This article presents research findings on tritium (3H) in plants at the Semipalatinsk Test Site (STS), including the perimeter of the 'Degelen' site, the riverside zone of the Shagan River, and a conditionally 'background' area-the southeastern part of the STS (SEP). The 3H content in plants was determined in tritiated free water (TFWT) and organically bound 3H (OBT). Plant samples were measured using an ultra-low-level liquid scintillation spectrometer. Maximum 3H concentrations in plants were detected at the 'Degelen' site (TFWT up to 51 ± 5 kBq/kg, ОBТ up to 15 ± 1 kBq/kg) and Shagan River (TFWT up to 39 ± 4 kBq/kg, ОBТ up to 13 ± 1 kBq/kg). The presence of 3H was recorded not only at underground nuclear sites but also in the conditionally 'background' area (TFWT up to 0.18 ± 0.02 kBq/kg, ОBТ up to 0.088 ± 0.028 kBq/kg). Research suggests that water plays a key role in 3H migration processes in the natural system of interest. The OBT/TFWT values for the study area varied on average from 0.3 to 0.7. The dose rate of internal irradiation of the studied plants varied from 6.3 × 10-6 (SEP) to 1.2 × 10-2 µGy/day (at the boundary of the 'Degelen' site), which is significantly lower than the safe exposure level for biota.

Experimental studies were carried out to evaluate the efficiency of fractional separation of radioactively contaminated soils with respect to gamma-emitting 137Cs and 241Am. The research was conducted using samples from radiation-hazardous objects (craters) located at the Semipalatinsk Nuclear Test Site and resulted from ground and excavation nuclear explosions. The most appropriate parameter reflecting the distribution pattern of artificial radionuclides 137Cs and 241Am across soil fractions resulting from nuclear blasts is the enrichment factor (Ef). Dry fractional separation can be recommended as a promising method for the decontamination of soils contaminated with cesium.

This paper presents research data on water contamination levels of artificial radionuclides and heavy metals in Karabulak Creek at the Semipalatinsk Test Site. The uranium isotopic composition has been studied (235U and 238U). Priority contaminants and the most 'contaminated' sections of the Karabulak creek were identified, and water quality-related indicators were also estimated. The environmental situation around Karabulak Creek at the «Degelen» site-at which underground nuclear tests have been conducted-was found to be unique and attributed to the combined effect of man-made radiation and natural factors and, in particular, to geochemical features of the region.

Tritium (3H) remains a prominent radionuclide detected in notable quantities in all environmental compartments of the Semipalatinsk Test Site (STS). This study presents data describing the levels of 3H travel in areas of the impact zones of radioactively contaminated STS locations - the Degelen site. Water, soil, sediments, air, and fluorite ore (Karadzhanly deposit product) 3H activity concentrations (including the speciation) were measured using liquid scintillation with spectrometric equipment "TRI-CARB 2900 TR" (PerkinElmer, USA). Plant samples were measured using "QUANTULUS 1220" (PerkinElmer, USA). Plant samples were measured using "QUAN-TULUS 1220" (PerkinElmer, USA). The high values were set in free water 3H in plants (TFWT)-up to 41 kBq/kg, in soils and bottom sediments (TSAW)-29 and 26 kBq/kg, respectively. The main source of 3H entering the environmental components is groundwater-up to 78 kBq/kg. Annual effective internal dose from 3H to personnel during operations at the Karadzhally fluorite deposit does not exceed Standards.

Despite the closure of the Semipalatinsk nuclear test site (STS) more than 30 years ago, the removal of radioactive contamination beyond the “Degelen” test site by water continues. Therefore, assessing the water resources formation at this test site is highly relevant, including for predicting the development of the radiation situation at the STS. In this case, isotope hydrology is the most promising method for understanding these processes. The aquatic environment at the “Degelen” test site consists of radioactively contaminated tunnel water, streams, and groundwater. The article presents the research results of the aquatic environment of the “Degelen” test site using the method of isotope hydrology with determination of stable isotopes of hydrogen and oxygen. The determination of the 3H concentration and the chemical composition of water were also determined. The analysis of the isotopic composition (δ2H, δ18O) of water showed that the tunnel and stream water are formed by precipitation (snow and rain). In summer, when precipitation is low, the condensation water significantly contributes to the recharge of “Degelen” test site water. The high radionuclide content of tunnel water leads to contamination to a greater extent of stream water, and, to the lesser extent, and groundwater. The 3H content in tunnel water can reach 260 kBq/L, in stream water – 58 kBq/L, which exceeds the standards established in the Republic of Kazakhstan.

This study aimed to assess the activity contamination levels and transfer of artificial radionuclides (241Am, 137Cs, 90Sr, and 239+240Pu) from soils to plants at underground nuclear test borehole locations in the Sary-Uzen site of the Semipalatinsk Test Site. Soil and vegetation samples were collected near warfare boreholes with different contamination patterns, conditionally "background" areas, and fallout plume sites. Peak activity concentrations in soils were recorded near borehole No. 102 for 137Cs and near borehole No. 215 for 241Am, 90Sr, and 239+240Pu. In plants, the highest 137Cs and 90Sr were observed near borehole No. 102, and that of 241Am and 239+240Pu near borehole No. 215. Transfer factors indicated that plant uptake followed the order: 90Sr > 137Cs > 239+240Pu > 241Am. Littoral-aquatic plants accumulated more 90Sr, whereas terrestrial plants accumulated more 239+240Pu. The maximum total exposure dose rate to vegetation reached 74 µGy/day. These findings highlight the influence of test type and contamination pattern on radionuclide behavior in ecosystems and provide a basis for radiological risk assessment in former nuclear test areas.

Despite the closure of the Semipalatinsk nuclear test site (STS) more than 30 years ago, water continues to transport radioactive contamination beyond the boundaries of the "Degelen" test site. Therefore, assessing the formation of water resources at this test site is highly relevant, particularly in terms of forecasting the development of radioactive contamination at the STS. In this case, isotope hydrology is the most promising method for understanding these processes. The aquatic environment at the "Degelen" test site consists of radioactively contaminated tunnel water, streams, and groundwater. This paper presents the research results regarding the determination of stable isotopes of hydrogen and oxygen for the aquatic environment of the "Degelen" test site. 3H concentrations and the chemical composition of water at the site were also determined. Analysis of the water's isotopic composition (delta 2H and delta 18O) showed that the tunnel and stream water are formed by precipitation (snowmelt and rain). In summer, when precipitation is low, atmospheric condensation contributes significantly to recharge at the "Degelen" test site. The high radionuclide content of tunnel water leads to the contamination of stream water, and, to a lesser extent, groundwater. The 3H content of tunnel water can reach 260 kBq/L, and that of stream water can reach 58 kBq/L, both of which exceed the established standards in the Republic of Kazakhstan.

In this study, we present radiometric measurements near the mothballed Grachevskoye uranium mining facility (MUMF) and the settlement of Saumalkol, located in northeast Kazakhstan. A pedestrian gamma spectrometric survey was conducted at locations of elevated gamma radiation. Spots with elevated gross activity values were detected in the northern part of the settlement and on a motor road. The pathways of radionuclides from the Grachevskoye MUMF to the area around the Saumalkol settlement were addressed. The migration ability of radionuclides and the process of radionuclide transport by ambient air did not have significant effects on the progression of the radioecological situation in the village. However, even after the mine was shut down, the concentration of uranium in the potable water intake well in the village increased eightfold (up to 240 µ/L). Radiological hazards were estimated to exceed recommended parameters.

This article presents the results of a study of the influence of radionuclide and chemical pollution on the morphological and anatomical parameters of Calamagróstis epigéjos plants growing in the territory of “Degelen” at the Semipalatinsk Test Site (STS). Quantitative data of morphological and anatomical parameters are given, and the content of radionuclides and toxic elements in samples of plants obtained. Statistical processing of the obtained data was conducted. The results revealed that elevated concentrations of radionuclides 137Cs and 90Sr, and the calculated absorbed dose, do not have effects on plants. Changes in the anatomical parameters of leaves and stems were observed at elevated concentrations of the elements: for leaves—Al, Pb, Sr, U, Ni, Rb, Sm; for stems—Al, Cr, Cd, U, Cu, Be, Ni, Sm, Fe. The mesophyll of the leaves and the epidermis of the stems were the most exposed to toxic elements. The data of the anatomical parameters are recommended to be used as indicative parameters of plants grown in chemically contaminated areas.

The article addresses the basic tools for creating geospatial Web applications focusing on three key software products: ArcGIS Online, ArcGIS Experience Builder and ArcGIS Enterprise SDK. Functionalities have been analyzed and compared. This covers advantages and disadvantages of each platform in the context of developing a Web application for the sustainable management of land resources and water bodies at the former Semipalatinsk Test Site in areas planned to be released to the economic turnover. Findings provide a comprehensive insight into the choice of the best tool to efficiently work out geospatial Web applications given specific tasks and specificity of the test site area.

A study of the bioavailability of a tightly bound tritium in the soil in situ under the conditions of the Semipalatinsk test site (STS) and in a laboratory vegetation experiment was conducted. Significant concentrations of organically bound tritium (OBT) were recorded in Stipa capillata plants growing on the territory of the STS. At the same time, tritium in the free water of plant tissues (TFWT) was not detected. In a model experiment using Cucumis sativus culture, the specific activity of tightly bound tritium in the composition of the solid phase of the soil and tritiated water (HTO) in the composition of the soil solution at the beginning and at the end of the experiment differed significantly. At the same time, TFWT activity in Cucumis sativus was 2 orders of magnitude less compared to the activity of tightly bound tritium in the soil and slightly differed from the activity of tritiated water in the soil solution, which is accessible to the root system of plants. The results of vegetation studies have shown that the direct source of tritium for experimental plants was a soil solution. However, changes in the tritium activity in the soil liquid and solid phases in vegetation vessels indicate that the source of tritiated water in the soil solution was a tightly bound form of radionuclide as a result of leaching processes. It is assumed that the possible causes of leaching of tightly bound radionuclide from the solid phase into the soil solution are the moisture regime, as well as the influence of the rhizosphere of plants.

The article presents characteristics of the plant cover at the “Aktan-Berli” site including the content of natural (40K, 232Th, 226Ra) and artificial (137Cs, 90Sr, 241Am, 239+240Pu, 3Н) radionuclides. It has been found that the plant cover of the site is represented by ecosystems of high Kazakh hammocks bordering on ecosystems of lowlands in the west and ecosystems of ancient alluvial and modern alluvial plains. The content of free-water 3Н (FWT) and organic constituent (OBT) is below the detection limit of the methodological instrumentation in use (<8 Bq/kg). The concentration of natural radionuclides is typical, especially for Kazakhstani soil. The range of 90Sr activity concentration in plants range from <0.7 to 6.7 Bq/kq, 137Cs – from <0.6 to 1.1 Bq/kg, the content of 241Am and 239+240Pu are below the detection limit in most cases (<0,2 Bq/kg). Values of the radiation dose rate of plants are below the accepted international criteria. In general, the content of radionuclides in the plant cover of the “Aktan-Berli” site is significantly below the maximum permissible levels of radioactive contamination of forage plants posing no hazard when using the territory of interest for economic activities.

This paper provides data of the reconnaissance (preliminary) radiation survey of mothballed uranium mining facilities (MUMF) and adjacent settlements in the southern part of the North-Kazakhstan region (NKR). It is shown that, according to the level of EDR values, MUMF locations, when the public periodically stays in these areas, do not pose any radiation hazard. The exception is Grachevskoe MUMF where EDR values reached up to 14.0 µSv/h. Around the settlements, EDR values vary from 0.1 to 0.5 µSv/h. Elevated values are noted on highways. Regulatory values of radon EEVA were also found to be significantly exceeded in Toksan bi vil. A minor excess of radon EEVA was detected in Novoukrainka vil. Exceedance of the content of 238U up to 4 MPC was detected in sources of drinking water supply. Exceedances of up to 5 MPC for 238U were also found in natural waters. The total alpha activity showed an excess of up to 15 MPC. Natural waters exhibit an excess of up to 10 MPC. Based upon the data analysis during the reconnaissance survey, the Grachevskoe MUMF and Novoukrainka settlement were selected for a detailed survey.

This paper presents the determination method of the exact geographical coordinates of aboveground nuclear tests (NT) epicenters based on the radioecological study results the example of the Semipalatinsk Nuclear Test Site. By testing the NT Epicenter software for determining the exact geographic coordinates of the NT centers, it was established that it is indeed possible to determine the exact coordinates of most of the aboveground NTs. Their locations are currently determined by the presence are currently determined by the presence of technogenic disturbance of the soil surface in the area of the alleged epicenter (the presence of a crater), as well as by comparing maps of radioactive contamination and a space image. The accuracy of the precise coordinates of the NT is highly dependent on the density of the auxiliary grid: the smaller the pitch of the auxiliary grid, the higher the accuracy of the NT epicenter.

The paper provides results of a long-term natural experiment with fruit and berry crops, grown in conditions of radioactive contamination at the territory of the former Semipalatinsk Test Site. The aim of the research is to study peculiarities in accumulation of artificial radionuclides by different species of trees and shrubs. The paper considers only one pathway of the radionuclide's intake, i.e. absorption of the elements by roots from soil. As the result quantitative parameters of Am-241, Cs-137, Sr-90, Pu239+240 transfer and distribution in different parts of the fruit and berry crops were found. At that radionuclides are not uniformly distributed in plants' organs and in most cases, it obeys the following regularity: leaves > branches > fruits. The difference in accumulation of Cs-137, Sr-90, Am-241 and Pu239+240 for various organs can be range as follows 1.8-77, 1.6-750, 1.9-76 and 3-182 times respectively. The maximum concentrations of Cs-137 in leaves of the researched plants more often were registered at the initial stages of vegetation period. Unlike Cs-137 concentration of Am-241 and Sr-90 in leaves of the researched plants grows usually from the very beginning till the end of the entire vegetation period. The character of transuranium radionuclides accumulation during several years was determined for researched plants. Data obtained can become input parameters for models used to describe the behavior of radioactive substances and assess the risk of contaminated fruit and berry crops for territories having unfavorable radiological situation.

This paper reports the activity concentrations of 137Cs, 90Sr, 239+240Pu, 241Am, and 3Н in the form of tritiated water (НТО) and organically bound tritium (ОBТ) in the tissues and organs of roe deer (Capreolus pygargus Pal., 1771) that inhabit the ‘Degelen’ test location of the Semipalatinsk Test Site. Tissues and organs were sampled from six deer by killing. The activity concentrations of specific radionuclides in the samples were measured using γ-, α-, and β-spectrometry. The radionuclide activity concentrations in the tissues and organs showed considerable variation, for example, 0.6–170 Bq kg-1 for 137Cs and 0.3–2.8×103 Bq kg-1 for 90Sr. The activity concentrations of radionuclides in animal muscular tissue did not exceed permissible values for the meat of wild animals. The tissues and organs in the roe deer were arranged as follows in descending order of their ability to accumulate 137Cs and 90Sr: for 137Cs, muscular tissue–kidneys–lungs–spleen–heart–liver–bone tissue; for 90Sr, bone tissue–liver–lungs–muscular tissue–spleen–heart–kidneys. The activity concentrations of 241Am and 239+240Pu did not exceed the minimum detectable activity. Therefore, no quantitative values could be determined for 241Am, and the 239+240Pu activity concentration could be derived for only one sample: 0.5±0.1 Bq kg-1 (liver). The distribution pattern of these radionuclides in the tissues and organs of the roe deer could not be determined because of insufficient data. The HTO volumetric activity in the tissues and organs of the examined animals ranged from 2.6×10−2 to 77 kBq l-1; activity concentration of OBT, 3.0×10−2 to 16 kBq kg-1; and OBT-to-HTO ratios, 2.0×10−3 to 5.3×102. This ratio can serve as an indicator of how long the examined animals stay in radioactively contaminated ecosystems. Within the ‘Degelen’ site, the activity concentrations of 90Sr and tritium, in the form of HTO and OBT, are expected to be high in the bone tissues, soft tissues, and organs, respectively.

The paper presents findings of water resources of Beskaragai village, Abai region. Macro-, micro-component and isotopic compositions of waters, general chemical parameters were obtained. It has been established that the isotopic composition of waters (2H and 18O) varies widely and is characterized by a constant “light” isotopic composition of groundwater. The studied water samples are classified as fresh and slightly subsaline according to the degree of mineralization. By the acidity level – neutral and slightly alkaline. According to the degree of hardness – soft, medium hard and hard. The ion composition of waters of the hydrocarbonate – sulfate – chloride and sodium – magnesium – calcium group is dominant.

This paper presents research on the assessment of the radioecological state of plant cover surrounding two research reactor facilities located within the Semipalatinsk Test Site (STS) as examples of nuclear fuel cycle facilities (NFC). Source data on the concentrations of artificial radionuclides in the plant cover were obtained. Quantitative values for 137Cs, 241Am, and 239+240Pu activity concentrations were determined in plants across the perimeters of the facilities, indicating that these compounds may be present in the associated media from the perspective of accumulative bioindication. The values determined for artificial radionuclides in the ‘soil‒plant’ system around the researched NFC facilities were attributed to radioactive contamination of the STS territory.

The transboundary Irtysh River flows through the territory of three states: China, Kazakhstan and Russia. Industrial enterprises are located in the Irtysh River basin at the territory of Kazakhstan. Also, the Semipalatinsk nuclear test site can affect the state of the Irtysh River water. For this reason, researches were carried out to determine the content of natural and anthropogenic radionuclides, macro-, microcomponents and heavy metals in the Irtysh River water. According to the results, no anomalous deviations in the concentration of radionuclides have been established. Except the radionuclide 3H, which almost constantly inputs in small quantities to the various components of the Irtysh River ecosystem with the Shagan River waters. In terms of the macrocomponent composition, only the Cl- content and the degree of water hardness exceed the standards of the Republic of Kazakhstan. In terms of heavy metals and microcomponents (a total of 16 elements were identified), near the Ust-Kamenogorsk city the Fe content is 1.2-2 times higher than the MPC. Results of the calculations of the comprehensive water pollution index (CWPI) of the Irtysh River water at the Kazakhstan territory correspond to standard clean water. The transboundary Irtysh River flows through the territory of three states: China, Kazakhstan and Russia.