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Okhrimchuk D, Hurtevent P, Gonze MA, Simon-Cornu M, Roulier M, Carasco L, Orjollet D, Nicolas M, Probst A. Long-term behaviour of Cs-137, Cs-133 and K in beech trees of French forests. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 277:107450. [PMID: 38762981 DOI: 10.1016/j.jenvrad.2024.107450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/04/2024] [Accepted: 05/12/2024] [Indexed: 05/21/2024]
Abstract
In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40-50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.
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Affiliation(s)
- D Okhrimchuk
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France
| | - P Hurtevent
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France.
| | - M-A Gonze
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France
| | - M Simon-Cornu
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France
| | - M Roulier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France
| | - L Carasco
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France
| | - D Orjollet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LEREN, PSE-ENV/SPDR/LT2S, PSE-ENV/STAAR/LRTA, F-13115 Saint-Paul-lez-Durance, France
| | - M Nicolas
- ONF/Département Recherche-Développement-Innovation, F-77330, Fontainebleau, France
| | - A Probst
- CRBE (Centre de Recherche sur la Biodiversité et l'Environnement), Université de Toulouse, CNRS, IRD, Toulouse INP, Université Toulouse 3 - Paul Sabatier (UT3), F-31062, Toulouse, France
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Itô H, Miura S, Komatsu M, Kanasashi T, Nagakura J, Hirai K. Variability in radiocesium activity concentration in growing hardwood shoots in Fukushima, Japan. PLoS One 2023; 18:e0293166. [PMID: 38064418 PMCID: PMC10707650 DOI: 10.1371/journal.pone.0293166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023] Open
Abstract
The radiocesium contamination caused by the Fukushima Daiichi Nuclear Power Plant accident has made it difficult to use coppice woods as bed logs for mushroom cultivation. Evaluating the variability in the radiocesium activity concentration of logs is necessary in order to predict how many coppice woodlands are available for producing mushroom bed logs. To clarify the variability in radiocesium activity concentrations and to estimate the sample size required to estimate these concentrations with sufficient accuracy, we modeled the log-transformed radiocesium activity concentrations in growing shoots of hardwoods. We designed two models: (1) a model with mean concentrations that varied among stands with a standard deviation that was the same among stands, and (2) a model with varying means and standard deviations. We fit the data pertaining to only Quercus serrata to both models and calculated the widely applicable information criterion values. Consequently, we adopted the simpler model (1). Applying the selected model to data for all species, we examined the relationship between the number of measurement individuals and the predictive distribution of the expected concentration. Based on previous recommendations and measurement costs, we proposed that five individuals would be appropriate for estimating radiocesium activity concentration in a stand.
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Affiliation(s)
- Hiroki Itô
- Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan
| | - Satoru Miura
- Forestry and Forest Products Research Institute, Tsukuba, Japan
| | | | - Tsutomu Kanasashi
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan
| | - Junko Nagakura
- Forestry and Forest Products Research Institute, Tsukuba, Japan
| | - Keizo Hirai
- Forestry and Forest Products Research Institute, Tsukuba, Japan
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Hayashi S, Watanabe M, Kanao Koshikawa M, Takada M, Takechi S, Takagi M, Sakai M, Tamaoki M. Explaining the variation in 137Cs aggregated transfer factor for wild edible plants as a case study on Koshiabura (Eleutherococcus sciadophylloides) buds. Sci Rep 2023; 13:14162. [PMID: 37644128 PMCID: PMC10465601 DOI: 10.1038/s41598-023-41351-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 08/24/2023] [Indexed: 08/31/2023] Open
Abstract
The aggregated transfer factor (Tag) is commonly used to represent the actual transfer of radiocesium from soil to wild edible plants, but the values have shown substantial variation since the Fukushima nuclear accident. To elucidate the factors causing this variation, we investigated the effects of spatial scale and vertical 137Cs distribution in the soil on the variation of Tag-137Cs values for one of the most severely contaminated wild edible plants, Eleutherococcus sciadophylloides Franch. et Sav. (Koshiabura). The variation in Tag-137Cs values was not reduced by direct measurement of 137Cs deposition in soil samples from the Koshiabura habitat, as a substitute for using spatially averaged airborne survey data at the administrative district scale. The 137Cs activity concentration in Koshiabura buds showed a significant positive correlation with the 137Cs inventories only in the organic horizon of soil from the Koshiabura habitat. The ratio of 137Cs inventories in the organic horizon to the total 137Cs deposition in soil exhibited substantial variation, especially in broad-leaved deciduous forests that Koshiabura primarily inhabits. This variation may be the cause of the wide range of Tag-137Cs values observed in Koshiabura buds when calculated from the total 137Cs deposition in soil.
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Affiliation(s)
- Seiji Hayashi
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan.
| | - Mirai Watanabe
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Masami Kanao Koshikawa
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Momo Takada
- National Institute of Advanced Industrial Science and Technology, 1‑1‑1 Higashi, Tsukuba, Ibaraki, 305‑8567, Japan
| | - Seiichi Takechi
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
| | - Mai Takagi
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Masaru Sakai
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
| | - Masanori Tamaoki
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
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Skoko B, Kovačić M, Lazarus M, Sekovanić A, Kovačić J, Sergiel A, Zwijacz-Kozica T, Reljić S, Petrinec B, Selva N, Huber Đ. 90Sr and stable element levels in bones of brown bears: long-term trends in bear populations from Croatia and Poland. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:32507-32522. [PMID: 36460888 DOI: 10.1007/s11356-022-24397-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
The aim of this study was to investigate the temporal trends and geographical differences in 90Sr and stable element (Ba, Ca, Mn, Sr, Pb, Zn) levels in the bones of Croatian and Polish brown bear (Ursus arctos) populations. Experimental data suggest that in the decades after nuclear weapon tests and the Chernobyl accident, 90Sr bone activity concentrations decreased from 352 to 11 Bq kg-1 in the Croatian bear population (period 1982-2015) and from 831 to 27 Bq kg-1 in Polish bears (period 1962-2020). Calculated effective and ecological half-lives were 9 and 13 years for Croatian bears, and 15 and 31 years for Polish bears, respectively. Different temporal trends were noted in levels of Ba, Mn, Pb and Zn between the two countries with majority of bones having lower Pb, Sr and Zn in Croatian than in Polish bears. Estimated values for the soil-to-bear transfer of 90Sr were the same order of magnitude in the studied populations. Contrary to this, the estimated transfer of stable Sr was an order of magnitude lower for the Croatian bear population compared to Polish bears. The observed differences in soil-to-bear transfer between stable Sr and 90Sr found for Croatian bears might suggest the need for careful consideration on the use of stable Sr data as an analogue for 90Sr. To our knowledge, this is the first study that analysed 90Sr activity in tissue of brown bears. As such, it provides insight into the fate and behaviour of one of the most relevant anthropogenic radionuclides at the top of the food chain.
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Affiliation(s)
- Božena Skoko
- Institute for Medical Research and Occupational Health, Ksaverska Cesta 2, 10000, Zagreb, Croatia
| | - Milica Kovačić
- Institute for Medical Research and Occupational Health, Ksaverska Cesta 2, 10000, Zagreb, Croatia
| | - Maja Lazarus
- Institute for Medical Research and Occupational Health, Ksaverska Cesta 2, 10000, Zagreb, Croatia.
| | - Ankica Sekovanić
- Institute for Medical Research and Occupational Health, Ksaverska Cesta 2, 10000, Zagreb, Croatia
| | - Jelena Kovačić
- Institute for Medical Research and Occupational Health, Ksaverska Cesta 2, 10000, Zagreb, Croatia
| | - Agnieszka Sergiel
- Institute of Nature Conservation, Polish Academy of Sciences, Aleja Adama Mickiewicza 33, 31-120, Kraków, Poland
| | | | - Slaven Reljić
- Faculty of Veterinary Medicine, Heinzelova Ulica 55, 10000, Zagreb, Croatia
| | - Branko Petrinec
- Institute for Medical Research and Occupational Health, Ksaverska Cesta 2, 10000, Zagreb, Croatia
| | - Nuria Selva
- Institute of Nature Conservation, Polish Academy of Sciences, Aleja Adama Mickiewicza 33, 31-120, Kraków, Poland
| | - Đuro Huber
- Institute of Nature Conservation, Polish Academy of Sciences, Aleja Adama Mickiewicza 33, 31-120, Kraków, Poland
- Faculty of Veterinary Medicine, Heinzelova Ulica 55, 10000, Zagreb, Croatia
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Decadal trends in 137Cs concentrations in the bark and wood of trees contaminated by the Fukushima nuclear accident. Sci Rep 2022; 12:11243. [PMID: 35788621 PMCID: PMC9253084 DOI: 10.1038/s41598-022-14576-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
Understanding the actual situation of radiocesium (137Cs) contamination of trees caused by the Fukushima nuclear accident is essential for predicting the future contamination of wood. Particularly important is determining whether the 137Cs dynamics within forests and trees have reached apparent steady state. We conducted a monitoring survey of four major tree species (Japanese cedar, Japanese cypress, konara oak, and Japanese red pine) at multiple sites. Using a dynamic linear model, we analyzed the temporal trends in 137Cs activity concentrations in the bark (whole), outer bark, inner bark, wood (whole), sapwood, and heartwood during the 2011–2020 period. The activity concentrations were decay-corrected to September 1, 2020, to exclude the decrease due to the radioactive decay. The 137Cs concentrations in the whole and outer bark samples showed an exponential decrease in most plots but a flat trend in one plot, where 137Cs root uptake is considered to be high. The 137Cs concentration ratio (CR) of inner bark/sapwood showed a flat trend but the CR of heartwood/sapwood increased in many plots, indicating that the 137Cs dynamics reached apparent steady state within one year in the biologically active parts (inner bark and sapwood) and after several to more than 10 years in the inactive part (heartwood). The 137Cs concentration in the whole wood showed an increasing trend in six plots. In four of these plots, the increasing trend shifted to a flat or decreasing trend. Overall, the results show that the 137Cs dynamics within forests and trees have reached apparent steady state in many plots, although the amount of 137Cs root uptake in some plots is possibly still increasing 10 years after the accident. Clarifying the mechanisms and key factors determining the amount of 137Cs root uptake will be crucial for predicting wood contamination.
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Tagami K, Hashimoto S, Kusakabe M, Onda Y, Howard B, Fesenko S, Pröhl G, Harbottle AR, Ulanowski A. Pre- and post-accident environmental transfer of radionuclides in Japan: lessons learned in the IAEA MODARIA II programme. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2022; 42:020509. [PMID: 35481492 DOI: 10.1088/1361-6498/ac670c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/13/2022] [Indexed: 06/14/2023]
Abstract
An international review of radioecological data derived after the accident at the Fukushima Daiichi nuclear power plant was an important component of activities in working group 4 of the IAEA Models and data for radiological impact assessment, phase II (MODARIA II) programme. Japanese and international scientists reviewed radioecological data in the terrestrial and aquatic environments in Japan reported both before and after the accident. The environmental transfer processes considered included: (a) interception and retention radionuclides by plants, (b) loss of radionuclides from plant and systemic transport of radionuclides in plants (translocation), (c) behaviour of radiocaesium in soil, (d) uptake of radionuclides from soil by agricultural crops and wild plants, (e) transfer of radionuclides from feedstuffs to domestic and wild animals, (f) behaviour of radiocaesium in forest trees and forest systems, (g) behaviour of radiocaesium in freshwater systems, coastal areas and in the ocean, (h) transport of radiocaesium from catchments through rivers, streams and lakes to the ocean, (i) uptake of radiocaesium by aquatic organisms, and (j) modification of radionuclide concentrations in food products during food processing and culinary preparation. These data were compared with relevant global data within IAEA TECDOC-1927 'Environmental transfer of radionuclides in Japan following the accident at the Fukushima Daiichi Nuclear Power Plant'. This paper summarises the outcomes of the data collation and analysis within MODARIA II work group 4 and compares the Japan-specific data with existing radioecological knowledge acquired from past and contemporary radioecological studies. The key radioecological lessons learned are outlined and discussed.
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Affiliation(s)
- Keiko Tagami
- National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Shoji Hashimoto
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Japan
| | | | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba, Japan
| | - Brenda Howard
- School of Bioscience, University of Nottingham, Loughborough, United Kingdom
- UK Centre for Ecology and Hydrology, Lancaster, United Kingdom
| | - Sergey Fesenko
- Russian Institute of Radiology and Agroecology, Obninsk, Russia
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Aggregated transfer factor of 137Cs in edible wild plants and its time dependence after the Fukushima Dai-ichi nuclear accident. Sci Rep 2022; 12:5171. [PMID: 35338183 PMCID: PMC8956574 DOI: 10.1038/s41598-022-09072-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/09/2022] [Indexed: 11/20/2022] Open
Abstract
We obtained the aggregated transfer factor (Tag) for 10 common edible wild plant species (four perennial spermatophytes, bamboo shoot, two tree species, and three perennial pteridophytes) in northeastern Japan. Measurement of Tag was carried out in 2012–2019 and we also used publicly available data for 2012–2019: food monitoring data and total deposition data from an airborne survey. The Tag obtained from actual measurements agreed well with Tag values calculated from the publicly available data. The sampling locations were only identified at the municipal level and uncertainty of the deposition for the publicly available data, and thus Tag values showed substantial variation. The Tag of the perennial spermatophytes, including bamboo shoot, and perennial pteridophytes showed single exponential decline with effective half-lives of approximately 2 years, whereas those of tree species did not show distinct temporal change. These results imply that data since 2014 are applicable for Tag estimation for long-term potential ingestion dose in the future to the public because of the slow decline. The calculated Tag values of all species for 2014–2019 ranged from 6.1 × 10−5 to 5.2 × 10−3 m2/kg-fresh mass. The maximum Tag value was observed for the tree koshiabura (Chengiopanax sciadophylloides) and the minimum value was observed for the perennial spermatophyte giant butterbur (Petasites japonica). Tree species showed higher Tag than spermatophyte and pteridophyte perennials.
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Thiessen KM, Hoffman FO, Bouville A, Anspaugh LR, Beck HL, Simon SL. Parameter Values for Estimation of Internal Doses from Ingestion of Radioactive Fallout from Nuclear Detonations. HEALTH PHYSICS 2022; 122:236-268. [PMID: 34898519 PMCID: PMC8677614 DOI: 10.1097/hp.0000000000001493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
ABSTRACT This paper suggests values or probability distributions for a variety of parameters used in estimating internal doses from radioactive fallout due to ingestion of food. Parameters include those needed to assess the interception and initial retention of radionuclides by vegetation, translocation of deposited radionuclides to edible plant parts, root uptake by plants, transfer of radionuclides from vegetation into milk and meat, transfer of radionuclides into non-agricultural plants and wildlife, and transfer from food and drinking water to mother's milk (human breast milk). The paper includes discussions of the weathering half-life for contamination on plant surfaces, biological half-lives of organisms, food processing (culinary factors), and contamination of drinking water. As appropriate, and as information exists, parameter values or distributions are specific for elements, chemical forms, plant types, or other relevant characteristics. Information has been obtained from the open literature and from publications of the International Atomic Energy Agency. These values and probability distributions are intended to be generic; they should be reviewed for applicability to a given location, time period, or season of the year, as appropriate. In particular, agricultural practices and dietary habits may vary considerably both with geography and over time in a given location.
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Affiliation(s)
| | - F. Owen Hoffman
- Oak Ridge Center for Risk Analysis, Inc., 102 Donner Drive, Oak Ridge, TN 37830
| | - André Bouville
- National Cancer Institute, National Institutes of Health, Bethesda, MD (retired)
| | | | | | - Steven L. Simon
- National Cancer Institute, National Institutes of Health, Bethesda, MD
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Shuryak I. Machine learning analysis of 137Cs contamination of terrestrial plants after the Fukushima accident using the random forest algorithm. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 241:106772. [PMID: 34768117 DOI: 10.1016/j.jenvrad.2021.106772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/29/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Radioactive contamination of terrestrial plants was extensively investigated and quantitatively modeled after the Fukushima nuclear power plant accident. This phenomenon, which is important for ecosystem functioning and protection of human health, is influenced by multiple factors, including plant species, time after the accident, and climate. Machine learning algorithms such as random forests (RF) have a record of strong performance on large multi-dimensional data sets, but, to our knowledge, combined data on post-Fukushima plant contamination with radionuclides were not yet subjected to a machine learning analysis. Here we performed such analysis on two large published data sets: (1) 137Cs activity concentrations in four common Japanese forest tree species. (2) Plant/soil 137Cs concentration ratios in multiple perennial plant species. The goal was to show the usefulness of machine learning for identifying and quantifying the main trends of 137Cs contamination in terrestrial plants. Each data set was split randomly into training and testing parts, RF was fitted and tuned on the training parts, and its performance was assessed on the testing parts by three metrics: coefficient of determination (R2), root mean squared error, and mean absolute error. Synthetic noise variables and the Boruta algorithm were used in a customized procedure to identify the most important predictor variables, which consistently outperformed random noise. Good agreement between observations and RF predictions (e.g. R2∼0.9 on testing data) was obtained on both data sets. The effects of the most important predictors (e.g. time after the accident, 137Cs land contamination level, and plant species) and interactions between them were quantified by partial dependence plots. These results of machine learning analyses of large data collections can help to complement previous modeling efforts, and to clarify the patterns of 137Cs contamination of plants after the Fukushima accident.
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Affiliation(s)
- Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th Street, VC-11-234/5, New York, NY, 10032, USA.
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Radiocaesium Contamination of Mushrooms at High- and Low-Level Chernobyl Exposure Sites and Its Consequences for Public Health. Life (Basel) 2021; 11:life11121370. [PMID: 34947901 PMCID: PMC8708313 DOI: 10.3390/life11121370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 11/17/2022] Open
Abstract
We compare the specific activities of 137Cs and 40K in stipes and caps of three different common mushroom species (Xerocomus badius, Russula ochroleuca and Armillariella mellea) measured at the Czech Chernobyl hot spot in the Opava area (Silesia) and at a low-exposed site at the Beskydy mountains in 2011. The highest values of 137Cs were found in caps of Xerocomus badius and Russula ochroleuca in the Opava area (11.8 and 8.77 kBq/kg, respectively). The source of 137Cs was verified by the measurement of the 134Cs/137Cs ratio. Based on our results, we estimate an effective dose per year due to radiocaesium intake in the two investigated areas for Xerocomus badius, one of the most popular edible mushrooms in the Czech Republic. In 2011, the effective dose reached the maximum value of 0.102 mSv in the Opava area and 0.004 mSv at the low-exposed site at the Beskydy mountains. Therefore, it does not represent a significant risk for public health.
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Sakai M, Tsuji H, Ishii Y, Ozaki H, Takechi S, Jo J, Tamaoki M, Hayashi S, Gomi T. Untangling radiocesium dynamics of forest-stream ecosystems: A review of Fukushima studies in the decade after the accident. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 288:117744. [PMID: 34243085 DOI: 10.1016/j.envpol.2021.117744] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
Forest-stream ecosystems are widespread and biodiverse terrestrial landscapes with physical and social connections to downstream human activities. After radiocesium is introduced into these ecosystems, various material flows cause its accumulation or dispersal. We review studies conducted in the decade after the Fukushima nuclear accident to clarify the mechanisms of radiocesium transfer within ecosystems and to downstream areas through biological, hydrological, and geomorphological processes. After its introduction, radiocesium is heavily deposited in the organic soil layer, leading to persistent circulation due to biological activities in soils. Some radiocesium in soils, litter, and organisms is transported to stream ecosystems, forming contamination spots in depositional habitats. While reservoir dams function as effective traps, radiocesium leaching from sediments is a continual phenomenon causing re-contamination downstream. Integration of data regarding radiocesium dynamics and contamination sites, as proposed here, is essential for contamination management in societies depending on nuclear power to address the climate crisis.
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Affiliation(s)
- Masaru Sakai
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan.
| | - Hideki Tsuji
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Yumiko Ishii
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Hirokazu Ozaki
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Seiichi Takechi
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Jaeick Jo
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Masanori Tamaoki
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Seiji Hayashi
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan
| | - Takashi Gomi
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan
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Atarashi-Andoh M, Koarashi J, Tsuduki K, Takeuchi E, Nishimura S, Muto K, Matsunaga T. Spatial variations in radiocesium deposition and litter-soil distribution in a mountainous forest catchment affected by the Fukushima nuclear accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 238-239:106725. [PMID: 34461367 DOI: 10.1016/j.jenvrad.2021.106725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
The Fukushima Dai-ichi Nuclear Power Plant accident caused serious 137Cs contamination in mountainous forest areas. To understand the spatial variation in soil 137Cs inventory in complex mountainous topography and the influencing factors, a whole-area investigation of 137Cs deposition in a broad-leaved forest catchment of a mountain stream was conducted using grid sampling. Across the catchment, organic and surface mineral soil layers were collected at 42 locations in 2013 and 6 locations in 2015. Cesium-137 deposition on the forest floor exhibited high spatial heterogeneity and altitude-dependent distribution over the catchment. The 137Cs retention ratio in the organic layer, determined as the inventory in the organic layer divided by the soil (organic and mineral soil layers) inventory, ranged from 6% to 82% in 2013, and the coefficient of variation was 0.6. The 137Cs retention ratios had positive correlations with the material inventory in the organic layer and the elevation. The 137Cs retention ratios in the organic layer were less than 20% in 2015, even at the locations where the retention ratio was higher than 55% in 2013. Although there was spatial variation in the migration speed, 137Cs migration from the organic layer to mineral soil was almost completed within 4 y of the deposition, suggesting a decrease in 137Cs circulation within the forest ecosystem. This study also examined a relationship between the 137Cs inventory and the air dose rate to assess the potential of using the air dose rate to estimate soil 137Cs inventory. Soil 137Cs inventories and air dose rates were highly positively correlated, indicating that measurement of air dose rate can provide an easier and quicker alternative to measurement of soil 137Cs inventory in forest ecosystems.
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Affiliation(s)
- Mariko Atarashi-Andoh
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan.
| | - Jun Koarashi
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Katsunori Tsuduki
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Erina Takeuchi
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Syusaku Nishimura
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Kotomi Muto
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Takeshi Matsunaga
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
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13
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Shuryak I. Quantitative modeling of radioactive cesium concentrations in large omnivorous mammals after the Fukushima nuclear power plant accident. Sci Rep 2021; 11:10049. [PMID: 33976327 PMCID: PMC8113437 DOI: 10.1038/s41598-021-89449-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/27/2021] [Indexed: 11/09/2022] Open
Abstract
Large quantities of radionuclides released by the Fukushima nuclear power plant accident entered terrestrial and marine ecosystems. The resulting radioactive contamination of large omnivorous wild mammals such as wild boar (Sus scrofa) and Asian black bear (Ursus thibetanus) varied greatly depending on location, season, and time after the accident. Quantitative modeling of how such factors influence radionuclide burdens in these species is important for enhancing current knowledge of chronic radionuclide exposure consequences in mammalian populations, and for assessing potential human risks from consumption of contaminated animal meat. Here we modeled the time course of radioactive cesium (134Cs + 137Cs) concentrations in boar and black bears from Fukushima Prefecture over ~ 7 years after the accident, using nonlinear robust and quantile regressions and mixed-effects modeling. To estimate predictive performance, models fitted to the full data set were compared with those fitted only to the first 3.5 years of data, and tested on the last 3.5 years of data. Ecological half-lives for radioactive cesium, and magnitudes and phase shifts for sinusoidal seasonal oscillations in cesium burdens, were estimated by each analysis method for each species. These results can improve the understanding and prediction of radionuclide concentrations in large mammals that inhabit radioactively contaminated areas.
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Affiliation(s)
- Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th Street, VC-11-234/5, New York, NY, 10032, USA.
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14
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Hashimoto S, Imamura N, Kawanishi A, Komatsu M, Ohashi S, Nishina K, Kaneko S, Shaw G, Thiry Y. A dataset of 137Cs activity concentration and inventory in forests contaminated by the Fukushima accident. Sci Data 2020; 7:431. [PMID: 33339821 PMCID: PMC7749123 DOI: 10.1038/s41597-020-00770-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/17/2020] [Indexed: 01/21/2023] Open
Abstract
The majority of the area contaminated by the Fukushima Daiichi Nuclear Power Plant accident is covered with forests. We developed a dataset for radiocaesium (137Cs) in trees, soil, and mushrooms measured at numerous forest sites. The 137Cs activity concentration and inventory data reported in scientific journal papers written in English and Japanese, governmental reports, and governmental monitoring data on the web were collated. The ancillary information describing the forest stands were also collated, and further environmental information (e.g. climate) was derived from the other databases using longitude and latitude coordinates of the sampling locations. The database contains 8593, 4105, and 3189 entries of activity concentration data for trees, soil, and mushrooms, and 471 and 3521 entries of inventory data for trees and soil, respectively, which were collected from 2011 to 2017, and covers the entire Fukushima prefecture. The data can be used to document and understand the spatio-temporal dynamics of radiocaesium in the affected region and to aid the development and validation of models of radiocaesium dynamics in contaminated forests.
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Affiliation(s)
- Shoji Hashimoto
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
| | - Naohiro Imamura
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Ayumi Kawanishi
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shinta Ohashi
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Kazuya Nishina
- Center for Regional Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaraki, 305-8506, Japan
| | - Shinji Kaneko
- Kansai Research Center, Forestry and Forest Products Research Institute, Fushimi, Kyoto, 612-0855, Japan
| | - George Shaw
- School of Biosciences, University of Nottingham, Sutton Bonington, Nottingham, LE12 5RD, United Kingdom
| | - Yves Thiry
- Research and Development Division, Andra, 1-7 Rue Jean-Monnet, 92298, Châtenay-Malabry cedex, France
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15
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Shinomiya Y, Kobayashi M, Tsurita T, Tsuboyama Y, Sawano S, Itoh Y, Ohnuki Y, Shichi K. Discharge of suspended solids and radiocesium into stream water in a forested watershed before and after line thinning with spur road construction. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 225:106418. [PMID: 33038692 DOI: 10.1016/j.jenvrad.2020.106418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/29/2020] [Accepted: 09/01/2020] [Indexed: 06/11/2023]
Abstract
In an experimental watershed located around 120 km southwest of the Fukushima Daiichi Nuclear Power Plant with a drainage area of 59.9 ha, suspended solids (SS) and radioactive cesium discharge from a forested headwater catchment were monitored before and after line thinning. The lower slopes in the experimental watershed were covered with plantation conifer trees (Japanese cedar), while the upper slopes were covered with deciduous trees. In 2012, line thinning was carried out at a thinning rate of 35% across 17% of the northeastern part of the watershed and across the remaining part in 2013. Spur roads were constructed along all tributaries without water, and logged trees were dragged and grappled using forestry machinery and transported along these roads to timber yards using forwarder-type forestry vehicles. A V-notch weir and a water level gauge were installed at the watershed outlet and stream water was sampled twice a month during base flow, whereas during flood flow, stream water samples of 1 L were collected every hour using an automatic water sampler. These samples were filtered through 0.5 μm glass fiber filters to measure the SS concentration. SS concentration data was collected for 21 floods before thinning and for 37 floods after thinning. A time-integrated SS sampler was installed in the stream close to the weir and SS samples were collected every two or three months to measure their Cs-137 concentrations. SS concentrations before (from July 2010 to August 2012) and after thinning (from October 2013 to December 2018) were compared, where the maximum SS concentrations before and after thinning were 211 and 790 mg L-1, respectively. It was discovered that some SS concentrations during flood flow were higher after carrying out thinning than before. Some ΣLss values (specific cumulative load of SS in a flood event) also showed the same results as the SS concentrations. Thus, it was clear that SS discharge immediately increases after thinning, but as it increases Cs-137 export is limited. This is related to a change in SS source brought about by the process of thinning, a decrease with time in the Cs-137 concentration in organic solid expected from that in litter, and a regrowth of vegetation on spur roads, protecting them against soil erosion. Therefore, it was concluded that thinning does not drastically increase Cs-137 export from a forested watershed.
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Affiliation(s)
- Yoshiki Shinomiya
- For. and For. Prod. Res. Inst, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Masahiro Kobayashi
- For. and For. Prod. Res. Inst, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Tatsuya Tsurita
- For. and For. Prod. Res. Inst, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Yoshio Tsuboyama
- For. and For. Prod. Res. Inst, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shinji Sawano
- Hokkaido Research Center, For. and For. Prod. Res. Inst, 7 Hitsujigaoka, Toyohira, Sapporo, Hokkaido, 062-8516, Japan
| | - Yuko Itoh
- For. and For. Prod. Res. Inst, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Yasuhiro Ohnuki
- Tohoku Research Center, For. and For. Prod. Res. Inst., 92-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate, 020-0123, Japan
| | - Koji Shichi
- Shikoku Research Center, For. and For. Prod. Res. Inst, 2-915 Asakuranishi, Kochi, Kochi, 780-8077, Japan
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16
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Nemoto Y, Oomachi H, Saito R, Kumada R, Sasaki M, Takatsuki S. Effects of 137Cs contamination after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident on food and habitat of wild boar in Fukushima Prefecture. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 225:106342. [PMID: 32949874 DOI: 10.1016/j.jenvrad.2020.106342] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 06/02/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
After the Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Station accident, wild boar was found to have greater radiocesium (137Cs) activity concentrations in their bodies than other wild animals in Japan; however, the reason for this remains unknown. To understand the mechanism of 137Cs transfer from the environment to wild boar, and the factors that affect variation in 137Cs contamination in wild boar, we sampled muscle and stomach contents from wild boar captured in Fukushima Prefecture and analyzed the relationships among 137Cs concentrations in muscle tissue and in the stomach contents, 137Cs ground deposition at capture sites, and wild boar food habits. Significant positive relationships were observed among 137Cs activity concentrations in muscle and stomach contents, as well as 137Cs deposition density at capture sites. These results suggest that 137Cs is transferred from the environment to plant and animal materials consumed by wild boar, and then from these foods to the bodies of wild boar through digestion. However, no correlation was observed between 137Cs concentrations in stomach contents and the presence of any particular food item in stomachs of wild boar, including mushrooms. These findings suggest mushrooms and underground food items, which were found to affect 137Cs concentrations in wild animals in Europe, were not important contributors to high levels of 137Cs contamination in Japanese wild animals.
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Affiliation(s)
- Yui Nemoto
- Fukushima Prefectural Centre for Environmental Creation, 10-2, Fukasaku, Miharu Town, Fukushima, 963-7700, Japan; Tokyo University of Agriculture, 1-1-1, Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
| | - Hitoshi Oomachi
- Fukushima Prefectural Centre for Environmental Creation, 10-2, Fukasaku, Miharu Town, Fukushima, 963-7700, Japan; Fukushima Prefecture, 2-16, Sugitsumatyou, Fukushima, Fukushima, 960-8670, Japan
| | - Rie Saito
- Fukushima Prefectural Centre for Environmental Creation, 10-2, Fukasaku, Miharu Town, Fukushima, 963-7700, Japan
| | - Reiko Kumada
- Fukushima Prefectural Centre for Environmental Creation, 10-2, Fukasaku, Miharu Town, Fukushima, 963-7700, Japan
| | - Masataka Sasaki
- Azabu University, 1-17-71, Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Seiki Takatsuki
- The Life Museum of Azabu University, 1-17-71, Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
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17
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Sakashita W, Miura S, Akama A, Ohashi S, Ikeda S, Saitoh T, Komatsu M, Shinomiya Y, Kaneko S. Assessment of vertical radiocesium transfer in soil via roots. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 222:106369. [PMID: 32801027 DOI: 10.1016/j.jenvrad.2020.106369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Several years after the Fukushima Daiichi Nuclear Power Plant accident, the surface mineral soil layer is believed to be the main reservoir of radiocesium (137Cs) in forest ecosystems in Japan. Dissolved 137Cs combines with clay minerals in the soil, and hence, it is not expected to easily infiltrate over time. However, previous studies have indicated that 137Cs derived from the older global fallout migrated deeper than that of the Chernobyl accident, and this cannot be explained by only the dissolved 137Cs vertical migration in the soil. Considering the carbon and nutrient dynamics in the forest floor, the 137Cs transfer process in soil via roots may alter its vertical distribution on a decadal scale. Therefore, in this study, we investigated the 137Cs activity concentrations in both roots and soil matrix, by considering four (0-20 cm) or six (0-30 cm) mineral soil layers taken at every 5 cm at seven study sites dominated by one of the six plant species (three coniferous forests, one deciduous forest, two deciduous forests covered by Sasa, and one bamboo forest) in eastern Japan in 2013. Comparing the results of 137Cs activity concentrations between roots and soil matrix taken at the same soil layer, roots at the surface (0-5 cm) layer often showed lower values than the soil matrix. However, roots deeper than 5 cm had higher activity concentrations than the soil matrix, conversely. The 137Cs inventories ratio of roots to soil matrix are about 1% at the 0-5 and 5-10 cm soil layer, and about 2% at the soil layers deeper than 10 cm. These results suggest that decomposition of root litter little affect the short-term vertical migration of 137Cs in the forest soil. However, it indicates that continuous production and mortality of roots with relatively high 137Cs activity concentrations have an important role for changing the vertical distribution of 137Cs on time scale of decades, particularly at deeper soil layers.
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Affiliation(s)
- Wataru Sakashita
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Department of Forest Soils, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Satoru Miura
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Akio Akama
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shinta Ohashi
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Department of Wood Properties and Processing, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shigeto Ikeda
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Department of Forest Soils, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Tomoyuki Saitoh
- Tohoku Research Center, FFPRI, 92-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate, 020-0123, Japan
| | - Masabumi Komatsu
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Department of Mushroom Science and Forest Microbiology, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Yoshiki Shinomiya
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Department of Forest Soils, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shinji Kaneko
- Kansai Research Center, FFPRI, 68 Nagaikyutaroh, Momoyama, Fushimi, Kyoto, 612-0855, Japan
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18
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Komatsu M, Suzuki N, Ogawa S, Ota Y. Spatial distribution of 137Cs concentrations in mushrooms (Boletus hiratsukae) and their relationship with soil exchangeable cation contents. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 222:106364. [PMID: 32791375 DOI: 10.1016/j.jenvrad.2020.106364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/19/2020] [Accepted: 07/19/2020] [Indexed: 06/11/2023]
Abstract
The activity concentrations of radiocesium (137Cs) in wild mushrooms are reported to vary according to species, genus or ecological types. In addition, the concentration fluctuates among the same species collected within the same area. Therefore, we investigated whether the 137Cs concentration of wild mushrooms would be (1) spatially biased, or (2) influenced by the 137Cs or exchangeable potassium concentrations in the soils below. We set two survey plots 300 m apart in a Himalayan cedar forest in Tsukuba, Japan, where ca. 30 kBq/m2 of 137Cs was deposited after the Fukushima Nuclear Power Plant accident. From these plots, we collected fruit-bodies (fungal structures for spore production) of co-occurring Boletus hiratsukae, a mycorrhizal species, as well as from the soil below. The mean 137Cs concentrations in the fruit-bodies were significantly different between the two plots, but no difference was observed in the soil 137Cs concentration between the plots. Significant spatial autocorrelation was observed in the 137Cs concentration in the organic layer for both sites, but no significant spatial autocorrelation was observed in the 137Cs of fruit-bodies. Therefore, the variation in the 137Cs concentrations of co-occurred B. hiratsukae was not explained by spatial bias or radioactivity in the below soil. In contrast, the exchangeable potassium concentration in the soil was negatively correlated with the 137Cs in the fruit-bodies. Our results suggest that the 137Cs absorption of wild mushrooms would be suppressed by the competitive effect of exchangeable potassium in the surrounding soils.
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Affiliation(s)
- Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Narimi Suzuki
- Department of Forest Science and Resources, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan
| | - Shuta Ogawa
- Department of Forest Science and Resources, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan; Nara Zoen Corporation, 1-13-3 Shinyokohama, Kohoku, Yokohama, Kanagawa, 222-0033, Japan
| | - Yuko Ota
- Department of Forest Science and Resources, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan
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19
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Kanasashi T, Miura S, Hirai K, Nagakura J, Itô H. Relationship between the activity concentration of 137Cs in the growing shoots of Quercus serrata and soil 137Cs, exchangeable cations, and pH in Fukushima, Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 220-221:106276. [PMID: 32560880 DOI: 10.1016/j.jenvrad.2020.106276] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Incorporation of radiocesium by plants via root uptake appears to be affected by some of the exchangeable cations in the soil and/or pH of the soil. However, few studies have examined the relationship between 137Cs in trees and soil properties in the area surrounding the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) after the accident in March 2011. To elucidate the relationships between the root uptake of 137Cs by deciduous broadleaved trees and soil properties, we measured the activity concentration of 137Cs in the growing shoots of coppiced konara oak (Quercus serrata) grown after the FDNPP accident and the amounts of total 137Cs; exchangeable (ex-) 137Cs, ex-K, ex-Mg, and ex-Ca; and pH (H2O) in soils collected from 34 forest stands in Fukushima between December 2016 and May 2017. Ex-137Cs showed a positive linear relationship with the activity concentration of 137Cs in the growing konara oak shoots, whereas ln-transformed ex-K, ex-Mg, ex-Ca, and pH (H2O) showed negative linear relationships with ln-transformed 137Cs activity concentrations in the growing shoots. However, only ex-137Cs and ex-K were identified as significant factors determining the activity concentration of 137Cs in konara oak according to multiple regression methods and a model selection using Akaike information criterion; ex-K had a stronger influence on the activity concentration of 137Cs in konara oak than ex-137Cs. In the present study, we demonstrated that soil ex-K negatively and non-linearly alters 137Cs activity concentration in deciduous broadleaved trees. We also noted that the relationship between 137Cs in deciduous broadleaved trees and soil ex-K in forests without K fertilization was similar to the relationships between 137Cs in other plants and ex-K in K-fertilized lands reported in previous studies of the FDNPP accident.
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Affiliation(s)
- Tsutomu Kanasashi
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Satoru Miura
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Keizo Hirai
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Junko Nagakura
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Hiroki Itô
- Hokkaido Research Center, Forestry and Forest Products Research Institute, 7 Hitsujigaoka, Toyohira, Sapporo, Hokkaido, 062-8516, Japan
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20
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Saito R, Nemoto Y, Tsukada H. Relationship between radiocaesium in muscle and physicochemical fractions of radiocaesium in the stomach of wild boar. Sci Rep 2020; 10:6796. [PMID: 32321942 PMCID: PMC7176735 DOI: 10.1038/s41598-020-63507-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/11/2020] [Indexed: 11/16/2022] Open
Abstract
After the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant in 2011, it became important to study radiation dynamics, assess internal radiation exposure and specify factors affecting radionuclide variation in wildlife. Therefore, it is necessary to investigate which physicochemical fractions of radiocaesium (137Cs) are absorbed from ingested material in species with high activity concentrations of 137Cs, such as wild boar. This study analysed the physicochemical fractions of 137Cs in the stomach contents of wild boar to evaluate the transfer from ingested food to muscle. The 137Cs activity concentration in muscle showed a significantly positive relationship with the 137Cs activity concentration in the exchangeable fraction, and the sum of the 137Cs activity concentrations in the exchangeable and bound to organic matter fractions. Seasonal variations were also found in the 137Cs activity concentration in the exchangeable fraction, and the sum of the 137Cs activity concentrations in the exchangeable and bound to organic matter fractions. These findings suggest that the proportions of the physicochemical fractions of 137Cs in the exchangeable and bound to organic matter fractions in the stomach contents are important factors affecting the increases and seasonal dynamics of the activity concentrations of 137Cs in wild boar muscle.
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Affiliation(s)
- Rie Saito
- Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan.,Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima-shi, Fukushima, 960-1296, Japan
| | - Yui Nemoto
- Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan
| | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima-shi, Fukushima, 960-1296, Japan.
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21
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Koarashi J, Atarashi-Andoh M, Nishimura S, Muto K. Effectiveness of decontamination by litter removal in Japanese forest ecosystems affected by the Fukushima nuclear accident. Sci Rep 2020; 10:6614. [PMID: 32313049 PMCID: PMC7171154 DOI: 10.1038/s41598-020-63520-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/31/2020] [Indexed: 11/09/2022] Open
Abstract
The Fukushima Daiichi nuclear power plant accident caused serious radiocesium (137Cs) contamination of forest ecosystems over a wide area. The removal of the forest floor litter layer has been considered a potential method for forest decontamination; however, its effectiveness remains largely unknown. We conducted a pilot-scale decontamination study in a deciduous broadleaved forest in Fukushima. The entire forest was decontaminated by removing the litter layer in July 2014, approximately 3.3 years after the accident, with the exception of two untreated plots. For three years after decontamination, we quantified 137Cs contamination levels in the litter and topsoil layers and in the tree leaves, in the untreated and decontaminated areas. The decreased inventories of litter materials and the litter-associated 137Cs in the decontaminated areas were observed only in the first year after decontamination. Generally, no decontamination effects were observed on the 137Cs transfer in tree leaves. The primary reason for this was the rapid shift in the main reservoir of 137Cs from litter layers to the underlying mineral soil, which differs from the observations in post-Chernobyl studies of European forest ecosystems. The results suggest that litter-removal decontamination can only be successful if it is implemented more quickly (within 1-2 years after the accident) for Japanese forest ecosystems.
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Affiliation(s)
- Jun Koarashi
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan.
| | - Mariko Atarashi-Andoh
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Syusaku Nishimura
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Kotomi Muto
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
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Thiry Y, Tanaka T, Dvornik AA, Dvornik AM. TRIPS 2.0: Toward more comprehensive modeling of radiocaesium cycling in forest. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 214-215:106171. [PMID: 32063289 DOI: 10.1016/j.jenvrad.2020.106171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
Because internal transfers can play a key role in radiocaesium persistence in trees, a reliable representation of radiocaesium recycling between tree organs in forest models is important for long-term simulations after radioactive fallout in Chernobyl and Fukushima. We developed an upgraded 2.0 version of the initial TRIPS ("Transfer of Radionuclides In Perennial vegetation System") model involving explicit differentiation between tree organs (i.e., foliage, branches, stemwood and bark). The quality of TRIPS 2.0 was evaluated by testing model outputs against independent datasets for pine stands in Belarus and Ukraine. Scenarios involving "hot particle" deposits in forest remained challenging, but in all other scenarios generally positive verification results for soil and tree compartments indicated that the TRIPS 2.0 model adequately combines the major relevant processes. Interestingly, the response of stemwood contamination to changes in radiocaesium availability in soil, as determined by soil conditions, was shown to be more sensitive than for other tree compartments. We recommend the conceptual tree discretization of TRIPS 2.0 for generic forest modeling for two reasons: 1) regardless of different soil conditions, there was concurrent good agreement between simulations and data for individual tree compartments (foliage, branches, stemwood and bark), and 2) the measurements necessary to estimate internal tree transfers are easily accessible to usual field monitoring in forest biogeochemistry (for details, see Goor, F. & Thiry, Y., 2004. Science of the total environment, 325(1-3), 163-180).
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Affiliation(s)
- Y Thiry
- French National Radioactive Waste Management Agency (Andra) - Research and Development Division, 92298, Chatenay-Malabry, France.
| | - T Tanaka
- EDF R&D, LNHE, 6 Quai Watier, 78400, Chatou, France.
| | - A A Dvornik
- Institute of Radiobiology of National Academy of Sciences of Belarus, 4, Fedjuninskogo Str., 246007, Gomel, Belarus.
| | - A M Dvornik
- Gomel State University, Sovetskaya St.104, 246019, Gomel, Belarus.
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Hashimoto S, Imamura N, Kaneko S, Komatsu M, Matsuura T, Nishina K, Ohashi S. New predictions of 137Cs dynamics in forests after the Fukushima nuclear accident. Sci Rep 2020; 10:29. [PMID: 31913315 PMCID: PMC6949301 DOI: 10.1038/s41598-019-56800-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/30/2019] [Indexed: 11/13/2022] Open
Abstract
Most of the area contaminated by the Fukushima Daiichi Nuclear Power Plant accident is covered by forest. In this paper, we updated model predictions of temporal changes in the 137Cs dynamics using the latest observation data and newly provided maps of the predicted 137Cs activity concentration for wood, which is the most commercially important part of the tree body. Overall, the previous prediction and latest observation data were in very good agreement. However, further validation revealed that the migration from the soil surface organic layer to the mineral soil was overestimated for evergreen needleleaf forests. The new prediction of the 137Cs inventory showed that although the 137Cs distribution within forests differed among forest types in the first 5 years, the difference diminished in the later phase. Besides, the prediction of the wood 137Cs activity concentrations reproduced the different trends of the 137Cs activity concentrations for cedar, oak, and pine trees. Our simulation suggests that the changes of the wood 137Cs activity concentration over time will slow down after 5–10 years. Although the model uncertainty should be considered and monitoring and model updating must continue, the study provides helpful information on the 137Cs dynamics within forest ecosystems and the changes in wood contamination.
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Affiliation(s)
- Shoji Hashimoto
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan. .,Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
| | - Naohiro Imamura
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shinji Kaneko
- Kansai Research Center, Forestry and Forest Products Research Institute, Fushimi, Kyoto, 612-0855, Japan
| | - Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Toshiya Matsuura
- Department of Forest Management, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Kazuya Nishina
- Center for Regional Environmental Research, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
| | - Shinta Ohashi
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
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Translocation of cesium in the branches of Japanese cedar (Cryptomeria japonica) and Konara oak (Quercus serrata). J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06996-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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25
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Komatsu M, Nishina K, Hashimoto S. Extensive analysis of radiocesium concentrations in wild mushrooms in eastern Japan affected by the Fukushima nuclear accident: Use of open accessible monitoring data. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113236. [PMID: 31546076 DOI: 10.1016/j.envpol.2019.113236] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
After the Fukushima Daiichi Nuclear Power Plant accident, there has been an increasing concern regarding the contamination of wild mushrooms with radiocesium (134Cs and 137Cs) in eastern Japan. In this study, we analyzed the radioactivity monitoring data of 3189 wild edible mushrooms of 107 species collected by the 265 local municipalities in eastern Japan to investigate the radiocesium levels in wild mushrooms. Results of the analysis showed that radiocesium concentrations in mushrooms were normalized with radioactivity deposition data from aircraft monitoring, and then we evaluated the effects of species, sampled location, sampling year and regional deviation between 134Cs and 137Cs activity of specimens using a hierarchical Bayesian approach considering spatial autocorrelation (an intrinsic CAR model). Normalized activity concentration by species ranged from 1.1×10-4 to 2.3×10-2 (m2 kg-1, fresh weight). As reported in previous studies, the mycorrhizal species tended to have higher radiocesium concentrations. Some saprophytic species (e.g. Pholiota lubrica) also had high concentrations. For the mushroom species that were also evaluated in the post-Chernobyl studies, we found that the same species had similar trends of absorption capacities. Our results indicate the extensive analysis of public monitoring data is helpful to understand the situation of mushroom contamination and evaluate the internal dose by ingestion of wild mushrooms according to species and areas.
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Affiliation(s)
- Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Kazuya Nishina
- Center for Regional Environmental Research, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki, 305-8506, Japan
| | - Shoji Hashimoto
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Isotope Facility for Agricultural Education and Research, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
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26
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Ayabe Y, Yoshida T, Kanasashi T, Hayashi A, Fukushi A, Hijii N, Takenaka C. Web-building spider Nephila clavata (Nephilidae: Arachnida) can represent 137Cs contamination of arthropod communities and bioavailable 137Cs in forest soils at Fukushima, Japan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:1176-1185. [PMID: 31412453 DOI: 10.1016/j.scitotenv.2019.06.158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/22/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Large areas of Fukushima's forests were contaminated with radiocesium (137Cs) after the Fukushima Dai-ichi Nuclear Power Plant accident. Most of the contaminated forests have not been decontaminated, and bioavailable 137Cs is likely to circulate within the forest environment's food web. Nephila clavata (Nephilidae: Arachnida) is a top predator in the forest arthropod community, and this web-building spider potentially consumes many arthropod species presented in the grazing and detrital food chains. We tested whether 137Cs in the spider could serve as a proxy for 137Cs contamination of these arthropod communities. We also examined whether N. clavata could serve as a proxy for soil bioavailable 137Cs. Nephila clavata was similarly or more contaminated with 137Cs compared with lower-trophic-level arthropods such as herbivores and other predators at the same trophic level. Thus, the 137Cs activity of N. clavata could represent the extent to which the arthropod community was contaminated with 137Cs. Data from nine 137Cs-contaminated sites in Fukushima showed a significant positive correlation between soil bioavailable 137Cs and N. clavata's 137Cs activity05 but the coefficient of determination was only moderate (R2 = 0.43), suggesting that N. clavata is only a weak proxy of soil bioavailable 137Cs. Our results also showed that the bioavailable fraction of 137Cs in Fukushima was strongly correlated with the total inventory and that the K and Na contents of the soil determined the soil-to-spider transfer factor for 137Cs and the 137Cs activity in N. clavata, respectively. These results improve our understanding of 137Cs transfer from the soil to arthropod species.
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Affiliation(s)
- Yoshiko Ayabe
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Tomohiro Yoshida
- Field Science Center, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
| | - Tsutomu Kanasashi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Akane Hayashi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Akihisa Fukushi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Naoki Hijii
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Chisato Takenaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
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27
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Malikova IN, Strakhovenko VD, Shcherbov BL. Distribution of radionuclides in moss-lichen cover and needles on the same grounds of landscape-climatic zones of Siberia. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 198:64-78. [PMID: 30592996 DOI: 10.1016/j.jenvrad.2018.12.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 12/06/2018] [Accepted: 12/14/2018] [Indexed: 06/09/2023]
Abstract
The radiation status of the landscape and climatic zones of Siberia at the turn of the 20th and 21st centuries is characterized using bioindicators/biomonitors: lichens, mosses, and needles, according to the results obtained at the sites of their joint growth. The maximal activity of 137Cs in these components is observed in the forest-tundra landscaped zone, polluted during the period of nuclear tests from the nuclear test site "Novaya Zemlya" and also due to slow migration of these elements to the soil under the arctic conditions. In the southern territories the specific activity of radiocesium in the moss-lichen cover and needles of conifers corresponds to the regional background, in the forest-tundra zone it sometimes exceeds it, but in general does not pose a threat to human health. Determined differences in the contents of radioactive elements in lichens and mosses that grow together on sites in different landscape zones of Siberia statistically not significant within one or two standard deviations, and recorded only in the range of 3ϭ at the level of significance 0.05. Specificity of radionuclide distribution in lichens, mosses and needles (differences for epigeals and epiphytic lichens; different species selected at one site, annual and perennial needles, etc.) made it possible to identify the causes of variations in their activities in different zones, along with landscape features of these zones. In the needles of conifers potassium concentration exceeds the content in lichens, at lower levels of thorium and 137Cs. The contents of uranium and thorium in the studied components in all landscape-climatic zones correspond to the natural ones, except for the single local territories, because of the possible anthropogenic influence.
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Affiliation(s)
- I N Malikova
- Sobolev Institute of Geology and Mineralogy SB RAS, Acad. Koptyug Ave. 3, Novosibirsk, 630090, Russia.
| | - V D Strakhovenko
- Sobolev Institute of Geology and Mineralogy SB RAS, Acad. Koptyug Ave. 3, Novosibirsk, 630090, Russia; Novosibirsk State University, Pirogov Str. 2, Novosibirsk, 630090, Russia
| | - B L Shcherbov
- Sobolev Institute of Geology and Mineralogy SB RAS, Acad. Koptyug Ave. 3, Novosibirsk, 630090, Russia
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28
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Saito R, Kabeya M, Nemoto Y, Oomachi H. Monitoring 137Cs concentrations in bird species occupying different ecological niches; game birds and raptors in Fukushima Prefecture. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 197:67-73. [PMID: 30544020 DOI: 10.1016/j.jenvrad.2018.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
This study was conducted to assess radiocesium accumulation in birds after the accident at Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station in 2011, with a particular focus on 137Cs, which has a long physical half-life. Results of 137Cs monitoring in four game bird species including two pheasant species and two duck species (copper pheasant, green pheasant, spot-billed duck and mallard) were assessed in Fukushima Prefecture. We also obtained samples from rescued raptors that died during treatment or rehabilitation at the Wildlife Symbiosis Centre in Fukushima Prefecture because of severe injury. We measured the muscle concentrations of 137Cs in four of these raptor species (black kite, northern goshawk, peregrine falcon and ural owl). Comparison of the two pheasant species showed that the copper pheasants inhabiting forested areas had higher 137Cs concentrations in muscle (Bq/kg, fresh mass) than the green pheasants inhabiting mountainous areas near human habitation (i.e., Satoyama). No clear tendencies were observed in 137Cs concentration in muscle of copper pheasants over time, but a tendency to decrease was observed in green pheasants over time. The difference in tendencies between species may be attributable to differences in their food habits and its 137Cs concentration, and also differences in the situation of 137Cs accumulation in their habitat. No significant differences were observed in 137Cs concentration in muscle between the resident spot-billed duck and migratory mallard because of the comparatively short biological of effective half-life of radiocesium. Analysis of 137Cs concentration in muscle of raptor revealed that the concentration was similar to, or lower than, those of pheasants and ducks.
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Affiliation(s)
- Rie Saito
- Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan.
| | - Masahiko Kabeya
- Wildlife Symbiosis Centre, 67 Nagakubo, Tamai, Ootama Village, Fukushima, 969-1302, Japan
| | - Yui Nemoto
- Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
| | - Hitoshi Oomachi
- Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
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29
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Thiry Y, Albrecht A, Tanaka T. Development and assessment of a simple ecological model (TRIPS) for forests contaminated by radiocesium fallout. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 190-191:149-159. [PMID: 29793757 DOI: 10.1016/j.jenvrad.2018.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/26/2018] [Accepted: 05/07/2018] [Indexed: 06/08/2023]
Abstract
The management of vast forested zones contaminated by radiocesium (rCs) following the Chernobyl and Fukushima fallout is of great social and economic concern in affected areas and requires appropriate dynamic models as predictive or questioning tools. Generally, the existing radio-ecological models need less fragmented data and more ecological realism in their quantitative description of the rCs cycling processes. The model TRIPS ("Transfer of Radionuclide In Perennial vegetation Systems") developed in this study privileged an integrated approach which makes the best use of mass balance studies and available explicit experimental data for Scots pine stands. A main challenge was the differentiation and calibration of foliar absorption as well as root uptake in order to well represent the rCs biocycling. The general dynamics of rCs partitioning was simulated with a relatively good precision against an independent series of observed values. In our scenario the rCs biological cycling enters a steady-state about 15 years after the atmospheric deposits. At that time, the simulations showed an equivalent contribution of foliage and root uptake to the tree contamination. But the root uptake seems not sufficient to compensate the activity decline in the tree. The initial foliar uptake and subsequent internal transfers were confirmed to have a great possible impact on the phasing of tree contamination. An extra finding concerns the roots system acting as a buffer in the early period. The TRIPS model is particularly useful in cases where site-specific integrated datasets are available, but it could also be used with adequate caution to generic sites. This development paves the way for simplification or integration of new modules, as well as for a larger number of other applications for the Chernobyl or Fukushima forests once the appropriate data become available. According to the sensitivity analysis that involves in particular reliable estimates of net foliar uptake as well as root uptake not disconnected from rCs exchange reactions in soil.
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Affiliation(s)
- Yves Thiry
- Andra, Research and Development Division, 1-7 rue Jean-Monnet, 92298 Châtenay-Malabry cedex, France.
| | - Achim Albrecht
- Andra, Research and Development Division, 1-7 rue Jean-Monnet, 92298 Châtenay-Malabry cedex, France
| | - Taku Tanaka
- EDF R&D, LNHE, 6 quai Watier, 78400 Chatou, France
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Nishina K, Hashimoto S, Imamura N, Ohashi S, Komatsu M, Kaneko S, Hayashi S. Calibration of forest 137Cs cycling model "FoRothCs" via approximate Bayesian computation based on 6-year observations from plantation forests in Fukushima. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 193-194:82-90. [PMID: 30218793 DOI: 10.1016/j.jenvrad.2018.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/10/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Predicting the environmental fate of 137Cs in forest ecosystems along with the concentrations of 137Cs in tree parts are important for the managements of radioactively contaminated forests. In this study, we calibrate the Forest RothC and Cs model (FoRothCs), a forest ecosystem 137Cs dynamics model, using observational data obtained over six years from four forest sites with different levels of 137Cs contamination from Fukushima Prefecture. To this end, we applied an approximate Bayesian computation (ABC) technique based on the observed 137Cs concentrations (Bq kg-1) of five compartments (leaf, branch, stem, litter, and soil) in a Japanese cedar plantation. The environmental decay (increment) constants of the five compartments were used as the summary statistics (i.e., the metric for model performance) to infer the five parameters related to 137Cs transfer processes in FoRothCs. The ABC technique successfully reconciled the model outputs with the observed trends in 137Cs concentrations at all sites during the study period. Furthermore, the estimated parameters are in agreement with the literature values (e.g., the root uptake rates of 137Cs). Our study demonstrates that model calibration with ABC based on the trends in 137Cs concentrations of multi compartments is useful for reducing the prediction uncertainty of 137Cs dynamics in forest ecosystems.
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Affiliation(s)
- Kazuya Nishina
- Center for Regional Environmental Research, National Institute for Environmental Studies, 305-8506, 16-2, Onogawa, Tsukuba, Ibaraki, Japan.
| | - Shoji Hashimoto
- Forestry and Forest Products Research Institute, 305-8687, 1, Matsunosato, Tsukuba, Ibaraki, Japan; The University of Tokyo, 113-8657, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Naohiro Imamura
- Forestry and Forest Products Research Institute, 305-8687, 1, Matsunosato, Tsukuba, Ibaraki, Japan
| | - Shinta Ohashi
- Forestry and Forest Products Research Institute, 305-8687, 1, Matsunosato, Tsukuba, Ibaraki, Japan
| | - Masabumi Komatsu
- Forestry and Forest Products Research Institute, 305-8687, 1, Matsunosato, Tsukuba, Ibaraki, Japan
| | - Shinji Kaneko
- Kansai Research Center, Forestry and Forest Products Research Institute, 612-0855, 68, Nagaikyutaro, Momoyama, Fushimi, Kyoto, Japan
| | - Seiji Hayashi
- Fukushima Branch, National Institute for Environmental Studies, 963-7700, 10-2, Fukasaku, Miharu, Fukushima, Japan
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31
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Nemoto Y, Saito R, Oomachi H. Seasonal variation of Cesium-137 concentration in Asian black bear (Ursus thibetanus) and wild boar (Sus scrofa) in Fukushima Prefecture, Japan. PLoS One 2018; 13:e0200797. [PMID: 30020989 PMCID: PMC6051634 DOI: 10.1371/journal.pone.0200797] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/03/2018] [Indexed: 11/22/2022] Open
Abstract
To elucidate and reduce the risk of radionuclide contamination in wildlife caused by the Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Station accident, it is important to understand radionuclide variations in the wild animal population. Here, we used environmental monitoring data and muscle samples collected from Asian black bear (Ursus thibetanus) and wild boar (Sus scrofa) from May 2011 to March 2016 to examine seasonal variation in radiocesium (137Cs) concentrations in muscle tissues (hereafter, muscle 137Cs) of these important game species in Fukushima Prefecture. We measured muscle 137Cs of bears and wild boars killed by hunters or in animal control culls. First, using a linear mixed model (LMM), we tested for a positive relationship between muscle 137Cs and 137Cs in the soil at the site of capture (hereafter, soil 137Cs) estimated from a soil 137Cs deposition map produced by the Japan Atomic Energy Agency. In the LMM, muscle 137Cs was positively related to estimated soil 137Cs, which corroborates the results of previous studies. The LMM regression coefficients differed between the two species, with wild boar muscle 137Cs being higher than that of bears sampled at the same locations. We then employed a generalized additive mixed model (GAMM) to estimate seasonal variation in the muscle 137Cs of the target species. GAMM showed that muscle 137Cs varied seasonally and that this seasonal variation also differed between the two species. In bears, muscle 137Cs decreased from spring to early autumn, before increasing in winter. Wild boar muscle 137Cs remained low during spring and summer and was high during autumn and early spring. These patterns are likely influenced by differences in diet, habitat use, and physiology between these two species.
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Affiliation(s)
- Yui Nemoto
- Research Department, Fukushima Prefectural Centre for Environmental Creation, Miharu Town, Fukushima, Japan
- * E-mail:
| | - Rie Saito
- Research Department, Fukushima Prefectural Centre for Environmental Creation, Miharu Town, Fukushima, Japan
| | - Hitoshi Oomachi
- Research Department, Fukushima Prefectural Centre for Environmental Creation, Miharu Town, Fukushima, Japan
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Lee SH, Oh JS, Lee KB, Lee JM, Hwang SH, Lee MK, Kwon EH, Kim CS, Choi IH, Yeo IY, Yoon JY, Im JM. Evaluation of abundance of artificial radionuclides in food products in South Korea and sources. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 184-185:46-52. [PMID: 29334620 DOI: 10.1016/j.jenvrad.2018.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 06/07/2023]
Abstract
Food samples are collected nationwide from January 2016 to February 2017 and their contents of artificial radionuclides are measured to address the growing concerns regarding the radioactive contamination of food products in Korea. Specifically, 900 food samples are collected for this study and their contents of representative artificial radionuclides 134Cs, 137Cs, 239,240Pu, and 90Sr are analyzed. The analysis shows that the activity concentrations of 137Cs in fish range from minimum detectable activity (MDA) to 340 mBq/kg of fresh weight. The concentration factor (CF) determined for 137Cs as a measure of its bioavailability is calculated to be ca. 74 and found to be very similar to that (100) recommended by the International Atomic Energy Agency. With an MDA of <0.221 mBq/kg, the results reveal that 239,240Pu values in fish are below the MDA. The activity concentrations of 137Cs and 90Sr are lower than the MDA in both shellfish and seaweed, while the activity concentrations of 239,240Pu in shellfish range from 0.26 to 2.18 mBq/kg, and for seaweed samples range from 2.07 to 3.38 mBq/kg. The atom ratios of 240Pu/239Pu in shellfish caught at the Korean coast vary from 0.209 to 0.237, with a mean of 0.227. The higher 240Pu/239Pu atom ratio determined in shellfish is thought to be caused by the plutonium transported from the Pacific Proving Grounds rather than other sources such as the Fukushima nuclear power plant accident. The activity concentrations of 137Cs in mushrooms are found to vary from 1.0 to 21.4 Bq/kg, with the highest concentrations observed in the Oak (shiitake) and Sarcodon asparatus. 134Cs is detected in three mushroom specimens collected from Jeju Island and about 3-3.6% of 137Cs present in the wild mushrooms native to the Jeju Island are introduced as a result of the Fukushima nuclear plant accident. The annual effective doses of 137Cs received through consumption of mushrooms and fish are 2.0 × 10-4 mSv yr-1 and 3.9 × 10-5 mSv yr-1, and those values are negligible compared to the annual effective doses limit of 1 mSv yr-1.
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Affiliation(s)
- S H Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
| | - J S Oh
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - K B Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - J M Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - S H Hwang
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - M K Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - E H Kwon
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - C S Kim
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - I H Choi
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - I Y Yeo
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - J Y Yoon
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - J M Im
- Korea Atomic Energy Research Institute, Daejeon, 34057, Republic of Korea
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Ikka T, Nishina Y, Kamoshita M, Oya Y, Okuno K, Morita A. Radiocesium uptake through leaf surfaces of tea plants (Camellia sinensis L.). JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 182:70-73. [PMID: 29197749 DOI: 10.1016/j.jenvrad.2017.11.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 11/09/2017] [Accepted: 11/21/2017] [Indexed: 06/07/2023]
Abstract
To clarify the source of radiocesium detected in newly emerged tea leaves contaminated just before the time of bud opening by fallout of radionuclides from Fukushima Dai-ichi Nuclear Power Plant, 137CsCl solution (0.185 M Bq mL-1) was applied to the front or the backside surfaces of mature leaves of tea plant (Camellia sinensis L. cv. Yabukita) at the time of bud opening. A 21 days after foliar application, the buds had grown and developed to the three- or four-leaf stage. In the front treatment, almost all (95%) of the applied 137Cs was present in the mature leaves (hot mother leaves). In the backside treatment, 68% of applied 137Cs also remained in hot mother leaves, but 22% and 10% was found in the new shoots attached to hot mother leaves and the other parts (non-applied mature leaves, stems and roots), respectively. The images of a hot leaf and its attached new shoots by imaging plate analysis revealed that the results coincided with those of the 137Cs distribution above. These suggested that radiocesium was primarily absorbed from the backside surface of tea leaves through the stoma, and then the greater part was transported to newly emerged tea organs during the new shoot growth period.
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Affiliation(s)
- Takashi Ikka
- Laboratory of Functional Plant Physiology, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan
| | - Yoshifumi Nishina
- Laboratory of Functional Plant Physiology, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan
| | - Mizuho Kamoshita
- Laboratory of Functional Plant Physiology, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan
| | - Yasuhisa Oya
- Radioscience Research Laboratory, Faculty of Science, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan
| | - Kenji Okuno
- Radioscience Research Laboratory, Faculty of Science, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan
| | - Akio Morita
- Laboratory of Functional Plant Physiology, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan.
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Komatsu M, Hirai K, Nagakura J, Noguchi K. Potassium fertilisation reduces radiocesium uptake by Japanese cypress seedlings grown in a stand contaminated by the Fukushima Daiichi nuclear accident. Sci Rep 2017; 7:15612. [PMID: 29142200 PMCID: PMC5688087 DOI: 10.1038/s41598-017-15401-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/20/2017] [Indexed: 12/03/2022] Open
Abstract
We analysed suppressive effects of potassium (K) fertilisation on radiocesium (137Cs) uptake by hinoki cypress (Chamaecyparis obtusa) seedlings from soils contaminated after the Fukushima Daiichi Nuclear Power Plant accident. Three-year-old seedlings were planted in a clear-cut forest (ca. 4 ha) during June–July 2014, and potassium chloride fertiliser (83 kg K ha−1) was applied twice (August 2014 and April 2015). 137Cs concentrations in the needles in the fertilised plots were one-eighth of those in the control (unfertilised) plots at the end of the second growing season (October 2015). Our results clearly indicated that K fertilisation reduced radiocesium transfer from soil to planted cypress seedlings. A linear mixed model analysis revealed that 137Cs concentrations in the needles were significantly affected by 137Cs inventory in the soil (Bq m−2) adjacent to the sampled seedlings, exchangeable K concentrations in surface mineral soils (0–5 cm) and fertilisation. The exchangeable K concentrations in surface soils in October 2015 did not differ from those in August 2014 (before fertilisation) in the fertilised plots and in the control plots. These results suggested that the levels of exchangeable K would temporarily increase by fertilisation during the growing season, and radiocesium uptake by tree roots was suppressed.
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Affiliation(s)
- Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Keizo Hirai
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Junko Nagakura
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
| | - Kyotaro Noguchi
- Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.,Tohoku Research Center, Forestry and Forest Products Research Institute, Morioka, Iwate, 020-0123, Japan
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Ohashi S, Kuroda K, Takano T, Suzuki Y, Fujiwara T, Abe H, Kagawa A, Sugiyama M, Kubojima Y, Zhang C, Yamamoto K. Temporal trends in 137Cs concentrations in the bark, sapwood, heartwood, and whole wood of four tree species in Japanese forests from 2011 to 2016. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:335-342. [PMID: 28965024 DOI: 10.1016/j.jenvrad.2017.09.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/05/2017] [Accepted: 09/13/2017] [Indexed: 06/07/2023]
Abstract
To understand the changes in radiocesium (137Cs) concentrations in stem woods after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, we investigated 137Cs concentrations in the bark, sapwood, heartwood, and whole wood of four major tree species at multiple sites with different levels of radiocesium deposition from the FDNPP accident since 2011 (since 2012 at some sites): Japanese cedar at four sites, hinoki cypress and Japanese konara oak at two sites, and Japanese red pine at one site. Our previous report on 137Cs concentrations in bark and whole wood samples collected from 2011 to 2015 suggested that temporal variations were different among sites even within the same species. In the present study, we provided data on bark and whole wood samples in 2016 and separately measured 137Cs concentrations in sapwood and heartwood samples from 2011 to 2016; we further discussed temporal trends in 137Cs concentrations in each part of tree stems, particularly those in 137Cs distributions between sapwood and heartwood, in relation to their species and site dependencies. Temporal trends in bark and whole wood samples collected from 2011 to 2016 were consistent with those reported in samples collected from 2011 to 2015. Temporal variations in 137Cs concentrations in barks showed either a decreasing trend or no clear trend, implying that 137Cs deposition in barks is inhomogeneous and that decontamination is relatively slow in some cases. Temporal trends in 137Cs concentrations in sapwood, heartwood, and whole wood were different among species and also among sites within the same species. Relatively common trends within the same species, which were increasing, were observed in cedar heartwood, and in oak sapwood and whole wood. On the other hand, the ratio of 137Cs concentration in heartwood to that in sapwood (fresh weight basis) was commonly increased to more than 2 in cedar, although distinct temporal trends were not found in the other species, for which the ratio was around 1 in cypress and pine and below 0.5 in oak, suggesting that 137Cs transfer from sapwood to heartwood shows species dependency. Consequently, the species dependency of 137Cs transfer within the tree appears easily, while that from the environment to the trees can be masked by various factors. Thus, prediction of 137Cs concentrations in stem wood should be carried out carefully as it still requires investigations at multiple sites with a larger sample size and an understanding of the species-specific 137Cs transfer mechanism.
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Affiliation(s)
- Shinta Ohashi
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan; Center for Forest Restoration and Radioecology, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan.
| | - Katsushi Kuroda
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Tsutomu Takano
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan; Center for Forest Restoration and Radioecology, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Youki Suzuki
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Takeshi Fujiwara
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Hisashi Abe
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Akira Kagawa
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Masaki Sugiyama
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Yoshitaka Kubojima
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Chunhua Zhang
- Department of Wood Properties and Processing, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Koichi Yamamoto
- Center for Forest Restoration and Radioecology, FFPRI, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
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Diener A, Hartmann P, Urso L, Vives I Batlle J, Gonze MA, Calmon P, Steiner M. Approaches to modelling radioactive contaminations in forests - Overview and guidance. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:203-211. [PMID: 28892730 DOI: 10.1016/j.jenvrad.2017.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/01/2017] [Accepted: 09/02/2017] [Indexed: 06/07/2023]
Abstract
Modelling the radionuclide cycle in forests is important in case of contamination due to acute or chronic releases to the atmosphere and from underground waste repositories. This article describes the most important aspects to consider in forest model development. It intends to give an overview of the modelling approaches available and to provide guidance on how to address the quantification of radionuclide transport in forests. Furthermore, the most important gaps in modelling the radionuclide cycle in forests are discussed and suggestions are presented to address the variability of forest sites.
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Affiliation(s)
- A Diener
- Bundesamt für Strahlenschutz (BfS), Ingolstaedter Landstr. 1, 85764 Oberschleissheim, Germany.
| | - P Hartmann
- Bundesamt für Strahlenschutz (BfS), Ingolstaedter Landstr. 1, 85764 Oberschleissheim, Germany
| | - L Urso
- Bundesamt für Strahlenschutz (BfS), Ingolstaedter Landstr. 1, 85764 Oberschleissheim, Germany
| | | | - M A Gonze
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), France
| | - P Calmon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), France
| | - M Steiner
- Bundesamt für Strahlenschutz (BfS), Ingolstaedter Landstr. 1, 85764 Oberschleissheim, Germany
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Ayabe Y, Hijii N, Takenaka C. Effects of local-scale decontamination in a secondary forest contaminated after the Fukushima nuclear power plant accident. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 228:344-353. [PMID: 28551564 DOI: 10.1016/j.envpol.2017.05.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 05/11/2017] [Accepted: 05/17/2017] [Indexed: 06/07/2023]
Abstract
We investigated whether local-scale decontamination (removal of the litter layer, superficial soil layer, and understory) in a secondary forest contaminated by the Fukushima nuclear power plant accident reduced 137Cs contamination of the soil and litter. We also measured 137Cs concentrations in plants and in the web-building spider Nephila clavata (Nephilidae: Arachnida), as an indicator species, to examine 137Cs contamination in arthropods. One month after decontamination, the total 137Cs contamination (soil + litter) was reduced by 20% (100 kBq·m-2) relative to that in an adjacent untreated (i.e., contaminated) area, which was however not statistically significant. Four months after decontamination, 137Cs in the decontaminated area had increased to a level similar to those in the untreated area, and the air radiation dose in the decontaminated area was about 2.1 μSv·h-1, significantly higher than that in the untreated area (1.9 μSv·h-1). This may have been attributed to a torrential rain event. Although no statistically significant reduction was observed, most spiders had a lower 137Cs contamination than that before the decontamination. This implied that the decontamination may have reduced 137Cs transfer from soil via litter to N. clavata through the detrital food chains, but may not have reduced the amount of 137Cs transfer through grazing food chains because the concentration of 137Cs in living tree leaves was not reduced by the decontamination. In autumn, about 2 kBq·m-2 of 137Cs was supplied from foliage to the ground by litterfall. The results suggested that removal of the litter and superficial soil layers in a contaminated forest may be ineffective. The present study suggests that the local-scale decontamination in a secondary forest had no effect on the reduction of 137Cs contamination in the treated area.
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Affiliation(s)
- Yoshiko Ayabe
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Naoki Hijii
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Chisato Takenaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
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Abstract
Meat of wild boars is not only known for high 137Cs activity concentrations but also for the remarkable constancy of these levels. Even decades after the Chernobyl accident, the 137Cs levels in wild boar meat in Central Europe have not declined but even partly increased. In the present study, we investigated an unusual hypothesis for this very unusual phenomenon: may the boars’ fat tissue act as a reservoir for radiocesium? We investigated fat and muscle tissues of four wild boars in Western Germany and found that the 137Cs concentrations in fat were in the range of 10–30% of the respective activities in muscle tissue. Hence, the hypothesis was refuted.
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Radiocaesium partitioning in Japanese cedar forests following the "early" phase of Fukushima fallout redistribution. Sci Rep 2016; 6:37618. [PMID: 27876870 PMCID: PMC5120304 DOI: 10.1038/srep37618] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 10/21/2016] [Indexed: 11/09/2022] Open
Abstract
Our study focused on radiocaesium (137Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. 137Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0-3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61-69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees' residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial 137Cs deposit for mature and young cedars, respectively.
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Strumińska-Parulska DI, Szymańska K, Krasińska G, Skwarzec B, Falandysz J. Determination of 210Po and 210Pb in red-capped scaber (Leccinum aurantiacum): bioconcentration and possible related dose assessment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:22606-22613. [PMID: 27557963 DOI: 10.1007/s11356-016-7473-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/15/2016] [Indexed: 04/16/2023]
Abstract
The paper presents the studies on 210Po and 210Pb activity determination in red-capped scaber (Leccinum aurantiacum (Bulliard) Gray) collected in northern Poland. The aims of the studies were to determine 210Po and 210Pb content in analyzed mushrooms, evaluate the bioconcentration levels, and estimate possible related annual effective radiation dose to mushrooms consumers. The activities of 210Po and 210Pb in red-capped scaber were un-uniform and depended on sampling sites. But 210Po and 210Pb activity concentrations did not reflect their concentrations in topsoil. The results showed that the consumption of analyzed mushrooms should not increase significantly the total effective radiation dose from 210Po and 210Pb decay.
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Affiliation(s)
| | - Karolina Szymańska
- Environmental Chemistry and Radiochemistry Department, Gdańsk University, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Grażyna Krasińska
- Environmental Chemistry and Radiochemistry Department, Gdańsk University, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Bogdan Skwarzec
- Environmental Chemistry and Radiochemistry Department, Gdańsk University, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Jerzy Falandysz
- Environmental Chemistry and Radiochemistry Department, Gdańsk University, Wita Stwosza 63, 80-308, Gdańsk, Poland
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Sanderson DCW, Cresswell AJ, Tamura K, Iwasaka T, Matsuzaki K. Evaluating remediation of radionuclide contaminated forest near Iwaki, Japan, using radiometric methods. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 162-163:118-128. [PMID: 27232824 DOI: 10.1016/j.jenvrad.2016.05.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 05/10/2016] [Accepted: 05/15/2016] [Indexed: 06/05/2023]
Abstract
Radiometric surveys have been conducted in support of a project investigating the potential of biofuel power generation coupled with remediation of forests contaminated with radionuclides following the Fukushima Daiichi accident. Surveys conducted in 2013 and 2014 were used to determine the distribution and time dependence of radionuclides in a cedar plantation and adjacent deciduous forestry subject to downslope radionuclide migration, and a test area where litter removal was conducted. The radiocaesium results confirmed enhanced deposition levels in the evergreen areas compared with adjacent areas of deciduous forestry, implying significant differences in depositional processes during the initial interception period in 2011. Surveys were conducted both with and without a collimator on both occasions, which modified the angular response of the detector to separate radiation signals from above and below the detector. The combined data have been used to define the influence of radionuclides in the forest canopy on dose rate at 1 m, indicating that, in evergreen areas, the activity retained within the canopy even by 2013 contributed less than 5% of ground level dose rate. The time dependent changes observed allow the effect of remediation by litter removal in reducing radionuclide inventories and dose rates to be appraised relative natural redistribution processes on adjacent control areas. A 15 × 45 m area of cedar forest was remediated in September 2013. The work involved five people in a total of 160 person hours. It incurred a total dose of 40-50 μSv, and generated 2.1 t of waste comprising forest litter and understory. Average dose rates were reduced from 0.31 μSv h-1 to 0.22 μSv h-1, with nuclide specific analyses indicating removal of 30 ± 3% of the local radiocaesium inventory. This compares with annual removal rates of 10-15% where radionuclide migration down-slope over ranges of 10-50 m could be observed within adjacent areas. Local increases were also observed in areas identified as sinks. The results confirm the utility of time-series, collimated, radiometric survey methods to account for the distribution and changes in radionuclide inventory within contaminated forests. The data on litter removal imply that significant activity transfer from canopy to soil had taken place, and provide benchmark results against which such remediation actions can be appraised.
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Affiliation(s)
- D C W Sanderson
- Scottish Universities Environmental Research Centre, East Kilbride, Glasgow G75 0QF, United Kingdom.
| | - A J Cresswell
- Scottish Universities Environmental Research Centre, East Kilbride, Glasgow G75 0QF, United Kingdom
| | - K Tamura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Japan
| | - T Iwasaka
- Miraishiko Inc., Kanegaya, Asahi-ku, Yokohama, Japan
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Gonze MA, Mourlon C, Calmon P, Manach E, Debayle C, Baccou J. Modelling the dynamics of ambient dose rates induced by radiocaesium in the Fukushima terrestrial environment. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 161:22-34. [PMID: 26153556 DOI: 10.1016/j.jenvrad.2015.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/01/2015] [Accepted: 06/03/2015] [Indexed: 06/04/2023]
Abstract
Since the Fukushima accident, Japanese scientists have been intensively monitoring ambient radiations in the highly contaminated territories situated within 80 km of the nuclear site. The surveys that were conducted through mainly carborne, airborne and in situ gamma-ray measurement devices, enabled to efficiently characterize the spatial distribution and temporal evolution of air dose rates induced by Caesium-134 and Caesium-137 in the terrestrial systems. These measurements revealed that radiation levels decreased at rates greater than expected from physical decay in 2011-2012 (up to a factor of 2), and dependent on the type of environment (i.e. urban, agricultural or forest). Unlike carborne measurements that may have been strongly influenced by the depuration of road surfaces, no obvious reason can be invoked for airborne measurements, especially above forests that are known to efficiently retain and recycle radiocaesium. The purpose of our research project is to develop a comprehensive understanding of the data acquired by Japanese, and identify the environmental mechanisms or factors that may explain such decays. The methodology relies on the use of a process-based and spatially-distributed dynamic model that predicts radiocaesium transfer and associated air dose rates inside/above a terrestrial environment (e.g., forests, croplands, meadows, bare soils and urban areas). Despite the lack of site-specific data, our numerical study predicts decrease rates that are globally consistent with both aerial and in situ observations. The simulation at a flying altitude of 200 m indicated that ambient radiation levels decreased over the first 12 months by about 45% over dense urban areas, 15% above evergreen coniferous forests and between 2 and 12% above agricultural lands, owing to environmental processes that are identified and discussed. In particular, we demonstrate that the decrease over evergreen coniferous regions might be due the combined effects of canopy depuration (through biological and physical mechanisms) and the shielding of gamma rays emitted from the forest floor by vegetation. Our study finally suggests that airborne surveys might have not reflected dose rates at ground level in forest systems, which were predicted to slightly increase by 5-10% during the same period of time.
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Affiliation(s)
- Marc-André Gonze
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire de Modélisation pour l'Expertise Environnementale (LM2E), Cadarache, Bâtiment 159, 13115 St Paul-lez-Durance, France.
| | - Christophe Mourlon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire de Modélisation pour l'Expertise Environnementale (LM2E), Cadarache, Bâtiment 159, 13115 St Paul-lez-Durance, France
| | - Philippe Calmon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire d'Etudes Radioécologiques en milieux Continental et Marin (LERCM), Cadarache, Bâtiment 151, 13115 St Paul-lez-Durance, France
| | - Erwan Manach
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire de Surveillance Atmosphérique et d'Alerte (LS2A), Le Vésinet, Bâtiment C8, 78116 Le Vésinet, France
| | - Christophe Debayle
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire de Surveillance Atmosphérique et d'Alerte (LS2A), Le Vésinet, Bâtiment C8, 78116 Le Vésinet, France
| | - Jean Baccou
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire Incertitude et Modélisation des Accidents de Refroidissement (LIMAR), Cadarache, Bâtiment 700, St Paul-lez-Durance 13115, France
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Ogawa H, Hirano Y, Igei S, Yokota K, Arai S, Ito H, Kumata A, Yoshida H. Changes in the distribution of radiocesium in the wood of Japanese cedar trees from 2011 to 2013. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 161:51-57. [PMID: 26774216 DOI: 10.1016/j.jenvrad.2015.12.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 12/24/2015] [Accepted: 12/24/2015] [Indexed: 06/05/2023]
Abstract
The changes in the distribution of (137)Cs in the wood of Japanese cedar (Cryptomeria japonica) trunks within three years after the Fukushima Dai-ichi Nuclear Power Plant (FDNP) accident in 2011 were investigated. Thirteen trees were felled to collect samples at 6 forests in 2 regions of the Fukushima prefecture. The radial distribution of (137)Cs in the wood was measured at different heights. Profiles of (137)Cs distribution in the wood changed considerably from 2011 to 2013, and the process of (137)Cs distribution change in the wood was clarified. From 2011 to 2012, the active transportation from sapwood to heartwood and the radial diffusion in heartwood proceeded quickly, and the radial (137)Cs distribution differed according to the vertical positon of trees. From 2012 to 2013, the vertical diffusion of (137)Cs from the treetop to the ground, probably caused by the gradient of (137)Cs concentration in the trunk, was observed. Eventually, the radial (137)Cs distributions were nearly identical at any vertical positions in 2013. Our results suggested that the active transportation from sapwood to heartwood and the vertical and radial diffusion in heartwood proceeded according to the vertical position of the tree and (137)Cs distribution in the wood approached the equilibrium state within three years after the accident.
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Affiliation(s)
- Hideki Ogawa
- Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan; Fukushima Prefectural Forestry Research Centre, Nishi-Shimasaka, Asaka, Koriyama, Fukushima 963-0112, Japan.
| | - Yurika Hirano
- Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Shigemitsu Igei
- Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Kahori Yokota
- Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Shio Arai
- Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Hirohisa Ito
- Fukushima Prefectural Forestry Research Centre, Nishi-Shimasaka, Asaka, Koriyama, Fukushima 963-0112, Japan
| | - Atsushi Kumata
- Fukushima Prefectural Forestry Research Centre, Nishi-Shimasaka, Asaka, Koriyama, Fukushima 963-0112, Japan
| | - Hirohisa Yoshida
- Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
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Tuovinen TS, Kolehmainen M, Roivainen P, Kumlin T, Makkonen S, Holopainen T, Juutilainen J. Nonlinear transfer of elements from soil to plants: impact on radioecological modeling. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2016; 55:393-400. [PMID: 27262316 DOI: 10.1007/s00411-016-0655-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/27/2016] [Indexed: 06/05/2023]
Abstract
In radioecology, transfer of radionuclides from soil to plants is typically described by a concentration ratio (CR), which assumes linearity of transfer with soil concentration. Nonlinear uptake is evidenced in many studies, but it is unclear how it should be taken into account in radioecological modeling. In this study, a conventional CR-based linear model, a nonlinear model derived from observed uptake into plants, and a new simple model based on the observation that nonlinear uptake leads to a practically constant concentration in plant tissues are compared. The three models were used to predict transfer of (234)U, (59)Ni and (210)Pb into spruce needles. The predictions of the nonlinear and the new model were essentially similar. In contrast, plant radionuclide concentration was underestimated by the linear model when the total element concentration in soil was relatively low, but within the range commonly observed in nature. It is concluded that the linear modeling could easily be replaced by a new approach that more realistically reflects the true processes involved in the uptake of elements into plants. The new modeling approach does not increase the complexity of modeling in comparison with CR-based linear models, and data needed for model parameters (element concentrations) are widely available.
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Affiliation(s)
- Tiina S Tuovinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
| | - Mikko Kolehmainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Päivi Roivainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Timo Kumlin
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Sari Makkonen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Toini Holopainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Jukka Juutilainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
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Beresford NA, Fesenko S, Konoplev A, Skuterud L, Smith JT, Voigt G. Thirty years after the Chernobyl accident: What lessons have we learnt? JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 157:77-89. [PMID: 27018344 DOI: 10.1016/j.jenvrad.2016.02.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 05/22/2023]
Abstract
April 2016 sees the 30(th) anniversary of the accident at the Chernobyl nuclear power plant. As a consequence of the accident populations were relocated in Belarus, Russia and Ukraine and remedial measures were put in place to reduce the entry of contaminants (primarily (134+137)Cs) into the human food chain in a number of countries throughout Europe. Remedial measures are still today in place in a number of countries, and areas of the former Soviet Union remain abandoned. The Chernobyl accident led to a large resurgence in radioecological studies both to aid remediation and to be able to make future predictions on the post-accident situation, but, also in recognition that more knowledge was required to cope with future accidents. In this paper we discuss, what in the authors' opinions, were the advances made in radioecology as a consequence of the Chernobyl accident. The areas we identified as being significantly advanced following Chernobyl were: the importance of semi-natural ecosystems in human dose formation; the characterisation and environmental behaviour of 'hot particles'; the development and application of countermeasures; the "fixation" and long term bioavailability of radiocaesium and; the effects of radiation on plants and animals.
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Affiliation(s)
- N A Beresford
- Centre for Ecology & Hydrology, Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP, UK.
| | - S Fesenko
- International Atomic Energy Agency, 1400 Vienna, Austria
| | - A Konoplev
- Institute of Environmental Radioactivity, Fukushima University, Kanayagawa 1, Fukushima, 960-1296 Japan
| | - L Skuterud
- Norwegian Radiation Protection Authority, 1332 Østerås, Norway
| | - J T Smith
- School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Building, Portsmouth, PO1 3QL, UK
| | - G Voigt
- r.e.m., Franz-Siegel-Gasse 26, 2380 Perchtoldsdorf, Austria
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Huang Y, Kaneko N, Nakamori T, Miura T, Tanaka Y, Nonaka M, Takenaka C. Radiocesium immobilization to leaf litter by fungi during first-year decomposition in a deciduous forest in Fukushima. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 152:28-34. [PMID: 26630038 DOI: 10.1016/j.jenvrad.2015.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/16/2015] [Accepted: 11/07/2015] [Indexed: 06/05/2023]
Abstract
Vast forest areas in eastern Japan have been contaminated with radio-isotopes by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Radiocesium (radioCs) is known to remain bioavailable in forest ecosystems for a long time, and it is necessary to terminate the cycling process to decontaminate the forest ecosystem. We observed radiocesium concentrations of leaf litter during decomposition on a forest floor where radiocesium ((137)Cs) contamination was ∼155 kBq/m(2). Litter bag experiments were conducted with newly fallen mixed deciduous leaf litter in a deciduous forest (alt. 610 m) about 50 km from the FDNPP. Litter bags were retrieved in April, June, August, October, and December 2012. Fresh litter (137)Cs concentration was ∼3000 Bq/kg in December 2011. During the decomposition process on the forest floor, litter (137)Cs concentration increased rapidly and exceeded 25,000 Bq/kg after 6 months, whereas potassium (K) concentration in the litter was rather stable, indicating that radiocesium and K showed contrasting dynamics during the early decomposition phase. Nitrogen, phosphorus, and (137)Cs contents were positively correlated to fungal biomass, evaluated by phospholipid fatty acids in the litter during decomposition. The increase of radiocesium concentration mainly occurred during from April to October, when fungal growth peaked. Therefore, this suggests fungal translocation of nutrients from outside the litter substrate (immobilization) is the mechanism to increase radiocesium in the decomposing litter. The amount of (137)Cs contained in the 1-year-old decomposed leaf litter was estimated to be 4% per area of the soil-contaminated (137)Cs.
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Affiliation(s)
- Yao Huang
- Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Yokohama 240-8501, Japan
| | - Nobuhiro Kaneko
- Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Yokohama 240-8501, Japan.
| | - Taizo Nakamori
- Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Yokohama 240-8501, Japan
| | - Toshiko Miura
- Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Yokohama 240-8501, Japan
| | - Yoichiro Tanaka
- Facility for RI Research and Education, Instrumental Analysis Center, Yokohama National University, 79-5 Tokiwadai, Yokohama 240-8501, Japan
| | - Masanori Nonaka
- Graduate School for Management of Technology, Niigata University, 2-8050 Igarashi, Niigata 950-2181, Japan
| | - Chisato Takenaka
- Graduate School of Bioagricultural Science, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
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Šprem N, Piria M, Barišić D, Kusak J, Barišić D. Dietary items as possible sources of (137)Cs in large carnivores in the Gorski Kotar forest ecosystem, Western Croatia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 542:826-832. [PMID: 26556746 DOI: 10.1016/j.scitotenv.2015.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/02/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
The mountain forest ecosystem of Gorski Kotar is distant from any significant sources of environmental pollution, though recent findings have revealed that this region is among the most intense (137)Cs contaminated area in Croatia. Therefore, the aim of this study was to investigate (137)Cs and (40)K load in three large predator species in the mountain forest ecosystem. Radionuclides mass activities were determined by the gamma-spectrometric method in the muscle tissue of brown bear (47), wolf (7), lynx (1) and golden jackal (2). The highest (137)Cs mass activity was found in lynx (153 Bq kg(-1)), followed by brown bear (132 Bq kg(-1)), wolf (22.2 Bq kg(-1)), and golden jackal (2.48 Bq kg(-1)). Analysis of 63 samples of dietary items suggests that they are not all potentially dominant sources of (137)Cs for wildlife. The most important source of radionuclides for the higher parts of the food-chain from the study area were found to be the mushroom species wood hedgehog (Hydnum repandum), with a transfer factor TF of 5.166, and blueberry (Vaccinium myrtillus) as a plant species (TF=2.096). Food items of animal origin indicated higher mass activity of radionuclides and therefore are possible moderate bioindicators of environmental pollution. The results also revealed that possible unknown wild animal food sources are a caesium source in the study region, and further study is required to illuminate this issue.
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Affiliation(s)
- Nikica Šprem
- University of Zagreb, Faculty of Agriculture, Department of Fisheries, Beekeeping, Game Management and Special Zoology, Svetošimunska cesta 25, 10000 Zagreb, Croatia.
| | - Marina Piria
- University of Zagreb, Faculty of Agriculture, Department of Fisheries, Beekeeping, Game Management and Special Zoology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Domagoj Barišić
- University of Zagreb, Faculty of Agriculture, Department of Fisheries, Beekeeping, Game Management and Special Zoology, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Josip Kusak
- University of Zagreb, Veterinary Faculty, Department of Biology, Heinzelova 55, 10000 Zagreb, Croatia
| | - Delko Barišić
- Laboratory for Radioecology, Centre for Marine and Environmental Research, Ruđer Bošković Institute, PO Box 160, Bijenička 54, 10002 Zagreb, Croatia
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Calmon P, Gonze MA, Mourlon C. Modeling the early-phase redistribution of radiocesium fallouts in an evergreen coniferous forest after Chernobyl and Fukushima accidents. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 529:30-39. [PMID: 26005747 DOI: 10.1016/j.scitotenv.2015.04.084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/22/2015] [Accepted: 04/22/2015] [Indexed: 06/04/2023]
Abstract
Following the Chernobyl accident, the scientific community gained numerous data on the transfer of radiocesium in European forest ecosystems, including information regarding the short-term redistribution of atmospheric fallout onto forest canopies. In the course of international programs, the French Institute for Radiological Protection and Nuclear Safety (IRSN) developed a forest model, named TREE4 (Transfer of Radionuclides and External Exposure in FORest systems), 15 years ago. Recently published papers on a Japanese evergreen coniferous forest contaminated by Fukushima radiocesium fallout provide interesting and quantitative data on radioactive mass fluxes measured within the forest in the months following the accident. The present study determined whether the approach adopted in the TREE4 model provides satisfactory results for Japanese forests or whether it requires adjustments. This study focused on the interception of airborne radiocesium by forest canopy, and the subsequent transfer to the forest floor through processes such as litterfall, throughfall, and stemflow, in the months following the accident. We demonstrated that TREE4 quite satisfactorily predicted the interception fraction (20%) and the canopy-to-soil transfer (70% of the total deposit in 5 months) in the Tochigi forest. This dynamics was similar to that observed in the Höglwald spruce forest. However, the unexpectedly high contribution of litterfall (31% in 5 months) in the Tochigi forest could not be reproduced in our simulations (2.5%). Possible reasons for this discrepancy are discussed; and sensitivity of the results to uncertainty in deposition conditions was analyzed.
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Affiliation(s)
- P Calmon
- Institute of Radiation Protection and Nuclear Safety, CE Cadarache-Bat 153, BP3-13115 St-Paul-lez-Durance Cedex, France
| | - M-A Gonze
- Institute of Radiation Protection and Nuclear Safety, CE Cadarache-Bat 153, BP3-13115 St-Paul-lez-Durance Cedex, France
| | - Ch Mourlon
- Institute of Radiation Protection and Nuclear Safety, CE Cadarache-Bat 153, BP3-13115 St-Paul-lez-Durance Cedex, France
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Monitoring Radiocesium Contamination of the Web Spider Nephila clavata (Nephilidae: Arachnida) in Fukushima Forests. ACTA ACUST UNITED AC 2015. [DOI: 10.4005/jjfs.97.70] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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