Determination of137Cs and90Sr in milk by the static method with an ion exchanger

This paper presents the method of⁹⁰Sr and¹³⁷Cs determination from 10 litres of milk. The preconcentration is made by the static method with a strong acid cation exchanger (OSTION KS).¹³⁷Cs from the eluent (8M HCl) is selectively eliminated with ammonium molybdophosphate and then the^137mBa gamma activity measured, using NaI(T1) detector.⁹⁰Sr as⁹⁰Y is determined after achievement of the radioactive equilibrium and measured by flow proportional counter. The method appears to be accurate, reproducible and permits to determine³² mBq¹³⁷Cs and 13 mBq⁹⁰Sr in the samples.     

Determination of90Sr and137Cs in mushrooms following the Chernobyl fallout

After the Chernobyl accident high concentrations of radionuclides were found in Sweden in mushrooms and the contents of⁹⁰Sr and¹³⁷Cs were measured. The level of⁹⁰Sr was generally low and, in proportion to¹³⁷Cs, 2–3 orders of magnitude lower than in the fallut. The contents of¹³⁷Cs varied among species and extreme local variations occurred. The ratio¹³⁴Cs/¹³⁷Cs diverged from other biological samples leading to the conclusion that old fallout was involved in the uptake.     

Calculation of artificial radionuclides in the ocean by an ocean general circulation model

The concentrations of three artificial radionuclides (⁹⁰Sr, ¹³⁷Cs and ^239+240Pu) introduced into seawaters from global fallout were simulated from 1957 to 1994 by using an ocean general circulation model. The distributions of the calculated ¹³⁷Cs and ⁹⁰Sr concentrations were in good agreement with the observed concentrations. The vertical distribution of the calculated ^239+240Pu concentration in the South Pacific also agreed with the observed data. However, the calculated ^239+240Pu concentrations in the North Pacific water columns were significantly underestimated in comparison with the observed data, which strongly suggests the presence of additional sources of plutonium input to the North Pacific.     

Artificial radioactive contamination of sediment samples along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of¹³⁷Cs were determined by in 11 sediment samples, collected along the Romanian sector of the Danube river and the Black Sea coast during 1994 γ-ray spectrometry. The concentrations of⁹⁰Sr in the same sediment samples were determined by β-counting of the⁹⁰Y oxalate, precipitated after strontium separation using a strontium extraction chromatography column. The concentration distributions of¹³⁷Cs and⁹⁰Sr are compared with the²³⁸Pu and^239,240Pu concentration distributions in the same samples, reported in a previous paper. The accumulation potential of¹³⁷Cs,⁹⁰Sr and plutonium isotopes in the river and sea sediments analysed is discussed.     

Separation of137Cs and90Sr from mineralizates of biological materials by dicarbolide of cobalt

The distribution of some radionuclides in the course of¹³⁷Cs and⁹⁰Sr extraction and scrubbing between organic and water phase was determined.¹³⁷Cs and⁹⁰Sr were isolated from the mixture of radionuclides in mineralized biological materials. Dicarbolide of cobalt i. e. 3,3′-commo-bis[undecahydro-1,2-dicarbo-3-closo-dodecaborate] was used as an extracting agent. Quantities of the extracted radionuclides were determined by gamma spectrometric technique. Single and repeated extraction of⁹⁰Sr with 0.01M resp. 0.1M dicarbolide of cobalt in nitrobenzene and scrubbing of coextracted radionuclides by 0.5M HNO₃ were studied. The extraction of⁹⁰Sr was investigated from solutions of a hydrofobizing agent in the same way. Finally, the quantitative extraction of¹³⁷Cs followed by the extraction of⁹⁰Sr from mixtures of radionuclides in a mineralized biological material was studied. Extraction yields from dry and wet mineralizates of biological tissues, from urine and milk were compared. Suitable working conditions for the separation procedures were selected.     

Depth distribution of137cesium,90strontium and210lead in sediments of lake Mondsee,Austria

¹³⁷Cs,⁹⁰Sr and²¹⁰Pb were determined in sediment cores from lake Mondsee /Austria/. The depth profiles show that¹³⁷Cs remains undisturbed, i.e. its distribution corresponds to the fallout deposition pattern.⁹⁰Sr, however, has been transported into the upper sediment layers. In this upper zone nearly constant levels of⁹⁰Sr and also of²¹⁰Pb/²¹⁰Po/were found. Comparison of the⁹⁰Sr and¹³⁷Cs profiles indicates that chemical processes must be responsible for the translocation of⁹⁰Sr as well as²¹⁰Pb, and not bioturbation, i.e. mixing of upper sediment layers by benthic organisms.Dedicated to Prof. Dr. Karl Schlögl, University of Vienna, for his 60th birthday.     

Determination of137Cs,90Sr and fallout Pu in the volcanic soil of Korea

The cumulative depositions of¹³⁷Cs,⁹⁰Sr and fallout Pu in the volcanic ash soil of Korea were determined. The average accumulated depositions of¹³⁷Cs,⁹⁰Sr and fallout Pu in the volcanic soil were much higher than those in other forest sites of Korea. From depth profiles, it was found that¹³⁷Cs,⁹⁰Sr and^239,240Pu in the volcanic soil are more mobile than those in other forest sites of Korea, and that the downward movement of⁹⁰Sr is faster than¹³⁷Cs and^239,240Pu. A significant correlation was found between the concentration of¹³⁷Cs and those of⁹⁰Sr and^239,240Pu. The activity ratios of²³⁸Pu/^239,240Pu and²⁴¹Pu/^239,240Pu in soils are close to those observed in the cumulative deposit from the global fallout of nuclear weapon testings.     

Selected radionuclides and heavy metals in skeletons of birds of prey from eastern Poland

Results of determination of ¹³⁷Cs, ⁹⁰Sr, ⁴⁰K, ^239+240Pu, and heavy metals: Mn, Zn, Pb, Cd, Ni, Cr, Co, and Cu in skeletons of 15 species of birds of prey from Eastern Poland were presented. The greatest amounts of ¹³⁷Cs and ⁹⁰Sr (70 Bq/kg and 33 Bq/kg, respectively) were found in rough-legged buzzards (Buteo lagopus), winter visitors, coming from former soviet nuclear test places. Concentrations of ^239+240Pu in raptors were negligible, only lesser-spotted eagles (Aquila pomarina) revealed slightly higher values. Median concentrations of ¹³⁷Cs and ⁹⁰Sr in raptors which feed predominantly on small mammals were higher in comparison to concentrations found in other ones preferring different trophy. The most noticeable was a very high lead concentration (reaching above 600 mg/kg) in birds which utilize un-retrieved hunting casualties as their prey.     

Mixing of atmospheric <Superscript>210</Superscript>Pb and <Superscript>7</Superscript>Be and <Superscript>137</Superscript>Cs and <Superscript>90</Superscript>Sr fission products in four characteristic soil types

Depth distribution of atmospheric ²¹⁰Pb and ⁷Be and ⁹⁰Sr and ¹³⁷Cs fission products was measured in two types of aeolian soils (desert dust and volcanic ash), irrigated paddy soil and strongly acidic soil. The depth dependence of ²¹⁰Pb, ⁷Be and ¹³⁷Cs show that these radionuclides have been diffused as solid soil particles in surface soil layers. In aeolian soil layers, about 50% of ⁹⁰Sr were diffused in surface soil layer and the remaining 50% had penetrated to deeper layers. The half of the fission particles containing ⁹⁰Sr were shown to have decomposed over the past 35 years.     

Radioanalytical determination of137Cs and89Sr in milk

Separation of Cs, Sr and Ca from their mixture was studied using solvent extraction and ion exchange techniques. More than 90% separation efficiency was achieved for Ca–Sr separation using ion exchange resin (Doulite C-20) while solvent extraction amounted to 88%. A proposed technique for determination of¹³⁷Cs and⁸⁹Sr in milk (after removal of organic matter) showed more than 80% accuracy for⁸⁹Sr determination and more than 90% for¹³⁷Cs determination.     

Ion exchange of 90Sr and 137Cs into 1‐vinyl‐2‐pyrrolidone–divinylbenzene cation‐exchange resin

Radiotracer batch ion‐exchange experiments were employed to investigate the uptake of ⁹⁰Sr and ¹³⁷Cs radioisotopes by various cation‐exchanged forms of a 30% cross‐linked macroporous 1‐vinyl‐2‐pyrrolidone–divinylbenzene cation‐exchange resin with 1.37 ml g^?1 pore volume, 0.0232 µm pore diameter and 271.2 m² g^?1 surface area. The uptake of ⁹⁰Sr and ¹³⁷Cs was determined by taking liquid aliquots at various time intervals from solutions over solids. The volume‐to‐solid ratio was kept at 200. The results of kinetic experiments for the carrier‐free ⁹⁰Sr and ¹³⁷Cs were evident in all cationic forms of the resin. The percentage uptake and distribution coefficient K_d values with carrier (0.005 M SrCl₂ and 0.01 M CsCl) concentrations were also determined, and the best results were obtained from the Li⁺ and H⁺ forms of the resin. Cerenkov counting (β^?‐counting) was used to observe the initial and final radioactivity in the liquid phase. All the experiments were carried out at room temperature and the radioactivity in each case was corrected for the background counts. Copyright © 2005 John Wiley & Sons, Ltd.     

Uptake of cesium and strontium by crystalline silicotitanates from radioactive wastes

Crystalline silicotitanate inorganic ion exchanger, with a sitinakite structure is candidate material for remediation of aqueous nuclear waste streams. The syntheses of crystalline silicotitanate (CST) and Nb-substituted crystalline silcotitanate (Nb-CST) were carried out under hydrothermal conditions and the products were characterized using techniques viz., XRD, SEM/EDS, DTA/TGA, surface area respectively. Batch experiments were carried out to study the kinetics of uptake of ¹³⁷Cs and ⁹⁰Sr, to estimate the decontamination factor (DF) values and distribution coefficients (K _d) for the above synthesized CST and Nb-CST samples from actual radioactive waste solutions. The DF values for uptake of Cs and Sr by Nb-CST after 24 h of equilibration was 355 and 136 whereas for CST it was found to be 40 and 176 respectively. The K _d values for uptake of Cs and Sr for Nb-CST after 24 h of equilibration was found to be 35,490 and 13,500 mL/g respectively whereas the K _d values for uptake of Cs and Sr for CST was found to be 4,025 and 17,525 mL/g respectively. The ion exchange capacity of Nb-CST towards ⁹⁰Sr and ¹³⁷Cs was estimated to be 11.8 and 3.2 meq/g respectively whereas the ion exchange capacity of CST towards ⁹⁰Sr and ¹³⁷Cs was estimated to be 14.6 and 4.4 meq/g respectively.     

Development of field portable sampling and analysis systems

A portable, field rugged, sampling and analysis system has been developed for the rapid screening of aqueous samples during scoping and remediation studies. Using field portable equipment, water is pumped through ion selective solid phase extraction (SPE) disks, at a flow rate of 150-250 ml/min, and counted for the radionuclide of interest in the field using portable detectors. SPE disks are currently available to selectively concentrate ⁹⁹Tc, ⁹⁰Sr, radiocesium (¹³⁴Cs and ¹³⁷Cs) and radium isotopes. In the field the radiocesium concentration is determined by gamma-spectrometry, ⁹⁰Sr and ⁹⁹Tc are determined by beta-counting. A one-liter sample can be processed and ready for counting within ten minutes. Using a 5-minute counting time, a detection limit of <50 pCi/l for ⁹⁹Tc or ⁹⁰Sr and ~50 pCi/l for ¹³⁷Cs has been achieved. Up to 10 liters of water have been processed for the analysis of ⁹⁹Tc and ¹³⁷Cs when lower limits of detection were required. The sampling and analysis system has been field tested at the Savannah River Site (SRS), Aiken SC, and the Hanford Site, Richland WA. The SRS H-area tank farm storm water runoff system was analyzed for ⁹⁰Sr and ¹³⁷Cs. Groundwater from the SX tank farm at the Hanford Site was analyzed for ¹³⁷Cs and ⁹⁹Tc. Groundwater from seeps below the 100-H area at Hanford was analyzed for ⁹⁰Sr and ⁹⁹Tc.     

A study on radionuclide association with soil components using a sequential extraction procedure

Measurements performed in 1986–1988 demonstrate that most of the radiocesium isotopes (¹³⁷Cs and¹³⁴Cs) deposited after the Chernobyl accident are still located in the upper soil layers (0–2 cm). The vertical migration appears to be slow, and only a small fraction of the radiocesium has been transferred into the biological cycle. Sequential extraction techniques have been utilized in order to investigate the degree of binding or association between deposited radionuclides (¹³⁷Cs,¹³⁴Cs and⁹⁰Sr) and components in soil. The results indicate that a major fraction of the radiocesium is associated strongly with organic and mineral materials in the litter or upper soil layers: less than 10% is easily leachable. The distribution of¹³⁷Cs throughout the fractions was similar to that determined for naturally occurring stable cesium (¹³³Cs), implying that isotopic exchange had been extensive. For⁹⁰Sr, the results show a relatively high leachable fraction. Therefore, present results indicate that radiocesium should be less mobile, and less available for root uptake, than⁹⁰Sr in soil.     

Quality assessment of hydrosphere in the vicinity of Czech nuclear power plants by radioanalytical methods

Summary The paper deals with the impact of nuclear plants and radioactive waste disposal on surface and ground water quality in their vicinity using various radiometric and radioanalytical methods. The impact of nuclear power plant Temelin on activation concentrations and fission products in hydrosphere, including tritium, was detected. The annual average tritium concentrations in Vltava River correspond to the previously calculated estimates for average and minimal quaranteed flow rates. The concentrations histories of ⁹⁰Sr and ¹³⁷Cs in surface water show a decreasing trend. This trend was not influenced by the nuclear power plant pilot operation. In the case of tritium, a concentration increase trend has been already observed since the startup of pilot operation. An attempt has made interpreting the sorption and diffusion data for radionuclides of cesium, strontium and tritium and technetium as representatives of multivalent elements. Sorption and diffusion data of ¹³⁷Cs and ⁹⁰Sr in contact with natural sorbent bentonite lead to the conclusion that both diffusion and batch sorption experiments can be simulated by an exchange model. Sorption of technetium on various bentonites plus additives materials is described. Retention of technetium on these solid phases is driven by sorption of reduced form of technetium Tc(IV).     

Environmental radioactivity in Romania Danube river area during 1986–1990

This paper presents the results of radioactivity studies of environmental factors such as surface water, sediment, aquatic vegetation and soil. The concentrations of¹³⁷Cs,⁹⁰Sr,³H, U, Ca, and Mg in water samples were determined by radiochemical and chemical methods. Gamma-spectrometric analyses were performed for all the samples. The analysis showed a decrease in concentrations of¹³⁷Cs in water, aquatic vegetation and sediment, but a constant level of¹³⁷Cs activity in soil (0–5 cm depth). The average concentrations of⁹⁰Sr,³H, U, Ca and Mg were about 7 mBq/l, 11 Bq/l, 0.6 g/l 60 mg/l and 11 mg/l, respectively.     

The Effect of Carbonate Soil on Transport and Dose Estimates for Long-Lived Radionuclides at a U.S. Pacific Test Site

The United States conducted a series of nuclear tests from 1946 to 1958 at Bikini, a coral atoll, in the Marshall Islands (MI). The aquatic and terrestrial environments of the atoll are still contaminated with several long-lived radionuclides that were generated during testing. The four major radionuclides found in terrestrial plants and soils are cesium-137, strontium-90, plutonium-239+240 and americium-241. Cesium-137 in the coral soils is more available for uptake by plants than ¹³⁷Cs associated with continental soils of North America or Europe. Soil-to-plant ¹³⁷Cs median concentration ratios (CR) (kBq·kg^-1 dry weight plant/kBq·kg^-1 dry weight soil) for tropical fruits and vegetables range between 0.8 and 36, much larger than the range of 0.005 to 0.5 reported for vegetation in temperate zones. Conversely, ⁹⁰Sr median CRs range from 0.006 to 1.0 at the atoll versus a range from 0.02 to 3.0 for continental silica-based soils. Thus, the relative uptake of ¹³⁷Cs and ⁹⁰Sr by plants in carbonate soils is reversed from that observed in silica-based soils. The CRs for ^239+240Pu and ²⁴¹Am are very similar to those observed in continental soils. Values range from 10^-6 to 10^-4 for both ^239+240Pu and ²⁴¹Am. No significant difference is observed between the two in coral soil. The uptake of ¹³⁷Cs by plants is enhanced because of the absence of mineral binding sites and the low concentration of potassium in the coral soil. Cesium-137 is bound to the organic fraction of the soil, whereas ⁹⁰Sr, ^239+240Pu and ²⁴¹Am are primarily bound to soil particles. Assessment of plant uptake for ¹³⁷Cs and ⁹⁰Sr into locally grown food crops was a major contributing factor in: (1) reliably predicting the radiological dose for returning residents and (2) developing a strategy to limit the availability and uptake of ¹³⁷Cs into locally grown food crops.     

Radioactivity of cattle fodder and milk after the Chernobyl accident

The radioactivities of⁹⁰Sr,¹³⁷Cs and¹³⁴Cs have been measured in soil, fodder and milk from the south-western region of Slovenia, Yugoslavia after the Chernobyl accident. Maximal concentrations of Sr-isotopes in samples and the rate of their decrease in a period up to two years after the accident are given. The transfer of radionuclides from soil to grass and from fodder to milk is discussed.     

Physical and chemical investigation of water and sediment of the Keban Dam Lake, Turkey:

Summary The gross alpha- gross beta-activity, ¹³⁷Cs and ⁹⁰Sr in the water and sediment samples taken from the Keban Dam Lake, Uluova Region, was investigated in 2003 and 2004. We have found that in spring the concentration of ¹³⁷Cs in the surface water and deep sediment changed between 0.001-0.01 Bq/l (0.4-2.5 Bq^.kg^-1) that of ⁹⁰Sr between 0.0001-0.009 Bq/l (0.1-9 Bq^.kg^-1) and in autumn the values were 0.0001-0.009 Bq/l (0.4-8 Bq^.kg^-1) for ¹³⁷Cs and 0.0002-0.005 Bq/l (0.6-4 Bq^.kg^-1) for ⁹⁰Sr, respectively. The results were presented in form of iso-curves.     

Selective removal of cesium and strontium by crystalline silicotitanates

Crystalline silicotitanate ion exchanger (58.5 mmol Ti, and 620 mmol Na) with 6 mmol of SiO₂ after 10 days of hydrothermal synthesis was optimized for selective removal of ⁹⁰Sr. Studies on X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy revealed that the silicotitanate is highly crystalline with bright cubic and rod like morphology with varying amounts of Ti, Si, Na, and O. The decontamination factor and distribution coefficient values for uptake of ¹³⁷Cs and ⁹⁰Sr from actual radioactive waste solutions by the ion exchanger after 24 h of equilibration was found to be 40 and 176 and 4025 ml g^?1 and 7525 ml g^?1, respectively. The exchange capacity for ⁹⁰Sr and ¹³⁷Cs was estimated to be 14.6 and 4.4 meq g^?1, respectively.