Levels Of 90Sr Research Articles

Estimation of Strontium-90 Concentrations in Pakistan Using Combination of TBP Solvent Extraction, Precipitation and Cherenkov Counting Methods

90Sr does not exist in nature. Its main sources in the environment are global fallout of past nuclear accidents or nuclear detonations. 90Sr is radiologically significant because of its relatively long physical and biological half-lives and its chemical resemblance to calcium. In order to estimate the radioactivity level of 90Sr around Pakistan Institute of Nuclear Science and Technology (PINSTECH) Islamabad, environmental samples (soil, water, vegetation, and water) and food samples (wheat, milk, poultry) were collected from the different selected sites around PINSTECH within the area of about 12.5 km radius. All samples were pretreated using the guidelines of International Atomic Energy Agency (IAEA) Technical Reports Series No. 295. 90Sr was indirectly determined through its progeny 90Y in secular radioactive equilibrium. 90Y was radiochemically separated using combination of Tri-n-butyl Phosphate (TBP) solvent extraction and precipitation. Finally, the activity was measured on Tri-Carb Liquid Scintillation Counter (LSC) through Cherenkov radiation. The activity concentrations of 90Sr in all samples were too low to be detected by the LSC system, except for a vegetation sample from Rawal Dam where a minimum activity of 0.16 ± 0.04 Bq/kg of fresh weight was found. No considerable activity concentration of 90Sr was found around PINSTECH research facilities.

Накопичення штучних та природних радіонуклідів у гідробіонтах р. Коноплянка (м. Камʼянське, Дніпропетровська область)

Purpose. To determine the radiation state of the ecosystem in the technologically modified Konoplyanka River in the area of ​​radioactive waste tailings dump and the mouth of the river (at the siteof confluence with the Zaporizhzhya (Dnipro) Reservoir), by analyzing the coefficients of radionuclides accumulation of natural and artificial origin in hydrobionts. Methodology. Classical sampling methods were used to determine natural (226Ra, 232Th, 40K) and artificial (137Cs, 90Sr) radionuclides in hydrobionts. The contents of radionuclides were determined in a certified laboratory at the “Dnipropetrovsk Regional Center for Disease Control and Prevention of the Ministry of Health of Ukraine” by the method of selective isolation of radionuclides based on the measurement of radiation on a scintillation beta spectrometer SEB - 0.XX and spectrum processing with the AK-1 software package. The measurement range of the beta spectrometer covers from 0.1 Bq to 10-4 Bq, which allows ensuring the control of artificial radionuclides in environmental objects in accordance with the regulatory documents of the “Permissible levels of radionuclides 137Cs and 90Sr in food and drinking water” (PLR–2006) and “Radiation Safety Standards of Ukraine–97” (RSSU–97) Findings. The study of the current radiation status of the Konoplyanka River in the summer-autumn period showed that the contents of artificial radionuclides in the water were significantly lower compared to normative data: the content of 137Cs was 15–19 times lower; 90Sr was 28–50 times lower. Among the different sampling sites, the highest content of 137Cs was recorded at site No3 (Konoplyanka River, old channel) and No1 (Konoplyanka River, top of the tailings dump). The study of artificial radionuclides in fish showed that their content did not exceed the normative values ​​for fish as food objects (137Cs content in fish was lower by 17–50 times, 90Sr by 16–62 times). By fish species, the highest content of artificial radionuclides was accumulated by benthic slow-moving fish (round goby) and the lowest by pelagic mobile fish (roach, bleak, bitterling). The difference in the contents of these fishes was 62% for 137Cs and 75% for 90Sr. At different sampling sites, the content of artificial radionuclides in fish did not differ significantly. The content of natural radionuclides in different fish species did not have general patterns, that is, each fish species selectively accumulated individual natural radionuclides. The accumulation coefficients of artificial radionuclides were the highest in demersal fish, which are characterized by a sedentary lifestyle and feed on benthic invertebrates (round goby), the accumulation coefficient of artificial radionuclides in planktonophagous fish was 40-69% lower. The coefficients of natural radionuclides accumulation were higher in planktonophagous fish (bleak, stone moroko) by 36–53% compared to benthophagous fish (roach, round goby). Originality. For the first time, data on the content of natural and artificial radionuclides in the hydrobionts from the Konoplyanka River at the conditions of technogenic influence in the industrial zone of the metallurgical and chemical industry were obtained. Practical Value. The results of the conducted research can be used to assess and monitor the radiation status of the Konoplyanka River, radioactive waste tailing dumps and develop a strategic program for the restoration of the ecosystem of techno-altered rivers with heavy techno-anthropogenic load. Keywords. Konoplyanka River, radionuclides, hydrobionts, molluscs, fish, tailings dumps.

Оптимізація пробопідготовки для визначення 90SR У харчових продуктах

The aim: To determine the possibility of conducting studies of the radionuclide 90Sr in food products in accordance with GN 6.6.1.1-130-2006 «Permissible levels of radionuclides 137Cs and 90Sr in food products and drinking wate»" without concentration by the ashing method. Materials and methods: The article describes the method of calculating the minimum measuring concentration of food products. According to the results of the calculations, the products that can be measured without concentration are determined. Analytical, statistical and computational research methods were used during the work. At the stage of sample preparation for measurement, the question often arises in which form to measure the sample - native or ashed. The specific activities of food products in their native form are in many cases lower than the minimum measurable concentration (MMС) on the spectrometer. Therefore, in order to decide in what form to prepare the sample for research, before starting work, it is necessary to compare the capabilities of the spectrometer, the minimum measured concentration and the permissible level of 90Sr content in the research product. In order to solve the question of the need for ashing of the sample, calculations of MMC were carried out for each food product, as well as the weight of the raw product, necessary to obtain 0.01 kg of ash per measurement was calculated. Results: Tables are compiled based on the results of the calculations. One includes products whose activity can be measured without ashing, and the other includes products with ashing. The use of such tables makes it possible to optimize sample preparation for the study of 90Sr by the spectrometric method. Of the 50 groups of food products, 17 have been identified that can be studied in their native form, which saves time for sample preparation and increases the performance of the spectrometer.

Selective removal of 90Sr by a novel IDA-chelating resin from contaminated groundwater

Selective removal of 90Sr by a novel IDA-chelating resin from contaminated groundwater

Strontium-90 levels in seawater southeast of Jeju Island during 2021–2023

This study introduces an efficient method for determining 90Sr activity levels in seawater, reducing the processing time to <3h for 50L of seawater. The key feature of the proposed method is the chemical separation of 90Y when it is in equilibrium with 90Sr, which is achieved by utilizing custom-made sample-loading equipment and an automated radionuclide separation instrument. As a result, the procedure consistently yields a recovery rate>90% for 90Y. Investigations of 90Sr levels were conducted in the ocean southeast of Jeju Island from November 2021 to January 2023. Owing to the regional ocean circulation, this region was among the first within the Korean Peninsula to experience the impact of the Fukushima-accident-derived radionuclides. Throughout the investigation period, the observed 90Sr activity concentration ranged from 0.57 to 1.0Bqm-3. No distinct temporal variation of 90Sr was observed in the selected area during the investigation.

Hygienic assessment of 90Sr and 137Cs contamination of water and fish in the lakes of the head part of the peripheral zone of the East Ural radioactive trace

Introduction. The article presents the results of studies of the specific activity of 90Sr and 137Cs in the water and fish of the Irtyash and Kazhakul lakes located in the peripheral zone of the head of the East Ural Radioactive trace in 2014-2017.&#x0D; Materials and methods. Determination of the levels of specific 90Sr and 137Cs in the water and the body of the resource-forming species of Siberian roach (soroga, chebak) Rutilus rutilus lacustris (Linnaeus, 1758) from the studied lakes was carried out over the period of 2012–2017. The measurements were carried out using standardized methods adopted in in the Federal State Budgetary Institution of Health “Central Medical and Sanitary Unit No. 71 of the Federal Medical and Biological Agency of Russia” (FGBUZ TsMSCH No. 71 of the Federal Medical and Biological Agency of Russia) and the Southern Ural.&#x0D; Results. The research was carried out over 2014 to 2017. Since the accident at the Mayak enterprise in the fall of 1957, the specific radioactivity of the water in the studied lakes was found to decrease. The concentration of 90Sr in the water of Irtyash lake was 0.019±0.008, and 137Cs – 0.028±0.009, and in Lake Kazhakul – 0.19±0.06 and 0.14±0.06, respectively. These values are much lower than the level of intervention according to NRB-99/2009. &#x0D; The water of the lakes is used to meet household needs. The water of Lake Irtyash is used for drinking water supply of the city of Ozersk. The specific activity of the raw mass of a roach carcass from the Irtyash and Kazhakul lakes for the accumulation of 90Sr is 2.7± 1.7 and 64.5±19 and 137Cs – 1.68± 0.8 and 38±33.5Bq/kg, respectively. All the samples studied separately according to 90Sr and 137Cs had levels of radioactive contamination at or below the regulatory compliance indicator (SanPiN 2.3.2.1078–01). At the same time, taking into account the absolute extended uncertainty (with a coverage factor of k = 2) roach from Kazhakul lake has a significant excess of the limit level of radioactive contamination.&#x0D; Limitations. Hydrochemical parameters of the aquatic environment in various reservoirs can vary significantly over time and affect the accumulation of radionuclides by hydrobionts. Therefore, the research results are relevant only for the research period. To obtain more reliable results, long-term comprehensive monitoring is necessary.&#x0D; Conclusion. Over the past 60 years after the accident at the Mayak enterprise in 1957, the levels of radioactive contamination of water and fish in the studied lakes Irtyash and Kozhakul have decreased by more than 10 times. Calculation of doses of ionizing radiation for certain groups of the population of areas contaminated as a result of accidents, living near lakes, is a complex task, for which additional research is needed.

Levels, sources, variations, and human health risk assessment of 90Sr and 137Cs in water and food around Sanmen Nuclear Power Plant (China) from 2011 to 2020.

Radioactivity monitoring around nuclear facilities is crucial to provide important baseline data for effective detection of radioactive leakage to the environment. We aim to establish a baseline study for monitoring radioactive levels of 90Sr and 137Cs around Sammen Nuclear Power Plant (SNPP) and to assess their associated health impact on surrounding residents. In this study, we collected water and food samples around the SNPP from 2011 to 2020 and determined for 90Sr and 137Cs activity concentrations. We statistically analyzed the temporal trends of 90Sr and 137Cs and evaluated their radiation exposure to the local residents. During this period, the activity concentrations of 90Sr and 137Cs varied within 1.2-9.9 mBq/L and 0.10-7.6 mBq/L in water, and 0.037-1.3 Bq/kg and 0.011-0.45 Bq/kg in food, respectively, with no significant seasonal variation trend. All reported activity concentrations of 90Sr and 137Cs were significantly lower than the recommended value of WHO and Chinese national standards. There is no indication of notable radioactive release into the study area due to the operation of SNPP during 2018-2020. The annual effective doses (AEDs) from the ingestion of 90Sr and 137Cs in water and food were well below the international permissible limits, indicating the radiation exposure around SNPP during 2011-2020 was kept at a safe level.

TIME PATTERN OF RADIONUCLIDE EMISSIONS AND DISCHARGES INTO THE NATURAL ENVIRONMENT OF THE PIVDENNOUKRAINSKA NPP SURVEILLANCE ZONE.

assessment of impact of operation of the Pivdennoukrainska Nuclear Power Plant (PUNPP) on the environment of surveillance zone (SZ) based on parameters of radiation monitoring within 2015-2021 period. socio-hygienic (analysis of the radiation monitoring parameters), analytical, statistical. The environmental radiation impact associated with emissions and discharges of radioactive substances originated in the production cycle of the PUNPP in everyday conditions was found as insignificant. The gas-aerosol atmospheric emissions of inert radioactive gases, long-lived nuclides, and 131I did not exceed the established permissible levels (PL) and amounted to a hundredth of a percent of the emission limit (EL) for the inert radioactive gases and long-lived nuclides, and a thousandth of a percent for radioactive iodine. Total atmospheric emissions of the 51Cr, 54Mn, 59Fe, 58Co, 60Co, 90Sr, 95Zr, 95Nb, 134Cs, 137Cs, and 3Н radionuclides by the PUNPP power units (actual and % of EL) did not exceed the established PL. Maximum average values of atmospheric air concentration of 137Cs in SZ forthe 2015-2021 period ranged from 2.858 μBq/m3 (PUNPP industrial site) to 1.986 μBq/m3 (Riabokoneve village, 33.5 km distance), and maximum average values of the 90Sr air concentration were from 1.310 μBq/m3 to 0.566 μBq/m3, respectively. According to radionuclide monitoring no significant change of the quality of surface water occurred upon the PUNPP discharges to the Pivdennyi Bug River. Specific activity of the 137Сs in agricultural products in the PUNPP SZ was insignificant and not exceeding the PL of the content in food products. Content of 137Cs in the samples from the PUNPP SZ did not exceed 1.0 % of the total activity. Average concentration of radionuclides in atmospheric air of the settlements in the PUNPP SZ was several orders of magnitude lower than that established by regulatory documents. The PUNPP discharges to the Pivdennyi Bug River, according to radionuclide parameters that are monitored, have not significantly changed the quality of surface water. The content of 90Sr and 137Cs was uniform in all observation radii of distance from the NPP, confirming the very low level of 90Sr and 137Cs environmental emission by the PUNPP. The content of 137Cs in agricultural products within the PUNPP SZ was significantly lower than PL.

Радіоекологічні дослідження на осушених ділянках ложа водойми-охолоджувача ЧАЕС

The results of radioecological monitoring of the research sites located on the drained areas and the coastal of the ChNPP cooling pond are presented. The features of the spatial distribution of the exposure dose rate, the density of soil radionuclide contamination by the emergency radionuclides were determined. The content of incorporated radionuclides in representatives of the genera Myodes and Sylvaemus were studied, the individual and interspecies variability of 137Cs and 90Sr levels in animals within the limits of one research site was determined. Currently, the indicators of radioactive contamination of biota in the drained areas of the cooling pond are within the variation of those values that are characteristic of most areas of the Chornobyl exclusion zone.

Clean feed as countermeasure to reduce the 90Sr and 137Cs levels in fish from contaminated lakes

Glubokoye Lake situated within the Chernobyl Exclusion Zone is highly contaminated with respect to radioactive caesium and strontium isotopes, which also is reflected in the contaminated fish. To utilize the fish resources in contaminated lakes, the present work presents for the first time the effectiveness of using clean feed to counteract contamination of radionuclides in fish. The study is based on a series of repeated experiments with Prussian carp (Carassius gibelio (Bloch, 1782)) kept in cages in the contaminated Glubokoye Lake during summer 2018-2021. By the addition of clean feed, the activity concentration of 137Cs in fish muscle tissues was lowered with a factor of 2-5 due to biodilution. Surprisingly, additional clean feed did not lead to further decrease in the uptake of 137Cs in fish. In contrast to 137Cs, the addition of clean feed increased the 90Sr activity concentration in fish by a factor of 2-4 compared to fish fed with naturally occurring feed items. Radioactive strontium accumulated mainly in the fish bones and the muscle tissue level was 2 orders of magnitude lower, similar to the distribution observed for stable Sr. By utilizing a new kinetic model describing the dynamics of strontium isotopes in bone tissues of fish, predictions fitted well with site-specific data, taking growth rates and aging into account. Results showed that clean feeding can be used to counteract high activity concentration of 137Cs in fish due to biodilution, but cannot counteract bioaccumulation of 90Sr. Findings highlighted that it is essential to understand underlying factors influencing the uptake pathways for contaminants, as access to clean feed could increase the growth and thereby reduce the body activity concentration of dietary associated radionuclides such as 137Cs (biodilution), as well as increase the transfer of dissolved compounds such as 90Sr directly from water to fish.

90Sr and stable element levels in bones of brown bears: long-term trends in bear populations from Croatia and Poland.

The aim of this study was to investigate the temporal trends and geographical differences in 90Sr and stable element (Ba, Ca, Mn, Sr, Pb, Zn) levels in the bones of Croatian and Polish brown bear (Ursus arctos) populations. Experimental data suggest that in the decades after nuclear weapon tests and the Chernobyl accident, 90Sr bone activity concentrations decreased from 352 to 11Bqkg-1 in the Croatian bear population (period 1982-2015) and from 831 to 27Bqkg-1 in Polish bears (period 1962-2020). Calculated effective and ecological half-lives were 9 and 13years for Croatian bears, and 15 and 31years for Polish bears, respectively. Different temporal trends were noted in levels of Ba, Mn, Pb and Zn between the two countries with majority of bones having lower Pb, Sr and Zn in Croatian than in Polish bears. Estimated values for the soil-to-bear transfer of 90Sr were the same order of magnitude in the studied populations. Contrary to this, the estimated transfer of stable Sr was an order of magnitude lower for the Croatian bear population compared to Polish bears. The observed differences in soil-to-bear transfer between stable Sr and 90Sr found for Croatian bears might suggest the need for careful consideration on the use of stable Sr data as an analogue for 90Sr. To our knowledge, this is the first study that analysed 90Sr activity in tissue of brown bears. As such, it provides insight into the fate and behaviour of one of the most relevant anthropogenic radionuclides at the top of the food chain.

Natural attenuation processes control groundwater contamination in the Chernobyl exclusion zone: evidence from 35 years of radiological monitoring

The Chernobyl Exclusion Zone (CEZ) contains the vast majority of radionuclides released by the accident in nuclear fuel particle form. We present and analyze groundwater measurements collected from the monitoring network in CEZ covering key aquifers over 35 years since the accident. These new data, together with a comprehensive analysis of historical data shows that 90Sr remains mobile in the subsurface environment, while groundwater concentrations of 137Cs, Pu isotopes and 241Am are relatively low, and are not of radiological concern. During the last two decades, 90Sr and 137Cs levels have declined or remained stable over time in the majority of monitoring locations. This is due to natural attenuation driven by gradual exhaustion of the fuel particle source, geochemical evolution of groundwater downstream from waste dumps and radionuclide retention in surface soil due to absorption and bio-cycling. Decommissioning of the cooling pond and construction of the ‘New safe confinement’ over Unit 4 (damaged reactor) also favored better protection of groundwater close to the Chernobyl plant site. Data from confined and unconfined aquifers, as well as rivers, evidence low radiological risks from groundwater contamination both outside the CEZ and to onsite “self-settlers”. Though several groundwater contamination “hot spots” remain in the vicinity of Unit 4, “Red Forest” waste trenches and surface water bodies with contaminated bottom sediments, the findings of this study support a monitored natural attenuation approach to groundwater management in the CEZ.

Online solid-phase extraction−inductively coupled plasma–quadrupole mass spectrometric quantification of 90Sr using 88Sr/86Sr isotope dilution method

Due to the lack of a correlation with the natural Strontium (Sr) isotopes, it is difficult to apply the isotope dilution (ID) method to an artificial radioactive mononuclide Strontium-90 (90Sr), in inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS). Meanwhile, online solid-phase extraction (SPE)-ICP-QMS (SPE-ICP-QMS) serves as an automatic sequential analytical technique for measuring the ultra-trace amounts of radionuclides; however, apparent assay values obtained using this method are often negatively affected by differences in the sample matrix composition between standard and actual samples. In this study, the pg L-1 level of 90Sr was successfully measured by combining online SPE-ICP-QMS and the ID method with 88Sr/86Sr ratios in one sample injection, without the radioactive standard. Although naturally occurring abundant isobaric 90Zr significantly influences 90Sr quantification during mass spectrometry, consecutive separations between automated SPE and dynamic reaction cell (DRC) oxidation enable 90Sr quantification, even in the presence of isobaric 90Zr (acceptable down to 5.7×10-9 of 90Sr/Zr in sample solution), using this method. Through this method, both radioactive 90Sr and naturally occurring Sr were simultaneously quantified using 88Sr-to-86Sr and 88Sr-to-90Sr ratios without radioactive 90Sr standard solutions. This simultaneous quantification of stable Sr and 90Sr was achieved within 15min with good recovery rates. The limit of detection of 90Sr was 1.1pgL-1 (equivalent to radioactivity 5.6 Bq L-1) for a 10mL injection. Finally, water collected from an actual contaminated water storage tank at the Fukushima Daiichi Nuclear Power Plant (Fukushima, Japan) was analyzed using the proposed method, and the obtained results agreed well with those obtained using conventional analytical methods.

Effect of 90Sr and 137Cs concentration on Hematological Parameters of Bats in the Chernobyl Exclusion Zone (Ukraine)

We examined the effects of the level of internal 90Sr and 137Cs concentrations on hematological parameters of bats captured in the Chernobyl Exclusion Zone (Ukraine). In total, 68 animals of six bat species were live-monitored with measurement of the whole-body activity concentrations of the two radionuclides (90Sr and 137Cs) and blood sampling for further analysis. We found statistically significant positive correlations between the blood neutrophil count and whole-body 90Sr activity concentration in individuals of Eptesicus serotinus; and between the neutrophil/lymphocyte ratio and 90Sr concentration, and between the red blood cell (RBC) count and 137Cs concentration in Vespertilio murinus. We did not observe any correlation between concentrations of 90Sr and 137Cs and hematological parameters in individuals of Pipistrellus nathusii. Moreover, none of these three species showed significant sexual (male versus female) or age (adult versus sexually immature) differences in 90Sr and 137Cs concentrations. Our results contribute to better knowledge and understanding of the eco-immunology of free-ranging bats in one of the most radioactively contaminated areas in the world — the Chernobyl Exclusion Zone. To our knowledge, this is the first study investigating the relationship between radionuclide contamination and hematological parameters of bats.

Комплексная гигиеническая оценка территорий в районе размещения строящегося регионального центра по обращению с радиоактивными отходами

The Regional center of conditioning and long-term storage of radioactive waste is being constructed in Primorsky Krai, where radioactive waste (RW) management сoncerns have been especially acute. The project involves intensification of activities related to RW management, as well as to building the new technology block for RW reprocessing, storage facility and boiler house. The study was aimed to perform environmental impact assessment of the territories in the vicinity of the Regional center of conditioning and long-term storage of radioactive waste prior to the facility commissioning. Radiation situation was assessed by radiometric and spectrometric methods; the levels of heavy metals were evaluated by atomic absorption spectrometry. Heavy metal (lead, nickel, copper, etc.) and arsenic levels exceeding or, in certain cases, similar to maximum permissible concentration (MPC) were found in soil and ground. Radiation situation is characterized by background levels of artificial radionuclides 137Cs and 90Sr in environmental media. Quality of water in wells and boreholes was largely compliant with the requirements established for groundwater used in decentralized water supply systems, with the exception of boreholes, in which the arsenic levels exceeding MPC were detected. The average annual public dose was 0.046 mSv excluding natural regional background radiation, which was below the dose limit. Carcinogenic health risks induced by radiation and chemical factors was 4×10–6 and 6×10–6 respectively. The obtained results form the basis for setting reference values of environmental contamination prior to the Regional center of conditioning and long-term storage of radioactive waste commissioning and can be used for regulatory supervision during the facility operation.

The investigation on the radioactivity level of 90 Sr in tea leaves in the vicinity of Ningde nuclear power plant

Objective To investigation the radioactivity level of 90Sr in tea leaves within and outside 30 km range of Ningde nuclear power plant. Methods The tea leaves within and outside the 30 km range of Ningde Nuclear Power Plant were collected from 2013 to 2018. According to “Radiochemical analysis of strontium-90 in water and ash of biological samples” (HJ 815—2016), the separation and analysis of 90Sr- 90Y were carried outusing the method of di (2-ethylhexyl) phosphate (HDEHP) chromatography. Results During the period of 2013-2018, the radioactivity concentrations of 90Sr in the tea leaves within the range of 30 km around the Ningde nuclear power plant were 0.486~13.29 Bq/kg and that of 90Sr in the tea leaves outside the range of 30 km around the nuclear power station were 1.021~17.19 Bq/kg. Conclusion During the six years of operation in Ningde Nuclear Power Plant, there was no increase in the radioactivity level of 90Sr in the tea leaves around the nuclear power plant. 摘要： 目的 了解宁德核电站 30 km 范围内和 30 km 范围外地区茶叶中 90Sr 放射性水平。 方法 于 2013—2018 年期 间采集宁德核电站 30 km 范围内和 30 km 范围外地区茶叶, 参照 HJ 815—2016 《水和生物样品灰中锶-90的放射化学 分析方法》中二-(2-乙基己基)磷酸脂萃取色层法进行样品中 90Sr- 90Y 的分离分析。 结果 2013—2018 年, 宁德核电站 30 km 范围内茶叶中 90Sr 的放射性活度浓度测量范围为 0.486~13.29 Bq/kg, 30 km 范围外茶叶中 90Sr 的放射性活度浓 度测量范围为 1.021~17.19 Bq/kg。 结论 宁德核电站运行 6 年间, 并未造成其周边茶叶 90Sr 放射性水平的提高。

Radial growth of Pinus sylvestris in the East Ural Radioactive Trace (EURT): Climate and ionizing radiation

The East Ural Radioactive Trace (EURT) resulted from the explosion at the Mayak Production Association in September 1957 (the Kyshtym accident). The majority of the Scots pine stands near the epicenter of the accident died in 1958–1959. Currently, we have found several small pine-birch stands with pine trees that are over 70 years old. Cores (96 samples) were analyzed employing dendrochronological methods to detect the effects of climate and ionizing radiation on the annual growth of trees. Tree-ring chronologies were developed for two control and three impact sites with different levels of radioactive contamination. In the first years after the accident, acute radiation exposure significantly reduced radial growth in trees in two contaminated sites, where initial contamination levels of 90Sr measured 3.7–26.6 MBq m−2; synchrony of the chronologies from the contaminated and control sites were disturbed. In the subsequent period, all chronologies have been highly synchronous. The Scots pine has revealed decreasing radial growth due to limitations in the amount of available moisture. The results suggest that both climate and ionizing radiation have limited the radial growth of pine trees. The effect of acute radiation contamination on the radial growth of trees was comparable to the effect of droughts – the main extreme climatic event in this region.

ФОНОВОЕ СОДЕРЖАНИЕ ТЕХНОГЕННЫХ И ПРИРОДНЫХ РАДИОНУКЛИДОВ В ДЕТОКСИЦИРУЮЩИХ И БИОЛОГИЧЕСКИ АКТИВНЫХ ВЕЩЕСТВАХ

For correctly assess the effectiveness and safety of the use of sorption-detoxifying agents and feed additives intended for animals receiving feed with an excess content of toxicants, it is necessary to take into account the background levels of radionuclides, toxic elements, pesticides and other technogenic and natural pollutants in the studied substances. The need for such studies is due both to the existence of areas with a naturally elevated level of natural toxicants in the sources of raw materials for the production of additives and drugs, and to the increasing anthropogenic influence, accompanied by the entry of xenobiotics into environmental objects. In series of radiometric studies, the specific activity of technogenic and natural radioactive isotopes (90Sr, 137Cs, 40К, 226Ra, 232Th) in a number of sorption-detoxifying and biologically active substances and preparations used in animal husbandry and veterinary medicine as part of feed additives and pharmacological agents was determined. It was found that in 43% of the studied samples, the level of specific activity of 1,1Sr in 3-90 times higher than allowed by the current standards. The maximum level of 90Sr, equal to (137±9) Bq/kg, was detected in perlite. The specific activity of 137Cs did not exceed the permissible level: in mineral sorbents its amount reached (40±7) Bq/kg, in organic and complex sorbents – (24±4), and in feed additives – (29±8) Bq/kg. The maximum levels of 40K were (1429±83) Bq/ kg in minerals (radionite) and (2613±100) Bq/kg in organic substances (lignohumate). The levels of 226Ra and 232Th did not exceed (153±13) and (79±13) Bq/kg, respectively, and were higher in the mineral samples.

Sensitive and accurate methods for determination of low activity level of 90Sr and 137Cs in grass/vegetable samples

Sensitive, precise and accurate methods for determination of low activity level of 90Sr and 137Cs in grass/vegetable samples by a low background β-counter were developed. The method for 90Sr determination was based on coprecipitation as carbonate, elimination of 210Bi and iron with a Microthene-TOA column, separation of 90Y with a Microthene-HDEHP column, and source preparation as Y2(C2O4)3. The method for 137Cs determination was based on Cs adsorption on ammonium molybdophosphate and precipitation as Cs3Bi2I9 for source preparation. The quality control tests indicated that the methods could provide accurate results. The method application showed that: (1) The mean yields of yttrium and cesium were 79 ± 6% and 84 ± 2%, respectively. (2) The activity concentrations of 90Sr in 9 grass/vegetable samples were in the range of 0.04-1.8 Bq kg-1, while that of 137Cs in the range of 0.022-0.18 Bq kg-1. And (3) the uptake rate of 90Sr from soil to grass/vegetable was much higher than that of 137Cs.

Content of radionuclides and public health of environmentally disadvantaged region

Relevance. The main source of radionuclide contamination in Kazakhstan is the Semipalatinsk nuclear test site (SNTS), where more than 460 nuclear explosions were made. There are still people living in some areas of the SNTS. The source of radionuclides entering the human body is animal food. The aim of the study was to study the content of 137Cs and 90Sr radionuclides in cattle meat and their impact on public health in areas close to the SNTS. Materials and methods. The data on the content of radionuclides were obtained at the Semipalatinsk Regional Veterinary Laboratory of the East Kazakhstan Region. The object of the study was meat of cattle (cattle) (67 samples) obtained in Abai, Borodulikhinsky, Zharminsky, Beskaragaysky districts and the city of Semipalatinsk, East Kazakhstan region, adjacent to the SNTS. The retrospective of the analyzed indicators was 10 years (1991-2000). The sources of information on the incidence of the entire population in the regions of East Kazakhstan region were data obtained from the Republican Center for Electronic Health for the period 2000-2015. Mathematical and statistical processing of the results was carried out using the applied statistical program Statistica-10. Results. The average content of 137Cs in cattle meat was 0.15 Bq/kg, and 90Sr - 0.11 Bq/kg. The dynamics revealed a 1.9-fold decrease in the level of 137Cs and a 2-fold decrease in the level of 90Sr. The consumption of cattle meat by residents was 14.7%. The average morbidity level of diseases of the musculoskeletal system was 3305 ppm. The morbidity of endocrine system diseases increased 1.4 times in dynamics. The morbidity level of diseases of the digestive system was 3358.9 ppm and decreased by 24.6% in dynamics. A correlation was found between the consumption of cattle meat and the morbidity level of diseases of the musculoskeletal system r=0.78. Conclusions. The study showed a positive trend of reducing the level of radionuclides in cattle meat among the studied regions. There was an increase in the average morbidity level of diseases of the musculoskeletal system by 1.2 times, and the endocrine system by 1.4 times. There is a trend to reduce the morbidity of diseases of the digestive system in the population of the studied regions. The revealed relationship between the consumption of cattle meat and the incidence of the musculoskeletal system diseases requires further study and monitoring.