Chornobyl Nuclear Power Plant Research Articles

Perinatal mortality after Chornobyl in contaminated regions of Ukraine.

Belarus and Ukraine were the countries most affected by the consequences of the Chornobyl nuclear power plant in 1986. A study of perinatal mortality in Belarus found a highly statistically significant increase in the 1990s in the most contaminated oblast Gomel but no increase during this period in the rest of Belarus. As a possible mechanism to interpret this increase as a late Chornobyl effect, it has been suggested that strontium-90 contained in Chornobyl fallout, incorporated during menarche, impairs the immune system of pregnant women which in turn increases perinatal mortality. In the present study, this hypothesis is tested using data from Ukraine. Annual data on perinatal mortality, in the period 1981-2006 were provided by the Ministry of Public Health of Ukraine. Trends in perinatal mortality rates in the most contaminated regions of Ukraine (Kyiv and Zhytomyr oblasts and the city of Kyiv; study region) were compared with rates in the rest of Ukraine (control region). To identify any differences in perinatal mortality trends between the study and control regions, the ratios of perinatal mortality rates in the study region to the rates in the control region were analyzed using the calculated strontium concentration as a predictor. A trend analysis of perinatal mortality rates in Ukraine revealed two bell-shaped deviations from a long-term exponential trend with maxima at the beginning and end of the 1990s. The same pattern was found in the data from the study and control regions, but the deviations were almost three times higher in the study region than in the control region. An analysis of the ratios of perinatal mortality rates in the study region to the rates in the control region (odds ratios) showed an increase and decrease during the 1990s which was approximated by a lognormal density distribution. The calculated strontium concentration, when used as a predictor, also fitted the data well. Thus, the data from Ukraine confirms the results from Belarus. The analysis of the odds ratios revealed about 1000 excess perinatal deaths in the study region in the period 1990-2004. The corresponding figure for Ukraine as a whole was estimated at 3500 perinatal deaths. It is hypothesized that the observed increase in perinatal mortality in the 1990s may be a late effect of incorporated strontium-90 on the immune system of pregnant women. The analysis is based on a theoretical model, as no data on strontium concentrations were available; the results should therefore be interpreted with caution. An updated study for Belarus would be desirable to corroborate the results.

FEATURES FUNCTIONING OF THE DETOXIFICATION SYSTEM AT THE THREAT TERMINATION OF PREGNANCY AS A CONSEQUENCE OF ACCUMULATION OF 137CS

To date, there is no consensus on the pathogenesis of miscarriage. In modern life, human health is signifi cantly infl uenced by environmental factors. In this regard, 37 years after the accident at the Chornobyl nuclear power plant, the question of remote cytogenetic and hereditary eff ects in the off spring of parents aff ected by radiation remains relevant. Ecosystems contaminated with radioactive substances are a source of exposure for humans. Internal irradiation is the cause of reproductive losses. Radiation stress aff ects the course of redox processes in the body. Biochemical indicators are markers of the infl uence of environmental factors on a person. The study is dedicated to determining the state of peroxide hemostasis in the case of miscarriage. Aim: to determine the peculiarities of the functioning of the detoxification system in case of miscarriage due to the accumulation of 137Cs.Material and methods. The fi rst (research) group included women with reproductive losses in anamnesis and signs oftermination of the current pregnancy; the second (control) group included women with an uncomplicated history and course of pregnancy. Additionally, the fi rst group was divided into subgroups according to pregnancy outcomes: А – 38 women who gave birth at 37-40 weeks, despite the complicated course of the current pregnancy, В – 13 women who gave birth at 28-36 weeks + 6 days, С – 9 women who birth at 22-27 weeks + 6 days. The state of peroxide hemostasis in women was studied using biochemical studies. Accumulation of 137Cs with diff erent activity was detected in the placentas of the examined women of both groups using β-spectrometry. Morphological examination of placentas was performed according to the protocol. The severity of placental damage was studied by Olympus BX51 and Axioskop 40 microscopes. Analyzing the results revealed a relationship between biochemical indicators, the activity of 137Cs, and pregnancy scenarios. Statistical data analysis was performed using Microsoft Excel (2016) and Fisher angular transformation. The diff erence between comparative values was considered signifi cant at p < 0.05 (probability index greater than 95 %). Permission to conduct research was obtained from the Medical Ethics Committee of the SI «Institute of Pediatrics, Obstetrics, and Gynecology named academic Elena M. Lukyanova of the National Аcademy of Мedical Sciences of Ukraine» (protocol No 3 of 07.06.2017).Scientifi c research work is to «Develop the latest and improve existing technologies for diagnosis, prevention, and treatmentof premature termination of pregnancy in women with miscarriage taking into account the passport of the placenta» (2018-2020). Code VN.20.00.02.18, state registration number 0118U000039, KPKV 6561040.Results. It has been confi rmed that the state of the environment plays a decisive role in the pathogenesis of miscarriage. Ithas been proven that placental dysfunction caused by abnormal oxidative stress due to the action of incorporated 137Cs leads to pregnancy termination. As a result of the depletion of the antioxidant reserve, the compensatory capabilities of the placenta decrease. It was established that activity in the placenta up to 1.0 Bq/kg of 137Cs does not aff ect the course of gestation. The compensatory capacity of the placenta remains preserved even with the accumulation of 1.1 to 4.4 Bq/kg of 137Cs. At the same time, it is possible to prolong the pregnancy until the term of timely delivery. Internal irradiation with an activity of 4.5-10.4 Bq/kg of 137Cs causes damage to the stroma of the maternal surface of the placenta and premature birth at 28-36 weeks + 6 days. At the same time, newborns are viable due to the preservation of compensatory reactions in the placenta. Accumulation of more than 10.4 Bq/kg of 137Cs causes antenatal death of the fetus and early premature birth due to damage to maternal and fetal structures of the placenta. An increase in the content of malondialdehyde and a decrease in the activity of superoxide dismutase in the blood indicate the severity of radiation damage.Conclusions. Internal exposure to 137Cs disrupts the architecture and functional capacity of the placenta. Extreme eff ectsdepend on the activity of 137Cs, the compensatory capabilities of the placenta, and the pregnant woman’s body. Activation of lipid peroxidation acts as a biochemical amplifi er of radiation exposure. An increase in the blood of malondialdehyde, diene conjugates, and free SH groups is associated with the severity of radiation damage. An early marker of primary placental dysfunction, premature birth, and antenatal fetal loss is an increase in MDA content in the blood by 12.0 % and a decrease in SOD by 6.5 % relative to permissible values. An early marker of exhaustion of the compensatory reserve is an increase in the content of MDA in the blood by 23.3 % and a decrease in SOD by more than 18.2 % relative to the permissible values. Decompensation of adaptation mechanisms in the system «mother- placenta-fetus» leads to antenatal losses.

TO THE 60TH ANNIVERSARY OF THE DEPARTMENT OF EARTH SCIENCES OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE

In the second part of the article, the main historical events in terms of dates, facts and personalities of the formation and development of the institutions of the Department of Earth and Space Sciences of the Academy of Sciences of the Ukrainian SSR from its foundation in 1963 to Ukraine’s independence in 1991 are listed in chronological order. The course of events related to name changes is given: Department of Earth and Space Sciences (1963–1972), Department of Earth Sciences (1972–1980), Department of Geology, Geophysics and Geochemistry (1980–1983) and Department of Earth Sciences (1983–1991). Considerable attention is paid to the significant contribution of the specialists of the Department of Earth Sciences of the Academy of Sciences of the Ukrainian SSR in eliminating the consequences of the largest technogenic and environmental disaster that occurred on April 26, 1986 at the Chornobyl nuclear power plant. It is considered the most important achievements of the institutions of the Department of Earth Sciences of the Academy of Sciences of the Ukrainian SSR in the period of formation and active development. In particular, scientific substantiation of the search for industrial oil and gas accumulations in the crystalline foundation of the sedimentary basins of Ukraine, volcanic and volcanogenic-sedimentary rocks of Transcarpathia and the Dnipro region, in the zones of active water exchange on the regional monoclines of Precarpathia, the Black Sea region. The doctrine of the formation of deep fault structures has been developed, and a technique has been developed for forecasting of combined traps of hydrocarbon accumulations in deep-seated Devonian and Carboniferous horizons of the Dnipro-Donetsk Basin. Significant results were obtained regarding the geological structure of the earth’s crust and the upper mantle of the lithosphere within the framework of international projects during regional seismic research within limits of Ukraine, Southeast Europe and India. The general regularities of the structure are established for various geostructures: shields, platforms, depressions, transition zones from continents to oceans, deep-sea depressions, structures of the ocean floor. The theoretical principles, methods and technical means of remote ocean research using artificial Earth satellites were developed, and the country’s first system for collecting, transmitting and processing information about the ocean’s physical fields was created. This is a kind of report of the most significant events and facts from the life of the Department of Earth Sciences of the National Academy of Sciences of Ukraine and personal information and scientific achievements of the members of the Academy elected in the considered period.

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.

Смертність через провідні непухлинні хвороби учасників ліквідації наслідків аварії на ЧАЕС та мешканців радіоактивно забруднених територій у віддаленому періоді після аварії

The purpose of the study: Based on a descriptive analysis, to determine the post-accident changes in the level and structure of mortality of participants in the chornobyl cleanup workers of the accident at the Chornobyl Nuclear Power Plant (ULNA) and residents of RADIATION- contaminated TERRITORIES )residents of the RZT) of Ukraine from the main non-neoplastic diseases depending on age, time since the date of the accident and gender. Materials and methods: Mortality from non-neoplastic pathology in 1986-1987 in ULNA, numbering 64,762, and residents of RZT, numbering 174,860, aged 18-60 on the date of the accident as a result of the accident at the Chornobyl nuclear power plant, was studied based on clinical-epidemiological and dose data of the State Register of Ukraine. Epidemiological, medical-statistical, analytical methods were used during the research. Research results: On the basis of descriptive analysis, a description of the level and structure of mortality from non-neoplastic diseases of the ULNA and the residents of the RZT was provided, both for the entire post-accident period and for five-year periods. In ULNA, mortality increased with each five-year period and in recent years has increased by 15.7 times compared to the initial period. In residents of the radioactively contaminated territory of Ukraine, the mortality rate increased for 25 years after the accident, with the highest rate in the period 2008-2012, regardless of age, with subsequent stabilization of the indicators. The structure of mortality among participants of the ULNA and residents of the RZT throughout the entire observation period remains unchanged and almost does not differ from the general mortality trends of the population of Ukraine. Diseases of the circulatory system, digestive organs, and respiratory organs are stable in terms of the frequency of the causes of death. Age, sex, and temporal differentiation of mortality, differences in nosological causes among defined categories of victims of the consequences of the accident at the Chornobyl nuclear power plant were revealed. Conclusions: During the post-accident observation period (1988-2017), diseases of the circulatory system, digestive organs, and respiratory organs remained the main causes of mortality in ULNA in and among residents of RZT aged 18–60 on the date of the Chornobyl accident. The dynamics of mortality in ULNA was characterized by growth during the entire period of observation, in residents of RZT – growth over 25 years with subsequent stabilization. It is necessary to take into account during dispensation the revealed features of mortality of ULNA and RZT in order to develop comprehensive measures to reduce the mortality of this contingent.

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.

Ретроспективний аналіз каріозного ураження твердих тканин зубів у дітей з радіаційно забруднених унаслідок аварії на Чорнобильській АЕС територій України

The relevance of the study is due to the presence of significant carious lesions of the hard tissues of the teeth in children from radiation-contaminated territories as a result of the accident at the Chornobyl nuclear power plant (ChNPP). Purpose - to conduct a retrospective analysis of the intensity of dental caries in children of Ukraine, residents of radiation-contaminated territories, taking into account the general state of health at different times after the accident at the ChNPP (1993-1996, 2001-2003, 2016-2018) as a basis for the further development of a complex of therapeutic and preventive measures for this pathology. Materials and methods. The object of the study: 1852 children aged 7-15 - residents of territories contaminated with radionuclides. Assessment of caries intensity of permanent teeth in accordance with WHO recommendations (2013) included determination of caries prevalence and index assessment of caries intensity of permanent teeth (PT): «decayed, missing, filled permanent teeth» (DMFT) and «decayed, missing, filled permanent teeth surfaces» (DMFS). Statistical processing of data was carried out using methods of variational statistics (statistical package «IBM SPSS Statistics 20.0.0»). Results. In 1993-1996 irradiated children from the III zone had a very high intensity of dental caries (DMFT - 7.25±0.77, DMFS - 10.92±1.77), twice as high compared to residents of the IV zone. In children from III and IV zones in 2001-2003 the intensity of dental caries was higher in the presence of somatic pathology. In 2016-2018 compared to the period 2001-2003 there was a significant (p<0.05) decrease in both indices of carious lesions, probably due to a decrease in the degree of exposure of children to radionuclides. Conclusions. During the period 1993-1996 the highest rates of dental caries intensity were determined in 15-year-old children from zone III compared to residents of zone IV. The intensity of dental caries during the periods of 2001-2003 and 2016-2018 decreased, although it remained at a high level, which requires the further development of a complex of treatment and prevention measures for this pathology. The research was carried out in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. Informed consent of the children's parents was obtained for the research. The authors declare no conflict of interests.

ЕКОЛОГО-ЕКОНОМІЧНІ НAСЛІДКИ AВAРІЇ НA ЧОРНОБИЛЬСЬКІЙ AЕС ТA ПЕРСПЕКТИВИ РОЗВИТКУ ТУРИЗМУ В РЕГІОНІ

The article examines the consequences of the Chernobyl accident, which led to radioactive contamination in the environment, which significantly exceeds acceptable levels of radiation safety. According to the data of the DSNS of Ukraine, as a result of the accident at the Chernobyl nuclear power plant, 95% of the territory of Ukraine became aware of high-level radioactive contamination. The main consequences of the accident were: radioactive contamination of warehouse parts by ecosystems: summer-, liquid-atmosphere, soil and soil surfaces; influx on living organisms; extraction of significant territories and natural resources from folk resources. The biggest blow, which is impossible to evaluate in penny equivalent, is that the accident took a toll on the health of Ukrainians. In this regard, the problem exists for both the current and future generations. The current relevance and necessity of investigating the traces of the accident at the Chernobyl nuclear power plant does not raise everyday doubts. Therefore, the development of environmental, medical, social and economical research will be sufficiently expanded on the scientific level and on the level of society. Today, tourists are increasingly interested in new types of tourism, which include unique tourist destinations, including those associated with manmade disasters. One of the worst man-made disasters in human history is the accident of 1986. At the Chornobyl Nuclear Power Plant there are some remarkable legacies to this day. For those who want to learn from their eyes and perceive the atmosphere of the legacy of this terrible catastrophe, there is more to come. The Chornobyl tourist route is popular among both foreign and domestic tourists. The legacy of the accident at the Chernobyl Nuclear Power Plant is complex and richly nuanced, and is being studied by a wide range of scientists – geographers, ecologists, economists, sociologists, etc. oh Ecological-geographical, landscape and medical-geographical aspects of the identified problems are developed in the scientific research of V. Baranovsky, D. Grodzinsky, V. Davidchuk, V. Dol Ina, M. Petrova, E. Sobotovicha, L. Sorokina, V. Shevchenko.

A PERMANENT MATHEMATICAL MODEL OF FILTRATION AND MIGRATION CONDITIONS BETWEEN THE PRIPYAT AND UZH RIVERS OF THE CHORNOBYL EXCLUSION ZONE

Background. Over the past 8–10 years, the radio-hydroecological and hydrogeological conditions of the Chornobyl Exclusion Zone have changed significantly. Under the influence of the decommissioning of the water-containing cooler, the levels, speed and direction of movement of groundwater have changed on a regional scale. New radiation-hazardous objects were created: Storage of spent nuclear fuel (SSNF-2) and Centralized storage of spent nuclear fuel (CSSNF). The impact of climate change on the regime of water bodies has also increased. To study the impact of radiation-hazardous objects on the water environment of the exclusion zone, to forecast changes in hydrogeological conditions under the influence of climate change and man-made loads, it is necessary to create an updated model of filtration and migration conditions with the possibility of its further adjustment and improvement. Methods. In creating and developing a constant mathematical model based on the finite difference method, the geological and hydrogeological conditions of the research area were considered. Spatial constructions were also carried out to visualize the geological structure using GIS technologies. The filtering scheme was drawn up for computational operations. The QGis program was used to construct the surfaces of geological horizons, and the Visual MODFLOW program was used to develop the filtration model. Results. A model of filtration and migration conditions of the Pripyat-Uzh interfluve of the Chornobyl Exclusion Zone was constructed. The distribution of groundwater levels and heads in the Buchach aquifer was obtained. Forecasts of the paths, directions and time limits of the spread of pollutants with underground water from radiation-hazardous objects have been made. We carried out forecasts of the impact of changes in the boundary conditions of the aquifer on the hydrodynamic parameters of groundwater to justify project decisions on improving the network of observation wells and determining the conditions of flooding of the Chornobyl nuclear power plant site. Forecasts of the impact of global warming on the underground water regime have been carried out. Conclusions. The forecast field of pressure distribution demonstrates the possibility of improving the radiological state of groundwater as a result of: increasing the thickness of the aeration zone and its sorption capacity and accelerating self-purification due to the growth of underground flow gradients. It is important that the unloading of polluted groundwater will not take place in the Pripyat River, but in the isolated residual lakes of the former cooling pond. It will take about 20 years for groundwater to reach the lakes from the Chornobyl nuclear power plant site.

RADIATION SITUATION IN THE CONTAMINATED TERRITORIES OF UKRAINE IN THE POST-CHORNOBYL PERIOD FROM 2013 TO 2022

Radiological tests analysis aimed to determine important issues regarding the safety of food products, feeds, medicinal herbs, etc., obtained from radioactively contaminated territories as a result of the accident at the Chornobyl nuclear power plant. The material for analysis was current documentation of the Regional State Laboratories of State Service of Ukraine on Food Safety and Consumers Protection in Zhytomyr, Volyn, Rivne, Chernihiv regions, Central Testing State Laboratory of State Service of Ukraine on Food Safety and Consumers Protection in Kyiv region and Kyiv city from 2013 to 2022. The analysis is conducted regarding contamination of food products, feeds, medicinal herbs, etc., with radionuclides 137Cs and 90Sr. The specialists of regional State Laboratories of State Service of Ukraine on Food Safety and Consumers Protection conducted 12 797 892 radiological tests, that showed 3 372 samples with higher than the permissible level content of 137Cs and 10 samples with higher than permissible level content of 90Sr. 137Cs is a main dose-forming radionuclide that has considerable influence on getting internal irradiation by population. There have been rare cases of contamination of food, feeds, and medicinal herbs with 90Sr. It was found that forest-based food (mushrooms, berries) – 62.1, milk – 22.7, meat of wild animals – 8.3, feeds – 1.8, and medicinal herbs – 0.8 had been mostly contaminated with 137Cs from the total number of samples with positive results for the specified period. Thus, analyzing the results of radiological tests over the past decade, it should be noted that even today, further radiological control of food products, feeds, etc. in radioactively contaminated territories is expedient and requires further implementation of anti-radiation protection actions established by current national legislation

VENTILATION CONTROL OF THE NEW SAFE CONFINEMENT OF THE CHORNOBYL NUCLEAR POWER PLANT BASED ON NEURO-FUZZY NETWORKS

The accident at the Chornobyl Nuclear Power Plant (ChNPP) in Ukraine in 1986 became one of the largest technological disasters in human history. During the accident cleanup, a special protective structure called the Shelter Object was built to isolate the destroyed reactor from the environment. However, the planned operational lifespan of the Shelter Object was only 30 years. Therefore, with the assistance of the international community, a new protective structure called the New Safe Confinement (NSC) was constructed and put into operation in 2019. The NSC is a large and complex system that relies on a significant number of various tools and subsystems to function. Due to temperature fluctuations and the influence of wind, hydraulic processes occur within the NSC, which can lead to the release of radioactive aerosols into the environment. The personnel of the NSC prevents these leaks, including through ventilation management. Considering the long planned operational term of the NSC, the development and improvement of information technologies for its process automation is a relevant task. The purpose of this paper is to develop a method for managing the ventilation system of the NSC based on neuro-fuzzy networks. An investigation of the current state of ventilation control in the NSC has been conducted, and automation tools for the process have been proposed. Using an adaptive neuro-fuzzy inference system (ANFIS) and statistical data on the NSC's operation, neuro-fuzzy models have been formed, which allows to calculate the expenses of the ventilation system using the Takagi-Sugeno method. The verification of the proposed approaches on a test data sample demonstrated sufficiently high accuracy of the calculations, confirming the potential practical utility in decision-making regarding NSC’s ventilation management. The results of this paper can be useful in the development of digital twins of the NSC for process management and personnel training.

Comorbid Conditions in Persons Exposed to Ionizing Radiation and Veterans of the Soviet-Afghan War: A Cohort Study in Kazakhstan.

This study investigated the prevalence and characteristics of comorbid conditions in patients exposed to ionizing radiation and those who were involved in the Soviet-Afghan war. This study analyzed the frequency and spectrum of morbidity and comorbidity in patients over a long-term period (30-35 years) following exposure to ionizing radiation at the Semipalatinsk nuclear test site or the Chornobyl nuclear power plant, and among participants of the Soviet-Afghan war. A cohort study, both prospective and retrospective, was conducted on 675 patients who underwent comprehensive examinations. Numerical data were analyzed using the Statistica 6 program. The results are presented as the mean±standard deviation, median, and interquartile range (25-75th percentiles). The statistical significance of between-group differences was assessed using the Student t-test and Pearson chi-square test. A p-value of less than 0.05 was considered statistically significant. We found a high prevalence of cardiovascular diseases, including hypertension (55.0%) and cardiac ischemia (32.9%); these rates exceeded the average for this age group in the general population. The cumulative impact of causal occupational, environmental, and ultra-high stress factors in the combat zone in participants of the Soviet-Afghan war, along with common conventional factors, contributed to the formation of a specific comorbidity structure. This necessitates a rational approach to identifying early predictors of cardiovascular events and central nervous system disorders, as well as pathognomonic clinical symptoms in this patient cohort. It also underscores the importance of selecting suitable methods and strategies for implementing treatment and prevention measures.

CHORNOBYL’S CURRENT DENDROFLORA: ANALYSIS OF NATURAL SUCCESSIONS IN THE ABANDONED URBAN PHYTOCOENOSES

The research on the dendroflora of Chornobyl town 30 years after the accident at the Chornobyl nuclear power plant reveal that the taxonomic composition of the town green spaces comprises of 87 species and 8 decorative forms of 29 families, 26 orders, 2 divisions. The composition of plantations is dominated by trees (63%), bushes (30%) and winding plants (7%). Despite the natural succession processes over the past 30 years, the plantations of Chornobyl are dominated by introducers, which make up 57% of the total number of taxa. The study of test areas reveals successional changes in the abandoned phytocoenoses of the town, which led to the expansion of the alien invasive species Acer negundo L., Robinia pseudoacacia L., Fraxinus pennsylvanica L. and Parthenocissus quinquefolia (L.) Planch. The spread of alien invasive species is facilitated by droughts of long periods and the decrease in groundwater level. Climate change and the lack of proper agrotechnical care result in fungal diseases, damages caused by the semi-parasitic species Viscum album L. on decorative and fruit trees and bushes, both also leading to their expel from the town plantations.

GIS-BASED LANDSCAPE MANAGEMENT OF THE UZH RIVER BASIN: A STRATEGY TO ENHANCE RIVER WATER QUALITY

The article includes the findings of a study on the Uzh River basin’s surface water’s quality. This region is extremely important because a fraction of it is radioactively contaminated because of the Chornobyl nuclear power plant accident. Considering this, the goal of this work was to conduct a geo-informational analysis of the state and structure of the landscapes of the Uzh River basin, to identify the surface water quality parameters of this region, and to identify potential correlations between these parameters. For this purpose, we spatially divided the territory of the basin into separate massifs, in each of which, using the method of automatic decoding, we determined the ratio of the structural components of landscapes, their disturbance by erosion processes, and compared them with ground data on the quality of surface water of the massifs. According to the salt composition, all the investigated massifs have good quality conditions. The Uzh River and its tributaries should be categorized as 4 (slightly polluted) based on the average values of the trophosaprobological state, but the extreme values in some places shifted to 5 (moderately polluted). Most of the listed toxic substances were present at average levels and, for the most part, did not exceed the permitted concentrations for category 4-slightly polluted. Extreme concentrations frequently reached category 6 (polluted), which was primarily brought on by anthropogenic activity and the buildup of radioactive materials. It was found that the degree of erosive landscape destruction and the degree of landscape stabilization significantly influence the value of the integrated water quality index. Since the collected data, a three-dimensional model was developed, allowing for accurate evaluations and projections of changes in the quality of surface water based on the structural characteristics of the land shafts. Considering that some of these territories are currently in the zone of radioactive contamination, the planning of changes in the landscape structure should be coordinated with the potential risks of surface water quality deterioration, and the model proposed in this article will have significant applied value in addressing this issue.

Psychological distress 35 years after the Chornobyl accident in the Lithuanian clean-up workers

ABSTRACT The adverse effects on the health of the Chornobyl nuclear power plant accident clean-up workers have been reported previously. However, there is a lack of studies on the mental health of Chornobyl clean-up workers. The current study explored psychological distress in a sample of Lithuanian clean-up workers 35 years after the accident. In total, 107 Lithuanian Chornobyl clean-up workers (Mage = 62.5) and 107 controls were included in the study. The Hospital Anxiety and Depression Scale (HAD) was used for the assessment of anxiety and depression. The depression symptoms were significantly higher in the clean-up workers compared to the control group. The prevalence of severe depression symptoms was 23.4% and 4.7% in the Chornobyl clean-up workers and control groups, respectively. The risk for severe depression was associated with Chornobyl clean-up work (adjusted OR = 5.9). No differences in the anxiety symptoms were found between clean-up workers and controls. The study revealed the deteriorated mental health of the Lithuanian Chornobyl clean-up workers 35 years after the disaster – in particular, high levels of depression. Psychosocial support programmes for clean-up workers should be provided to mitigate the adverse effects of the disaster.

Ecological Half-Life of 137Cs in Fish

In this study, the long-term (i.e., over a 27-year period) dynamics of 137Cs content are presented for seven species of fish in both the cooling pond (CP) of the Chornobyl Nuclear Power Plant and the Kaniv Reservoir (KR). The decline of 137Cs specific activity in fish exhibits various patterns. For certain years in the KR, fish belonging to different ecological groups experienced an increase rather than a decrease in specific activity levels of 137Cs. From 2012 to 2014, the concentration of 137Cs in all studied species in the KR ranged from 4 to 23 Bq/kg. In the CP during 2012–2013, fish still showed high contamination levels, ranging from 770 to 8300 Bq/kg. The ecological half-life (Teco) was determined for all the studied fish species. For most fish species (i.e., P. fluviatilis, B. bjoerkna, A. brama, S. lucioperca, A. aspius), the shortest 137Cs Teco values were obtained in the CP, being a highly radiocaesium-contaminated waterbody. In contrast, two fish species (R. rutilus and S. glanis) in the CP exhibited a considerably slower rate of 137Cs removal from their bodies compared to even the relatively cleaner KR. Moreover, the 137Cs Teco in R. rutilus and S. glanis was nearly twice as long as that observed in other species within the CP. We assume that the redistribution of 137Cs in the body of fish is affected by multidirectional mechanisms: accumulation, retention, and/or excretion. The functioning of these mechanisms can vary among different fish species. The observed level of 137Cs content in a particular fish species at a given time point results from the combined effects of these mechanisms. Fish likely have the ability to absorb and accumulate radiocaesium in their bodies selectively, and this demand appears to be species-specific.

Skeletal abnormalities in juvenile fish from the cooling pond of the Chornobyl nuclear power plant

Skeletal abnormalities in juvenile fish from the cooling pond of the Chornobyl nuclear power plant

Chornobyl radiation spikes are not due to military vehicles disturbing soil

On 25th February 2022, increased gamma radiation dose rates were reported within the Chornobyl Exclusion Zone (CEZ). This coincided with Russian military vehicles entering the Ukrainian part of the CEZ from neighbouring Belarus. It was speculated that contaminated soil resuspension by vehicle movements or a leak from the Chornobyl Nuclear Power Plant complex may explain these spikes in radiation dose rates. The gamma dose rate monitoring network in the CEZ provides a crucial early warning system for releases of radioactivity to the environment and is part of the international safeguards for nuclear facilities. With the potential for further military action in the CEZ and concerns over nuclear safety, it is essential that such anomalous readings are investigated. We evaluate the hypotheses suggested to explain the apparent gamma dose rate increases, demonstrating that neither military vehicle-induced soil resuspension nor a leak from the Chornobyl Nuclear Power Plant are plausible. However, disruption of the Chornobyl base-station's reception of wireless signals from the gamma dose rate monitoring network in the CEZ may potentially explain the dose rate increases recorded.

Numerical simulation of the radioactive contamination of Ukraine after the Chornobyl disaster: the influence of the input meteorological data on the results uncertainty

In this article we assess the sensitivity of the numerical simulations of the radioactive 137Cs contamination of Ukraine caused by the Chornobyl nuclear power plant accident in 1986 to the input meteorological data. The atmospheric transport, dispersion, and deposition (dry scavenging and rain washout) of the radioactive aerosols was simulated using the CALPUFF dispersion model. The source parameterization of the 137Cs emissions during the active phase of the catastrophe (26 April—May 5 of 1986) was adopted from the previously published literature results. Seventeen different versions/realizations of the input meteorology for CALPUFF simulations were prepared with the regional prognostic meteorological model WRF by combining the available global atmospheric reanalyses for 1986 (NNRP, ERA-Interim, ERA5, CFSR) and the model’s physical parameterizations (microphysics, radiation processes, boundary/surface layer physics). The assessment of the simulation uncertainty was carried out in two different ways. In the first approach, the uncertainty was estimated as the width of the distribution of the calculated 137Cs surface concentrations (adjusted to the logarithmic scale), which were obtained with different versions of the input meteorology. The second approach was based on the statistical comparison of the calculated 137Cs contaminations and the corresponding measured values obtained during a complex assessment of the aftermath of the disaster made at the beginning of 1990s. Two statistical metrics were used: the geometric mean bias and the geometric mean variance. The results of our study demonstrate that even when using somewhat unified meteorological data (atmospheric reanalysis), the results of the radioactive contamination calculations at the same spatial locations can differ by several orders of magnitude. We find that the uncertainty depends not only on the distance to the source of the emissions but also on the physical mechanism (wet or dry deposition) responsible for the formation of the local contamination

Circulation of 137Cs in Various Forest Plants in the Chornobyl Exclusion Zone during the Year

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.