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A method of 90Sr determination in natural waters was tested in this study. The method included the steps of strontium preconcentration by a carbonate-containing zirconium hydroxide (Termoxid-3 K), strontium stripping with 1 M HCl and preparation of a counting source, followed by its measurement using a low background alpha/beta radiometer UMF-2000. Using the described method, we have determined activity concentrations of 90Sr in 16 samples of natural water collected at the territories of Sverdlovsk region and Chelyabinsk region (Middle Urals, Russia) as well as 8 samples from observing wells at a radioactive waste storage facility and 3 samples from observing wells at a point of radioactive waste final disposal. The dependence of strontium chemical yield in the method on calcium concentration and water hardness was determined. It was shown that strontium chemical yield was constant (81 ± 2%) for natural waters with a hardness less than 5.2 mmol/L and calcium concentration less than 76 mg/L; thus, a control of strontium chemical yield is not necessary for such water samples. A decrease of strontium chemical yield to 66.5 ± 1.5% was observed at higher calcium concentrations up to 178 mg/L. The method provided a minimum detectable activity of 90Sr as low as 0.02 Bq/L. [ABSTRACT FROM AUTHOR]

The optimal conditions for the synthesis of a pelletized sorbent based on mixed Mn(III, IV) oxide by reacting aqueous solutions of MnSO4 and KMnO4 in an alkaline medium were determined: Mn2+/MnO4– molar ratio 1.70–1.80; pH of the reaction mixture 11.0–12.5; calcination temperature 220°C. For the sorbent fabricated under optimal conditions, the values ​​of the distribution coefficient (Kd) of 90Sr in 0.01 M CaCl2 solution, static exchange capacity for calcium, hydromechanical strength of granules, and Kd of 90Sr as a function of the concentration of sodium and calcium ions were established. The sorbent afforded higher sorption characteristics with respect to strontium compared to known sorbents. A technology for producing pilot batches of the sorbent named MDM, was developed. Examples of the use of the MDM sorbent for the purification of various types of liquid radioactive waste from strontium and radium radionuclides are reported. [ABSTRACT FROM AUTHOR]

The purpose of the present research was to study peculiarities in the accumulation of natural and artificial radioisotopes in medicinal plant raw material using nettle (Urtica dioica L.) leaves as an example. The specific activities of the main long-lived artificial radioisotopes (cesium-137 and strontium-90) and naturally occurring radionuclides (thorium-232, potassium-40, and radium-226) in experimental samples of upper soil layers and nettle leaves were determined on a RADEK MKGB-01 spectrometer-radiometer. All studied samples of nettle leaves collected in natural and artificial phytocenoses of Voronezh Region met existing radiation safety requirements (first group). A correlation analysis of the specific activities of artificial and natural radionuclides in the soil and nettle leaves showed a close relationship between these numerical indicators that confirmed their contamination primarily through soil. The specific activities of strontium-90, cesium-137, thorium-232, potassium-40, and radium-226 in the medicinal plant raw material increased as their specific activities in the soil increased. High accumulations of cesium-137 and potassium-40 from the upper soil layers were noted for nettle leaves growing in Voronezh Region. A detailed analysis of the dependence of the calculated accumulation coefficients of natural and artificial radioisotopes in nettle leaves revealed trends toward their decrease with increases in the specific activities of the radionuclides in the soil, which indicated physical mechanisms for regulating their uptake into the plant were present. [ABSTRACT FROM AUTHOR]

The paper presents the results of radioecological studies conducted in fish farms of the Dnipropetrovsk region. The distribution of radionuclides of natural and artificial origin is an urgent problem for various types of ecosystems, given the different routes of entry of these substances. The level of accumulation of radionuclides in the waters of the Zelenodolsk, Krynychansk and Kryvorizk fish farms was determined in a course of the presented study prior to the 2022 russian invasion of Ukraine. Content indicator of radium-226 in water ranged from 3.8 to 7.4 Bq/kg, thorium-232 - from 2.95 to 44.4 Bq/kg, potassium-40 - from 74.2 to 82.4 Bq/kg. Obtained in the present study results evidence that bottom sediments significantly accumulate the radionuclides. The registered content of radium-226 in them was from 30.1 to 14.8 Bq/kg, thorium-232 - from 9.6 to 41.5 Bq/kg, potassium-40 from 134.8 to 182.2 Bq/kg. The coefficients of accumulation of natural radionuclides in water and bottom sediments was registered as ranging from 1.4 to 5 for radium-226, from 0.82 to 3.3 for thorium-232, from 1.72 to 2.26 for potassium-40. The content of artificial radionuclides in water and bottom sediments determined in the study corresponded with their biochemical properties. In water, their value ranged from 0.13 to 1.8 Bq/kg for cesium-137 and from 0.05 to 0.08 Bq/kg for strontium-90. Taking into account the fact that bottom sediments accumulate a significant proportion of pollutants from water, the determined indicators were significantly higher than those in water, namely, from 5.6 to 10.4 Bq/kg for cesium-137 and from 1.5 to 2, 4 Bq/kg for strontium-90. The coefficients of accumulation of radionuclides of artificial origin in water and bottom sediments ranged from 3.3 to 80 for the content of cesium-137 and from 18.7 to 48 for the content of strontium-90. The levels of accumulation of natural radionuclides in the body of silver carp and carp were studied. The level of potassium-40 in the body of silver carp is lower than that of radium-226 and thorium-232 and ranges from 20.2 to 34.4 Bq/kg in all three fish farms. The same amount of radium-226 and thorium-232 was noted in the silver carp of the Krynychan fish farm which was on the level of 47 Bq/kg. In carp, the levels of natural radionuclides were significantly higher in all three fish farms. The content of cesium-137 was registered as approximately the same in silver carp and carp, with the exception of the Kryvyi Rih fish farm, where its level was significantly lower in the body of carp. Strontium-90 content was found in similar amounts in both types of fish. The concentration of radionuclides did not exceed the permissible levels.

The subject of this research is the vertical migration of strontium-90 in peatlands of the European Subarctic region of Russia. The activity level of strontium-90 has been determined in peat samples, and the physicochemical parameters of peat deposits have been studied. The specific activity of the radionuclide has been determined using beta radiometric methods with radiochemical preparation according to the methodology. The physicochemical parameters of the peat have been determined using weight-based methods according to the specified procedures. The influence of physicochemical parameters on the vertical migration of the radionuclide in peatlands has been evaluated using correlation analysis. The results have shown that the specific activity of strontium-90 in peat deposits ranges from 0.25 to 7.7 Bq/ kg. The results are consistent with typical values for all soils in Russia. The average value of the specific activity of strontium-90 in peat deposits is estimated to be 1.5±0.02 Bq/kg, which is below the established minimum values and average parameters for all soils in Russia. The pathways of vertical migration of strontium-90 in peat deposits demonstrate a downward direction with various trajectories. These pathways serve as a trace of past global atmospheric radioactive fallout. The vertical migration of strontium-90 in peat is associated with the organic matter content, ash content in peatlands, and recent local atmospheric fallout from nuclear fuel facilities. The research results provide valuable information for predicting the migration of strontium-90 into aquifers under changing environmental conditions due to the Arctic's rapid climate warming. [ABSTRACT FROM AUTHOR]

Strontium-90 (90Sr) is a major radioactive component that has attracted great attention, but its detection remains challenging since there are no specific energy rays indicative of its presence. Herein, a biosensor that is capable of rapidly detecting Sr2+ ions is demonstrated. Simple colorimetric method for sensitive detection of Sr2+ with the help of single-stranded DNA was developed by preparing MnO2 nanorods as oxidase mimic catalysis 3,3′,5,5′-tetramethylbenzidine (TMB). Under weakly acidic conditions, MnO2 exhibited a strong oxidase-mimicking activity to oxidize colorless TMB into blue oxidation products (oxTMB) with discernible absorbance signals. Nevertheless, the introduction of a guanine-rich DNA aptamer inhibited MnO2-mediated TMB oxidation and reduced oxTMB formation, resulting in blue fading and diminished absorbance. Upon the addition of strontium ions to the system, the aptamers formed a stable G-quadruplex structure with strontium ions, thereby restoring the oxidase-mimicking activity of MnO2. Under the best experimental conditions, the absorbance exhibits a linear relationship with the Sr2+ concentration within the range 0.01–200 μM, with a limit of detection of 0.0028 µM. When the concentration of Sr2+ from 10−8 to 10−6 mol L−1, a distinct color change gradient could be observed in paper-based sensor. We successfully applied this approach to determine Sr2+ in natural water samples, obtaining recoveries ranging from 97.6 to 103% with a relative standard deviation of less than 5%. By providing technical solutions for detection, our work contributed to the effective monitoring of transportation of radioactive Sr in the environment. [ABSTRACT FROM AUTHOR]

This study was conducted to confirm the Cs-137 and Sr-90 adsorption properties of illite. In the experimental method, illite was added to Cs-137 and Sr-90 solutions and stirred. And Following the completion of the adsorption reaction, the solid/liquid phase was separated using a centrifuge, and the adsorption rate was calculated by measuring the radioactivity concentration of the separated liquid phase using a gamma nuclide analyzer, Liquid Scintillation Count (LSC). As a result of the experiment, after reacting for 30 min, 94% of Cs-137 was adsorbed. And 84.26% of Sr-90 was adsorbed. [ABSTRACT FROM AUTHOR]

The paper presents the results of radioecological studies conducted in fish farms of the Dnipropetrovsk region. The distribution of radionuclides of natural and artificial origin is an urgent problem for various types of ecosystems, given the different routes of entry of these substances. The level of accumulation of radionuclides in the waters of the Zelenodolsk, Krynychansk and Kryvorizk fish farms was determined in a course of the presented study prior to the 2022 russian invasion of Ukraine. Content indicator of radium-226 in water ranged from 3.8 to 7.4 Bq/kg, thorium-232 - from 2.95 to 44.4 Bq/kg, potassium-40 - from 74.2 to 82.4 Bq/kg. Obtained in the present study results evidence that bottom sediments significantly accumulate the radionuclides. The registered content of radium-226 in them was from 30.1 to 14.8 Bq/kg, thorium-232 - from 9.6 to 41.5 Bq/kg, potassium-40 from 134.8 to 182.2 Bq/kg. The coefficients of accumulation of natural radionuclides in water and bottom sediments was registered as ranging from 1.4 to 5 for radium-226, from 0.82 to 3.3 for thorium-232, from 1.72 to 2.26 for potassium-40. The content of artificial radionuclides in water and bottom sediments determined in the study corresponded with their biochemical properties. In water, their value ranged from 0.13 to 1.8 Bq/kg for cesium-137 and from 0.05 to 0.08 Bq/kg for strontium-90. Taking into account the fact that bottom sediments accumulate a significant proportion of pollutants from water, the determined indicators were significantly higher than those in water, namely, from 5.6 to 10.4 Bq/kg for cesium-137 and from 1.5 to 2, 4 Bq/kg for strontium-90. The coefficients of accumulation of radionuclides of artificial origin in water and bottom sediments ranged from 3.3 to 80 for the content of cesium-137 and from 18.7 to 48 for the content of strontium-90. The levels of accumulation of natural radionuclides in the body of silver carp and carp were studied. The level of potassium-40 in the body of silver carp is lower than that of radium-226 and thorium-232 and ranges from 20.2 to 34.4 Bq/kg in all three fish farms. The same amount of radium-226 and thorium-232 was noted in the silver carp of the Krynychan fish farm which was on the level of 47 Bq/kg. In carp, the levels of natural radionuclides were significantly higher in all three fish farms. The content of cesium-137 was registered as approximately the same in silver carp and carp, with the exception of the Kryvyi Rih fish farm, where its level was significantly lower in the body of carp. Strontium-90 content was found in similar amounts in both types of fish. The concentration of radionuclides did not exceed the permissible levels. [ABSTRACT FROM AUTHOR]

The optimal conditions for the preconcentration of 90Sr from natural water samples with carbonate-containing zirconium hydroxide of T-3K grade were determined. A method was developed for the determination of 90Sr in natural waters with strontium concentration with T-3K sorbent of a low detection limit: 0.03 Bq/L from 1 L water samples, 0.02 Bq/L from 2 L sample. The method was tested during monitoring of 90Sr in natural reservoirs in the Sverdlovsk oblast and Chelyabinsk oblast and in water samples from monitoring and observation wells in a long-term RW storage facility locations. It was shown that the developed method can be used without constant monitoring of the yield of strontium in the concentrate for natural waters with a calcium concentration of ≤76 mg/L and a total hardness of ≤5.2 mM, but in view of the established elution yield of 91 ± 1 and 81 ± 2% from 1 and 2 L water samples, respectively, which simplifies and speeds up the analysis. With higher hardness of natural waters, the strontium elution yield as a function of calcium concentration or water hardness reported in the article can be used to determine the yield of strontium in the concentrate. [ABSTRACT FROM AUTHOR]

Nuclear weapons testing in the atmosphere during the 1950s and 1960s deposited fallout throughout the world, exposing all humans to food and water before the Limited Test Ban Treaty ended large-scale tests. The largest effort to measure in vivo fallout in humans, performed by Washington University (USA), collected over 300,000 deciduous teeth to document a sustained increase in Strontium-90 (Sr-90) during testing and a sharp decline after the test ban. Sr-90 patterns and trends in teeth were consistent with those of bones and milk. Sr-90 is still detectable in about 100,000 of the teeth, which were never tested. Tooth donors were born during atmospheric testing (1946–1965) and thus exposed to fallout in utero and during infancy/childhood, when exposures pose the greatest health risk. Preliminary analysis of global fallout's health risk in the United States indicates recent cancer mortality in several high-fallout areas exceeded that of states with the lowest fallout, peaking for the cohort born in the early 1960s, when fallout was highest. These findings support subsequent measurement of Sr-90 in deciduous teeth of persons who died of diseases such as cancer, along with controls, a novel approach to assessing fallout hazards. [ABSTRACT FROM AUTHOR]

Extramedullary plasmacytoma (EMP) is a benign round cell tumor that is most commonly found in cutaneous locations in dogs and occurs less frequently in the oral cavity. They are highly radiosensitive, are distinct from systemic multiple myeloma syndrome and wide surgical excision is typically curative. This report describes five cases of non-invasive oral EMP in dogs treated with a combination of marginal excision and strontium-90 plesiotherapy. All five cases had narrow or incomplete margins on histopathologic evaluation but experienced no recurrence after combination therapy. Plesiotherapy radiation may offer a potential adjunct treatment for non-invasive oral EMP by providing a superficial dose of radiation that complements a less invasive surgical removal. The combination of plesiotherapy and marginal excision may offer an alternative to wide surgical excision for non-invasive oral EMPs. [ABSTRACT FROM AUTHOR]

Artificially introduced into the environment 90Sr is highly radiotoxic, so its content levels in foodstuff and biota require constant monitoring for radiological protection. Most analytical procedures used for 90Sr determination are time-consuming, and therefore, a faster approach is needed. Employing the Bateman equation enables more efficient exploitation of the secular equilibrium between 90Sr and its daughter radionuclide 90Y in the calculations. This article describes a method for computing the 90Sr activity concentration, while accounting for 90Y activity. The developed approach was tested and validated in terms of its applicability in everyday analysis.

The solvent extraction of the 90Y/90Sr pair from carbonate media with mixtures of aromatic dihydroxy compounds and a quaternary ammonium salt—methyltrioctylammonium carbonate (MTOAC)—in toluene and butyl acetate was studied. It was found that MTOAC increases the distribution coefficients of both the extractant itself and its solvate with yttrium due to the formation of a mixed complex of yttrium and a dihydroxyaromatic ligand with MTOAC. During extraction from alkaline carbonate media in the pH range of 12–13.5 with mixtures of 0.01 M 2,3-dihydroxynaphthalene and 0.015 M MTOAC in butyl acetate or toluene, the distribution coefficients of yttrium exceed 80; the separation factors of the 90Y/90Sr pair under these conditions are more than 105. Dilute solutions of hydrochloric, nitric, and sulfuric acids can be used for the complete stripping of yttrium. The studied mixtures are chemically stable and do not change the extraction properties upon multiple extraction/stripping cycles. Model experiments on the leaching of yttrium from natural samples showed that the percentage of stable yttrium extraction from sand is 70–80%, while the percentage of yttrium extraction from soil is 50–60%. [ABSTRACT FROM AUTHOR]

Sr(II) sorption was performed using collected groundwater and soil samples surrounding the long-distance radioactive liquid effluent pipelines of a proposed nuclear power plant in China. The species, Sr2+ and SrSO4(aq), mainly contributed to the sorption process. And Sr(II) sorption, fitted well by the pseudo-second-order kinetic model, indicated that chemical sorption occurred and was dependent on the sorption capacity of soil samples. Moreover, a linear relation of solid–liquid distribution coefficients (Kd) with cation exchange capacity and pH was obtained through Pearson correlation coefficient (r) and multiple regression analysis. [ABSTRACT FROM AUTHOR]

Objective: To explore the separation condition for 90Sr using crown ether resin, in order to establish a fast method for analysis of 90Sr in food and environmental samples. Methods: Stable strontium isotope (88Sr) was used to simulate the radioactive 90Sr, and the concentration of 88Sr in elution solution was detected using inductively coupled plasma mass spectrometry (ICP–MS). The separation conditions were investigated through batch experiment. Results: Under the optimized experimental conditions, the maximum adsorption capacity of crown ether resin was 22.28 ​mg/g. 4.0–8.0 ​mol/L nitric acid made it easier for the Sr2+ to load on the resin, and 20 ​mL ultrapure water was used to rinse the chromatographic column to achieve a good separation effect, by which the recoveries of Sr2+ were nearly close to 100%. The average recovery rates of 4 samples were 60.25%, 69.26%, 75.09% and 66.33%, respectively. Conclusions: Crown ether resin has very good selectivity and adsorption for 90Sr. The optimized conditions were high-efficiency and easy to operate. The separation method has great potential for the fast analysis of 90Sr in food and environmental samples.

Artificially introduced into the environment 90Sr is highly radiotoxic, so its content levels in foodstuff and biota require constant monitoring for radiological protection. Most analytical procedures used for 90Sr determination are time-consuming, and therefore, a faster approach is needed. Employing the Bateman equation enables more efficient exploitation of the secular equilibrium between 90Sr and its daughter radionuclide 90Y in the calculations. This article describes a method for computing the 90Sr activity concentration, while accounting for 90Y activity. The developed approach was tested and validated in terms of its applicability in everyday analysis. [ABSTRACT FROM AUTHOR]

Radionuclide contamination in foods has been a public concern in Japan after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. To estimate time and regional trends of daily intake and annual committed effective dose of strontium-90 (90Sr) after the accident, we analysed Market basket samples using a low background 2π gas-flow counter. Samples were collected from six regions, once a year from 2013 to 2018. There appeared to be little variation in estimated daily intake and annual committed effective dose of 90Sr across the time periods and regions. The estimated maximum annual committed effective dose of 90Sr was 0.00076 mSv/year, a value sufficiently lower than the intervention exemption level, 1 mSv/year, in foods in Japan. There was no noticeable difference between the range of estimated daily intake of 90Sr in this study compared with daily intake measured before the FDNPP accident. These results suggested that no obvious increase in dietary intake of 90Sr was observed after the FDNPP accident, and that the effects on commercial foods from 90Sr due to the FDNPP accident were negligible. [ABSTRACT FROM AUTHOR]

This work presents the results of evaluating the effect of some organic compounds on the efficiency of strontium removal by a granular sorbent based on manganese oxide. Sodium dodecyl sulfate has not a noticeable effect on the sorption characteristics of the sorbent. It has been shown that Trilon-B in concentrations up to 10–3 mol/L has a positive effect on the efficiency of strontium removal, which is, probably, the result of the processes of partial reduction of the surface of the material. Under dynamic conditions, the presence of Trilon-B leads to rapid destruction of the sorbent due to the formation of Mn-EDTA complexes. The presence of humic and fulvic acids in the solution at a concentration of less than 10–4 g/L in neutral media increases the efficiency of strontium removal in micro- and macro-concentration. Under dynamic conditions, the presence of humic acid increases the value of the effective filter cycle up to 50% breakthrough by 1.9 times compared to the control experiment; however, it reduces the value of the decontamination factor coefficient due to the formation of Sr-HA complexes. [ABSTRACT FROM AUTHOR]

Background210Bi is one of the most important interferences in the analysis of 90Sr by extractive chromatography. It is verified by the leaching curve that bismuth and yttrium are completely adsorbed on the chromatographic column in the bis(2-ethylhexyl) phosphate (HDEHP) extraction chromatography, and this two components can not be completely separated, resulting in higher measurement results of 90Sr.PurposeThis study aims to provide a modified method to eliminate 210Bi interference in the analysis of 90Sr by bis(2-ethylhexyl) phosphate (HDEHP) extraction chromatography.MethodsBy collecting the eluent, measuring the content of strontium, yttrium, lead and bismuth in the eluent and drawing the leaching curve, the adsorption and elution behavior of strontium, yttrium, lead and bismuth in the P204 resin were investigated. The residual 210Bi after column separation was experimentally removed by Bi2S3 precipitation or by measuring the sample source repeatedly and correcting the result with formulas.ResultsThe experimental results show that the relative deviation between the modified 90Sr activity and the reference value is within 23% when the activity ratio of 210Bi to 90Sr is not bigger than 5. The results of 90Sr calculated by the modified method for environmental samples are in good agreement with the measured results after bismuth removal by Bi2S3 precipitation.ConclusionsThe interference of 210Bi in the analysis of 90Sr by extractive chromatography can be eliminated by measuring the sample source repeatedly and correcting the result with formulas.

The United States detonated 67 nuclear weapons in the Marshall Islands from 1946 to 1958. While there has been significant study of the aftereffects of these explosions over the decades that followed, few values of strontium-90 (90Sr) contamination have been reported. Sediment cores from the Bravo test crater in Bikini Atoll and Lacrosse crater near Runit Island (Enewetak Atoll) were assessed for 90Sr and cesium-137 (137Cs) concentrations, which were found to be measurable in all cores. 90Sr values were found to be roughly consistent across the tested cores. Ratios of 90Sr/137Cs are elevated compared to values measured previously at other sites of weapons testing and nuclear accidents. These findings suggest the need to further investigate 90Sr concentrations in the northern Marshall Islands to assess the safety of current residents in light of the potential for 90Sr conveyance and to provide input regarding resettlement of currently unoccupied islands and atolls.

A qualitative approach to discern the relative contributions of 137Cs and 90Sr in-solution with a monitoring probe is described, based on a comparison of X- and γ-ray photon spectra. The bremsstrahlung yield from 90Sr has been measured as a function of distance (x) from a cerium bromide scintillation detector relative to the 137Cs γ-ray full-energy peak response. The utility of two, count-independent shape factor parameters has been compared: the ratio of the sum of the counts in the 60–800 keV region to the full-energy peak response associated with the 137Cs 662 keV γ-ray line, termed for the benefit of this paper as SF1, and the ratio of counts in the 60–350 keV region to those in the 350–450 keV region, defined in this work as SF2. These parameters probe the presence of isotopes associated with clear full-energy spectral lines and bremsstrahlung, respectively. They have been calibrated as a function of x with sealed sources in the laboratory and both are observed to be asymptotic as x → 0. This approach has been tested with a variety of open, laboratory-based liquid samples comprising 90Sr and 137Cs, and in a water-based, contaminated medium in the field associated with a sump at a low-level waste disposal facility on the former fast reactor site at Dounreay, UK. The highest response in both SF1 and SF2 measured in this work is observed in these on-site measurements, consistent with x → 0 , implying both 90Sr and 137Cs presenting together in solution. This is consistent with prior, laboratory-based analysis of the sump media, and suggests that the β−-emitter contribution (anticipated to comprise 90Sr and 90Y) is very near the probe, consistent with the solution being in contact with it. This is of relevance where the β−/γ composition of contaminated groundwater, in-situ, is not well understood or where migratory changes in activity are suspected. [ABSTRACT FROM AUTHOR]

The research was aimed at studying the accumulation of natural and artificial radionuclides in medicinal plant raw materials (MPMs) and determining approaches to standardization of natural radionuclides in them using plants growing in Voronezh Region as examples. A total of 36 collection sites of soil and MPM located throughout Voronezh Region and diverse in terms of anthropogenic impact were selected. Pharmacopoeial species of MPM were used as research subjects. All MPMs met the requirements of GPM.1.5.3.0001.15 for specific activity of cesium-137 and strontium-90 and for the total indicator of compliance with radiation safety requirements and its determination accuracy. The obtained specific activities of natural radionuclides in most cases exceeded the numerical values for radionuclides of anthropogenic origin. Asupplement to general pharmacopoeia monograph GPM.1.5.3.0001.15 establishing the additional numerical indicator "Effective specific activity of natural radionuclides not greater than 165 Bq/kg" is proposed to monitor contamination of MPM with natural radionuclides. These recommendations are based on an analysis of greater than 360 MPM samples from territories subject to various anthropogenic impacts. However, they are preliminary in nature and require additional research on MPMs from other regions of the Russian Federation. [ABSTRACT FROM AUTHOR]

At the end of 36 years after the Chernobyl disaster, about 5 million people still live in the radioactively contaminated territories of Russia, Ukraine, and Belarus, and the density of radioactive contamination by Cesium-137 and Strontium-90 will remain radiologically significant for decades. We assessed cervical and endometrial cancer primary incidence (new cases) in the female population from the Bryansk region living in conditions of chemical, radioactive, and combined environmental contamination for 2000–2020. We found a significant increase in the long-term trend in the primary incidence of cervical and endometrial cancer in all the studied groups, regardless of the environmental conditions of residence (p < 0.00001). We did not find statistically significant differences in the incidence of cervical and endometrial cancer in women, regardless of the level of chemical, radioactive, and combined environmental contamination. However, women living in environmentally unfavorable areas (in total, in the territories of chemical, radioactive, and combined contamination) are statistically significantly more likely to develop endometrial cancer in terms of relative risk compared to environmentally safe (control) areas (RR 1.17 (1.08–1.27)). No such pattern was found for cervix cancer. It should be noted, since environmentally safe (control) areas have a certain level of contamination (albeit low), RR is underestimated. [ABSTRACT FROM AUTHOR]

A physicochemical properties of carbonate-containing zirconium hydroxide T-3K sorbent as well as selective 90Sr sorption from natural waters were studied. It was shown that sorbent consist of ZrO2 (46.39%), Na2O (1.78%) and Al2O3 (1.42%) as the major components in microporous carbonate-containing zirconium hydroxide where sorption of 90Sr occurs due to formation of sparingly soluble strontium carbonate. Affinity of the T-3K sorbent for alkaline earth ions corresponded to the reverse trend of carbonates solubility: Sr > Ba > Ca ≫ Mg and maximum strontium sorption was observed at pH 7–10. Distribution coefficients of strontium were (1.3 ± 0.1) × 103 mL/g for low mineralized water with calcium content of 16 mg/L and 95 mL/g for seawater; static exchange capacity of the sorbent was 30.4 ± 0.5 mg/g. [ABSTRACT FROM AUTHOR]

90Sr is one of the most hazardous contaminants in the environment. In this work, the radioactive level of 90Sr in soil along the Hai River in Tianjin, China, was detected to investigate the background radioactivity level of Tianjin and assess its hazards to humans and the environment. Twenty-seven soil samples were collected from 12 sampling points along the Hai River. The soil samples were pretreated by microwave digestion and separated by Sr-specific resin. The recovery rate of carrier (88Sr) was detected by inductively coupled plasma-mass spectrometry (ICP-MS) and the radioactivity of 90Sr of the samples was detected by a liquid scintillation counter (LSC). The recovery rate of carrier was between 45.83 and 83.38%, and the average recovery rate was 71.58%. The radioactivity concentration of 90Sr in soil samples ranged from 0.251 to 0.865 Bq/g, and the average radioactivity concentration was 0.419 Bq/g. In addition, the method had a minimum detection limit (MDL) of 0.292 Bq/g, with only one sample below it, and the average error was 0.096. In conclusion, the radioactivity concentration of 90Sr in the soil along the Hai River was extremely low, and it would hardly affect the human body and the biosphere. [ABSTRACT FROM AUTHOR]

Strontium-90 (Sr-90) contamination in food is a major public health issue. Several radiochemical methods are available for the determination of Sr-90. However, the application of these procedures is not focused on solid foods, but only on liquid (milk, water, etc.) and environmental matrices, and they were not fully validated. The aims of this work were to establish and validate a fast, sensitive method for the determination of Sr-90 in solid food matrices such as meat and dairy products, seafood, vegetables, and animal feed, using a specific resin for extraction and ultra-low-level liquid scintillation counting for detection. The method was optimised and validated according to relevant legislation. Good analytical performance was obtained, including high specificity and linearity together with low measurement uncertainty (13.1%). The minimal detectable activity was 11 mBq kg−1, and the mean repeatability (CV%) and recovery values were 10.7% and 100.1%, respectively. These parameters assured method applicability for official food safety controls. The method was applied to reference materials and submitted to proficiency test round to confirm its reliability for Sr-90 quantification in solid foodstuffs and feed. The newly established method may be broadly applicable to complex matrices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption of Sr by ethyl butyl phosphonate silica was demonstrated for the first time. • Hydrodynamic adsorption was possible, with reasonable capacity, at a high flow-rate. • Optimal operating pH and maximum adsorption capacity were quantified. • The silica shows greater capacity for Sr than for transition metals. • Evidence suggests that the silica matrix directly interacts with the adsorption process; not just the functional group. [ABSTRACT FROM AUTHOR]

Strontium-90 (90Sr) is a major contaminant at nuclear legacy sites. The mobility of 90Sr is primarily governed by sorption reactions with sediments controlled by high surface area phases such as clay and iron oxides. Sr2+ adsorption was investigated in heterogeneous unconsolidated aquifer sediments, analogous to those underlying the UK Sellafield nuclear site, with grainsizes ranging from gravels to clays. Batch sorption tests showed that a linear K d adsorption model was applicable to all grainsize fractions up to equilibrium [Sr] of 0.28 mmol L−1. Sr2+ sorption values (K d ; Langmuir q max) correlated well with bulk sediment properties such as cation exchange capacity and surface area. Electron microscopy showed that heterogeneous sediments contained porous sandstone clasts with clay minerals (i.e. chlorite) providing an additional adsorption capacity. Therefore, gravel corrections that assumed that the > 2 mm fractions are inert were not appropriate and underestimated K d (bulk) adsorption coefficients. However, K d (<2 mm) values measured from sieved sediment fractions, were effectively adjusted to within error of K d (bulk) using a surface area dependant gravel correction based on particle size distribution data. Amphoteric pH dependent Sr2+ sorption behaviour observed in batch experiments was consistent with cation exchange modelling between pH 2–7 derived from the measured cation exchange capacities. Above pH 7 model fits were improved by invoking a coupled cation exchange/surface complexation which allowed for addition sorption to iron oxide phases. The overall trends in Sr2+ sorption (at pH 6.5–7) produced by increasing solution ionic strength was also reproduced in cation exchange models. Overall, the results showed that Sr2+ sorption to heterogeneous sediment units could be estimated from K d (<2 mm) data using appropriate gravel corrections, and effectively modelled using coupled cation exchange and surface complexation processes. • Sr sorption was determined in a range of heterogeneous aquifer sediments. • Gravels contained porous sandstone clasts containing clays and iron oxides. • K d (bulk) could be estimated from K d (<2 mm) using appropriate gravel corrections. • pH and ionic strength effects could be modelled as cation exchange processes. [ABSTRACT FROM AUTHOR]

The sorption characteristics of modified humic acid-based sorbents obtained from peat from the Gurovskoye deposit are studied. The functional and elemental composition of the sorbents is determined, and the molecular weight characteristics of the sorbent components are analyzed. The sorption of 137Cs and 90Sr from liquid media depends on the pH value and the type and concentration of competing cations. The maximum adsorption capacity was calculated by fitting the obtained sorption isotherms to the Langmuir equation: the highest values ​​are achieved on HA-2 (257 mg Cs/g) and HA-5 (310 mg Sr/g). The dependence of the sorption-selective characteristics of the sorption materials with respect to cesium and strontium was determined depending on the functional composition. The humic acid-based sorbents are recommended for the extraction of cesium and strontium radionuclides in a wide range of liquid media, including environmental objects, based on the results of this study. [ABSTRACT FROM AUTHOR]

This study presents a rapid and novel sequential separation strategy based on extraction chromatography for determining 90Sr, 210Pb and 210Po in drinking water samples. It involves the use of Sr resin for the separation and then liquid scintillation counting and alpha spectrometry for the determination. The experimental results obtained showed that the proper acidic solution to quantitatively retain the aforementioned radionuclides is 3 M HNO3. The optimum eluents were determined for obtaining quantitative recoveries (70–80%) of 90Sr, 210Pb and 210Po. The method was validated with intercomparison water samples and is satisfactory in terms of minimum detectable activities, which are 50% lower than that established in RD 314/2016. [ABSTRACT FROM AUTHOR]

Sr-90 is utilized as a raw material in various fields such as nuclear batteries, medical applications, and industrial use as a beta particle source. Therefore, high-purity Sr-90 is required to increase the thermal efficiency of nuclear battery operation or to prevent side effects on the human body during its use in medical therapy. Sr-90 is present in spent nuclear fuel and can be separated via reactive distillation through a pyrochemical process developed at the Korea Atomic Energy Research Institute, where Ba is obtained simultaneously via co-precipitation owing to its chemical similarity. In addition, Sr-90 decays into Zr-90 during the storage period after separation. Therefore, Ba and Zr-90 should be separated to obtain high-purity Sr-90 nuclides. In the present study, a separation and purification process is developed for the recovery of Sr-90 from a waste mixture containing Sr-90, Ba, and Zr-90. To separate Ba and Zr-90, the chromate precipitation reaction is modified via pH control, which can enhance the precipitation efficiency of Ba and prevent the co-precipitation of Sr owing to the excess amount of precipitants. A systematic study is conducted to optimize Sr-90 separation and purification processes, where a high yield of 84.3% is obtained, and a high purity exceeding 99.9% is maintained. [ABSTRACT FROM AUTHOR]

In this paper, DGA-normal resin has been used for the chemical separation of Sr and Y from Cs as well as other elements in standard solutions. The decontamination factor of Cs was tested in different acidic media. It was found that 8 M HNO3 was the most effective rinsing solution with a Cs decontamination factor exceeding 400,000. Application of the DGA-normal resin allows the separation of Y and Sr from other interfering beta emitter isotopes. This resin is suitable for 90Sr and 90Y separation in contaminated Fukushima soil samples giving the prospect of 90Sr measurement in a direct (90Sr) and indirect way (90Y). [ABSTRACT FROM AUTHOR]

The Fukushima Daiichi Nuclear Power Plant accident (2011) released large amounts of radioactive substances into the environment and generated highly radioactive debris. Post-accident countermeasures are currently in the phase of fuel debris removal, which requires the analysis of radioactive contaminants in the environment and fuel. The spectra of solely β-emitting nuclides, such as 90Sr, overlap; thus, an effective method for nuclide separation is desired. Since conventional methods for high-dose sample analysis pose substantial exposure risks and generate large amounts of secondary radioactive waste, faster procedures allowing for decreased radiation emission are highly desirable. In this study, we developed a 90Sr2+ quantitation technique based on liquid scintillation counting (LSC)–coupled capillary transient isotachophoresis (ctITP), along with two-point detection and relying on the rapid concentration, separation, and fractionation of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-complexed 90Sr2+ in a single run. The applicability of our method for the analysis of real-world samples was verified by conducting addition-recovery experiments using a seawater reference material and radioactive liquid waste obtained from the radioactive waste treatment facility at the Japan Atomic Energy Agency. The recovery determined by LSC was 95–113%, indicating successful quantitative analysis. 90Sr recovery was determined to be 90.1% from a contaminated water sample obtained from the Fukushima Daiichi Nuclear Power Plant, which was analyzed using the standard addition of 90Sr. The sensitivity (detection limit = 0.016 Bq) of the proposed method on a radioactivity basis was equal to or higher than that of the conventional method using ion exchange-LSC (0.012–0.07 Bq). Our method allows for the handling of high-dose radioactive samples at the microliter level and is substantially faster than conventional ion exchange protocols, whereas ctITP has not been used for practical applications due to inaccurate collection and lack of a suitable chemical system. The concentration–separation–fractionation protocol in ctITP is successful due to the existence of a rare inert Sr2+ complex and precise fractionation. This study establishes a pathway toward safer and more practical analysis of radionuclides. [Display omitted] • 90Sr quantitation method requiring microliter-scale samples is developed & validated. • 90Sr concentration, separation, & fractionation by CE/LSC are achieved in one run. • Sr ion strongly complexes with UV-active probe (DOTA) to facilitate detection. • High analytical performance is due to the kinetic inertness of the Sr-DOTA complex. [ABSTRACT FROM AUTHOR]

The liquid radioactive waste (LRW) management at the Ukrainian nuclear power plants is an urgent problem since the scheme of treatment of radionuclide-bearing solutions by deep evaporation with subsequent crystallization of radionuclides in the form of soluble salts has a number of serious drawbacks and the final products of the treatment (vat residue, spent sorbents and sludges, salts) do not meet the ac-ceptance criteria for long-term storage and disposal. One of the promising LRW treatment schemes is the one using methods of selective sorption by natural and modified sorbents. The article presents the results of the study of the kinetics of 90Sr and 137Cs sorption by natural, acid- and alkaline-modified zeolites from Sokirnyt’ske deposit. The maximum degree of sorption on natural zeolite during the experiment (14 days) was 55% for 90Sr and 90% for 137Cs. The maximum degree of 90Sr and 137Cs sorption on alkaline-modified zeolite was 62.2% and 98.78%, respectively. For acid-modified zeolite, the maximum sorption degree of 90Sr was 18% and of 137Cs – 85%. Thus, it can be infered that among the studied zeolites, the most effective sorbent of 90Sr and 137Cs is alkaline-modified zeolite (Na-form). Sodium hydrox-ide modification of the natural zeolite increases the sorption degree of both 90Sr and 137Cs by 10 15%. The results of determining the forms of being of the adsorbed radionuclides indicated that the sorption of 90Sr on natural and alkaline-modified zeolites is characterized by up to 20% predominance of ion-exchangeable forms, and sorption on acid-modified zeolite – by the equality of exchangeable and non-exchangeable forms. The sorption of 137Cs on natural and alkaline-modified zeolites is characterized by up to 10% predominance of ion-exchangeable form. In the case of the alkaline-modified zeolite, 10% predominance of non-exchangeable adsorbed cesium form was observed during the first 2 days of the experiment. During the sorption of 137Cs on alkaline-modified zeolite, double predominance of the exchangable form over the non-exchangeable was observed during the whole experiment (14 days).

AIM: To evaluate the risk factors leading to recurrence in patients with ocular surface squamous neoplasia (OSSN) METHODS: The records of 112 patients with OSSN who underwent treatment and follow-up between February 1999 and August 2018 were reviewed retrospectively. RESULTS: Totally 67 patients (59.8%) were male and 45 patients (40.2%) were female. The mean age at presentation was 63.7y (range 22-87y). Partial lamellar scleroconjunctivectomy (PLSC) was performed in 105 (93.7%) cases and enucleation was performed in 7 (6.3%) cases due to bulbus invasion as the first step treatment. Treatments used in addition to PLSC included cryotherapy in 78 eyes (74.3%), alcohol epitheliectomy in 57 eyes (54.3%) for presence of corneal involvement, and amniotic membrane transplantation in 17 eyes (16.2%) for ocular surface reconstruction. Topical mitomycin C was used in 10 patients (9.5%) and strontium-90 (Str-90) treatment in 4 (3.8%) patients because surgical margins were tumor positive at the histopathological examination. Postoperative histopathologic diagnoses were squamous cell carcinoma (52 cases), carcinoma in situ (44 cases), moderate conjunctival intraepithelial neoplasia (11 cases), and mild conjunctiva intraepithelial neoplasia (5 cases). At a mean follow-up of 20.1mo, tumor recurrence was observed in 21 (18.8%) cases. The rate of recurrence was found to be lower in cases that underwent supplemental cryotherapy compared to those that did not (P