Contamination Density Research Articles

ОГЛЯД РЕЗУЛЬТАТІВ ДОСЛІДЖЕНЬ ЗАБРУДНЕННЯ КАХОВСЬКОГО ВОДОСХОВИЩА ЦЕЗІЄМ-137 І СТРОНЦІЄМ-90, ЯКІ ПРОВОДИЛИСЬ ПІСЛЯ АВАРІЇ НА ЧОРНОБИЛЬСЬКІЙ АЕС (1986-1921 РР.)

The available data on the state of radioactive contamination of water and bottom sediments of the Kakhovka Reservoir were analyzed in order to assess the possible deterioration of the quality of the environment based on the indicators of radioactive contamination in the zone of influence of the emergency discharge of water due to destruction of the Kakhovka NPP dam by the Russian military. Contamination of the Kakhovka Reservoir with 137Cs occurred mainly through the fallouts of this radionuclide with aerosols on the water surface in May 1986. A much smaller part of this radionuclide transported by water runoff directly from the headwaters of the Dnieper basin. Strontium-90 entered the reservoir exclusively by water pathway starting from October 1986. The steady trends of decreasing activity of both radionuclides in water has been observed since 1987. Approximately to 1996 137Cs activity concentrations had decreased to pre-accident level, 90Sr activity demonstrated a slow decrease and by 2022 remained slightly higher than pre-accidental level. The average levels of contamination of the Kakhovka reservoir bottom with 137Cs and 90Sr turned out to be the lowest compared to the other reservoirs of the Dnieper cascade. It was shown that in 1994 137Cs activity levels were 0.06 Ci/km2(2,2 kBq/m2) on 80% of the bottom surface (submerged former floodplain of the Dnieper) and were lower than on the territory adjacent to the reservoir. In the areas of silt accumulation (former channel of the Dnieper) 137Cs activity was on average three times higher. Balance calculations based on the data of radiation monitoring of water showed that the amount of 137Cs activity in the bottom sediments in the period 1987-2022 halved due to natural radioactive decay, the amount of 90Sr activity decreased by approximately 20%, since activity losses due to natural radioactive decay were partially compensated by the constant supply of this radionuclide with water runoff from the contaminated part of the catchment. After a catastrophic water leak from the reservoir, the Dnieper floodplain had exposed. According to the calculations, the average density of soil contamination of the ехposed areas with 137Cs does not exceed 0.03 Ci/km2 (1,1 kBq/m2), with 90Sr – less than 0.1 Ci/km2 (3,7 kBq/m2). Silt deposits of the former Dnieper channel, which had an increased level of 137Cs contamination, were re-suspended, probably, and carried out into the Dnipro-Bug estuary and further into the Black Sea. However, according to our assumptions, this should not have a negative effect on the radioecological state of the sea, because the 137Cs activity concentrations in the water of north-western part of the Black Sea were always 20-30 times higher than in the Dnieper water.

Сучасний радіологічний стан орних угідь Народицької об'єднаної територіальної громади

Current radiological conditions and the possibility of returning to economic use of radionuclide-contaminated agricultural lands of the Narodychi United Territorial Community of the Korosten District of the Zhytomyr Region were assessed. The lands had been withdrawn from use in accordance with the Law of Ukraine "On the Legal Regime of the Territory Exposed to Radioactive Contamination as a Result of the Chornobyl Disaster" (Law) and marked in the State Land Cadastre of Ukraine as "radioactively contaminated land". It is shown that in accordance with the requirements of the Law on soil contamination density with 137Cs, 90Sr, 238-240Pu the lands currently do not belong to the zone of unconditional (mandatory) resettlement and even the zone of guaranteed voluntary resettlement and have no legal grounds for restrictions on their use. Predictive assessment of contamination of crops with 137Cs and 90Sr growing on the considered fields was performed. The assessments show which from the fields can be used to produce without countermeasure products below the permissible levels.

Content and Distribution of Radionuclides in the Profile of Light Gray Forest Soil and Agrocenosis Plants

The results of long-term radiation monitoring of light gray forest soil and cultivated plants of the reference area are presented. Correlation analysis has determined the relationship between the distribution of artificial and natural radionuclides in the soil profile with its agrochemical properties. The distribution of radionuclides in the soil profile is determined by the intensity of the podzolic process. The profile shows the eluvial-illuvial differentiation of radionuclides, when an increase in their accumulation occurred in the illuvial horizon. According to the density of contamination of the surface soil layer with cesium-137 and strontium-90, a satisfactory level of the environmental situation was determined, according to which the soil of the site is classified as uncontaminated. Rows of cultivated plants with an increasing ability to accumulate caesium-137 and strontium-90 from the soil have been constructed. The grain of all grain crops accumulated less cesium-137 and strontium-90 compared to straw. All grown plant products of all types of crops fully met veterinary and hygienic standards for the content of caesium-137 and strontium-90 in feed (green mass, straw and feed grain) and food grains. The coefficients of accumulation and transfer of caesium-137 and strontium-90 from soil to plants were calculated.

Accumulation Radiocesium (137cs) By Plants of the Dnipro River’s Floodplain Ecosystems after Chernobyl Contamination

The analysis of radiocesium (137Cs) accumulation by plants of forest, marsh, meadow, psamophytic, and ruderal communities in the Dnipro River floodplain (Ukraine) was carried out. The species specificity of radiocesium accumulation by plants of specific biotopes and the direct dependence of the plant accumulation coefficient on the density of biotope contamination with radionuclides were confirmed. Differences in different radiocesium accumulation by plants of different ecosystems are probably related to the fact that the bioavailability of radiocesium strongly depends on soil properties. In the analyzed statistical model, the processes of accumulation and dissipation of 137Cs are significant.

Results of modern radiation-hygienic surveys of settlements of Bryansk Oblast of the Russian Federation bordering the Republic of Belarus. Part 3: Radionuclide content in agricultural food products

The third article in a series of publications devoted to the results of studying the current radiation situation in the territories of the Bryansk region bordering the Republic of Belarus presents results of studies of the content of radionuclides (137Cs and 90Sr) in samples of agricultural food products produced in the personal subsidiary plots of the population. The regularities of changing 137Cs and 90Sr content in samples of cow’s milk and potatoes depending on the level of radioactive contamination of the territory were studied; the present values of the quantities characterizing the distribution of the ratio of the activity concentration of radionuclides in agricultural food products to the density of radioactive contamination of the soil of the territory were deter -mined. The ratios of average values of 137Cs activity concentration in milk from stalled and grazing periods for cattle were analyzed. The results of the study show that some dairy product samples (less than 1%) do not meet the radiological safety criterion. Exceedances of the hygienic standards were not found in the studied samples of potatoes, vegetables, and meat of farm animals.

Dense Contaminants Mixing Into the Saltwater Wedge in Coastal Aquifers: Laboratory and Numerical Investigations

AbstractThe saltwater‐freshwater mixing zones in coastal aquifers can host complex physical exchange and biogeochemical transformations. The land‐sourced dense contaminant plumes could be transferred into the mixing zone of the saltwater wedge due to the density effect prior to discharge to the sea. However, the mixing process between dense contaminants and the saltwater wedge has not received much attention, largely due to the lack of physical evidence. This study used laboratory experiments and numerical simulations to investigate the transport and discharge behaviors of variable‐density contaminant plumes in tidally influenced unconfined coastal aquifers. Results demonstrate that the highly dense contaminants mix with the underlying saltwater and finally merge with the saltwater wedge. This process significantly extends the contaminant discharge durations, thereby reducing the peak value of contaminant efflux. The dense contaminants are elongated along the landward margin of the saltwater wedge, leading to a larger spreading area (Ms) than that of constant‐density contaminants. The sensitivity analysis indicates that the high density of contaminants acts as a trigger to induce the mixing of them and wedges. The higher hydraulic conductivity, lower dispersivities and reduced inland freshwater flux significantly increase the residence times (Rt) and discharge duration (Dt) by enhancing the mixing of dense contaminants with seawater. In contrast, both Rt and Dt values are not only non‐monotonic functions of tidal amplitudes but also less sensitive to tidal effects. Compared with the non‐tidal condition, however, the addition of tides significantly increases both Rt and Ms values of dense contaminant plumes. The results presented herein provide valuable insights into the mechanisms of dense contaminants mixing into saltwater wedges, which could guide practitioners in designing effective strategies to protect coastal environments from land‐sourced contaminants.

Absolute Method for Measuring Environmental Radioactive Materials Using Imaging Plates

Abstract We had previously developed a measurement method using an imaging plate (IP) to evaluate and address surface contamination caused by the release of radioactive materials during the Fukushima nuclear accident. The measurement units for the surface contamination density were in relative values [described as relative luminescence levels measured in luminescence arbitrary units (LAU)], but the evaluation was required in absolute values, such as Bq cm−2, to enable appropriate control of exposure doses. This study establishes a method for converting the IP measurements of surface contamination density due to environmental radioactivity into absolute values. Soil contaminated with radioactive materials from the Fukushima nuclear accident was collected to create a working reference material (WRM). The conversion coefficient for surface contamination density was calculated using the WRM values measured with an IP and high-purity germanium detectors. The IP measurement values were converted into the surface contamination density using the conversion coefficient. The WRM values measured with the IP and high-purity germanium detectors were 324.1 LAU and 32.22 ± 2.27 Bq cm−2, respectively. The surface contamination density conversion factor was calculated as 0.0994. The surface contamination density on the roof of the Tsukuba City facility was re-evaluated using the conversion factor. The average value of 29,972 Bq m−2 matched the amount of radioactive material fallen in Tsukuba City. By standardizing the measurement conditions for surface contamination when using IPs, we successfully quantified the surface contamination density with an accuracy comparable to that of conventional methods. This method is expected to make a significant contribution to efficient radiation safety management.

Features of the modern distribution of 137Cs in soils under overmoistened growth conditions of black alder forests in Zhytomyr Polissia, Ukraine

Research on the modern distribution of 137Cs in soils of different forest site types in black alder (Alnus glutinosa (L.) Gaerth.) stands was conducted. In forest litter, there is not a high percentage of its total activity in soil: in moist fairly fertile site type (C3) – 13.4 %, damp fairly fertile site type (C4) – 16.3 %, and wet fairly fertile site type (C5) – 3.8 %. The mineral part of the soil in moist and damp fairly fertile site type is characterized by decreased density of radioactive contamination of soil layers with depth. In wet fairly fertile site type, this indicator increases to a depth of 6 - 8 cm and decreases with further deepening. A 10-cm layer of moist fairly fertile site type (C3) contains 61.8 % of the total radionuclide activity in soil, damp fairly fertile site type (C4) – 68.1%, and wet fairly fertile site type (C5) – 70.1 %, correspondingly; a 20-cm layer has 75.4, 78.3, 91.9 % and a 30-cm layer – 80.9, 82.2, 96.0 % of the total radionuclide activity.

Experience of using the portable gamma spectrometer MKS AT6101D for in situ measurements of the density of <sup>137</sup>Cs soil contamination in the Bryansk region of Russia

We have tested applicability of the commercially available portable spectrometer-dosimeter MKS AT6101D (the manufacturer: ATOMTEX, Belarus) to measure the density of 137Cs soil contamination (inventory of 137Cs in soil) in situ. The study was performed in 2015–2020 at the territories of the Bryansk region of Russia contaminated due to the Chernobyl accident. The in situ measurements were performed in the 17 ground plots (7 grasslands and 10 kitchengargens) for which the 137Cs inventory and the mean migration depth of the radionuclide in soil was available from laboratory (ex situ) measurements of soil samples. It was found that the in situ data obtained with the method that was provided by the manufacturer of the instrument required additional correction on the vertical distribution of 137Cs in the soil. The correction procedure was developed; in 2020–2021, it has been successfully tested in 114 kitchengarden plots located at the settlements in the zones of radioactive contamination in the Bryansk region.

Current status of reference location in the basic model for assessment of external radiation doses to the population living in radioactively contaminated areas after the Chernobyl accident

An open plot of virgin land is the reference location in the basic model used to date to estimate the effective dose of external exposure to the population living in a radioactively contaminated area. As our field observations in the Bryansk region of Russia have shown, at present it is very difficult to find truly reference plots of virgin land due to the fact that many virgin meadows were plowed or reclaimed for more than 30 years after the Chernobyl accident. Without special instrumental survey, such disturbed meadow areas can easily be confused with areas of virgin soil. Therefore, the situation with the use of open areas of virgin soil as the reference location has changed dramatically since the first years after the Chernobyl accident. It requires a change in the approach to choosing such a location for the model and/or some revision of the structure of the model itself. Firstly, we propose and justify the use of a permanently cultivated kitchengarden plot as the reference location. The second way to resolve the current difficult situation with the presence of a sufficient number of the virgin soil sites could be excluding the very concept of “reference location” from the model. In this case, when calculating the effective dose of external radiation, it is proposed to directly use the values of the gamma radiation dose rate in the air normalized to the 137Cs contamination density of soil. The values of the normalized dose rate should be experimentally determined in the required time period for each of the locations taken into account in the model.

Побудова картосхем щільності забруднення 137Cs сільськогосподарських угідь за сукупністю результатів обстеження

A methodology for mapping the density of 137Cs contamination of agricultural land is proposed and tested. The methodology is based on data on gamma-dose rate measurements, gamma-logging results, and direct determination of 137Cs in soil samples, which were obtained by different organizations in different years. It allows to generalize all available information on 137Cs contamination of the lands and significantly improves the representativeness of estimates of the spatial distribution of the radionuclides at the mapping.

Dynamics of radioactive contamination of lingonberry (Vaccinium vitis-idaea L.) in the forests of Zhytomyr Polissia (Ukraine) since the Chernobyl Nuclear Accident

The article presents results of study of levels of radioactive soil contamination and 137Cs activity concentration in the aboveground part of lingonberry (Vaccinium vitis-idaea L.) phytomass and berries on permanent experimental plots in different years since the Chernobyl Nuclear Power Plant accident (forest site type conditions — moist fairly infertile pine site type (B3), soils — soddy-podzolic sandy-loam on fluvioglacial sands). The research was conducted at the Poliskyi Branch of the Ukrainian Research Institute of Forestry and Forest Melioration named after G.M. Vysotsky over the years 1998–2021, utilized methods generally accepted in forest science and radioecology were used. Results were processed using statistical analysis. To substantiate the research, an official reporting data from forestry enterprises of the Volyn, Rivne and Zhytomyr regions were used. An analytical review of the state of research on this problem revealed that at the last 10–15 years there were no scientific publications on the study of 137Cs contamination of lingonberry. It was demonstrated that there was significant reduction in the density of radioactive soil contamination and 137Cs activity concentration in the aboveground part of lingonberry phytomass and berries in the forests of the research region over the observation period. It was found that the main part of the total 137Cs activity is currently located in the upper (10 cm) layer of the mineral part of the soil — 74.7% where root systems of herbaceous and dwarf-shrub species are concentrated in forest ecosystems. It was established that a considerable content of the radionuclide is retained in the aboveground part of lingonberry phytomass even with low density of radioactive soil contamination. It was found that in 1998, at relatively low value of soil 137Cs contamination density (49±5.6 kBq∙m–2), specific activity of 137Cs in aboveground phytomass of lingonberry was 8043±511 Bq∙kg–1, while in 2021 (value of soil 137Cs contamination density 22±0.3 kBq∙m–2) — 1046±182 Bq∙kg–1. The values of radionuclide transfer coefficients in 1998 were quite significant and varied within wide range: in the air-dry aboveground phytomass from 33.4 to 164.1 m2∙kg–1∙10–3 and in the fresh berries, from 9.5 to 26.0 m2∙kg–1∙10–3. Dependencies between density of radioactive soil contamination and the content of 137Cs in the aboveground part of lingonberry phytomass and berries were calculated, which can be applied in the practice of their harvesting. It was found that lingonberry belongs to the group of plants characterized by the high content of 137Cs in the aboveground vegetative phytomass. Harvesting of lingonberry leaves for the production of medicinal products should be restricted in all areas contaminated with 137Cs. Lingonberry fresh berries can be harvested in areas with a radioactive soil contamination density up to 74 kBq∙m–2.

Development of contamination detection system combined with various remote devices

The detection of alpha and beta contamination locations is important for decontaminating nuclear facilities. In the high radiation dose rate environment at the decommissioning sites, the contamination measurement by the workers is not effective. Thus, we developed a remote automatic contamination measurement system using a new scintillator-based detector. A 50 mmφ × 100-μm-thick YAlO3(Ce)(YAP:Ce) scintillator was coupled with a flat panel-type multianode photomultiplier tube. The detector was installed downwards at the bottom of a robot. It has an energy measurement capability, and the energy measurement could discriminate the alpha particles from the beta and 222Rn alpha particles. With the energy information, alpha and beta particles could be identified and mapped simultaneously. In addition, a slow-moving robot could be used to obtain statistically sufficient counts in a single run measurement, allowing the evaluation of surface contamination density using only alpha particles. The remote automatic contamination measurement system will be useful in visualizing the contamination distribution in environments that are inaccessible to workers.

CURRENT RADIOLOGICAL STATUS OF CONTAMINATED MEADOWS AND PASTURES AND ASSESSMENT OF THE POSSIBILITY OF THEIR RETURN TO USE

Meadows and pastures are the fodder base for milk and meat production. The rehabilitation and return to economic use of the radionuclide-contaminated meadows and pastures is an important and urgent national economic task. The criterion of returning radionuclide-contaminated meadows and pastures to economic use may be individual doses to residents who consume milk and meat produced on these lands. Values that determine the doses are the terrestrial density of soil contamination and permissible levels of radionuclides in food products (PL-2006). Considering abandoned agricultural lands, it is necessary to note the time that passed after the accident. The contamination of the territory by 137Cs and 90Sr decreased in more than 2 times due to radioactive decay only. The decreasing due to radioactive decay and self-remediation processes (fixation of radionuclides by soil, their redistribution in the root layer of the soil, etc.) resulted in declining of radioactive contamination of products. This allows us to consider the issue of returning reclaimed lands to use in accordance with the current radiological criteria and existing legal acts. Agricultural lands are a territorial resource and the main means of agricultural production, therefore the rehabilitation of the lands will contribute to the development of both individual producers and settlements as a whole. After the Chornobyl accident, in accordance with the Law of Ukraine "On the Legal Regime of the Territory Exposed to Radioactive Contamination Due the Chornobyl Catastrophe", the territory exposed to radioactive contamination had been divided into zones. However, the belonging of the lands to a zone does not guarantee that the products produced there will meet the requirements of PL-2006. Therefore, in 1998, taking into account the type of soil, the UIAR assessed the maximum permissible levels of soil contamination which ensure the fulfillment of the requirements of PL-2006 in terms of the content of 137Cs in produced products. However, in the 25 years that have passed since the establishment of these levels and the cesium transfer factors into plants have decreased significantly. Therefore, the values of the maximum permissible levels of soil contamination are conservative and their use leads to conservative conclusions. The current radiological state of meadows and pastures contaminated with radionuclides and the possibility of returning them to use were assessed. It is shown that most of the considered abandoned lands actually belong to the third zone of radioactive contamination. Some of the lands belong to the second zone of radioactive contamination - radiation-hazardous lands. It was found that the restrictions set in the recommendations for conducting agriculture in the conditions of radioactive contamination for the production of milk and meat are very conservative. Assessment of the possibility of using contaminated meadows and pastures for milk and meat production requires more precise and targeted forecasting methods.

Effect of plant growth regulators on accumulation of radiocaesium in potato tubers

An important place among the problems of modern agriculture is occupied by the problems of rational use and protection of land and the ecologically dangerous state of the environment. The Zhytomyr region is one of the most affected by the accident at the Chernobyl nuclear power plant. A significant part of agricultural land has a density of contamination with cesium-137 up to 5 Ki/km2, which is 75 % of all contaminated land in the districts, about 20 % of agricultural land has a density of contamination from 5 to 15 Ki/km2, 5 % – above 15 Ki/km2. On lands with a higher density of pollution, it is necessary to apply a complex of agrochemical, agrotechnical and organizational measures to reduce the transfer of radionuclides from the soil to plants. Solving problems related to farming in radioactively contaminated territories occupies one of the leading places in the complex of measures to mitigate the consequences of the Chernobyl accident. The purpose of the research was to establish the effect of different doses and types of plant growth regulators on the productivity of potatoes, the level of radioactive contamination in the agro-ecological conditions of Polissia. Our research was carried out in the agro-ecological conditions of Polіssia LLC. Councilors of Ovrutsky district of Zhytomyr region. The transition of the radioactive isotope cesium-137 from the soil to the plants depends on the content of exchangeable potassium in the soil, the saturation of the soil-absorbing complex with bases, the reaction of the soil solution, the bonification of the soil, and the content of humus. When the agrochemical parameters of the soil improved, in particular when the content of exchangeable potassium in the soil increased from 2.3 mg/100 g of soil to 14.8 mg/100 g of soil, the specific activity of radiocesium in plants de-creased by 3.4 times. The results of our research show that the foliar treatment of potato plants with Biosil and Poteitin contributed to a decrease in the specific activity of tubers from 29.2 to 6.4–2.1 Bq/kg. It was established that foliar spraying of potato plants with Biosil and Poteitin contributed to the reduction of the coefficient of 137Cs transition to 0.03 and 0.01.

Geometry factor for in-situ soil contamination density estimation

A method is proposed for estimating the density of soil contamination with gamma-emitting radionuclides (Bc·m-2) in situ (in the field without sampling). The method allows to take into account the peculiarities of the distribution of radionuclides along the soil profile at a given site by the ratio of scattered and non-scattered photon fluxes. The scope of application has been expanded and the uncertainty of the previously developed method used for radiological examination of agricultural lands contaminated with 137Cs without sampling has been reduced. The proposed method of remote assessment of the pollution density practically does not introduce an additional error in comparison with the traditional method, which includes soil sampling and subsequent analysis in laboratory conditions. The duration of the spectrum set and its automatic processing at a 137Cs contamination density of more than 100 kBq·m-2 does not exceed 1 min.

Estimated 137Cs Radioactivity in the Gap Between the Top and Middle Covers at a Shield Plug in the Fukushima Daiichi Nuclear Power Station Unit 2

The contamination density of 137Cs deposited in the gap between the top and middle covers of the shield plug in the Fukushima Daiichi Nuclear Power Station Unit 2 was estimated using three types of measurement results. Owing to the extremely high dose rate on the entire operation floor, including the top of the shield plug, only remotely measured dose rates, such as ambient dose equivalent rates, were obtained using robots. Based on three types of measurements, significantly higher concentrations of 137Cs were observed than previously estimated. An estimation based on the measurements of the ambient dose equivalent rate inside the hole also demonstrated that the contamination density in the gap between the top and middle covers varied significantly at different positions of the cover. The results obtained will significantly aid in future decommissioning scenarios, and will be important for examining the progress of an accident.

Stability of blood lead levels in children with low-level lead absorption.

Current child blood lead (Pb) screening guidelines assume that blood lead levels (BLLs) are relatively stable over time, and that only youngest children are vulnerable to the damaging effects of lower-range BLLs. This study aimed to test the stability of lower-range (≤ 10 μg/dL) child BLLs over time, and whether lower-range BLLs diminished with age among children aged 6 months to 16 years living in a lower-income neighborhood with a density of pre-1986 housing and legacy contamination. Age, sex, family income, age of residence, and/or residence proximity to point sources of Pb, were tested as potential additional factors. Capillary blood samples from 193 children were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Multiple imputation was used to simulate missing data for 3 blood tests for each child. Integrated Growth Curve models with Test Wave as a random effect were used to test BLL variability over time. Among N = 193 children tested, at Time 1 testing, 8.7% had the BLLs ≥ 5 μg/dL (CDC "elevated" BLL reference value at the time of data collection) and 16.8% had BLLs ≥ 3.5 μg/dL (2021 CDC "elevated" BLL reference value). Modeling with time as a random effect showed that the variability of BLLs were attributable to changes within children. Moreover, time was not a significant predictor of child BLLs over 18 months. A sex by age interaction suggested that BLLs diminished with age only among males. Of the additional environmental factors tested, only proximity to a major source of industrial or vehicle exhaust pollution predicted child BLL variability, and was associated with a small, but significant BLL increase (0.22 μg/dL). These findings suggest that one or two BLL tests for only infants or toddlers are insufficient for identifying children with Pb poisoning.

Methods for express assessment of the radiation situation using a mobile laboratory in emergency situations

Methods for express assessment of the radiation situation in situ with the use of a mobile laboratory have been developed. During making decisions on protective measures application in the acute period of a radiological accident, the proposed methods make it possible to promptly assess the values of the volumetric activity of air in the breathing zone (Bq·m-3) and the contamination density of the territory with gamma-emitting radionuclides (Bq·m-2). These methods also allow to determine the activity (Bq) of the detected local radiation source. The scope of application has been expanded and the uncertainty of the previously developed method used for radiological survey of agricultural lands contaminated with cesium-137 without sampling has been reduced. It has been established that in the presence of not only caesium-137, but also caesium-134, cobalt-60, and iodine-131 on the radioactive trace, the proposed methodological approach makes it possible to quickly select the appropriate spectral regions for each pollutant and calibrate the detection units for the current radionuclide composition.

Influence of daily feeding ration of cattle on the transfer of 137Cs and 90Sr to animal organisms and manure in the agroecosystems of Central Forest-Steppe

The ration of feeding for large cattle was investigated and analyzed in terms of the transfer of 137Cs and 90Sr to muscle tissue, bones, milk, and manure biomass. The specific activity of radionuclides 137Cs and 90Sr was determined in the daily feeding ration of animals. It was found that the soil contamination density of 137Cs at the «Nadiya» farm ranged from 104.2 to 396.5 Bq/m2, while for 90Sr, it ranged from 9.4 to 36.2 Bq/m2. The fields at the «Ivanivske» farm had soil contamination densities of 137Cs ranging from 37.5 to 283.6 Bq/m2 and 90Sr ranging from 7.4 to 32.1 Bq/m2. The soil contamination density of 137Cs at the NNDC BNAU ranged from 4.18 to 8.66 Bq/m2, while for 90Sr, it ranged from 0.44 to 0.88 Bq/m2. The results of the ration assessment indicate that the average daily intake of 137Cs from feed into the animal’s body at the «Nadiya» farm was 375.3±84.2 Bq/kg, and for 90Sr, it was 345.1±98.2 Bq/kg. Significantly lower amounts of radionuclides from the ration entered the animals’ bodies at the «Ivanivske» farm, with an average daily intake of 137Cs at 174.9 Bq/kg and 90Sr at 236.0 Bq/kg. The lowest transfer coefficients of 137Cs and 90Sr from the daily ration to the body were observed at the NNDC BNAU, with 8.56 Bq for 137Cs and 9.69 Bq for 90Sr. It was determined that, overall, the muscle tissue of animals received 6.37% of 137Cs and 0.06% of 90Sr from the ration at the «Nadiya» farm; 2.0% of 137Cs and 0.02% of 90Sr at the «Ivanivske» farm, and 2.22% of 137Cs at the NNDC BNAU. In the case of bones, it was 6.47% of 90Sr at the «Nadiya» farm; 5.47% of 90Sr at the «Ivanivske» farm, and 0.41% of 90Sr at the NNDC BNAU. The obtained results confirmed that 137Cs is capable of evenly accumulating in all organs of the animal, while 90Sr selectively or predominantly accumulates in specific organs. It was established that under conditions of prolonged intake of radionuclides through the ration into the body of large cattle, 85–90% is excreted with the manure biomass.