confirmed activation of neutrophil and macrophage signatures in CEZ wolves and suppression of several adaptive immune-related signatures (p &amp;lt; 0.05 vs BLR and YLS). A signature including immune checkpoint targets was also significantly differentially expressed in CEZ wolves. In TCGA, Cox PH analysis identified 23 genes over-expressed in CEZ wolves with significant positive prognostic impact in ≥ 2 human tumor types. PTPN6, previously identified to have positive prognostic value in bladder cancer1, was also prognostic in three additional tumor types. In human bladder cancer, genes identified as differentially regulated in CEZ wolves were disproportionately associated with improved survival. As predicted, gene signature variations in CEZ wolves reveal a distinct immune profile, likely shaped by prolonged radiation exposure. These findings, along with evidence of polygenic selection, suggest adaptation to multigenerational radiation exposure (an oncogenic stress). Notably, the enrichment of genes with positive prognosis in human cancer overexpressed in CEZ wolves present a valuable model to explore genetic underpinnings of cancer immunity and advance our understanding of cancer resilience in humans. Reference: 1Shen C. et al. The Analysis of PTPN6 for Bladder Cancer: An Exploratory Study Based on TCGA. Dis Markers. 2020. Citation Format: Christina Y. Yu, Cara N. Love, Merzu Belete, Hareesh Chandrupatla, Lauren K. Brady, Sriram Sridhar, Shane C. Campbell-Staton. Polygenic adaptation and co-regulatory dynamics in Chernobyl wolves: Unveiling immune and oncogenic stress interactions with implications for human cancer resilience [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7322.

Environmental radiation exposure at Chornobyl has not systematically affected the genomes or chemical mutagen tolerance phenotypes of local worms

The 1986 disaster at the Chornobyl Nuclear Power Plant transformed the surrounding region into the most radioactive landscape known on the planet. Whether or not this sudden environmental shift selected for species, or even individuals within a species, that are naturally more resistant to mutagen exposure remains an open question. In this study, we collected, cultured, and cryopreserved 298 wild nematode isolates from areas varying in radioactivity within the Chornobyl Exclusion Zone. We sequenced and assembled genomes de novo for 20 Oscheius tipulae strains, analyzed their genomes for evidence of recent mutation acquisition in the field, and observed no evidence of an association between mutation and radioactivity at the sites of collection. Multigenerational exposure of each of these strains to several chemical mutagens in the lab revealed that strains vary heritably in tolerance to each mutagen, but mutagen tolerance cannot be predicted based on the radiation levels at collection sites, and Chornobyl isolates were not systematically more resistant than strains from undisturbed habitats. In sum, the absence of mutational signatures does not reflect unique capacity for tolerating DNA damage.

Biological activity of sod-podzolic soils at different levels of radioactive contamination

The biological (enzymatic) activity of sod-podzolic soils has been investigated in the zone of mandatory resettlement and in the alienation zone of the Chornobyl Nuclear Power Plant (CNPP) under the influence of ionizing radiation. Gas chromatographic methods were used to determine potential nitrogenfixing (nitrogenase) activity, biochemical methods were applied to study the activity of hydrolytic enzymes (cellulase and protease) responsible for the decomposition of plant residues in the soil, as well as enzymes involved in oxidative-reductive reactions of organic matter transformation (catalase and polyphenoloxidases). Statistical analysis was also employed. The results of the conducted research indicate that a relatively low increase in the total dose rate in the radioactive contamination area (from 0.2 to 1.6 µGy/h) at Polygon No. 1 (the zone of mandatory resettlement near the village of Khrystynivka, Narodychi district, Zhytomyr region) stimulated potential nitrogenase activity of soil diazotrophs and the activity of both hydrolytic enzymes and oxidoreductases. High dose rates (up to 22.2, 61.6, and especially up to 84.0 mGy/h) at Polygon No. 2, located in the alienation zone of the CNPP directly in the area of the former Red Forest, led to a decrease in soil enzymatic activity. Thus, the obtained results unequivocally demonstrate the different nature of the impact of ionizing radiation levels on the biological activity of sod-podzolic soils. The more radioactive soil in the zone of mandatory resettlement stimulates the enzymatic activity of soil microbiota. This could be attributed to adaptive changes in the development and activity of microorganisms or changes in the composition of their communities, with a prevalence of radio-tolerant microbiota representatives. It is also possible that the manifestation of a radiobiological effect, such as radiation stimulation (radiation hormesis), accelerating the growth and development of microorganisms, may occur. In the alienation zone of the CNPP, with high radioactive contamination, the negative influence of ionizing radiation on the metabolism of soil microorganisms is preserved. The obtained results are highly correlated with the indicators of the abundance of nitrogen-fixing microorganisms in the investigated soils, as well as microorganisms representing the saccharolytic (fungi and cellulolytic bacteria) and peptolytic (ammonifiers) pathways of plant residue degradation, as previously demonstrated by us.

War drives forest fire risks and highlights the need for more ecologically-sound forest management in post-war Ukraine.

Since 24 February 2022, Ukraine has experienced full-scale military aggression initiated by the Russian Federation. The war has had a major negative impact on vegetation cover of war-affected regions. We explored interactions between pre-war forest management and the impacts of military activities in three of the most forested Ukrainian areas of interest (AOI), affected by the war. These were forests lying between Kharkiv and Luhansk cities (AOI 'East'), forests along the Dnipro River delta (AOI 'Kherson'), and those of the Chornobyl Exclusion Zone (AOI CEZ). We used Sentinel satellite imagery to create damaged forest cover masks for the year 2022. We mapped forests with elevated fire hazard, which was defined as a degree of exposure to the fire-supporting land use (mostly an agricultural land, a common source of ignitions in Ukraine). We evaluated the forest disturbance rate in 2022, as compared to pre-war rates. We documented significant increases in non-stand replacing disturbances (low severity fires and non-fire disturbances) for all three of the AOIs. Damaged forest cover varied among the AOIs (24,180 ± 4,715ha, or 9.3% ± 1.8% in the 'East' AOI; 7,293 ± 1,925ha, or 15.7% ± 4.1% in the 'Kherson' AOI; 7,116 ± 1,274ha, or 5.0% ± 0.9% in the CEZ AOI). Among the forests damaged in 2022, the 'Kherson' AOI will likely have the highest proportion of an area with elevated fire hazard in the coming decades, as compared to other regions (89% vs. 70% in the 'East' and CEZ AOIs respectively). Future fire risks and extensive war-related disturbance of forest cover call for forest management to develop strategies explicitly addressing these factors.

Nuclear accident sites and tourism: a comparative analysis of the Chernobyl and Fukushima exclusion zones

ABSTRACT This article aims to explore similarities and differences in the relationship between nuclear accident sites and tourism through a comparative study of two culturally different exclusion zones, namely Chernobyl (Ukraine) and Fukushima (Japan). Although the causes of the nuclear catastrophe were different, today it is possible to confirm some similarities in the transition and recovery process between these contaminated and abandoned sites. A range of grassroots initiatives lead to movements that try to look at nuclear accident sites from a new perspective. These activities include the ones that are planned and conducted to develop the sites as tourist destinations. In addition, in the context of war in Ukraine, the article shows, through the Stone’s darkest-lightest indicator, how the narration of the places of cultural dissonances changes with the changing geopolitical reality. In order to achieve the aim of this paper, a comparative analysis was conducted referring to qualitative data collected in the Chernobyl Exclusion Zone and secondary data on both Chernobyl and Fukushima exclusion zones. The following interviews with tourists, participatory observation and collected online sources of these two post-catastrophe sites have first and foremost provided a better understanding of the cultural dissonances emerging in these spaces.