Radioactive Cs Research Articles

Radiocesium contamination in house dust within evacuation areas close to the Fukushima Daiichi nuclear power plant

Outdoor decontamination efforts have been ongoing since the Fukushima Daiichi nuclear power plant (FDNPP) accident; however, little is known about indoor contamination. Therefore, house dust was sampled based on particle size in 21 wooden buildings (19 residential houses and 2 community centers) within the evacuation area close to the FDNPP, Fukushima Prefecture, Japan. Activities of radiocesium (137Cs) per gram of house dust increased with decreasing particle size (mean: 6.1 × 103, 2.6 × 103, 1.6 × 103, 7.5 × 102, 5.0 × 102, and 4.6 × 102 Bq/g for <4–20, 20–63, 63–180, 180–500, 500–1000, and 1000–2000 μm, respectively). The 137Cs concentrations in house dust were inversely related to the square of distance from the FDNPP for <4–1000 μm particles. From the results of the multiple linear regression analysis, distance from the FDNPP and direction from the FDNPP (northwest) were significantly related to the radioactivity of house dust. It was found that 19%, 33%, and 48% of 137Cs in house dust were extracted in water, 1 M HCl, and not extracted, respectively. Considering the bioaccessibility and assuming a 20 mg/day daily intake of house dust, the daily doses would be 7.2 Bq/day (mean) and 18 Bq/day (95th percent quantile). These results provide valuable insight into indoor radioactive Cs contamination in the area around the FDNPP and possible oral exposure to indoor radioactive Cs after returning home.

Study on the sorption process on geological materials of long-lived radioactive isotopes 90Sr and 137Cs in model systems with the use of short-lived isotopes of 85Sr, 134Cs

The objective of this work was to determine the sorption properties of soil underneath the National Radioactive Waste Disposal facility (NRWD) in Rozan (NE Poland) for strontium (Sr) and caesium (Cs). The soil underneath the disposal was mainly sands consisted with quartz. The NRWD is a Low and Intermediate Level Wastes type facility. The procedure was new for our laboratory and turned out to be simple and effective. Sorption process analyses were carried out according to pH, ionic strength, time changes and tracer concentration in the solution. We also determined the Langmuir adsorption isotherms.

Mass Attenuation Coefficient Measurements of Some Nanocarbon Allotropes: A New Hope for Better Low Cost Less-Cumbersome Radiation Shielding Over A Wide Energy Range

The mass attenuation coefficients of graphene, MWNTs and, SWNTs have been measured for gamma energy range 356 to 1332 keV from the radioactive sources 60Co, 133Ba and 137Cs using a well calibrated gamma ray spectrometer consisting of a 3 x 3 NaI(Tl) scintillation detector coupled to a PC based 8K nuclear Multi Channel Analyser (MCA). In an interesting way results showed that MWNTs had the highest values of mass attenuation coefficients indicating their potential use as the best shielding material.

Особливості виносу 137Сs зерновими та зернобобовими культурами в умовах Житомирського Полісся

The purpose. To find out features and character of removal of radioactive nuclides by grain and leguminous crops in Zhitomir Polissia for formation of economically effective and ecologically balanced systems of agrarian production in the region. Methods. Sampling and preparation of samples for measurements was carried out with the help of standard procedures. Results. Variability of correlation between potential ability of agricultural plants to accumulate radioactive nuclides and intensity of torrents of removal of radioactive nuclides with crops is revealed. Efficient fertilizer systems are selected for decrease of accumulation of radioactive nuclides by grain and leguminous crops. Conclusions. Radioecological situation in the low-purity agroecosystems of Ukrainian Polissia owing to termination of counter-measures varies extremely slowly and is completely determined by physical disintegration of radioactive nuclides 137Cs and raise of motility of 90Sr in the system «soil — plant». Therefore it is necessary to possess the full information on properties of soils and density of contamination with the purpose of optimum utilization of resources at conducting counter-measures that, in its turn, demands scientific accompaniment.

The Effects of Apple Pectin Intake on Decreasing Internal Radioactive Cesium Levels: A Single-armed Pilot Study

Background: Since 2011, Minamisoma Municipal General Hospital, which is located 23 km north of the Fukushima Daiichi nuclear plant, acquired a whole-body counter (WBC) and began measuring the internal contamination levels of local residents. Objective: To examine whether or not the intake of apple pectin decreases the level of radioactive Cesium (Cs) in the body. Methods: Eighteen participants (sixteen males and two females aged 44–81 years), in whom more than a total of 20 Bq/kg of radioactive Cs-137 and Cs-134 were detected using the WBC, were screened. We measured internal radioactive Cs levels in the participants and compared the change in Cs levels between the observation and intervention periods with the intake of apple pectin. Initially, the participants received dietary education to avoid increasing levels of radioactive Cs through daily food consumption. After four weeks, the participants in whom more than 10 Bq/kg of radioactive Cs had been detected were instructed to eat a jelly with 3 grams of apple pectin, daily, for a period of four weeks. Results: Although the decrease in the radioactive Cs level in participants during the apple pectin intake period exceeded the decrease during the observation period (-9.6% and -11.7%, respectively), no significant difference in the decrease was observed between the two periods. Conclusion: This pilot study did not reveal any significant effects of apple pectin. This result may have been caused by low internal contamination levels of the participants and the distribution of food free from radioactive contamination in Fukushima. Keywords: Apple pectin, whole-body counter, internal contamination, radioactive cesium, dietary education, daily food consumption.

Comprehensive study of the mountainous lake sediments in relation to natural and anthropogenic processes and time (Ma\u0142y Staw Lake, Poland)

The Sudety Mts. form a chain of mountains in the South of Poland and during the last 200 years were subjected to strong industrial and agricultural pressure. The records of these human-induced changes are stored in natural archives like lake sediments. For the comprehensive study, three sediment cores taken from Mały Staw Lake (Sudety Mts.) were analyzed for the concentration of K, Na, Mn, Fe, Cu, Mg, Zn, Cd, Cr, Ni, Pb and radioactivity of 137Cs and 210Pb. As a result of the studies, the bathymetry map was developed and the sources of solid material supplied to the lake were identified. The geochronology studies of the cores were performed using 210Pb method, to evaluate model of time changes in the sediment. Radioactivity of 210Pbuns (determined indirectly by 210Po) ranged from 1051 ± 64 to 12 ± 8 Bq kg−1. The 137Cs radioactivity was determined directly by gamma spectrometry and varied from 525 ± 37 Bq kg−1 for top layers to 9.80 ± 5.40 Bq kg−1 for the bottom of the core. Two characteristic peaks of 137Cs radioactivity related to the global fallouts after nuclear weapons testing and the Chernobyl accident were observed and used to confirm 210Pb dating method. Chemometrics analysis of the chosen metal’s concentrations combined with sample dating showed distinct imprint of human activity on the studied area.

Numerical analysis of highly efficient laser-based method of radioactive Cs isotope separation utilizing light-induced drift in D1 and D2 transitions in rare gases

ABSTRACTWe investigated the feasibility of separating radioactive Cs isotopes using the effects of light-induced drift (LID). LID is the massive flow of particles caused by the difference between the collision frequencies of the buffer particles in the optically connected ground and excited states. We numerically evaluated the LID velocities of Cs-133, Cs-135, and Cs-137 in rare gases based on the currently available experimental technologies. The calculations were performed utilizing the steady-state analytical model and assuming that all of the collisions were strong. The velocity-dependent collision cross-sections were estimated using the WKB approximation with the recently developed ab initio atom–atom interaction potentials. A maximum velocity of more than 10 m/s was obtained when He was utilized as the buffer gas, and the expected maximum annual throughput was approximately 600 g, which is sufficient for practical purposes. We also examined the negative effects that were neglected in the employed model.

Developing Adsorption Reagents and Treatment Systems for Radioactive Cs

Developing Adsorption Reagents and Treatment Systems for Radioactive Cs

Radioactivity analysis of soil samples taken from the western and northern shores of Lake Van, Turkey

In this study, concentrations of the radioactive isotopes 226Ra, 232Th, 40K and 137Cs were measured in soil samples from the shores of Lake Van using a high purity germanium detector. Activity concentrations obtained for these nuclides were compared with world average values. The average 226Ra, 232Th and 40K activity concentrations calculated for the soil samples were higher than the world average values reported by UNSCEAR. The lowest 226Ra, 232Th and 40K activity concentrations were recorded in sample T-1 whereas the highest values were recorded in sample T-11. Concentrations of 137C in the samples ranged between 0.91 ± 0.01 and 29.68 ± 0.33Bqkg−1. In order to evaluate the radiological hazards resulting from natural radioactivity, radium equivalent activities, absorbed dose rates, and internal and external hazard indices were calculated and the results were compared with internationally recognized values.

Proposing an Approximate Mathematical Model to Conduct the Calculations of Radioactive Cs137 in the Plant

This study aims at calculating theoretically the radioactive of cesium Cs 137 in the plant of Nineveh governorate by selecting 50 positions as samples of the study. The calculations are carried out by constructing a mathematical model that determines theoretically the radioactive of cesium Cs 137in the plant. In this paper, the main features and process of mathematical modeling is stated and used clearly in the process of constructing the mathematical model which conducts the determination of the radioactive of cesium Cs 137. The values calculated by the proposed mathematical model show that Cs 137 radioactive range is: (1.0832 in (A42 & A42) – 4.1020 in (A48)) Bq/kg in plant. These calculations are conducted by comparing the results, obtained from the constructed model, with the values of other references. The result of this comparison shows good agreement with other literatures.

Quantifying the Mechanisms of Site-Specific Ion Exchange at an Inhomogeneously Charged Surface: Case of Cs+/K+ on Hydrated Muscovite Mica

Adsorption and mobility of radioactive Cs+ isotopes in soil are among the most important factors affecting the long-term environmental footprint of nuclear accidents such as Chernobyl (1986) and Fukushima Daiichi (2011). In particular, Cs+ ions can be retained through their exchange with K+ naturally present in muscovite mica, one of the common soil mineral components. The ClayFF force field allowed us to realistically represent local inhomogeneities of the structure, composition, and charge on the muscovite (001) surface and to identify three structurally different types of adsorption sites. We performed molecular dynamics simulations of Cs+ and K+ adsorption at the hydrated muscovite surface and used quasi-one-dimensional site-specific potential of mean force calculations to quantify the energetics of ion exchange in this system for each individual site and for the entire muscovite surface on average. Irrespective of the type of adsorption site, both K+ and Cs+ cations are preferably adsorbed on the bas...

Adsorption and desorption behaviors of cesium on rayon fibers coated with chitosan immobilized with Prussian blue

Rayon fiber coated with chitosan (CTS) that contained immobilized Prussian blue (KFe) (KFe/CTS/rayon) were investigated for the removal of cesium ion (Cs+) from contaminated water. The morphology and mechanical strength of the fibers were observed using scanning electron microscopy (SEM) and a universal testing machine, respectively. The Cs+ concentration was determined by inductively coupled plasma-atomic emission spectroscopy. SEM images revealed that the surface of the KFe/CTS/rayon fiber showed the most roughness. It was found that Cs+ was absorbed from the water by the KFe on the fibers in a molar ratio of 1:1 (Cs+:KFe). After treating the KFe/CTS/rayon fiber with 1% HNO3 for 3h, 48.8% Cs+ desorption was observed. Woven fibers were interlaced with either 2 or 4 lines of the KFe/CTS/rayon fiber from 16 bobbins. The tensile strengths of those fibers were 19.06 and 14.25MPa, respectively. When silver cotton was used as the core axis of the woven fiber, the tensile strength of the fibers interlaced with 2 and 4 lines increased to 27.18 and 25.17MPa, respectively. Moreover, the results of hot tests using radioactive Cs+ showed that the woven KFe/CTS/rayon fibers could absorb up to 1000Bqg−1 from an initial concentration of 8000Bqkg−1.

Development of a Cherenkov light imaging system for studying the dynamics of radiocesium in plants

ABSTRACTHigh-resolution images of radiocesium (137Cs) distribution are required to study cesium kinetics in plants. A Cherenkov light imaging system can visualize fine distributions of radionuclides emitting beta particles using an optical camera. To evaluate the linearity of the system, an imaging test was performed with point sources of 137Cs, with a radioactivity of 10–2000 kBq. The results indicated that the system has a good linearity between the image intensity and the radioactivity of 137Cs. We developed an imaging system for plants using this system to study radiocesium movement in intact plants. To demonstrate the ability to image radiocesium in a plant, an experiment was performed with an intact soybean plant for four days. The root of an 11-day-old soybean plant was dipped in 20 mL of a culture solution containing 137Cs with a radioactivity of 10 MBq without potassium. After one day, the solution was replaced with one with potassium but no 137Cs. The soybean plant was in healthy condition in the system, and the high-resolution serial images indicated that 137Cs was transported to the shoot and accumulated in the node. Therefore, Cherenkov light imaging is promising for imaging radiocesium in intact plants.

Radioactive artificial 137Cs and natural 40K activity in 21 edible mushrooms of the genus Boletus species from SW China

This study, for the first time, presents the results of activity concentration determinations for 137Cs and 40K in a high number (21 species, 87 composite samples, and 807 fruiting bodies) of mushrooms of the genus Boletus from across Yunnan in 2011–2014 and Sichuan (Boletus tomentipes) using high-resolution high-purity germanium detector. Activity concentrations of 137Cs demonstrated some variability and range from <4.4 to 83 ± 3 Bq kg−1 dry biomass in caps and from <3.8 to 37 ± 3 Bq kg−1 dry biomass in stipes, and of 40K, respectively, from 420 ± 41 to 1300 ± 110 and from 520 ± 61 to 1300 ± 140 Bq kg−1 dry biomass. No significant variations were observed regarding 137Cs and 40K activity concentrations among the same Boletus species from different sampling sites. No activity concentrations from 134Cs were detected in any mushrooms. Internal dose rates estimated were from intake of 1 kg of mushrooms per annum for 137Cs range for species and regions from around <0.0031 to 0.047 ± 0.003 μSv, while those for 40K were from around 0.22 ± 0.04 to 1.2 ± 0.1 μSv. The overall intake of 137Cs was low since low contamination was found in Boletus species.

Permeable reactive barriers based on natural zeolites from Kazakhstan in solving ecological problems: Mathematical model and simulation

In view of ecological problems stemming from the leakage of reservoirs with liquid radioactive wastes (LRW) and groundwater contamination with radioactive Cs+ and Sr2+, we have estimated the physicochemical (including sorption) characteristics of clinoptilolite-bearing tuff (CBT) from the Chankanai deposit in Kazakhstan. Data were obtained on the chemical and phase composition of CBT, its total cationexchange capacity, and equilibrium (exchange isotherms) and kinetic (diffusion coefficients) characteristics in sorbing radioactive Cs+ and Sr2+ from 0.07 n CaCl2 solution (model solutions of groundwaters). We proved that CBT efficiently sorbs Cs from this solution and practically does not sorb Sr and elucidated the reasons for the low selectivity with respect to Sr2+. Based on the equilibrium and kinetic characteristics of the process, a mathematical model is suggested for Cs sorption under dynamic conditions. The protection lifetime of the clinoptilolite-based geochemical barrier is evaluated.

Determining the resolution energy of a radiant source from the gamma energy of the source

This study was conducted to measure energy resolution by measuring energy gamma using HPGe detector, using radioactive sources 137Cs, 22Na, and 60Co. It was found that by determining the gamma energy of a radiant source from the selected sources of measurement the energy resolution could be found. The energy of gamma ray could also be found. The resolution of the HPGe detector was directly proportional to the energy of gamma-ray and its efficiency was exponentially proportional to the gamma-ray energy.

Radiation shielding and gamma ray attenuation properties of some polymers

In the present work we investigated the gamma radiation parameters as mass attenuation coefficients ?/?, the total atomic scattering cross-sections ??, the electronic scattering cross-sections se, the effective atomic numbers Zeff, and the effective electron densities Neff for some polymers such as polyoxymethylene (CH2O), poly acrylonitrile (C3H3N), natural rubber (C5H8), poly ethyl acrylate (C5H8O2), polyphenyl methacrylate (C10H10O2), and polyethylene tetraphthalate (C10H8O4). The gamma ray photons were detected by NaI(Tl) detector with resolution of 8.2 % at 662 keV, using radioactive gamma ray sources 57Co, 133Ba, 137Cs, 54Mn, 60Co, and 22Na at energies 122, 356, 511, 662, 840, 1170, 1275, and 1330 keV. Values of ?/? for the chosen polymers decrease with increasing energy. The results of investigated data are useful in plastic industry, building materials, agriculture fields radiation shielding, accelerator centers, polymer industry, medical field, etc.

福島県の里山における植物，土壌，底砂中放射性セシウムの長期変動

福島県の里山における植物，土壌，底砂中放射性セシウムの長期変動

Comparison of coastal area sediment-seawater distribution coefficients (Kd) of stable and radioactive Sr and Cs

Values of the sediment-seawater distribution coefficient (Kd) in Japanese coastal areas were compared for stable and radioactive Sr and Cs, respectively, in order to clarify whether or not the constant exchangeable fraction in sediment of 20% for the ocean margin (the IAEA recommended method) for all elements was reasonable. Global fallout origin 90Sr and 137Cs concentrations in sediment and seawater were obtained from open data sources as collected in 1964–2010 and 319 and 1506 Kd values were calculated, respectively. When the values were classified into about 10 y intervals from the 1960's to 2000's, Kd values of the two most recent decades did not show any difference for 90Sr and 137Cs. The geometric means of the most recent Kd values in 2000–2010 were 1.2 × 102 L kg−1 for 90Sr and 5.8 × 102 L kg−1 for 137Cs. The stable Sr and Cs concentration data in sediment and seawater samples collected in 2000–2011 were used to calculate stable Sr and Cs Kd values based on the IAEA's recommended method and values were compared. It was found that the stable Sr Kd (geometric mean = 5.3) was much less than that of Kd-90Sr, while stable Cs Kd (geometric mean = 1.7 × 103) was higher than that of Kd-137Cs. Thus, it was judged to be unsuitable to estimate the Kds of these radionuclides by apply a factor of 0.2 to the total concentration of Sr and Cs in Japanese coastal sediment, assuming 20% was the exchangeable fraction. It is likely that applying the constant exchangeable fraction percentage to all elements will sometimes lead to overestimated or underestimated values.

Enhanced desorption of Cs from clays by a polymeric cation-exchange agent

We report on a new approach to increase the removal of cesium from contaminated clays based on the intercalation of a cationic polyelectrolyte into the clay interlayers. A highly charged cationic polyelectrolyte, polyethyleneimine (PEI), was shown to intercalate into the negatively charged interlayers and readily replaced Cs ions adsorbed on the interlayers of montmorillonite. The polycation desorbed significantly more Cs strongly bound to the clay than did single cations. Moreover, additional NH4+ treatment following the PEI treatment enhanced desorption of Cs ions that were less accessible by the bulky polyelectrolyte. This synergistic effect of PEI with NH4+ yielded efficient desorption (95%) of an extremely low concentration of radioactive 137Cs in the clay, which is very difficult to remove by simple cation-exchange methods due to the increased stability of the binding of Cs to the clay at low Cs concentrations.