[en] Nuclear chirality has been intensively studied for the last several years in the context of experimental as well as theoretical approach. Characteristic gamma selection rules have been predicted for the strong chiral symmetry breaking limit that has been observed in Cs isotopes. The presented analysis shows that the gamma selection rules cannot be attributed only to chiral symmetry breaking. The selection rules relate to structural composition of the chiral rotational bands, i.e., to odd particle configuration and the deformation of the core. (author)

[en] Radiocaesium added to organic soils remains plant-available far longer than might be predicted from the behaviour of the element in mineral soils. To investigate this, the distributions of radiocaesium added to a low-ash peat and a peaty podzol were studied using sequential extraction with ammonium acetate, sodium pyrophosphate, sodium hydroxide, and ammonium acetate after peroxidation. Comparisons were made with the distribution reported for mineral soils. Changes in distribution between soil phases with time were measured on a sequence of samples treated with radiocaesium over a period of 4 years. Extractions were performed on soils pretreated with HF to remove mineral matter, on soil fractions enriched or depleted in mineral matter isolated physically by means of wet sieving, and on soil fractions obtained by density separation with chloroform and ''Nemagon''. These experiments showed that, even in a highly organic peat, the mineral components were important for the eventual fixation of radiocaesium. Oxidizable organic matter corresponding to humin also strongly retained caesium. (Author)

[en] An experiment was carried out to provide a data set specifically designed to allow the development of a model to describe the dynamic behaviour of radiocaesium in sheep tissue. A single intraruminal dose of ¹³⁴CsCl was given to each of 15 Scottish Blackface ewes, aged 1-2 years. Radiocaesium activity concentrations were measured at various time intervals after dosing in blood, faeces and urine and, after slaughter, in a range of tissues and digestive tract contents. A first order compartment model was developed comprising nine compartments representing various organs and tissues in the body. Rate constants for the model were obtained by optimisation to the experimental results. A limited validation of the model was carried out by using it to calculate tissue transfer coefficients (F_f and biological half-lives (T_0.5) of radiocaesium in sheep. The values generated compare favourably with published figures. Applications for the model and constraints on its usage are examined along with possibilities for further development. (Author)

[en] A relationship to determine the biological half-life of caesium isotopes in man was proposed in 1972. This relationship is reviewed in the light of subsequent data in clearance rates of caesium. Values for use in planning radiological protection of the public are suggested. 11 refs.; 3 figs.; 1 table

[en] Lake sediment cores and samples of stream sediments from the catchment of Oevre Heimdalsvatn have been collected. The lake sediments exhibit apparently unsystematic spatial distribution of radiocaesium. This is ascribed to irregular bathygraphy. However, the radiocaesium concentration increased with increasing percentage of organic matter, water content, and with distance from the main inlet. There was no correlation with lake depth. Stream sediments were scarce because of torrential conditions but those present had activities in line with the lake sediments. Therefore they constitute a small potential for further supply of radiocaesium to the lake. Measurements of export from the catchment and retention in the lake show that the total radiocaesium activity in the sediments may remain unchanged or even increase during the years to come. (author)

[en] In this present work, the kinetic reaction constants including the forward (kf, Cs adsorption onto granite) and backward (kb, Cs desorption from granite) rate constants of Cs on granite were determined by fitting the experimental data from both adsorption and desorption experiments with a pseudo first-order reaction model. In the case of Cs adsorption, both forward and backward rate constants are consistent with one another as Cs loading less than 0.1 mM. In contrast, both forward and backward reaction constants from desorption experiment dramatically increase as the Cs loading increases. Rearrangement of these desorption data by linearization technique, a notable instantaneous desorption process appears, which profoundly influences the determination of the rate constants. Based on our fitting results, the rate constants including both forward and backward reactions determined from Cs adsorption onto granite are much suitable to represent the adsorption behavior, in which the recommended values are of 0.42 and 0.03 h^-1, respectively. (author)

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No abstract available

[en] A series of incubation experiments was performed to investigate the release of caesium from either undisturbed or resuspended freshwater sediment which had not been previously dried. Ammonium and potassium ions readily released caesium from resuspended material but treatment of the overlying water with hydrochloric acid (pH 4) or nitrilo triacetic acid did not enhance release of caesium from undisturbed sediment. Caesium was released from undisturbed sediment when it was treated with 0.5 mol litre^-1 NaC1, but the release of 0.5% was low compared with the release which occurs from resuspended sediment treated with lower concentrations of sodium chloride. The smaller release observed in the experiments with undisturbed rather than resuspended sediments was attributed to the interstitial waters being buffered by redox and solid phase reactions. There was minimal release (0.05%) from undisturbed sediment after 40 days of either oxic or anoxic incubation, but the magnitude of the release was consistent with assumed ammonia concentrations in the pore-waters of the surface sediments and experiments which investigated the ammonia-induced release from resuspended wet sediment. It was suggested that the observed elevated contributions in the bottom waters of lakes could be largely due to remobilization from sinking particles rather than release from the sediment. (Author)

[en] In order to solve difficulties in collection of river suspended solids (SS) such as frequent observations during stochastic rainfall events, a simple passive collection system of SS has been developed. It is composed of sequentially connected two large-scale filter vessels. A portion of river water flows down into the filter vessels utilizing a natural drop of streambed. The system enable us to carry out long-term, unmanned SS collection. It is also compatible with dissolved component collection. Its performance was validated in a forested catchment by applying to radiocesium and stable carbon transport. (author)