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Статті в журналах з теми "Radiocesium transfert"
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Laceby, J. P., C. Chartin, O. Evrard, Y. Onda, L. Garcia-Sanchez, and O. Cerdan. "Rainfall erosivity in subtropical catchments and implications for erosion and particle-bound contaminant transfer: a case-study of the Fukushima region." Hydrology and Earth System Sciences Discussions 12, no. 7 (July 30, 2015): 7225–66. http://dx.doi.org/10.5194/hessd-12-7225-2015.
Повний текст джерелаАнотація:
Abstract. The Fukushima Dai-ichi nuclear power plant (FDNPP) accident in March 2011 resulted in a significant fallout of radiocesium over the Fukushima region. After reaching the soil surface, radiocesium is almost irreversibly bound to fine soil particles. Thereafter, rainfall and snow melt run-off events transfer particle-bound radiocesium downstream. Erosion models, such as the Universal Soil Loss Equation (USLE), depict a proportional relationship between rainfall and soil erosion. As radiocesium is tightly bound to fine soil and sediment particles, characterizing the rainfall regime of the fallout-impacted region is fundamental to modelling and predicting radiocesium migration. Accordingly, monthly and annual rainfall data from ~ 60 meteorological stations within a 100 km radius of the FDNPP were analysed. Monthly rainfall erosivity maps were developed for the Fukushima coastal catchments illustrating the spatial heterogeneity of rainfall erosivity in the region. The mean average rainfall in the Fukushima region was 1387 mm yr−1 (σ 230) with the mean rainfall erosivity being 2785 MJ mm ha−1 yr−1 (σ 1359). The results indicate that the majority of rainfall (60 %) and rainfall erosivity (86 %) occurs between June and October. During the year, rainfall erosivity evolves positively from northwest to southeast in the eastern part of the prefecture, whereas a positive gradient from north to south occurs in July and August, the most erosive months of the year. During the typhoon season, the coastal plain and eastern mountainous areas of the Fukushima prefecture, including a large part of the contamination plume, are most impacted by erosive events. Understanding these rainfall patterns, particularly their spatial and temporal variation, is fundamental to managing soil and particle-bound radiocesium transfers in the Fukushima region. Moreover, understanding the impact of typhoons is important for managing sediment transfers in subtropical regions impacted by cyclonic activity.
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Laceby, J. Patrick, Caroline Chartin, Olivier Evrard, Yuichi Onda, Laurent Garcia-Sanchez, and Olivier Cerdan. "Rainfall erosivity in catchments contaminated with fallout from the Fukushima Daiichi nuclear power plant accident." Hydrology and Earth System Sciences 20, no. 6 (June 23, 2016): 2467–82. http://dx.doi.org/10.5194/hess-20-2467-2016.
Повний текст джерелаАнотація:
Abstract. The Fukushima Daiichi nuclear power plant (FDNPP) accident in March 2011 resulted in the fallout of significant quantities of radiocesium over the Fukushima region. After reaching the soil surface, radiocesium is quickly bound to fine soil particles. Thereafter, rainfall and snowmelt run-off events transfer particle-bound radiocesium downstream. Characterizing the precipitation regime of the fallout-impacted region is thus important for understanding post-deposition radiocesium dynamics. Accordingly, 10 min (1995–2015) and daily precipitation data (1977–2015) from 42 meteorological stations within a 100 km radius of the FDNPP were analyzed. Monthly rainfall erosivity maps were developed to depict the spatial heterogeneity of rainfall erosivity for catchments entirely contained within this radius. The mean average precipitation in the region surrounding the FDNPP is 1420 mm yr−1 (SD 235) with a mean rainfall erosivity of 3696 MJ mm ha−1 h−1 yr−1 (SD 1327). Tropical cyclones contribute 22 % of the precipitation (422 mm yr−1) and 40 % of the rainfall erosivity (1462 MJ mm ha−1 h−1 yr−1 (SD 637)). The majority of precipitation (60 %) and rainfall erosivity (82 %) occurs between June and October. At a regional scale, rainfall erosivity increases from the north to the south during July and August, the most erosive months. For the remainder of the year, this gradient occurs mostly from northwest to southeast. Relief features strongly influence the spatial distribution of rainfall erosivity at a smaller scale, with the coastal plains and coastal mountain range having greater rainfall erosivity than the inland Abukuma River valley. Understanding these patterns, particularly their spatial and temporal (both inter- and intraannual) variation, is important for contextualizing soil and particle-bound radiocesium transfers in the Fukushima region. Moreover, understanding the impact of tropical cyclones will be important for managing sediment and sediment-bound contaminant transfers in regions impacted by these events.
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Shinano, T. "Review: Agricultural Countermeasure against Radiocesium Contaminated Field." Journal of Biomedical Research & Environmental Sciences 2, no. 4 (April 7, 2021): 228–31. http://dx.doi.org/10.37871/jbres1217.
Повний текст джерелаАнотація:
In 2011, Great East Japan Earthquake and subsequent tsunami caused severe damage on the TEPCO’s nuclear power plants in Fukushima prefecture. A large area of agricultural fields in Eastern Japan was suffered by substantial amount of radioactive materials (especially radiocesium) and tremendous efforts has been taken to remediate the contaminated fields. Though phytoremediation was expected to be effective to remove radiocesium, it did not work at least in this area. Actually physical decontamination was carried out, while it is still required to mitigate the transfer of the remaining radiocesium to the crops. For this purpose potassium application is adopted as a reliable method.
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Holleman, D. F., R. G. White, and A. C. Allaye-Chan. "Modelling of radiocesium transfer in the lichen-reindeer/caribou-wolf food chain." Rangifer 10, no. 3 (September 1, 1990): 39. http://dx.doi.org/10.7557/2.10.3.819.
Повний текст джерелаАнотація:
The environmental contaminate radiocesium (cesium-137) has been shown to be of value as a marker in food selection and intake studies. Its greatest potential value as a food marker is in the subarctic/arctic regions, particularly in the lichen to reindeer/caribou to wolf food chain. A kinetic model describing the movement of radiocesium through the food chain has been developed using the SAAM computer program and is presented here. The program has been written so that the various paramenters affecting the transfer of radiocesium in the food chain can be altered more realistically to describe the system being modeled. The values of the parameters as given in this example are realistic for interior Alaska, however caution should be exercised in the application of the present results to regions that may be vastly different from the Alaskan interior without first evaluating the parameters and assumptions of the model.
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Vitorovic, D., G. Vitorovic, B. Mitrovic, and V. Andric. "Natural sepiolite efficiency in reducing 137Cs transfer and deposition into meat and edible organs of broiler chickens." Biotehnologija u stocarstvu 27, no. 2 (2011): 183–88. http://dx.doi.org/10.2298/bah1102183v.
Повний текст джерелаАнотація:
The objectives of the present study were to examine the level of radiocesium deposit in meat and edible organs of broiler chickens as well as to investigate efficiency of natural sepiolite in reducing 137Cs deposition in meat, liver and gizzard of alimentary contaminated broiler chickens. Broiler chickens (six weeks of age) were fed with the standard diet and each broiler was given a single oral dose of 137Cs, total activity of 3750 Bq. The broilers were divided into two groups (10 broilers per group). The group 1 was control (received only radiocesium). The broilers of the group 2, in addition to radiocesium received natural sepiolite solution (2 g sepiolite per bird). After 24 hours, all broilers, from each group, were stunned and killed. The samples of meat, (breast and legs), liver and gizzard were taken from each broiler, for gamma spectrometry determination of radiocesium activity. After 24 hours of contamination, 56 % of introduced 137Cs radioactivity was deposited in the meat (breast and legs muscles), 1 % in the liver and 2,4 % in the gizzard of broiler chickens 42 days of age. Natural sepiolite demonstrated insufficient protective action. Compared to the control group, percentage reduction (decreasing percentage) of 137Cs deposition in meat was 16%, in liver 5% and in gizzard 12%.
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Jones, Bernt-E. V., Olof Eriksson, and Magnus Nordkvist. "Radiocesium metabolism in reindeer." Rangifer 10, no. 3 (September 1, 1990): 45. http://dx.doi.org/10.7557/2.10.3.822.
Повний текст джерелаАнотація:
Abstract: Early in the era of atmospheric nuclear weapon tests, the reindeer was found to be an interesting animal concerning the transfer of environmental radioactive contaminants to man via the production of contaminated reindeer meat. The reason for the high transfer factors for some radionuclides is the feeding habits of the reindeer with a substantial intake of lichens, especially in the wintertime. One effect of the seasonal changes in feeding is also a considerable cyclic, seasonal variation in radiocesium content of soft tissues. The effective half-life of radiocesium was determined to about 30 days in an experiment where a herd of reindeer was moved form a high (>20 kBq/m2137Cs) to a low (<3 kBq/m2 137Cs) contamination area. The fractional transfer of 137Cs, during natural grazing, was determined to about 0.65 d/kg during wintertime on the low- contamination area and about 0.30 d/kg in summertime grazing in a more contaminated area. The radiation dose received by reindeers in Sweden after the Chernobyl accident was calculated to <200 mSv/a. The dose rate would be highest during the later part of winter but would not exceed 1 mSv/d.
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Shizuma, Kiyoshi, Wim Ikbal Nursal, and Yushi Sakurai. "Long-Term Monitoring of Radiocesium Concentration in Sediments and River Water along Five Rivers in Minami-Soma City during 2012–2016 Following the Fukushima Dai-ichi Nuclear Power Plant Accident." Applied Sciences 8, no. 8 (August 7, 2018): 1319. http://dx.doi.org/10.3390/app8081319.
Повний текст джерелаАнотація:
Radiocesium monitoring in sediments and river water has been conducted along five rivers in Minami-Soma City during 2012–2016 to clarify the temporal changes of radiocesium contamination in these rivers. Sampling has been performed annually under normal flow conditions. Sediment and river water samples were collected from four or five sampling sites along each river. Gamma-ray measurements of sediments were performed using a low-background Ge detector and unfiltered river water was utilized to determine radiocesium concentration using a well-type Ge detector. The 137Cs concentration in sediments was highest at upstream sites and slowly decreased to downstream sites for all rivers reflecting the high radioactive contamination in the upstream area. Temporal decrease of the 137Cs concentration was observed in sediments and river water for each river. The effective half-lives were 1.3–2.1 y for sediments, and 0.9–2.1 y for river water from rivers with upstream dams. On the undammed river, the effective half-lives were 4.7 y and 3.7 y for sediment and river water, respectively. Much longer effective-half-lives might reflect the direct transfer of radiocesium from forests and plains to the river. The 137Cs concentration in riverbed was low in downstream areas, however, accumulation of 137Cs over the floodplain was observed. Rapid decrease of 137Cs contamination through rivers will put residents at ease, but high accumulation of radiocesium over floodplains should be noted for future river decontamination.
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Lepage, H., O. Evrard, Y. Onda, I. Lefèvre, J. P. Laceby, and S. Ayrault. "Depth distribution of radiocesium in Fukushima paddy fields and implications for ongoing decontamination works." SOIL Discussions 1, no. 1 (September 19, 2014): 401–28. http://dx.doi.org/10.5194/soild-1-401-2014.
Повний текст джерелаАнотація:
Abstract. Large quantities of radiocesium were deposited across a 3000 km2 area northwest of the Fukushima Dai-ichi nuclear power plant after the March 2011 accident. Although many studies have investigated the fate of radiocesium in soil in the months following the accident, the potential migration of this radioactive contaminant in rice paddy fields requires further examination after the typhoons that occurred in this region. Such investigations will help minimize potential human exposure in rice paddy fields or transfer of radioactive contaminants from soils to rice. Radionuclide activity concentrations and organic content were analysed in 10 soil cores sampled from paddy fields in November 2013, 20 km north of the Fukushima power plant. Our results demonstrate limited depth migration of radiocesium with the majority concentrated in the uppermost layers of soils (< 5 cm). More than 30 months after the accident, 81.5 to 99.7% of the total 137Cs inventories was still found within the < 5 cm of the soil surface, despite cumulative rainfall totalling 3300 mm. Furthermore, there were no significant correlations between radiocesium migration depth and total organic carbon content. We attributed the maximum depth penetration of 137Cs to maintenance (grass cutting – 97% of 137Cs in the upper 5 cm) and farming operations (tilling – 83% of 137Cs in the upper 5 cm). As this area is exposed to erosive events, ongoing decontamination works may increase soil erodibility. We therefore recommend the rapid removal of the uppermost – contaminated – layer of the soil after removing the vegetation to avoid erosion of contaminated material during the subsequent rainfall events. Remediation efforts should be concentrated on soils characterised by radiocesium activities > 10 000 Bq kg−1 to prevent the contamination of rice. Further analysis is required to clarify the redistribution of radiocesium eroded on river channels.
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Evrard, Olivier, Thomas Chalaux-Clergue, Pierre-Alexis Chaboche, Yoshifumi Wakiyama, and Yves Thiry. "Research and management challenges following soil and landscape decontamination at the onset of the reopening of the Difficult-to-Return Zone, Fukushima (Japan)." SOIL 9, no. 2 (September 6, 2023): 479–97. http://dx.doi.org/10.5194/soil-9-479-2023.
Повний текст джерелаАнотація:
Abstract. Twelve years after the nuclear accident that occurred at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011, radiocesium contamination (with a large dominance of 137Cs, with a 30-year half-life) remains a major concern in various municipalities of north-eastern Japan. The Japanese authorities completed an unprecedented soil decontamination programme in residential and cultivated areas affected by the main radioactive plume (8953 km2). They implemented a complex remediation programme scheme to remediate soils that are fundamental to life on Earth, relying on different decision rules depending on the waste type, its contamination level and its region of origin, after delineating different zones exposed to contrasted radiation rates. The central objective was not to expose local inhabitants to radioactive doses exceeding 1 mSv yr−1 in addition to the natural levels. At the onset of the full reopening of the Difficult-to-Return Zone (DTRZ) in spring 2023, the current review provides an update of a previous synthesis published in 2019 (Evrard et al., 2019). Although this ambitious soil remediation and reconstruction programme has almost been completed in the 12 municipalities of Fukushima Prefecture in which an evacuation order was imposed in at least one neighbourhood in 2011, from the 147 443 inhabitants who lived there before the accident, only 29.9 % of them had returned by 2020. Waste generated by decontamination and tsunami cleaning/demolition work is planned to have been fully transported to (interim) storage facilities by the end of 2023. The cost of the operations conducted between 2011 and 2020 for the so-called “nuclear recovery” operations (including decontamination) was estimated by the Board of Audit of Japan in 2023 as JPY 6122.3 billion (∼ EUR 44 billion). Decontamination of cropland was shown to have impacted soil fertility, and potassium fertilisation is recommended to limit the transfer of residual radiocesium to new crops. In forests that cover 71 % of the surface area of Fukushima Prefecture and that were not targeted by remediation, radiocesium is now found in the upper mineral layer of the soil in a quasi-equilibrium state. Nevertheless, 137Cs concentrations in forest products (including wood for heating and construction, wild plants, wildlife game, mushrooms) often keep exceeding the threshold values authorised in Japan, which prohibits their exploitation in the area affected by the main plume. Radionuclides from forests were shown to be exported in dissolved and particle-bound forms to downstream river systems and floodplains, although multiple monitoring records showed the continuous decrease in radiocesium concentrations in both river water and sediment across the main plume between 2011 and 2021. Fish contamination is now generally found to be below the threshold limits although reputational damage remains a major concern for local fishing communities. The remobilisation of radiocesium from sediment accumulated in reservoirs of the region is also of potential concern as it may lead to secondary contamination of fish or irrigation waters supplied to decontaminated fields. Overall, this synthesis demonstrates the need to continue monitoring post-accidental radiocesium transfer in these environments and to keep sharing data in order to refine our predictive understanding of radiocesium mobility and consolidate the tools available to model contaminant transfer in ecosystems. In forests in particular, novel countermeasures and wood uses remain to be developed and tested. Furthermore, the hydrologic connectivity between soils under different ecosystems greatly influences long-term radiocesium transport. The consequences of extreme phenomena (e.g. typhoons, forest fires) that may become more frequent in the future as a result of global change in these contaminated environments should be further anticipated.
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Dvořák, Petr, Petr Snášel, and Katarína Beňová. "Transfer of Radiocesium into Wild Boar Meat." Acta Veterinaria Brno 79, no. 9 (2010): S85—S91. http://dx.doi.org/10.2754/avb201079s9s085.
Повний текст джерелаАнотація:
The aim of the study was to find the sources of 137Cs in wild boar food in the natural ecosystem. The main emphasis is focused on the analyses of wild boar muscles and the content of wild boar stomach. Boars weighing 20 to 100 kg were killed at two locations. The highest specific activities of muscles were measured in boars originated from the Dvorce location; the average specific activity in boars killed on 14 April 2007 and 9 March 2008 achieved 132 Bq kg-1. Due to high fluctuation the differences between the mean values of 31 Bq kg-1 in males and 43 Bq kg-1 in females were not significant. Earthworms from grass fields with a specific activity of 16 Bq kg-1, rootlets from the Šabrava location with 200 Bq kg-1 and Elaphomyces granulatus fruiting bodies with 4,743 Bq kg-1 and 2,858 Bq kg-1 are the components of boar food with the 137Cs specific activities higher than that of the detection limit. Consequently, underground mushrooms probably represent the main source of radiocesium in the food chain of boars. A remarkable reduction of 137Cs specific activities in boar muscles is not expected at the post-Chernobyl radiocesium contaminated locations with the occurrence of Elaphomyces granulatus within next two decades.
Дисертації з теми "Radiocesium transfert"
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Sombre, Lionel. "Contribution à l'étude du transfert du radiocesium (¹³⁴Cs et ¹³⁷Cs) dans une chaîne alimentaire d'eau douce simplifiée eau-algue verte (Scenedesmus obliquus)-mollusque filtreur (Dreissena polymorpha) /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376099977.
Повний текст джерела
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Sombre, Lionel. "ESSAI DE MODELISATION DU TRANSFERT DU RADIOCESIUM (p1sp3sp4sCs et p1sp3sp7sCs) DANS UNE CHAINE ALIMENTAIRE D'EAU DOUCE SIMPLIFIEE : eau-algue verte (scenedesmus obliquus)-mollusque filtreur (dreissena polymorpha)-poisson (barbus barbus)." Aix-Marseille 1, 1988. http://www.theses.fr/1988AIX11183.
Повний текст джерелаАнотація:
Le transfert du radiocesium est etudie dans une chaine alimentaire d'eau douce simplifiee (eau-algue verte - mollusque filtreur-poisson). Ce travail decrit en particulier le transfert du #1#3#4cs et du #1#3#7cs entre l'eau, les mollusques et les poissons. Un modele mathematique de transfert du radiocesium est construit a partir des resultats experimentaux et ce pour differents scenarios de rejet accidentel du radioelement. A long terme les poissons sont principalement radiocontamines par la chaine alimentaire (mollusques). La courriture est responsable de 50% a 90% de la radioactivite des barbeaux. Une simulation d'un apport accidentel de #1#3#7cs de type tchernobyl dans un ecosysteme de type meuse permet de prevoir que les poissons accumuleront de 10a 20 bq/kg frais (resultats corrobores par des mesures de terrain). Un modele riviere est egalement etudie afin de preciser les flux de contamination radioactive de l'eau, des matieres en suspension et des sediments par le radiocesium. Les sediments fixent 80% de la radioactivite, ils sont caracterises par un kd de 400
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Belharet, Mokrane. "Modélisation numérique du transfert du radiocésium dans les chaines trophiques pélagiques marines suite à l'accident nucléaire de Fukushima Dai-ichi (côte Pacifique du Japon)." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30339/document.
Повний текст джерелаАнотація:
Une forte contamination radioactive du milieu marin, notamment par le 137Cs, s'est produite dans le Pacifique nord-ouest suite à l'accident nucléaire de Fukushima Dai-ichi survenu le 11 mars 2011. Deux sources majeures ont été à l'origine de cette contamination, les retombées atmosphériques (sèches et humides) et les rejets liquides directement en mer. Cette radioactivité a été transférée aux organismes marins conduisant à la contamination de plusieurs espèces pélagiques et benthiques. Dans le cadre de l'étude des conséquences de cet accident sur le milieu marin, une première modélisation de la dispersion du 137Cs dans les eaux de la côte Pacifique du Japon a été réalisée par le groupe SIROCCO, permettant ainsi d'estimer l'évolution spatio-temporelle de la concentration de ce radionucléide dans l'eau et de déterminer son terme source, c'est-à-dire sa quantité globale rejetée en mer sous forme liquide. Ce travail de thèse s'inscrit dans la même démarche et vise, par une approche de modélisation, à étudier le transfert du 137Cs aux chaines trophiques pélagiques de la côte Est du Japon, composées par les populations planctoniques, les poissons planctonivores, et les poissons carnivores. Le couplage d'un modèle radioécologique, spécifiquement développé pour cette étude, à un modèle de l'écosystème composé d'un modèle NPZD (Nutrients-Phytoplankto-Zooplankton-Detritus) et d'un modèle de circulation régionale, s'est imposé comme la méthode la plus adaptée à l'étude de la contamination des populations planctoniques dans des conditions post-accidentelles. Les résultats de cette étude ont montré des niveaux de contamination assez élevés de ces populations notamment aux alentours de la centrale où les concentrations estimées sont environ 4 ordres de grandeur supérieures à celles observées avant l'accident. En dépit de ces concentrations élevées, le débit maximal de la dose absorbée reste largement au-dessous du débit de référence à partir duquel les effets sur les populations sont ressentis. Cette étude a aussi mis en évidence la prédominance de la voie trophique dans les processus d'accumulation du césium par ces espèces, ainsi que la présence d'une légère bioamplification chez les classes de taille de zooplancton. Le modèle radioécologique développé pour étudier la contamination des espèces nectoniques est structuré en taille. Chaque espèce est composé d'un ensemble de cohortes dont le nombre est fonction de la durée de vie de l'espèce et de sa fréquence de reproduction. Contrairement aux modèles classiques, le taux d'ingestion de la nourriture par l'organisme ainsi que son régime alimentaire ne sont pas constants dans le temps mais généralement variables en fonction de la taille de l'organisme. Dans cette approche le processus de prédation est considéré comme étant totalement opportuniste. Les résultats sont généralement satisfaisants et le modèle a été validé dans les conditions d'équilibre pré-accidentelles ainsi que dans les conditions post-accidentelles. L'importance de la prise en compte des mouvements migratoires de certaines espèces dans ce type de modèle a été mis en évidence notamment dans les conditions accidentelles caractérisées par une forte variabilité spatiale de la concentration du radionucléide dans la colonne d'eau. Les niveaux de contamination estimés pour les différentes espèces sont largement supérieurs à ceux observés avant l'accident, avec une tendance à l'augmentation lorsque la taille de l'individu augmenteHuge amounts of radionuclides, espicially 137Cs, were released to the coastal northwestern Pacific ocean after the Fukushima nuclear power plant accident, that occurred on 11 March 2011. The resultant radiocesium contamination was quickly transferred to marine biota resulting in elevated cesium levels in various organisms. Using a modelling approach, this work aims to study the 137Cs transfer to the marine pelagic food chains, from plankton populations to the large piscivorous fishes. Coupling the radioecological model, developed in this study, with an ecosystem model comprising an NPZD biogeochemical model and a regional ocean circulation model, is appeared to be the most adapted tool for modelling of plankton populations contamination in this accidental situation. The results of this study showed high contamination levels in the plankton populations, especially in the vincity of the power plant, where the maximal concentrations are estimated to be about 4 orders of magnitude higher than those observed before the accident. In spite of these high contamination levels, the maximum 137Cs absorbed dose rates for phyto- and zooplankton populations were estimated to be well below the 10 Gy/h benchmark value, from which a measurable effect on the marine biota can be observed. This study has also highlighted the predominance of the cesium uptake from food and the presence of biomagnification potential at this trophic level. The radioecological model developed to study the nektonic species contamination is based on the individual size. In this approach, each species is represented by a set of cohorts. The number of these cohorts is a function of the species life span and reproduction frequency. Unlike traditional approaches, the organism ingestion rate and diet composition considered in this modelling approach are not constant, but vary over the time according to the size of the organism. The model results are in general satisfactory, and the validation is carried out in both equilibrium and accidental situations. This study highlighted the importance of the organism migratory movements in the radioecological modelling espicially in the accident situations caracterized by a very high spatial variability of radionuclides concentrations in the seawater. The detailed caracteristics of 137Cs concentration dynamics in the different species are discussed. The contamination levels estimated for the different species are significantly higher than those observed before the accident, with a clear tendency to increase with individual size
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Chalaux, Thomas. "Impact of decontamination and recultivation of agricultural soils on sediment and radiocaesium transfers in Fukushima rivers." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASJ037.
Повний текст джерелаАнотація:
D'importantes quantités de radionucléides (principalement du radiocésium) se sont déposées sur les sols du nord-est du Japon après l'accident de la centrale nucléaire de Fukushima Daiichi en mars 2011. Dès fin 2013, les autorités japonaises ont entrepris un programme sans précédent de décontamination à grande échelle dans les zones cultivées et résidentielles touchées par le panache radioactif (8953 km2). L'objectif principal était de ne pas exposer les habitants à des doses radioactives supérieures à 1 mSv an-1 en plus du niveau naturel, afin de permettre un retour rapide des habitants et la reprise des activités agricoles. Dans ces zones, la décontamination a consisté à décaper sur 5 cm la couche supérieure de sol concentrant le radiocésium (90-99%) et à la remplacer par du sable saprolitique extrait de carrières locales ouvertes à cet effet. Cependant, la décontamination n'a concerné qu'une petite partie du paysage, puisque les terres agricoles couvrent moins de 10 % de cette région. En outre, comme les terres agricoles ont commencé à être remises en culture, de nombreuses questions ont été soulevées quant à l'impact de ces travaux de décontamination sur le transfert du radiocésium dans les rivières et à travers les paysages. Une approche de traçage sédimentaire multi-proxy a été mis en place pour quantifier l'évolution des sources de sédiments et de radiocésium associé aux particules transitant par le système hydrographique drainant le panache radioactif depuis l'accident. Ce grâce à l'analyse combinée de carottes de sédiments et de dépôts de crues fluviales prélevés dans toute la région. En 2021, les autorités japonaises ont annoncé la réouverture potentielle de certaines parties de la zone de retour difficile (Difficult-to-Return zone) à partir du printemps 2023 sans décontamination obligatoire. Les recherches actuelles ont permis de reconstituer et de comparer les sources et les transferts de sédiments et de radiocésium dans trois bassins versants contrastés (barrage de Mano, barrage de Yokokama et barrage de Ogaki) où différents modes de gestion (et calendriers) ont été mis en œuvre. Cela permettra de mieux comprendre l'impact des différentes décisions de gestion et de leur calendrier (décontamination précoce ou tardive) sur les transferts de sédiments et de radiocésium dans ces conditions post-accidentelles uniquesSignificant quantities of radionuclides (mainly radiocesium) were deposited on the soils of Northeastern Japan after the accident of the Fukushima Daiichi Power Plant in March 2011. Starting from late 2013, the Japanese authorities initiated an unprecedented large-scale decontamination programme in cultivated and residential areas affected by the main radioactive plume (8953 km2). The main objective was not to expose local inhabitants to radioactive doses exceeding 1 mSv yr−1 in addition to the natural levels, in order to allow a rapid return of the local inhabitants and the resumption of agricultural activities. In these areas, decontamination consisted of removing the uppermost 5-cm layer of soil that concentrated radiocesium (90-99%) and then replacing it with saprolite sand extracted from local quarries opened for this purpose. Decontamination targeted a minor proportion of the landscape, as farmland covers less than 10% of this region. Furthermore, as agricultural land started to be re-cultivated, many questions were raised regarding the impact of this decontamination work on the transfer of radiocesium into rivers and across landscapes. A multi-proxy sediment tracing approach was designed to quantify the evolution of sources of sediment and particle-bound radiocesium transiting river systems draining the main contamination plume since the accident, through the combined analysis of sediment cores and river flood deposits collected across the region. In 2021, Japanese authorities announced the potential reopening of parts of the Difficult-to-Return zone without obligatory decontamination from Spring 2023 onwards. The current research reconstructed and compared the sources and transfers of sediment and radiocesium in three contrasted catchments (i.e., Mano Dam, Yokokama Dam and Ogaki Dam) where different management modes (and schedules) were implemented. This will shed light into the impact of different management decisions and their timing (early-decontamination or late-decontamination) on sediment and radiocesium transfers in these unique post-accidental conditions
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賴淑瑛. "= Distribution and transfer of radiocesium in the terrestrial." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/01524834283215709526.
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Baláš, Josef. "Transfer radiocesia do svaloviny brojlerových kuřat a možnosti jeho ovlivnění." Doctoral thesis, 2000. http://www.nusl.cz/ntk/nusl-86340.
Повний текст джерелаЧастини книг з теми "Radiocesium transfert"
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Masumori, Masaya, Natsuko I. Kobayashi, Keitaro Tanoi, Naoto Nihei, Satoru Miura, and Tsutomu Kanasashi. "Challenge to Resume Production of Mushroom Bed Logs by Potassium Fertilizer Application." In Agricultural Implications of Fukushima Nuclear Accident (IV), 197–202. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9361-9_17.
Повний текст джерелаАнотація:
AbstractIn order to resume production of mushroom bed logs in a forested area where radiocesium was deposited, it is important to reduce its absorption from the soil. In this study, we found that aggregated transfer factors of radiocesium in Konara oak (Quercus serrata Murray) shoots were low in forests with high amounts of exchangeable potassium in the soil. Moreover, application of potassium fertilizer to the soil surface increased the amount of exchangeable potassium in the soil, thereby suppressing absorption of radiocesium by newly planted Konara oak trees.
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Ii, Ichio. "Annual Reduction of Transfer Factors of Radiocesium from Soil to Rice Cultivated in a KCl Fertilized and Straw Plowed-in Paddy Field from 2015 to 2021." In Agricultural Implications of Fukushima Nuclear Accident (IV), 17–32. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9361-9_3.
Повний текст джерелаАнотація:
AbstractWe performed consecutive field trials of rice cultivation for 10 years (2012–2021) to elucidate how to reduce radiocesium absorption by rice and to resume safe rice cultivation in a partially decontaminated paddy soil in the Iitate Village in Fukushima prefecture, Japan. Our previous report (Ii and Tanoi (2016) Consecutive field trials of rice cultivation in partially decontaminated paddy fields to reduce radiocesium absorption in the Iitate village in Fukushima prefecture. In: Nakanishi TM, Tanoi K (eds) Agricultural implications of the Fukushima nuclear accident. Springer, Tokyo, pp 55–76) of the results in 2012 and 2013 showed that K fertilization can reduce the radiocesium level of the brown rice less than the standard for food (100 Bq/kg). This report of the subsequent years (2014–2021) shows more than 80% reduction of 137Cs concentration in the brown rice and straw at KCl fertilized and straw plowed-in paddy soil. The transfer factor of 137Cs from soil to brown rice reduced from 0.0022 in 2015 to 0.0003 in 2019 and that to straw reduced from 0.0262 in 2015 to 0.0028 in 2019, respectively. Exchangeable positive ions of the soil were also analyzed. Multiple regression analyses of all data of transfer factor in 2015–2019 to year (ageing) and exchangeable K ion as variables show that the main causal factor is year (ageing) with some supportive effect of increase of exchangeable K ion. This implicates that radiocesium in soil was gradually transformed to a form more difficult to be absorbed by rice, that is, 137Cs immobilization or fixation on clay minerals by ageing, not only in early years after the accident (2011–2015), but also in later years (2015–2019). This implication was supported by comparative analysis of exchangeable 137Cs of dry soil of 2017, 2018, and 2019 (Ii et al., Radioisotopes 70:63–72, 2021). The results in 2020 and 2021 show those transfer factors have reached at bottom levels. Further this field work also shows the robustness of the rice cultivation that we could harvest rice far below the safety standard, even though the paddy field suffered floods by typhoons in September 2015 and in October 2019.
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Kaneko, Nobuhiro. "Contamination and Transfer of Radiocesium in Soil Ecosystem." In Radiocesium Dynamics in a Japanese Forest Ecosystem, 167–76. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8606-0_10.
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Sato, Mamoru. "Transport of 137Cs into Fruits After External Deposition onto Japanese Persimmon Trees." In Agricultural Implications of Fukushima Nuclear Accident (IV), 85–111. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9361-9_10.
Повний текст джерелаАнотація:
AbstractPrior to the Fukushima Daiichi accident, radiocesium released during previous nuclear accidents was deposited in periods when fruit was growing on fruit trees and radiocaesium deposited onto surface of soil and leaf was assumed to be the main route of transfer into fruit trees. In contrast, fruit trees in Japan were in their dormancy phase, so radiocesium was deposited onto external branches of the trees and onto orchard soils after the Fukushima Daiichi nuclear power plant accident in March 2011. While data had previously been compiled on root to fruit transfer, there were few studies identifying and quantifying the relative importance of external deposition and translocation compared with root to fruit transfer. This study quantified the transfer rate (TRf) of 137Cs applied to leaves and calyx into Japanese persimmon, which is an important fruit crop in Fukushima prefecture. The study examined the effects of leaf position on branches where radiocesium was administered and of fruit load on the transport of 137Cs into fruit before bud burst. When 137Cs was applied to leaves, derived TRf were higher after radiocesium application at the fruit growing stage than at the young fruit stage. There was no significant difference in TRf in mature fruit when contamination occurred via calyx or via leaves. However, the TRf via calyx contamination was higher at the young fruit stage, whereas the TRf via leaves result in an opposite trend. The TRf was dependent on the distance between fruit and the contaminated leaves. The effect of fruit thinning was verified contaminating the central of 5 consecutive fruiting shoots (bearing one fruit per each). The TRf of 137Cs from leaves into fruit on the contaminated fruiting shoot was higher where fruits on the shoots adjacent to the central one were picked off (fruit thinning) than where no fruit thinning was applied. The TRf of 137Cs into fruit on the uncontaminated fruiting shoot was lower than in fruits of contaminated shoots. There was a significant correlation between the amount of 137Cs and 40K as well as the concentration in the fruit on the contaminated fruiting shoot. TRf and aggregated transfer factors (Tagf-b) of 137Cs into fruits were also studied after application of radiocesium at dormancy to apical fruiting mother shoots or to 2-year-old lateral branches. When the apical fruiting mother shoot was contaminated, the TRf of the combined mature fruits collected from uncontaminated fruiting mother shoots was less than a quarter of the TRf of fruit growing on the contaminated apical mother shoot (on the same 2-year-old lateral branch). In contrast, when the 2-year-old lateral branch was contaminated, the TRf and Tagf-b into fruit were similar for both the fruit on both the apical and other fruiting mother shoots. These results indicate that the transfer of 137Cs to other parts of the fruit from the apical fruiting mother shoot is limited, whereas from the 2-year-old lateral branches, the transfer of 137Cs to fruit is similar on all the fruiting mother shoots. The results as well as the comparative experiment of fruit loads were consistent with the hypothesis that the transfer of 137Cs was controlled by the sink strength and activity of fruits. Tagf-b values of 137Cs applied to apical fruiting mother shoot and 2-year-old lateral branch into fruits before bud burst were about 10−3 to 10−4 m2 kg−1 based on dry and fresh weights, respectively. A significantly higher concentration of 137Cs and Tagf-b values were derived when fruit thinning was carried out than when fruits were not thinned. Refraining from intensive fruit thinning may be a useful remediation option that could reduce 137Cs activity concentrations in Japanese persimmon fruits.
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Takata, Daisuke. "Progress Toward Managing Radiocesium Contamination in Orchards." In Agricultural Implications of Fukushima Nuclear Accident (IV), 113–32. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9361-9_11.
Повний текст джерелаАнотація:
AbstractIn this chapter, we introduce the effects of radiocesium spread by the Fukushima Daiichi nuclear accident on fruit trees, especially the change of radiocesium in soil, trees, and fruits after accident. Investigation of the dynamics of radioactive cesium in fruit trees before the Fukushima Daiichi Nuclear Power Plant accident, and points verified after the accident at Chernobyl. As the occurrence of the accident and radioactive contamination of the orchard, the radioactive Cs localized in the bark and the transfer process to the fruit were discussed. We will explain the implementation status of the cases investigated in Japan after the accident, the actual investigation in the field, and the verification test using potted trees in Japan. It also introduces estimates of the concentration of radioactive cesium in fruits and measures to reduce radioactive cesium that have been implemented in Fukushima Prefecture. Finally, we will discuss our thoughts on the resumption of shipping of Anpo-gaki, the social implementation of research results so far, and future challenges.
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Nemoto, Keisuke, and Naoto Nihei. "Transfer of Radiocesium to Rice in Contaminated Paddy Fields." In Agricultural Implications of the Fukushima Nuclear Accident (III), 9–14. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-3218-0_2.
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Kobayashi, Riona, Masaya Masumori, Takeshi Tange, Keitaro Tanoi, Natsuko I. Kobayashi, and Satoru Miura. "Effect of Exchangeable and Nonexchangeable Potassium in Soil on Cesium Uptake by Quercus serrata Seedlings." In Agricultural Implications of Fukushima Nuclear Accident (IV), 171–84. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9361-9_15.
Повний текст джерелаАнотація:
AbstractIn general, potassium in soil greatly reduces radiocesium uptake by plants. Using four extraction methods, we investigated forms of potassium retained in soils from Quercus serrata (Konara oak) forests in nine regions across Japan to investigate the effect of potassium on the transfer factor of cesium in oaks. Of the potassium extracted with ammonium acetate (exchangeable K), hydrogen peroxide (H2O2-K), boiling nitric acid (HNO3-K), and tetraphenyl boric acid (TPB-K), HNO3-K, which is considered to be an indicator of nonexchangeable K content, showed the highest correlation with the transfer factor of cesium in Konara oak. H2O2-K showed the second highest correlation coefficient with cesium concentration in Konara oak. On the other hand, no significant correlation was found for exchangeable K with ammonium acetate solution, which is used to determine cesium uptake characteristics of crops. In addition, large variations were observed for all four forms of K. To determine characteristics of cesium uptake and transfer to trees, it is necessary to consider various forms of K, including nonexchangeable K.
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Saito, Takashi, Yasukazu Suzuki, Shigeto Fujimura, and Hirofumi Tsukada. "Studies on Radiocesium Transfer in Agricultural Plants in Fukushima Prefecture." In Radiation Monitoring and Dose Estimation of the Fukushima Nuclear Accident, 135–40. Tokyo: Springer Japan, 2013. http://dx.doi.org/10.1007/978-4-431-54583-5_13.
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Kanyar, B., N. Fulop, A. Kerekes, and L. Kovacs. "Modelling the Radiocesium Content in Milk and Comparison with the Measured Data after the Chernobyl Accident." In Reliability of Radioactive Transfer Models, 135–40. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1369-1_15.
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Takeda, Akira. "Soil Properties Affecting Soil-to-Crop Transfer of Fukushima-Derived Radiocesium." In Behavior of Radionuclides in the Environment III, 377–87. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6799-2_17.
Повний текст джерелаТези доповідей конференцій з теми "Radiocesium transfert"
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Oforiwaa, Priscilla Obeng, Liang Manchun, and Su Guofeng. "System Modelling Approach of Radionuclide Soil-to-Plant Transfer for Nuclear Emergencies Decision; Case Study - China." In 2021 28th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icone28-60416.
Повний текст джерелаАнотація:
Abstract Nuclear Energy Development is gradually gaining root in the energy mix of the Chinese society. It is quite evident to develop all possible emergency evaluation situation in the event of nuclear energy. Nuclear Emergency falls under the relative serious emergency incident grades according to the degree of social harm done and the extent of repercussions and other factors. This paper illustrates system modelling predictions of the transfer of radiocesium from soil-to-plant during nuclear emergency. Planned discharges of radionuclides are passed by mathematical models that can be used as tools to evaluate the effective ways of countermeasure actions in an event of an emergency. The empirical approach often associates with considerably uncertainty due to the large variability in the transfer factor The mechanistic approach also presents complexities and a large amount of specific parameters makes this approach impractical for nuclear emergency preparedness and response purposes. The semi-mechanistic approach factorizes more soil and plant parameters than the empirical approach. Therefore, it is applicable to a wider range of environmental conditions. The nuclear emergency adapts the parameterization of the Absalom model which is sufficiently robust and practical, hence fit more for the purpose of planning and responding to nuclear emergencies as compared to the empirical and mechanistic approaches.
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Oforiwaa, Priscilla Obeng, Xiaole Zhang, and Guofeng Su. "An Empirical Study of Radionuclides Behavioral Characteristics in Oceanic Biota From Waste Water Ejection." In 2024 31st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/icone31-132278.
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Abstract The concept of ecosystem changes of radionuclides is important to ensure product management for food safety. The Fukushima nuclear accident which happened in recent years released a massive concentration of radiocesium into the ocean and subsequent water bodies across Japan. In this research, our main mandate is to study the behavior of some radionuclides (Cesium (CS) 137, Strontium (Sr) 90, Carbon (C) 14, and Tritium (H3). These radionuclides transfer occurs through aquatic pathways to aquatic animals as confirmed in a simulation and air monitoring surveys. The decay characteristics and the transfer medium in Pisceverous Fish species, Benthic Fish species, and Forage Fish in the Pacific Ocean; understanding the decay mode, and transfer model is the driving force of the development of systematic policy models for a nuclear emergency. The oceanic study concentration in some sea mammals and herbivores was developed using the exponential double dynamic model. The results indicate that Pisceverous fish species such as octopus and squid are predicted to have a higher concentration at the onset of an emergency. On the Allometric scale a predicted concentration of 0.766mSv of radioisotope concentration in an oyster fish. The southern belt oysters are observed to contain a higher sediment property, thus the susceptibility of concentration in this fish species is higher than its normal level.