State and projection of the radiation situation on the territory of Belarus after the Chernobyl accident

The dynamics of the radiation situation in the Republic of Belarus is presented. The contamination of the territory of Belarus for different radionuclides is given for example: iodine-131, caesium-137 strontium-90 and plutonium isotopes. The dynamics of the contamination of caesium-137, in the surface water of the rivers of Belarus is shown. At present, the radiation situation of the territory of Belarus has stabilized, however, the result of the monitoring shows that in the soil and objects of the environment the accumulation of americium-241 is observed and in course of time its concentration will increase. Forecast of distribution of caesium-137 on the territory of Belarus shows that the contamination of more than 37 kBq·m⁻² will be observed in 2016 at the area more than 28300 km². That account 14% from the total territory of Belarus.     

Migration rates of radionuclides deposited after the Chernobyl accident in various North German soils.

In three soils typical for Northern Germany including Eutric Cambisol, Orthic Podsol and Eutric Histosol (Food and Agriculture Organization nomenclature), distributions of 90Sr, 134Cs, 137Cs and 239Pu + 240Pu in the soil profiles were determined. Sampling was performed more than 3 years after deposition of Chernobyl fallout nuclides. Migration rates calculated with a compartmental model showed no significant differences between Cs originating from either atomic weapons or Chernobyl fallout. This result indicates that Chernobyl Cs may have reached sorption equilibrium with the soil matrix 3 years after the accident. Both the compartmental model and the dispersion equation reproduce distributions of most of the activities, but fail to reproduce some (minor) activity fractions that show increased mobility.     

中国不同类型土壤中稀土元素的形态分布特征

采用中子活化分析地中国不同地带土壤中的稀土元素含量分布模型及其赋存形态进行了系统的研究。结果表明，黄棕壤，褐土，淋溶黑钙土及白浆土中稀土元素的分布均为轻稀土富集，Ｅｕ亏损型，砖红壤，红壤为轻稀土富集，Ｃｅ亏损型。     

Radiation dose assessment for137Cs from fish in the Aegean Sea before and after the Chernobyl accident

The effective doses from fish in the Aegean Sea have been calculated for the nuclide¹³⁷Cs covering the period 1975–1982. The effective dose varies between 3×10^–5 and 10×10^–5 mSv y^–1 for adults and 14×10^–5 to 56×10^–5 mSv y^–1 for children, while the cumulative effective dose for the period 1975–1982 equals to 40.86×10^–5 and 229.57×10^–5 for both adults and children of 10 y old, respectively. When compared to doses derived from the Chernobyl accident /May 1986/ it was found that the additional dose incurred by Greek individuals in May 1986 was approximately equal to the cumulative dose of 8 y contribution period /1975–1982/ for adults and to a year's contribution for children of 10 y old.     

Water Dynamics in Starch Based Confectionery Products including Different Types of Sugar

Starch-based confectionery products were prepared using different types of sugar. In addition to using different sugar, starch was replaced with soy protein isolate (SPI) in some of the products. ¹H NMR spin-lattice relaxation experiments were performed for the collection of products in a broad frequency range from 4 KHz to 30 MHz to get insight into the influence of different sugar types and SPI on the dynamics of water in composite gel systems. The relaxation data have been decomposed into relaxation contributions associated with two different pools of water molecules characterized by different mobility. The translation dynamics of water molecules has been quantitatively described in terms of a dedicated relaxation model. The influence of the sample composition (the type of sugar and/or the presence of SPI) on the water mobility was thoroughly discussed. The results indicate that the addition of soy protein does not affect water dynamics for samples including sucrose. In addition, as the complementary measurements, physical properties of the products, such as the moisture content, water activity and texture, were investigated in terms of X-ray diffraction and thermogravimetric analysis.     

Two Approaches for Sequential Extraction of Radionuclides in Soils: Batch and Column Methods

Abstract

A three-step sequential extraction protocol designed by Community Bureau of Reference (BCR) is applied to two types of soil (sandy and sandy-loam) which had been previously contaminated with a radionuclide aerosol containing ¹³⁴Cs, ⁸⁵Sr and ^110mAg. This scheme is applied using both batch and column methods. The radionuclide distribution obtained with this scheme depends both on the method and on soil type. Compared with the batch method, column extraction is an inadvisable method. Kinetic aspects seem to be important, especially in the first and third fractions. The radionuclide distribution shows that radiostrontium has high mobility, radiocaesium is highly retained by clay minerals whereas Fe/Mn oxides and organic matter have an important role in radiosilver retention.     

Mobility of 137Cs Related to Speciation Studies in Contaminated Soils of the Chernobyl Area

Chernobyl derived ¹³⁷Cs present in upper soil layers can still remain available to cation exchange and hence to downward migration. More than its physico-chemical deposit forms (fuel particles and/or condensed aerosols), radiocesium mobility is influenced by soil properties. Although all the soils studied contain illitic clay minerals, different ¹³⁷Cs fixation levels were observed due to: (1) the reactivity state of sorption sites with a low radiocesium content in soil, and (2) the presence, or absence, of organic matter complexes inhibiting cation sorption on clays.     

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.     

Isotopic composition of plutonium immissions in Austria after the Chernobyl accident

Alpha-spectrometric Pu determinations in aerosol samples collected after the Chernobyl accident in Austria show a²³⁸Pu/²³⁹ (240)Pu ratio in the range of 0.33–0.76 with a most reliable value of 0.47. From²⁴¹Am measurements in old Pu preparations and air filter analyses also²⁴¹Pu activities have been calculated. The ratio²⁴¹Pu/^{239 (240)}Pu during the main contamination period is 74.6±5.7, when maximum²⁴¹Pu concentrations in air achieved 4.5–6.0 mBq/m³.     

The Influence of Electric Parameters on the Dynamics of the Electrokinetic Decontamination of Soils

Elution chromatographic separation of lithium isotopes was carried out with aminobenzo-15-crown-5 bonded merrifield resin. This resin have a capacity of 0.24 meq/g dry resin. By column chromatography using 1.0M NH₄Cl solution as an eluent, a single separation factor 1.026 was obtained from the elution curve and isotope ratios according to the Glucckauf theory. The heavier isotope, ⁷Li was concentrated in the resin phase, while the lighter isotope, ⁶Li enriched in the solution phase.     

Aerosol and gaseous radioidine concentration in the air of Prague after the Chernobyl accident

Data on¹³¹I concentration in the atmosphere of Prague observed during the first days after the Chernobyl accident are presented. The sampling device enabling the differentiation between aerosol-fixed and gaseous form of¹³¹I is briefly described. The highest total¹³¹I concentration, 63 Bq.m^–3, was observed between 30 April and 1 May. Until 9 May the level of¹³¹I activity ranged between 14 and 1 Bq.m^–3 and then dropped below 1 Bq.m^–3. The content of gaseous¹³¹I was found to be a significant and represented on average 60–80% of its total activity.     

Distribution of radionuclides in the environment in northern Italy after the Chernobyl accident.

Soon after the Chernobyl nuclear accident, the air-pumping stations in Pavia (northern Italy) were alerted. In a few days, a rapid increase in radionuclide concentration in air particulates was observed. Consequently, an environmental radioactivity monitoring programme was started in which several matrices such as soil, grass, vegetables and cows' milk were subjected to direct gamma-ray spectrometry. The radioactivity distribution and its variation with time is presented, discussed and compared with other available data. Detection limits, precision and accuracy are also reported, and depth profiles in soils for 137Cs are presented and correlated with soil quality parameters. A survey of environmental radioactivity in soil, in a search for residual Chernobyl fallout, was carried out and a map of the 137Cs distribution over a large area in northern Italy is presented and discussed.     

Isotopic composition of the radioactive fallout in Eastern Poland after the Chernobyl accident

After the Chernobyl accident the radioactivity of air, soil, dust and grass samples, originating from Eastern Poland was investigated by gamma-ray techniques. The isotopic composition of the radioactive fission products in these samples was determined. By combining the obtained results with those from other groups the evolution of the activity ratio in air for some isotopes was gathered. It is suggested that this evolution may be related to the differences in the deposition velocities of various elements. The distributions of the activity ratio in the measured samples indicate different transport and deposition properties for the volatile and nonvolatile fission products. It is concluded that the main part of the released nonvolatile products was deposited in the form of hot particles.     

Fractionation and Determination of Different Lead Species in Contaminated Soils

A new approach was proposed to fractionating soil lead species differing in mobility and biological availability. Ground solid samples were retained as a stationary phase in a rotating coiled column while continuously pumping aqueous solutions of salts and complexing agents necessary for the sequential leaching of different element species. It was shown that field-flow fractionation in a rotating coiled column is suitable for separating three lead species in an automatic mode within 4 h, as compared to several days for conventional methods of sequential extraction. The study of lead elution curves at different fractionation steps provides additional information about its mobilization under changing environmental conditions.     

Determination of239Pu in soil samples from Austria after the Chernobyl accident

As a consequence of the reactor accident at Chernobyl on Tuesday 29 April 1986 the environmental radioactivity in Austria increased for above the level recorded before. Depending on the amount of precipitation the deposition of radioactive fallout showed great differences. Many soil samples collected /during the period from June 15 to September 15/ from Lower-Austria, Styria and Burgenland were analyzed for²³⁹Pu. The concentration found for²³⁹Pu ranged between 2.9 and 9.2 fCi g^–1. The highest concentration was detected in the soil of south-eastern part of Austria /Radkersburg/.²³⁹Pu concentration increased with depth from which soil samples were taken.     

Radionuclides migration in the geosphere and their sorption on natural sorbents

This report identifies a number of mechanisms that retard radionuclide migration, describes methods that are used to study such retardation phenomena and evaluates the extent to which this methods may be used to diagnose radionuclide migration through various types of geologic media. A qualitative, quantitative and applicable basis for ion exchange modelling in clay have provided. Caesium and strontium are taken as a reference elements, and itsK _d values obtained from both batch and diffusion experiments are explained and independently predicted by the model.     

Chemical fraction of radiactive cesium in atmospheric aerosol in Prague after the Chernobyl accident

Aerosol filters exposed during the period of direct contamination after the NPP accident at Chernobyl have been analyzed with the aim to determine the physicochemical forms of¹³⁷Cs. A modified sequential analysis of solubility according to Tessier was used. It was shown that the content of water-soluble radiocesium fraction (about 45%) was substantially lower when compared with the analysis results of aerosols collected in the U.K. Another marked difference was found in the case of undissolved residue, where, on the contrary, the¹³⁷Cs content was higher. No significant differences were found in the composition of samples collected during the time period of, May 1–May 6, 1986. In a sample collected in a later period a lower percentage of water soluble¹³⁷Cs fraction and a higher percentage of¹³⁷Cs in the undissolved residue was found.     

Foliary contamination in the area of Bratislava (Czecho-Slovakia) after the Chernobyl accident

The contamination of leaves of some ornamental and fruit-tree plants (18 species), herbs (6) and early leafy vegetable (2) were assessed in the region of Bratislava and its vicinity through the first months after the Chernobyl accident. The levels of contamination showed local and temporal dependence. In October compared to its levels five months earlier, foliar contamination showed a relative 12- to 200-fold decrease of radioactivity. The effective half-life of the mixture of fission products in cumulative fallout on leaves of vegetation changed depending on time after the accident from 4 days (on day 10) to 150 days (after 2 months). The soluble fraction of radioactive contaminants on plant foliage ranged from 0.12 to 0.64.     

Nuclear Reactions and Radionuclides in the Study of Fullerenes

Radiochemical techniques have been applied in various ways to the study of fullerenes and metallofullerenes for the past several years, and they have provided invaluable information pertaining to the stability, structures, and formation of the novel carbon material. This paper reviews those experimental results that have fully shown the usefulness and uniqueness of radionuclides demonstrated in the field of fullerene science.     

淹水还原条件对不同土壤中镧形态分布的影响

以旱作条件为参照,研究淹水还原条件对镧形态分布的影响。结果表明:淹水还原条件对内源镧B1态:水溶态、可交换态与碳酸盐结合,B2态:铁锰氧化物结合态,B3态:有机质及硫化物结合态的分布没有显著影响;对于外源镧,B1和B3态受淹水条件影响较大,相对于旱作条件,其浓度有增加的现象,淹水条件下B2态在中性土壤中含量稳定,酸性土壤中含量下降,而碱性土壤中含量则上升,产生变化的具体机制还有待进一步研究。两种模拟条件下外源镧3种形态的分布未达到显著性差异。不论在旱作还是淹水条件下,3种土壤中外源镧各形态浓度顺序相同,B1和B2态为:黄红壤黄褐土砂姜黑土,B3态为:砂姜黑土黄褐土黄红壤;两种模拟条件下,3种土壤中的外源镧有进入残渣态的趋势,但并不明显,且不同土壤的各形态对残渣态的贡献不同。