Accumulation and discharge behavior of Cs-137 by zebra fish (Brachydanio rerio) in different aquatic environments

The uptake and release kinetics of¹³⁷Cs from water by the tropical fishBrachydanio rerio has been studied under controlled laboratory condition. The accumulation of this radionuclide from food was avoided by feeding the fishes separately in an inactive environment. A steep inverse dependence of bioconcentration factor (BCF) with potassium concentration has been observed. This can formally be described by the equation BCF=5.2 · [K⁺]^–0.44. The elimination rate constant K in fresh water conditions has been found to have a magnitude of 0.014±0.03 d^–1 which corresponds to a biological half-life of 51±10 days. The uptake and release kinetics ofBrachydanio rerio has been compared with earlier studies of fresh water fishes.     

Influence of major cations of sea water on the desorption of137Cs from marine sediments

Desorption studies of¹³⁷Cs from marine sediments by artificial sea water and artificial sea water devoid of individual major cations such as Na, K, Ca, Mg and Sr indicated that only Na and K were effective in the desorption of¹³⁷Cs. Studies with various ionic strengths ranginf from 0.01 to 1.6M KCl and NaCl solutions showed that KCl desorbs constantly about 45%¹³⁷Cs at and above an ionic strength of 0.1. In case of NaCl, the percent desorption increases linearly with ionic strength. The difference in desorption by K and Na is attributed to the contraction of the clay mineral layers by K ion and expansion of the layers by Na ion.     

239+240Pu and137Cs concentrations in salmon (Oncorhynchus keta) collected on the Pacific coast of Japan

Salmon (Oncorhynchus keta) samples were collected on the Pacific coast of Japan and analyzed for their^239+240Pu and¹³⁷Cs concentrations in six places, i.e., muscle, viscera, gill, gonad, skin and spine. The^239+240Pu concentrations in muscle ranged from 0.07 to 0.14 mBq/kg (wet) and had the lowest value among the six regions. The mean^239+240Pu concentrations in viscera, gonad and spine were more than 1 mBq/kg (wet_ while those in muscle and skin were one order of magnitude lower. The largest amounts of^239+240Pu were accumulated in gonad. The^239+240Pu/¹³⁷Cs activity ratios in all positions were lower than that of the global fallout ratio of 0.022, suggesting that¹³⁷Cs could be accumulated with greater ease than^239+240Pu in all positions and ratios of uptake differed remarkably from position to position. The total accumulations of^239+240Pu and¹³⁷Cs in salmon were 1.32 and 328 mBq/individual, respectively.     

Isolation of137Cs from excreta by dicarbolide of cobalt

Extraction by polyhedral complex compound of the formula H⁺ [(π-(3)-1,2-B₉C₂H₁₁)₂Co⁻] further on referred to as dicarbolide-H⁺ and its chloro-derivate H⁺[B₁₈C₄H₁₅Cl₇Co⁻] further on referred to as Cl-dicarbolide-H⁺ in nitrobenzene was used for the analysis of¹³⁷Cs in urine and faeces after internal contamination. The dependence of distribution ratio on the acidity of analysed solutions was determined. The effect of urine dilution was assessed as well as the effect of various concentrations of the extraction agents on the distribution ratio of¹³⁷Cs. The effect of phase ratio at the different concentrations of isotopic carrier was assessed, as well as the effect of potassium ions on the decrease of the distribution ratio at the extraction of¹³⁷Cs by dicarbolide-H⁺ or its chloro-derivate. The possibility of isolation of¹³⁷Cs by extraction and the isolation of¹³⁷Cs by ion-exchange absorbents and by ammonium molybdophosphate was compared. The values of distribution coefficient were determined at various concentrations of nitric acid and the isotopic carrier. The dependence of coextraction of some activated radionuclides and fission products by dicarbolide-H⁺ on the nitric acid concentration in the solute was determined. The effect of mass of contaminated faeces on the value of the distribution ratio of¹³⁷Cs by the extraction was evaluated. As a result, a suggestion was given for the rutine isolation procedure of¹³⁷Cs extraction with dicarbolide-H⁺ from the excreta contaminated by a mixture of radionuclides.     

Half-life of134Cs determined by gamma spectrometry

The half-life of¹³⁴Cs obtained by gamma spectrometry from the change of the¹³⁴Cs to¹³⁷Cs activity ratio is 2.04±0.03 years.     

A simple preparation of calibration curve standards of134Cs and137Cs by serial dilution of a standard reference material

Two sets of calibration standards for¹³⁴Cs and¹³⁷Cs were prepared by small serial dilution of a natural matrix standard reference material, IAEA-154 whey powder. The first set was intended to screen imported milk powders which were suspected to be contaminated with¹³⁴Cs and¹³⁷Cs. Therefore the concentration range of the calibration standards were about 40–400 Bq/kg. The precision of the preparation of the standard with about 7 Bq/kg of¹³⁴Cs and 39 Bq/kg of¹³⁷Cs at measurement time was 7.4% and 3.2%, respectively. The preparation of a similar standard by spiking the matrix with radioisotope solutions resulted in a poorer precision, about double that of the former technique. The other set of calibration standards was prepared to measure the environmental levels of¹³⁷Cs in commercial Venezuelan milk powders. Their concentration ranged from 3–10 Bq/kg of¹³⁷Cs. The accuracy of these calibration curves was checked by using IAEA-152 and A-14 milk powders. Their measured values were in good agreement with their certified values. Finally, it is shown that these preparation techniques by serial dilution of a standard reference material were simple, rapid, precise, accurate and cost-effective.This work was partly funded by a research contract PC-075 from the Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICIT).     

Sorption characteristics of137Cs onto clay minerals: Effect of mineral structure and ionic strength

The sorption behavior of¹³⁷Cs onto kaolinite, bentonite, illite, and zeolite was studied at different ionic strengths of Na⁺, K⁺, Ca²⁺. A significant effect of ionic strengths on the sorption has been observed. Clay minerals with 21 structure (bentonite, illite) showed much higher sorption than that of 11 structure (kaolinite). Zeolite showed high selectivity for¹³⁷Cs sorption. Sorption behavior of¹³⁷Cs on clay minerals can be explained by their surface charge characteristics originated from mineral structure.     

Modes of137Cs desorption from marine sediments by sea water

Sea water is observed to be a good desorbing agent for¹³⁷Cs from marine sediments. Investigations on the sites of¹³⁷Cs binding and their abundance by desorption over extended periods indicated that, whatever the time of contact of sorption,¹³⁷Cs has three modes of desorption: fast component with desorption half-time of 30–50 min, medium component with desorption half-time of 25–50 h and slow component with desorption half-time of 31–112 days. These are expected to be sites of ion exchange, slower exchange and trapped Cs in the clay mineral layer lattices.     

Ion-solvent interaction in nonaqueous solutions. II. Spin-lattice relaxation times of23Na and133Cs

The spin-lattice relaxation time (T ₁) of ²³ Na was measured in solutions of NaClO ₄ and (or) NaBr in formamide,N-methylformamide,N,N-dimethylformamide (DMF), MeCN, Me₂CO, tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO), and ¹³³ Cs in a solution of CsCl in formamide. The values of (1/T ₁) ₀ obtained by extrapolation are discussed in terms of current theories of quadrupolar magnetic relaxation of ionic nuclei. A correlation was found between (1/T ₁) ₀ for ²³ Na and Gutmann's donor numbers.For Part I, see ref. 1.     

Die Reaktion von Cyanid-Ionen mit Trimethylgallium. Die Kristallstrukturen von [Cs{CN(GaMe3)2}]n und [Cs(Toluol)2{CN(GaMe3)2}]n

The Reaction of Cyanide Ions with Trimethylgallium. The Crystal Structures of [Cs{CN(GaMe₃)₂}]_n (1) and [Cs(toluene)₂{CN(GaMe₃)₂}]_n (2) CsCN reacts with GaMe₃ in the molar ratio of 1 : 2 in the absence of additional solvent to the metalate [Cs{CN(GaMe₃)₂}] ( 1 ). 1 can be recrystallized from MeCN/toluene, forming [Cs(toluene)₂{CN(GaMe₃)₂}] ( 2 ). If CsCN is treated with one equivalent GaMe₃ in Et₂O at 20 °C, the metalate [Cs(NCGaMe₃)] can be isolated. 1 – 3 were characterized by NMR, IR, and MS techniques. In addition, X-ray structure analyses of 1 and 2 were prepared. According to the structural characterization 1 consists of a helix of Cs⁺ ions and side-on coordinated anions [Me₃GaCNGaMe₃]^–, running along [010]. π-Electron-Cs⁺ contacts between Cs cations and toluene molecules are dominating the structure of 2 . The residual equatorial positions at the [Cs(toluene)₂]⁺ sandwich-ion are occupied by Cs⁺-hydrogen(methyl) interactions. A three-dimensional network is the result of the contacts between cations and anions.     

Retention of Cs on zeolite, bentonite and their mixtures

The sorption behavior of cesium on zeolite and bentonite minerals and their mixtures was studied by means of a batch method and a tracer technique. All experiments were carried out in the presence of CsCl spiked with ¹³⁷Cs and NaCl as a supporting electrolyte in varying concentrations. The distribution coefficients (K _D) did not show significant differences at low Cs⁺ loadings while they decreased in the high loading region. Freundlich and D-R isotherms were applied to the adsorption data of zeolite and bentonite. Adsorption capacities and mean energies calculated from D-R isotherm parameters decreased by increasing ionic strength on both minerals. The identification of the specific uptake sites was attempted on the basis of the Freundlich isotherm. Experimentally observed distribution coefficients of Cs on two mineral mixtures were smaller than theoretically calculated values, except at the highest NaCl concentration.     

Determination of135Cs in sodium from an in-pile loop by activation analysis

Several months after shut-down,¹³⁷Cs and¹³⁴Cs were the main activities in coolant residues from an in-pile sodium loop where a fuel pin had failed at 40000 MWd/t burn-up, FR2-reirradiation of coolant residues increased¹³⁴Cs and generated¹³⁶Cs, thus indicating the presence of stable¹³³Cs and of long-lived¹³⁵Cs in the samples. The amount of¹³⁵Cs calculated from¹³⁶Cs activities was of the same quantity as the number of¹³⁷Cs atoms.     

Synthesis and Crystal Structure of Cs(VO2)3(TeO3)2, a New Layered Cesium Vanadium(V) Tellurite

Synthetic Cs(VO₂)₃(TeO₃)₂ is built up from infinite sheets of distorted octahedral V^VO₆ groups, sharing vertices. These octahedral layers are “capped” by Te atoms (as parts of pyramidal [Te^IVO₃]^2– groups) on both faces of each V/O sheet, with inter‐layer, 12‐coordinate, Cs⁺ cations providing charge compensation. Cs(VO₂)₃(TeO₃)₂ is isostructural with M(VO₂)₃(SeO₃)₂ (M = NH₄, K). Crystal data: Cs(VO₂)₃(TeO₃)₂, M_r = 732.93, hexagonal, space group P6₃ (No. 173), a = 7.2351(9) Å, c = 11.584(2) Å, V = 525.1(2) ų, Z = 2, R(F) = 0.030, wR(F ²) = 0.063.     

Retention of137Cs by algal polysaccharides

The retention of¹³⁷Cs in algal polysaccharides has been studied. Alginic acid showed higher retention value than the tested alginate samples. The retention of¹³⁷Cs in carrageen types and agar was first investigated. The binding capacities were found to be equal for carrageenan types and agar.     

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.     

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.     

137Cs transfer from forage to milk and its removal by clay treatment

Since April 29, 1986, the radioactive contamination resulting from the accident of the Chernobyl reactor has been measured in various kinds of matrixes, with particular regard to Northern Italy. Here we present the data obtained for¹³⁷Cs from several measurements effected on milk and dairy products over the period of one year. In particular, we have studied the transfer kinetics of¹³⁷Cs from forage to milk by feeding dairy cows with forage of known activity and we have evaluated the body Cs absorption by measuring the percentages of Cs eliminated with milk as well as with urine and feces. Further, the decay rate of¹³⁷Cs in milk has been assessed and the results of the kinetic, analysis are reported. We have also evaluated the efficacy of various clay materials in removing Cs from milk. Here we report the results of adsorption kinetics for the grey clay which resulted the most effective material.     

Temperature dependence of nqr spectra in MSbBrF3 (M=Na,Cs, NH4) and Cs3Sb2Br9

Conclusions We have studied the temperature dependence of the NQR parameters of¹²³Sb and⁸¹Br in the range 77–360 K for the complexes of MSbBrF₃ (M=Na, Cs, NH₄) and Cs₃Sb₂Br₉. We have established the temperature regions for which piezoelectric properties appear in the crystal hydrate NaSbBrF₃.H₂O, and in the compounds MSbBrF₃ (M=Na, NH₄) and Cs₃Sb₂Br₉ anomalous changes appear in the dependences of the quadrupole coupling constant, the asymmetry parameter of the electric field gradient for the antimony atoms and the resonance frequency of the bromine atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1501–1504, July, 1987.     

Extraction of137Cs by cobalt dicarbolide

The possibility of the use of chlorinated cobalt dicarbolide, H⁺C₄B₁₈H₁₅Cl₇Co⁻, it nitrobenzene for the selective extraction of¹³⁷Cs from mixtures of⁹⁵Zr−⁹⁵Nb,¹⁰⁶Ru-¹⁰⁶Rh and¹⁴⁴Ce was studied. The effect of aqueous phase acidity on the distribution ratio of Cs, Ru and Zr as well as the effect of the amount of isotopic and non-isotopic carriers of alkali metals on the distribution ratio were determined. Separation factors for cesium from ruthenium, zirconium and cerium were calculated, all being extracted from nitric acid solutions. The efficiency of cesium separation was verified by gamma-spectrometry.     

Retention behaviour of Cs(I), Sr(II), Tc(VII) and Np(V) on smectite-rich clay

The smectite-rich natural clay is being considered as a backfill and buffer material for Indian repository programme. In the present study, batch sorption measurements have been performed at trace concentrations for one of the minor actinide elements [Np(V)] and for the long lived fission products, Cs(I), Sr(II), and Tc(VII) on purified and conditioned smectite-rich clay at varying conditions of pH and ionic strength. In case of Cs(I) and Sr(II) the sorption was found to increase with pH. At any pH the sorption was found to decrease with increasing ionic strength of the suspension maintained with NaCl. Further, at any pH the sorption of Sr(II) is less than the corresponding value for Cs(I). This is indicative of effect of size selectivity on the sorption by the clay. Tc(VII), on the other hand, is poorly retained by the clay, which can be explained in terms of the negative charge on the TcO₄ ^? ion, which has negligible interaction with the predominantly negatively charged clay surface. In the case of Np(V), the sorption was found to increase albeit, slowly compared to Cs(I) and Sr(II) with pH, and it with no effect of ionic strength on the sorption at all pH values. This suggests that Np(V) primarily interacts with the surface sites via inner sphere complexation mechanism.