Activity concentration of radium-226 in agricultural soils

Both Indian mustard and sunflower were grown in a hydroponic solution treated with different concentration activities of ¹³⁴Cs or with different amounts of copper or with both in order to investigate the interaction between copper and radiocesium. It was found that ¹³⁴Cs activity concentration applied in the nutrient solution exerted more influence on the uptake and translocation of copper by Indian mustard than by sunflower. Indian mustard grown in hydroponic solution containing certain levels of copper and being treated with higher ¹³⁴Cs activity concentration showed higher uptake of copper than sunflower. However, in the case of root copper concentrations, sunflower showed significantly higher copper immobilization by roots than Indian mustard. It was also found that the presence of copper in the hydroponic solution did modify radiocesium uptake by both species. The application of 1 mg/l in the growth medium could greatly increase the uptake of ¹³⁴Cs by both species. With 3 mg/l concentration of copper amended to the solution, the accumulation of ¹³⁴Cs by both species was decreased compared to the 1 mg/l copper treatment. These lines of evidence show that there is stronger interaction between copper and radiocesium in Indian mustard than in sunflower during the root uptake through nutrient solution.     

Radiocesium tracer obtained from mushrooms

Some species of higher fungi growing at localities with increased contamnation by fission products from radioactive fallout /about 10–20 kBq¹³⁷Cs m^–2 and more/ contain up to 200 kBq of radiocesium-¹³⁷Cs and¹³⁴Cs, per kilogram d. m. Simple isolation of the rationcesium preparation of fruittbodies of suchn mushroom accumlators of radiocesium is described.     

Investigation of radiocesium biokinetics in Manila clam (Ruditapes philippinarum)

This study was carried out to better understand the biokinetics of radiocesium in clams living in sediment. The accumulation and depuration kinetics of ¹³⁴Cs were investigated in the Manila clam (Ruditapes philippinarum) under controlled laboratory conditions. The concentration factor was found to be 3.0 for ¹³⁴Cs in the whole body; however, the concentration factor in the soft part of the clams (12) was significantly higher than those in the whole body and shell (0.80). The depuration kinetics of the radionuclide were described by a two-component exponential model for the whole body. The biological half-lives in the fast and slow components were found to be 0.63 and 22.1 days, respectively. The depuration kinetics for ¹³⁴Cs in the soft parts were described by a single-component exponential model with a resultant the biological half-life of 18.0 days.     

TG–FTIR analysis applied to the study of thermal behaviour of some edible mushrooms

The article is devoted to the study on the thermal behaviour of three species of edible mushrooms: Boletus edulis (foot and cap), Pleurotus ostreatus (foot and cap), Lactarius deterrimus (cap) by the TG–FTIR-coupled technique, in air, over the 30–900 °C temperature range. The analysis of the TG–DTG–DTA curves reveals the thermal degradation mechanism to be complex and specific to every species under the recording conditions applied. A similar degradation mechanism is noticed for the foot and cap of Pleurotus ostreatus in comparison with the Boletus edulis and Lactarius deterrimus species where the mechanisms are different. The TG–FTIR analysis, combustion heats and IR spectra of the starting samples also support these results. The initial degradation temperatures from TG–DTG indicate the temperature range where these species are thermally stable and their nutrient features maintained making them proper for food. The TG–FTIR analysis gives information on the gaseous species evolved by the thermal degradation bringing thus a contribution to the elucidation of the changes developing by processing the edible mushrooms (industrialization, conservation, culinary preparations, etc.) at temperatures above the initial degradation temperature. At the same time, the environmental impact, when the mushroom failed cultures are burned, is also important.     

Uptake and release kinetics of134Cs by Goldfish (Carassius auratus) and137Cs by Zebra Fish (Brachydanio rerio) in controlled aquatic environment

The uptake and release kinetics of¹³⁴Cs by Goldfish (Carassius auratus) and¹³⁷Cs by Zebra Fish (Brachydanio rerio) from aquatic media of different ionic compositions and temperature was studied in controlled laboratory conditions. The accumulation of radiocesium in the case ofBrachydanio rerio is observed to be strongly dependent on the potassium ion concentration of the aquatic medium, but in the case ofCarassius auratus this dependence is quite weak. The biological half-lives of the cesium isotopes incorporated into the fish investigated in the present work vary from 19 to 80 days and are influenced by the temperature and the ionic composition of the aquatic medium.     

An Efficient Approach to Model the Long-Term Radiocesium Contamination of Mushrooms and Berry Plants

Since 1987, a coniferous forest in Bavaria has continuously been monitored for radiocesium. About 350 soil samples and about 450 samples of different species of mushrooms and berry plants were analyzed for ¹³⁴Cs and ¹³⁷Cs. Based on this extensive data set a radioecological model for the long-term contamination of mushrooms and berry plants was developed. To keep the model as simple as possible without losing predictive power, it was especially designed to describe the vertical migration of radiocesium in forest soil, a key process which governs the temporal evolution of activity levels in mushrooms and berry plants.     

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.     

Uptake of alpha and beta emitters by mushrooms collected and cultured in Spain

Almost all studies on the radioactive content of mushrooms have been centered on ¹³⁷Cs and, to a lesser extent, on ⁴⁰K. Other alpha and beta emitters have not been fully investigated and, therefore, their contribution to the dose due to consumption of mushrooms is not taken into consideration. We have studied the incorporation of several radionuclides: into mushrooms using two approaches — laboratory and natural conditions. Pleurotus eryngii was cultured under controlled laboratory conditions, and was found that ¹³⁴Cs was incorporated to a greater extent in the mushroom than the rest of radionuclides, and ²³⁹Pu at least. These results were confirmed by the uptake under natural conditions: ¹³⁷Cs > ^228,230,232Th ^234,238U ⁹⁰Sr >> ^239+240Pu. The contribution of thorium and uranium to the dose due to mushroom consumption in Spain is of the same order of magnitude as that of ¹³⁷Cs.This revised version was published online in November 2005 with corrections to the Cover Date.     

Dietary intakes of radioactive cesium for Ukrainians

Daily intakes of ¹³⁴Cs and ¹³⁷Cs in Ukrainians were estimated in relation to the health effects on habitants after the Chernobyl accident. Two hundred and sixty-eight diet samples were collected from 25 oblasts (regions) using a duplicate portion method. For Ukrainians, the range and median daily intakes of ¹³⁷Cs were 0.53–571 and 8.8 Bq per person, respectively. Intakes of ¹³⁴Cs were also detected in highly ¹³⁷Cs contaminated areas. Daily intakes of ¹³⁴Cs were in the range of not detected to 3.6 Bq per person. Using the highest radiocesium intakes, annual effective doses for ¹³⁴Cs and ¹³⁷Cs were estimated to be 2.5·10⁻² and 2.7 mSv, respectively.     

Levels of cesium radionuclides in mosses in the eastern Black Sea area of Turkey

Moss samples collected from the eastern Black Sea about 6.5 years after the Chernobyl accident have been analyzed for radiocesium activity.¹³⁴Cs activity was also detected in all the samples beside¹³⁷Cs radionuclide. The levels of total cesium activity in the mosses proved that the coastal zone in the eastern Black Sea region was highly contaminated.     

Long-term transfer of <Superscript>137</Superscript>Cs from soil to mushrooms in a semi-natural environment

The radioactive contamination following the Chernobyl accident resulted in high concentrations of ¹³⁷Cs in several mushrooms species. Mushroom samples were collected in a forest environment between 1986 and 2007 and the transfer of ¹³⁷Cs to two edible species, Suillus variegatus and Cantharellus spp., was investigated. The ¹³⁷Cs uptake by the collected samples did not decrease over time and in Cantharellus spp. a significant increase was observed. Most of the ¹³⁷Cs in soil still appears to be available for uptake and radioactive decay of the radionuclide is likely the main factor for the reduction of ¹³⁷Cs in a forest ecosystem.     

Determination of radiocesium in environmental water samples using copper ferro(II)cyanide and sodium tetraphenylborate

Summary A procedure for the radiochemical separation and radiochemical purification of radiocesium (¹³⁴Cs and ¹³⁷Cs) in bulk environmental water samples is proposed. Radiocesium was removed from the water by cation-exchange with copper ferro(II)cyanide and was purified by precipitation with sodium tetraphenylborate. The influence of the concentration of potassium in the water sample on the chemical yield was investigated. The validation of the proposed method was carried out by analyzing reference materials. The application of the method was demonstrated with the determination of the concentration of radiocesium in water samples from rivers around NPP “Kozloduy”, Bulgaria, Danube and Ogosta.     

Speciation of essential and toxic elements in edible mushrooms: size‐exclusion chromatography separation with on‐line UV–inductively coupled plasma mass spectrometry detection

Size‐exclusion liquid chromatography was coupled to UV and inductively coupled plasma mass spectrometry (ICP‐MS) for detection to perform elemental speciation studies on different edible mushrooms. Molecular weight (MW) distribution patterns of several elements among different fractions present in various edible mushrooms are presented. The association of the elements with the high and low MW fractions was observed using sequential detection by UV and ICP‐MS. Separation was performed using a Superdex 75 column. Variability of the fractionation patterns with three different extraction media (0.05 mol l^?1 NaOH; 0.05 mol l^?1 HCl; hot water at 60°C) was evaluated for mushroom species. A comparative elemental speciation study was performed in order to determine the differences in the fractionation patterns of silver, arsenic, cadmium, mercury, lead, and tin in Boletus edulis, Agaricus bisporus, and Lentinus edodes. Differences in the fractionation patterns of the elements were found to depend on the mushroom species and the extraction medium. Most of the elements were associated with high mw fractions. It was not possible to assess the trace metal contributions from the mushroom growth media. Copyright © 2004 John Wiley & Sons, Ltd.     

Rapid determination of Cs and precise Cs/Cs atomic ratio in environmental samples by single-column chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry

For source identification, measurement of ¹³⁵Cs/¹³⁷Cs atomic ratio not only provides information apart from the detection of ¹³⁴Cs and ¹³⁷Cs, but it can also overcome the application limit that measurement of the ¹³⁴Cs/¹³⁷Cs ratio has due to the short half-life of ¹³⁴Cs (2.06 y). With the recent advancement of ICP-MS, it is necessary to improve the corresponding separation method for rapid and precise ¹³⁵Cs/¹³⁷Cs atomic ratio analysis. A novel separation and purification technique was developed for the new generation of triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The simple chemical separation, incorporating ammonium molybdophosphate selective adsorption of Cs and subsequent single cation-exchange chromatography, removes the majority of isobaric and polyatomic interference elements. Subsequently, the ICP-MS/MS removes residual interference elements and eliminates the peak tailing effect of stable ¹³³Cs, at m/z 134, 135, and 137. The developed analytical method was successfully applied to measure ¹³⁵Cs/¹³⁷Cs atomic ratios and ¹³⁵Cs activities in environmental samples (soil and sediment) for radiocesium source identification.     

Specificity of Lichen Species in Respect to 137Cs Binding

Abstract

The aim of this work was to investigate the significance of species specificity on the efficiency of ¹³⁷Cs isolation from lichens. It was shown that a 5% solution of both ammonium oxalate and phosphoric acid was able to solubilize 77.5% of ¹³⁷Cs from Cetraria islandica, 47.6% from Cladonia fimbriata and 46.4% from Usnea barbata. Since the tested lichen species had similar specific radioactivities (i.e. amount of ¹³⁷Cs) the difference could be explained by the existence of different types of bonds between radiocesium and the corresponding binding sites. Crystals precipitated from these extracts incorporated most of the soluble ¹³⁷Cs. The amount and specific radioactivity of the crystals varied between lichen species which could also be interpreted as the presence of specific ions in each lichen that either participated in crystal formation or inhibited the process. The potential of a tested solution to extract and “concentrate” ¹³⁷Cs in crystalline form may be a tool to correlate mass and radioactivity of ¹³⁷Cs.     

Migration of 134Cs in unsaturated soils at a site in Egypt

To demonstrate the safety performance assessment for the disposal of ¹³⁴Cs radionuclide in a geological formation, several investigations were required to calculate the possible release of radionuclides into groundwater. This research examined the sorption behavior of radioactive cesium (¹³⁴Cs) in natural groundwater. Cesium chloride (10^-6 to 10^-2 mol^.l^-1) was used as a carrier, traced with ¹³⁴Cs radionuclide. Distribution coefficients of radiocesium for sorption and desorption were measured on natural soil samples of different grain size fractions (400 to 36 mm). Cesium sorption and desorption were found reversible at cesium chloride concentrations between 10^-6 mol^.l^-1 to less than 10^-3 mol^.l^-1. Sequential extraction procedures showed that the cesium sorption on soils were of various types: those easily desorbed, ion-exchanged, bound to carbonate, iron oxides, and organic matter. To demonstrate the safety performance assessment for the disposal of ¹³⁴Cs radionuclide in a geological formation, several investigations were required to calculate the possible release of radionuclides into groundwater. This research examined the sorption behavior of radioactive cesium (¹³⁴Cs) in natural groundwater. Cesium chloride (10^-6 to 10^-2 mol^.l^-1) was used as a carrier, traced with ¹³⁴Cs radionuclide. Distribution coefficients of radiocesium for sorption and desorption were measured on natural soil samples of different grain size fractions (400 to 36 mm). Cesium sorption and desorption were found reversible at cesium chloride concentrations between 10^-6 mol^.l^-1 to less than 10^-3 mol^.l^-1. Sequential extraction procedures showed that the cesium sorption on soils were of various types: those easily desorbed, ion-exchanged, bound to carbonate, iron oxides, and organic matter.     

Relationship between particle size and radiocesium in fluvial suspended sediment related to the Fukushima Daiichi Nuclear Power Plant accident

We collected fluvial suspended sediments in Fukushima after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident and analyzed the ¹³⁷Cs concentration in bulk and size-fractioned samples to investigate the particle-size-dependent distribution of radiocesium. The ¹³⁷Cs concentration in bulk suspended sediments decreased from August to December 2011, possibly reflecting a decrease of radiocesium concentration in its source materials. Smaller particles had higher radiocesium concentrations, reflecting larger specific surface areas. Silt- and sand-size fractions occupied more than 95 % of the total ¹³⁷Cs in the suspended sediments. The contribution of clay-size fractions, which had the highest ¹³⁷Cs concentration, was quite small because of their low frequency. A line of the data showed that the particle size distribution of radiocesium was essential to evaluate the migration and distribution of radiocesium in river systems where radiocesium is mainly present as particulate form after the FDNPP accident.     

Local distribution of radioactivity in tree leaves contaminated by fallout of the radionuclides emitted from the Fukushima Daiichi Nuclear Power Plant

We analyzed fresh and dead leaves collected in forests in Fukushima after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, using autoradiography. Both fresh and dead leaves of Cryptomeria japonica were contaminated by radionuclides (¹³⁴Cs and ¹³⁷Cs). Contamination of the fresh leaves was possibly attributed to interception of radionuclides by tree canopies, whereas the dead leaves indicated the direct deposition of radionuclides by fallout and/or washout of radionuclides intercepted by tree canopies. Translocation of radiocesium from a contaminated branch to new leaves growing after the FDNPP accident was not clearly observed, although transfer of radiocesium from leaf parts to male flowers occurred. Fallen leaves of Quercus serrata, which started growing after the FDNPP accident, did not show radioactivity, indicating that significant amounts of translocation from other parts to new leaves did not occur. Fallen leaves of Q. serrata collected from a litter showed hot spots originating from direct fallout. Needles of Pinus densiflora were also contaminated by fallout. Leaching with pure water removed soluble fractions of radiocesium and hot particles from the surface of the contaminated leaves, but significant amounts of radioactivity remained. This means that foliar absorption occurred in both fresh and dead leaves. Further leaching experiments using surfactant and acetone could not remove the remaining radiocesium from the leaves. The leaching experiments indicate that radiocesium in the contaminated leaves is strongly fixed in leaf tissues and is not readily released unless leaf tissues are decomposed.     

Accumulation of103Ru,137Cs and134Cs in fruitbodies of various mushrooms from Austria after the Chernobyl incident

Various mushrooms from Austria were analyzed for¹⁰³Ru,¹³⁷Cs and¹³⁴Cs after the reactor accident at Chernobyl /19.6.–26.10. 1986/ by -spectroscopy. The following concentration (nCi/kg wet weight) values were found:¹⁰³Ru 0.1–4 nCi/kg,¹³⁷Cs 0.5–104 nCi/kg,¹³⁴Cs 0.3–42 nCi/kg. The concentration of cesium isotopes in Cantharellus cibarius /lower Austria/, Leccinum scabrum /lower Austria/ and Xevocomus badius /lower Austria/ was considerably higher than in other mushroom samples.     

Anomalously high activities of <Superscript>137</Superscript>Cs in soils and vegetation on and near a diabase outcrop in La Sierra de Lema,Venezuela

As a result of routine soil sampling to determine the ¹³⁷Cs background activities country-wide in Venezuela, it was decided to further investigate El Mirador (Lookout) area at the base of the Sierra de Lema mountain range. In April 2003 (A), soil samples were collected at eight sites on and around the edge of the diabase outcrop to confirm that this area had anomalously high ¹³⁷Cs activities. In July 2003 (B), not only soil samples were collected again, but also black mat, palm tree leaves and trunks, fruit bushes leaves and its fruit and fern leaves. The ¹³⁷Cs content was measured by high resolution gamma-ray spectroscopy by a comparative method with reference materials. The ¹³⁷Cs activity values range from 16.3 to 30.8 Bq·kg-1 in the soil samples collected in July 2003, 20.7–32.1 Bq·kg⁻¹ for the black mat, 26.3–38.4 Bq·kg⁻¹ for the palm leaves, 16.8–31.2 Bq·kg⁻¹ for the palm trunks and 17.6–27.3 Bq·kg⁻¹ for the fruit bush leaves, while, the ¹³⁷Cs activity values for the whole fruit were between 23.4 and 30.7 Bq·kg⁻¹; but, the value of the ¹³⁷Cs activity in the center of the fruit (the edible part) was 51.6 Bq·kg⁻¹, and the value of the ¹³⁷Cs activity for the fern leaves was 51.8 Bq·kg⁻¹. Thus, most of the ¹³⁷Cs activity values determined in the soil, black mat and vegetation samples from El Mirador (Lookout) were considered anomalously high with respect to those found near the equator and in other areas of Venezuela. Only the center of the fruit from the Clusia grandiflora bushes and the fern leaves had high activity ratios, about a factor of three and could be considered as biomonitors that concentrate and retain the ¹³⁷Cs. Finally, these anomalously high ¹³⁷Cs activities have been attributed not only to the rich organic soils, as sinks, but also due to the affect of the cloud forests.