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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] [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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Ohmae Y, Sakashita W, Sakata T, Imamura N, Miura S, Akama A, Shinomiya Y. Effect of litter removal five years after the Fukushima accident on 137Cs uptake by Japanese cedar. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 273:107390. [PMID: 38295586 DOI: 10.1016/j.jenvrad.2024.107390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 02/02/2024]
Abstract
Removal of litter-associated 137Cs from the forest floor (litter removal) can reduce the 137Cs uptake by plants; however, the proposed effective period for litter removal was 1-2 years after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. This is because the 137Cs in forest soil migrates rapidly from the litter to surface mineral soil layers in Japanese forests, and thus the effectiveness of litter removal will quickly become limited. However, it is unknown whether this approach can be applied to forests whose vertical migration of 137Cs in the forest soil is relatively slow. Herein, we compared the 137Cs activity concentration in the inner bark of the Japanese cedar (Cryptomeria japonica) between litter removal (conducted in September and October 2016, 5 years after the accident) and in control areas in Kawauchi Village, Fukushima Prefecture, where the vertical migration of 137Cs was relatively slow from the litter to surface mineral soil layers. Air dose rates (ambient dose equivalent) in the litter removal area were significantly lower than those in the control area in 2022, and the 137Cs inventory in the forest soil in litter removal area also tended to be lower than that in the control area. In Japanese cedars with similar levels of outer bark contamination, the 137Cs activity concentration in the inner bark in the litter removal area was significantly lower than that in the control area, and consistent trends were also found when comparing the 137Cs activity concentration in the leaves of Stephanandra incisa and Wisteria floribunda obtained from the same forest. Thus, the litter removal 5 years after the FDNPP accident may have reduced the 137Cs uptake in Japanese cedar in an evergreen coniferous forest where the vertical migration of 137Cs is relatively slow in the forest soil.
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Affiliation(s)
- Yoshimi Ohmae
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - 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
| | - Tadashi Sakata
- 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
| | - Naohiro Imamura
- Hokkaido Research Center, FFPRI, 7 Hitsujigaoka, Toyohira-ku, Sapporo, Hokkaido, 062-8516, 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
| | - Yoshiki Shinomiya
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
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Koarashi J, Atarashi-Andoh M, Nishimura S. Effect of soil organic matter on the fate of 137Cs vertical distribution in forest soils. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115177. [PMID: 37354569 DOI: 10.1016/j.ecoenv.2023.115177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/01/2023] [Accepted: 06/20/2023] [Indexed: 06/26/2023]
Abstract
Understanding the fate of the vertical distribution of radiocesium (137Cs) in Japanese forest soils is key to assessing the radioecological consequences of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The 137Cs behavior in mineral soil is known to be primarily governed by interaction with clay minerals; however, some observations suggest the role of soil organic matter (SOM) in enhancing the mobility of 137Cs. Here we hypothesized that soil organic carbon (SOC) concentration profile determines the ultimate vertical pattern of 137Cs distribution in Japanese forest soils. In testing this hypothesis, we obtained soil samples that were collected before the FDNPP accident at four forest sites with varying SOC concentration profiles and quantified the detailed vertical profile of 137Cs inventory in the soils roughly half a century after global fallout in the early 1960 s. Results showed that the higher the SOC concentration in the soil profile, the deeper the 137Cs downward penetration. On the basis of the data for surface soils (0-10 cm), the 137Cs retention ratio for each of the 2-cm thick layers was evaluated as the ratio of 137Cs inventory in the target soil layer to the total 137Cs inventory in and below the soil layer. A negative correlation was found between the ratio and SOC concentration of the layer across all soils and depths. This indicates that the ultimate fate of 137Cs vertical distribution can be predicted as a function of SOC concentration for Japanese forest soils, and provides further evidence for SOM effects on the mobility and bioavailability of 137Cs in soils.
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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; Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Ibaraki 319-1194, Japan
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Andresen JL, Oughton DH, Birkemoe T, Sverdrup-Thygeson A. Trophic food chain transfer of radiocaesium from reindeer meat to the blowfly Calliphora vicina and the parasitoid wasp Nasonia vitripennis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 867:161558. [PMID: 36640889 DOI: 10.1016/j.scitotenv.2023.161558] [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: 11/11/2022] [Revised: 12/22/2022] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
The role of insects in the transfer of radionuclides has received little attention, despite their key role in nutrient cycling within ecosystems. In this study, we investigated the trophic food chain transfer of radiocaesium (137Cs) from reindeer meat to the blowfly Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) and further from blowfly pupae to the parasitoid wasp Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae). Radiocaesium was transferred to blowfly larvae during their feeding stage, with the highest whole-organism to food source concentration ratios (CRwo-fs) being found in actively feeding third instar blowfly larvae, with CRwo-fs in the range of 0.68-0.90. CRwo-fs in blowfly larvae at later developmental stages (i.e., post-feeding stage, prepupal stage, pupal stage, and adult stage) were significantly lower, with CRwo-fs in adult flies in the range of 0.07-0.10. Modelling of the data indicated that >70 % of the radiocaesium present in third instar feeding stage larvae was removed exponentially with excreta prior to pupariation. Furthermore, on average 49 % of the radiocaesium activity concentration assimilated in the metamorphing blowfly pupa was retained in the pupal case after the adult blowfly had emerged. When blowfly pupae were parasitised by parasitoid wasps, a greater proportion of radiocaesium was retained in the parasitised pupal case, with only 2-3 % of the activity concentration in the meat being found in the wasps, providing further evidence to support that radiocaesium is biodiluted in insect food chains. Our results indicate that carcass decomposition driven by insects directly affects the fate of radiocaesium retained in vertebrate carcasses and we discuss these findings in connection to radiocaesium cycling and dispersion in terrestrial ecosystems.
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Affiliation(s)
- Jonas L Andresen
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway; Centre for Environmental Radioactivity, Ås, Norway.
| | - Deborah H Oughton
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway; Centre for Environmental Radioactivity, Ås, Norway
| | - Tone Birkemoe
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Anne Sverdrup-Thygeson
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
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Meusburger T, Lettner H, Hubmer A, Hörger AC, Friedl G, Tippelt G, Marbach M. Effective half-lives for 137Cs in dairy milk from alpine ecosystems and the controlling factors. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2023; 259-260:107102. [PMID: 36657357 DOI: 10.1016/j.jenvrad.2022.107102] [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: 12/23/2021] [Revised: 12/15/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Alpine regions in the federal state of Salzburg (Austria) have been intensively contaminated by Chernobyl fallout, necessitating long-term monitoring programs. The sites predominately affected are those in areas with soil developed on silicate bedrock, as these soils tend to be acidic, favouring high transfer factors for 137Cs. In addition, nutrient deficiency, low mineral and high organic matter content, and tough climatic conditions are causing the slow migration of 137Cs in the soil, which are associated with long effective half-lives in the biosphere. As a quantitative measure for effective half-lives, milk has been collected at nine alpine seasonal stock farming sites since 1988; at four sites, the monitoring is still ongoing (2020). For the period between 1999 and 2020, the decrease of 137Cs can be reasonably fitted with one effective half-life describing the time-trend. The effective half-lives obtained by this procedure vary between 9.3 ± 0.9 years and 18.8 ± 3.4 years. The effective half-lives show a weak negative correlation with the half-value depth of 137Cs, defined as the depth of the upper soil layer containing half of the deposited fallout inventory. The majority of the inventory is bound in the rooting zone of 0-10 cm, which is reflected by the small half value depths in the range between 3.2 and 4.4 cm. The soils investigated are acidic with pH values between 3.78 and 4.88, showing a pronounced negative correlation with the effective half-lives of 137Cs in milk. The data indicate that in these soils rich in organic matter, which are also almost totally devoid of clay minerals and have a very low clay size fraction, pH may be the dominating factor influencing the effective half-lives of 137Cs plant uptake and the subsequent contamination of milk.
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Affiliation(s)
- Tobias Meusburger
- Radiological Measurement Laboratory / Biological Physics, Dpt. of Chemistry and Physics of Materials, Salzburg University, Austria.
| | - Herbert Lettner
- Radiological Measurement Laboratory / Biological Physics, Dpt. of Chemistry and Physics of Materials, Salzburg University, Austria.
| | - Alexander Hubmer
- Radiological Measurement Laboratory / Biological Physics, Dpt. of Chemistry and Physics of Materials, Salzburg University, Austria.
| | | | | | - Gerold Tippelt
- Dpt. of Chemistry and Physics of Materials, Salzburg University, PLUS Salzburg University, Hellbrunnerstrasse 34, 5020, Salzburg, Austria.
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Manaka T, Komatsu M, Sakashita W, Imamura N, Hashimoto S, Hirai K, Miura S, Kaneko S, Sakata T, Shinomiya Y. Ten-year trends in vertical distribution of radiocesium in Fukushima forest soils, Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 251-252:106967. [PMID: 35930867 DOI: 10.1016/j.jenvrad.2022.106967] [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: 03/14/2022] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
To elucidate interannual changes in the vertical distribution of 137Cs in forest ecosystems contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident, we investigated 137Cs inventories in forest soils (both organic and mineral soil horizons) at 10 sampling plots with different 137Cs deposition levels and dominant species for up to 10 years after the accident. We examined the temporal variation of the 137Cs inventories by depth with exponential regression models (assuming that the transition and partitioning of 137Cs are still active) and exponential offset regression models (assuming a shift to a stable 137Cs distribution, defined as the "quasi-equilibrium steady-state" in the Chernobyl accident). In the organic horizon, the 137Cs inventories were exponentially decreasing, and it might take more time to converge in the quasi-equilibrium steady-state at most plots. In the mineral soil horizon, most of 137Cs was found in the surface layer of the mineral soil horizon (0-5 cm). In this layer, the inventories first increased and then become relatively constant, and the exponential offset model was selected at most plots, suggesting entry into the quasi-equilibrium steady-state over the observation period. Although we also observed exponentially increasing trends in a lower layer (5-10 cm) of the mineral soil horizon, there was no clear increasing or decreasing trend of 137Cs inventory in the deeper mineral soil layers (10-15 and 15-20 cm). Our calculation of the relaxation depth and migration center revealed that downward migration of 137Cs is not significant in terms of the overall 137Cs distribution in the mineral soil horizon over 10 years.
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Affiliation(s)
- Takuya Manaka
- Department of Forest Soils, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Ibaraki, 305-8687, Japan.
| | - Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, FFPRI, Tsukuba, Ibaraki, 305-8687, Japan; Center for Forest Restoration and Radioecology, FFPRI, Tsukuba, Ibaraki, 305-8687, Japan
| | - Wataru Sakashita
- Department of Forest Soils, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Ibaraki, 305-8687, Japan; Center for Forest Restoration and Radioecology, FFPRI, Tsukuba, Ibaraki, 305-8687, Japan
| | - Naohiro Imamura
- Department of Forest Soils, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Ibaraki, 305-8687, Japan
| | - Shoji Hashimoto
- Department of Forest Soils, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Ibaraki, 305-8687, Japan
| | - Keizo Hirai
- Department of Forest Soils, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Ibaraki, 305-8687, Japan
| | - Satoru Miura
- Center for Forest Restoration and Radioecology, FFPRI, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shinji Kaneko
- Kansai Research Center, FFPRI, Kyoto, Kyoto, 612-0855, Japan
| | - Tadashi Sakata
- Department of Forest Soils, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Ibaraki, 305-8687, Japan; Center for Forest Restoration and Radioecology, FFPRI, Tsukuba, Ibaraki, 305-8687, Japan
| | - Yoshiki Shinomiya
- Center for Forest Restoration and Radioecology, FFPRI, Tsukuba, Ibaraki, 305-8687, Japan
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Ota M, Koarashi J. Contamination processes of tree components in Japanese forest ecosystems affected by the Fukushima Daiichi Nuclear Power Plant accident 137Cs fallout. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151587. [PMID: 34838924 DOI: 10.1016/j.scitotenv.2021.151587] [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: 06/30/2021] [Revised: 10/30/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
In forests affected by the Fukushima Daiichi Nuclear Power Plant accident, trees became contaminated with 137Cs. However, 137Cs transfer processes determining tree contamination (particularly for stem wood, a prominent commercial resource) remain insufficiently understood. We propose a model for simulating dynamic behavior of 137Cs in a forest tree-litter-soil system and applied it to contaminated forests of cedar plantation and natural oak stand in Fukushima to elucidate relative impact of distinct 137Cs transfer processes determining the tree contamination. The transfer of 137Cs to the trees occurred mostly (>99%) through surface uptake of 137Cs trapped by needles and bark during the fallout. Root uptake of soil 137Cs was several orders of magnitude lower than the surface uptake over a 50-year period following the accident. As a result, internal contamination of the trees proceeded through an enduring recycling (translocation) of 137Cs absorbed on the tree surface. A significant surface uptake of 137Cs through bark was suggested, contributing to 100% (leafless oak tree) and 30% (foliated cedar tree; the remaining uptake occurred at needles) of the total uptake by the trees, although that pathway still needs to be evaluated by experimental evidence. It was suggested that the activity concentration of 137Cs in stem wood of the trees at these sites are currently (as of 2021) decreasing by ~3% per year, mainly through radioactive decay of 137Cs and partly through dilution effect from tree growth. Although further refinement of the model is recommended, for example by including tree species specific 137Cs transportation in stem, these findings provide vital information for planning of forestry reactivation in Fukushima; e.g., removal of forest floor organic layer will not reduce the tree contamination for a long term because of the 137Cs absorption via the tree surface substantially greater than root uptake of 137Cs deposited to the floor.
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Affiliation(s)
- Masakazu Ota
- Research Group for Environmental Science, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan.
| | - Jun Koarashi
- Research Group for Environmental Science, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan
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Takahashi J, Hihara D, Sasaki T, Onda Y. Evaluation of contribution rate of the infiltrated water collected using zero-tension lysimeter to the downward migration of 137Cs derived from the FDNPP accident in a cedar forest soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151983. [PMID: 34843790 DOI: 10.1016/j.scitotenv.2021.151983] [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: 08/20/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 06/13/2023]
Abstract
The vertical distribution of 137Cs in forest soil is important for predicting air dose rates and future cycling in forest ecosystems. However, there are many unexplained questions about the mechanisms of its downward migration. In this study, the 137Cs flux by rainfall infiltration was observed for three years from August 2017 using zero-tension lysimeters in a mature cedar forest where monitoring of the vertical distribution of 137Cs has been conducted since 2011. As a result, the 137Cs concentration in infiltrated water through the litter layer, 5 cm and 10 cm showed a tendency to be high in summer, but no such seasonal variation was found at 20 cm. Although the 137Cs inventory in the litter layer has been exponentially decreasing, the annual 137Cs fluxes in infiltrated water through the litter layer were almost the same in three years, and about 0.14-0.17% of the deposition density of 137Cs. Comparing these 137Cs fluxes with the apparent amounts of downward migration of 137Cs estimated from the change in the vertical distribution of 137Cs, the contribution rate of the infiltrated water to downward migration of 137Cs from litter to soil was calculated to be 8.5-17.7%. Similarly, the contribution rate in mineral soil layers was calculated to be 0.6-0.8% on a measured basis and estimated to be 3.0 ± 0.2% after correcting the amount of collected water, which is a problem with zero-tension lysimeter. It indicates that rainfall infiltration can explain a small part of the downward migration of 137Cs, thus further studies are required to clarify the contribution rate of remaining mechanisms such as advection-diffusion, colloidal transport, physical mixing, bioturbation, and growth and death of plant roots.
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Affiliation(s)
- Junko Takahashi
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Japan.
| | - Daichi Hihara
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan
| | | | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Japan
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Tajima S, Yoshida S, Fukui T, Nihei N, Kobayashi NI. Cesium-137 stored on and discharged from banks of an agricultural canal in Iitate, Fukushima. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 241:106775. [PMID: 34781091 DOI: 10.1016/j.jenvrad.2021.106775] [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: 04/10/2021] [Revised: 11/02/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
This study aimed to investigate the dynamics of 137Cs around banks along an agricultural canal for paddy fields in Iitate, Fukushima, Japan. Five plots (2.4-12.6 m2) on the banks were monitored intermittently during six time periods from May 2018 to November 2019. We directly collected runoff water samples discharged from the banks followed by partitioning it into particulate and dissolved fractions and determining 137Cs in them. To investigate the source of 137Cs in the runoff water, we sequentially extracted 137Cs in various chemical forms from litter samples collected on the banks. The results showed that the discharge rates of the dissolved 137Cs per unit area from the plots were lower than those observed at the downstream of the agricultural canal, whereas more than 50% of the 137Cs discharged from the plots was in the dissolved fraction. Moreover, the results indicate that 137Cs stored in the standing plants and the litter was the primary source of the dissolved 137Cs discharged into the agricultural canal. The concentrations of the water-soluble 137Cs in the litter per plot area may have been retained by the sufficiently higher concentrations of 137Cs in litter in other chemical forms and those in the standing plants, which are the source of the litter.
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Affiliation(s)
- Satoshi Tajima
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
| | - Shuichiro Yoshida
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-8657, Japan
| | - Taku Fukui
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-8657, Japan
| | - Naoto Nihei
- Faculty of Food and Agricultural Sciences, Fukushima University, 1 Kanayagawa, Fukushima, 960-1296, Japan
| | - Natsuko I Kobayashi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-8657, 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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11
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Contamination of Slovak Bilberry (Vaccinium Myrtillus L.) with Radiocaesium 137Cs in Selected Slovak Locations. FOLIA VETERINARIA 2021. [DOI: 10.2478/fv-2021-0017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract
The aim of this study was to determine the activity of post-Chernobyl 137Cs in Slovak bilberry (Vaccinium myrtillus L.) from selected locations of Slovakia depending upon: the season, location and the soil-plant transfer factor (TF). The 137Cs activity was determined in samples of forest soil and bilberry bushes (stems, leaves and fruits) growing on the soil in three locations: Arboretum Mlyňany (1), Hodruša-Hámre (2) and Javorníky (3). Altogether we collected 35 samples; namely 15 samples from Arboretum Mlyňany, 10 samples from Hodruša-Hámre and 10 from Javorníky. The samples of soil were examined also for the activity of 40K. The samples were collected in the spring, summer and autumn in the years 2019 and 2020 and were analysed by a gamma-ray spectrometry method. The highest levels of 137Cs activity concentrations were determined in Hodruša-Hámre in September where they reached 161 ± 13 Bq.kg−1 in the soil, 3.95 ± 1.07 Bq.kg−1 in the stems and 14.7 ± 4.26 Bq.kg−1 in the leaves. The lowest levels were determined in the Arboretum Mlyňany in October where the 137Cs activity in the soil reached 13.1 ± 1 15 Bq.kg−1, while in the stems, leaves and fruits it was lower than the minimum detectable level. In the latter location, we also determined the highest activity of 40K, the radioactive isotope physiologically and metabolically similar to 137Cs. The mass activity of 137Cs in all samples of bilberries were lower than the minimum detectable activity (MDA). The comparison of the results obtained in this study with the limit for total mass activity of radiocaesium (134Cs + 137Cs) in the food (600 Bq.kg−1) allowed us to conclude that the fruits, stems and leaves of Slovak bil-berries present neither health nor environmental risk.
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Chaif H, Coppin F, Bahi A, Garcia-Sanchez L. Influence of non-equilibrium sorption on the vertical migration of 137Cs in forest mineral soils of Fukushima Prefecture. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 232:106567. [PMID: 33689934 DOI: 10.1016/j.jenvrad.2021.106567] [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: 11/06/2020] [Revised: 02/12/2021] [Accepted: 02/21/2021] [Indexed: 06/12/2023]
Abstract
Sorption hypotheses and models are required for the prediction of 137Cs migration in soils contaminated after nuclear reactor accidents and nuclear weapons tests. In assessment models, the Kd (distribution coefficient) hypothesis for sorption, which assumes that sorption is instantaneous, linear and reversible, has often been coupled with the convection-diffusion equation (CDE) to model 137Cs migration. However, it fails to describe 137Cs migration velocities which often decrease with time. Alternative equilibrium-kinetic (EK) hypotheses of 137Cs sorption/desorption have been suggested by laboratory experiments but have not been fully validated in field conditions. This work addressed the influence and magnitude of non-equilibrium 137Cs sorption in field conditions by reinterpreting, with an inverse approach, series of 137Cs profiles measured in mineral soils of forest plots located in Fukushima Prefecture (2013-2018). Our results show that the inclusion of non-equilibrium sorption significantly improves, compared to the equilibrium hypothesis, the realism of simulated 137Cs profiles. Fitted sorption parameters suggest a fast sorption kinetic (half-time of 1-7 h) and a pseudo-irreversible desorption rate (half-time of 3.2 × 100-3.4 × 106 years), whereas equilibrium sorption (4.0 × 10-3 L kg-1 on average) only affects a negligible portion of 137Cs inventory. By June 2011, such EK parameters fitted on our plots realistically reproduced profiles measured in the same forest study site (Takahashi et al., 2015). Predictive modeling of 137Cs profiles in soil suggests a strong persistence of the surface 137Cs contamination by 2030, with exponential profiles consistent with those reported after the Chernobyl accident. This study demonstrates that hypotheses and parameters of 137Cs sorption can be partially inferred from in situ measurements. However, further experiments in controlled conditions are required to better estimate the sorption parameters and to identify the processes behind non-equilibrium sorption.
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Affiliation(s)
- Hamza Chaif
- Institute of Radiological Protection and Nuclear Safety (IRSN), PSE-ENV, SRTE, LR2T, CE Cadarache, 13115, Saint Paul les Durance Cedex, France.
| | - Frédéric Coppin
- Institute of Radiological Protection and Nuclear Safety (IRSN), PSE-ENV, SRTE, LR2T, CE Cadarache, 13115, Saint Paul les Durance Cedex, France.
| | - Aya Bahi
- Institute of Radiological Protection and Nuclear Safety (IRSN), PSE-ENV, SRTE, LR2T, CE Cadarache, 13115, Saint Paul les Durance Cedex, France.
| | - Laurent Garcia-Sanchez
- Institute of Radiological Protection and Nuclear Safety (IRSN), PSE-ENV, SRTE, LR2T, CE Cadarache, 13115, Saint Paul les Durance Cedex, France.
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13
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Manaka T, Ohashi S, Ogo S, Otsuka Y, Furusawa H. Sorption and desorption experiments using stable cesium: considerations for radiocesium retention by fresh plant residues in Fukushima forest soils. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07749-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
AbstractWe conducted sorption experiments with stable cesium (133Cs) solution in different organic matter samples, aiming to understand the sorption of radiocesium (134Cs and 137Cs) in the initial throughfall by fresh plant residues (e.g., needles, wood, and bark from Japanese cedar trees) in the Oi horizon in forests in Fukushima. Among the organic matter samples, bark and wattle tannin sorbed relatively large amounts of Cs, whereas wood and cellulose powder sorbed small amounts. In contrast, samples containing clay minerals showed much higher Cs sorption. We also conducted desorption experiments, and suggested that Cs on the organic matter samples were relatively mobile.
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14
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Tanaka S, Kakinuma H, Adati T, Atarashi-Andoh M, Koarashi J. Transfer of 137Cs to web-building spiders, Nephila clavata, and its pathways: a preliminary study using stable carbon and nitrogen isotope analyses. J NUCL SCI TECHNOL 2021. [DOI: 10.1080/00223131.2021.1894255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Sota Tanaka
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
| | - Hotaru Kakinuma
- Department of International Agricultural Development, Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Tokyo, Japan
| | - Tarô Adati
- Department of International Agricultural Development, Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Tokyo, Japan
| | - Mariko Atarashi-Andoh
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
| | - Jun Koarashi
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
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15
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Difference of ecological half-life and transfer coefficient in aquatic invertebrates between high and low radiocesium contaminated streams. Sci Rep 2020; 10:21819. [PMID: 33311547 PMCID: PMC7733484 DOI: 10.1038/s41598-020-78844-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/23/2020] [Indexed: 12/20/2022] Open
Abstract
The Fukushima accident emitted radioactive substances into the environment, contaminating litter, algae, sand substrate, aquatic invertebrates, and fish in freshwater streams. Because these substances have substantial effects on stream ecology over many years, it is necessary to clarify the diffusion and decay mechanisms of radiocesium. The transfer coefficient differed among aquatic invertebrate groups, likely due to the differences in habitat. The ecological half-life of cesium was longer where the air dose rate was lower. The transfer coefficient was also higher in areas with lower air dose rate. The radiocesium concentration in algae was inversely related to stream current velocity in the radiocesium-contaminated area. However, this relationship was not observed in the lower air dose rate area: the radiocesium concentration in algae in the rapid-velocity areas tended to be higher than that in the slow-velocity areas. This reverse trend would lead to a longer period of freshwater contamination. The radiocesium concentration would continue to decrease in highly contaminated areas, but it would be difficult to reduce the radiocesium concentration in less-contaminated areas because different contamination mechanisms are at work. Controlling the water flow is key to regulating radiocesium concentration in freshwater ecosystems.
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Manaka T, Ono K, Furusawa H, Ogo S, Miura S. Chemical sequential extraction of O horizon samples from Fukushima forests: Assessment for degradability and radiocesium retention capacity of organic matters. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 220-221:106306. [PMID: 32658642 DOI: 10.1016/j.jenvrad.2020.106306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/08/2020] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
To investigate how radiocesium (137Cs) is retained in the O horizon via interactions with organic matter, we collected O horizon samples in Japanese cedar (Cryptomeria japonica) and konara oak (Quercus serrata) forest sites in Fukushima during the 8 years following the Fukushima Dai-ichi Nuclear Power Plant accident. To assess degradability and 137Cs retention capacity of organic matter, we conducted chemical sequential extraction with organic solvent and sulfuric acid, collecting the following fractions: organic solvent extractives (Fraction 1), acid-soluble carbohydrates (Fraction 3), and acid-insoluble residue (Fraction 4). In all samples, across sampling years and sites, 137Cs content in Fractions 1, 3, and 4, as a proportion of the total 137Cs content, was 0.0-23.6%, 18.4-42.9%, and 44.8-76.0%, respectively. Generally, 137Cs is considered to be electrostatically bound to organic matter and relatively mobile, making it easily extractable by sulfuric acid treatment. However, we observed a relatively high proportion of 137Cs in Fraction 4, suggesting strong retention of 137Cs and their immobility in the O horizon. Complex organic matter such as lignin or tannin may contribute this retention. We also noted that some part of 137Cs may be also retained by clay minerals in the O horizon. Although organic matter in Fractions 1 and 3 is considered to decompose faster than that in Fraction 4, over the observation period the 137Cs proportion and net rate of decrease in 137Cs content (in total and in each fraction) remained nearly constant. This result implies that decomposition of organic matter and the consequent release of bound 137Cs may be partly compensated by additional input of 137Cs from the canopy and 137Cs recycling by soil microorganisms. Our study highlights the potential role of organic matter in the O horizon as a temporary reservoir of 137Cs and a driver of the 137Cs cycle in forest ecosystems.
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Affiliation(s)
- Takuya Manaka
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Kenji Ono
- Tohoku Research Center, Forestry and Forest Products Research Institute, 92-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate, 020-0123, Japan
| | - Hitomi Furusawa
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Sumika Ogo
- Department of Mushroom Science and Forest Microbiology, 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
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17
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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: 4] [Impact Index Per Article: 1.0] [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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18
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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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19
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Teramage MT. Temporal distribution of Fukushima-derived 137Cs in coniferous forest soil evaluated based on compartment-exponential model. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:36913-36921. [PMID: 31741278 DOI: 10.1007/s11356-019-06803-6] [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: 04/29/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
Based on the compartment and exponential models, the distribution of Fukushima-derived 137Cs was evaluated at four sampling dates in undisturbed coniferous forest soil. The compartment model was employed to evaluate the dynamic of 137Cs in the three sub-sections of the forest floor (FF), namely undergrowth (UG), litter layer (OL), and fragmented litter layer (OF), while the exponential model was administrated to describe its distribution below the FF. According to the compartment model, the derived ecological half-life of 137Cs in the UG, OL, and OF layers was 0.97, 1.1, and 4.9 years, respectively, indicating 137Cs resides much longer in the OF layer. Hence, this soil section remains a potential source of radiation dose mainly due to its high 137Cs content associated with low attenuation effect. Below the OF layer, the 137Cs distribution was well described by exponential model and its derived relaxation lengths were in the range of 0.8-1.4 cm, implying the migration of 137Cs in mineral soil is very slow and almost intact during the observation time. Collectively, our results highlighted that the compartment model for the FF and the exponential model for the soil below the FF are adequate enough to generate essential information. Thus, the potential decontamination measures should have to be chosen on their effect on the FF's 137Cs. Graphical abstract.
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Affiliation(s)
- Mengistu T Teramage
- Hawassa University, College of Agriculture, P.O. Box 676, Hawassa, Ethiopia.
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20
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Muto K, Atarashi-Andoh M, Matsunaga T, Koarashi J. Characterizing vertical migration of 137Cs in organic layer and mineral soil in Japanese forests: Four-year observation and model analysis. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 208-209:106040. [PMID: 31518883 DOI: 10.1016/j.jenvrad.2019.106040] [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: 02/19/2019] [Revised: 06/20/2019] [Accepted: 08/27/2019] [Indexed: 06/10/2023]
Abstract
Because of the Fukushima Dai-ichi Nuclear Power Plant accident, forest ecosystems in wide areas were contaminated with 137Cs. It is important to characterize the behavior of 137Cs after its deposition onto forest surface environments for evaluating and preventing long-term radiation risks. In the present study, 137Cs vertical distributions in the soil profile were observed repeatedly at five forest sites with different vegetation types for 4.4 years after the accident in 2011, and 137Cs migration in the organic layer and mineral soil was analyzed based on a comparison of models and observations. Cesium-137 migration from the organic layer to the underlying mineral soil was represented by a two-component exponential model. Cesium-137 migration from the organic layer was faster than that observed in European forests, suggesting that the mobility and bioavailability of 137Cs could be suppressed rapidly in Japanese forests. At all sites, 137Cs transfer in mineral soil could be reproduced by a simple diffusion equation model with continuous 137Cs supply from the organic layer. The diffusion coefficients of 137Cs in the mineral soil were estimated to be 0.042-0.55 cm2 y-1, which were roughly comparable with those of European forest soils affected by the Chernobyl Nuclear Power Plant accident. Model predictions using the determined model parameters indicated that 10 years after the accident, more than 70% of the deposited 137Cs will migrate to the mineral soil but only less than 10% of the total 137Cs inventory will penetrate deeper than 10 cm in the mineral soil across all sites. The results of the present study suggest that the 137Cs deposited onto Japanese forest ecosystems will be retained in the surface layers of mineral soil for a long time.
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Affiliation(s)
- Kotomi Muto
- 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
| | - Takeshi Matsunaga
- 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.
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21
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Koarashi J, Nishimura S, Atarashi-Andoh M, Muto K, Matsunaga T. A new perspective on the 137Cs retention mechanism in surface soils during the early stage after the Fukushima nuclear accident. Sci Rep 2019; 9:7034. [PMID: 31065040 PMCID: PMC6504853 DOI: 10.1038/s41598-019-43499-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/25/2019] [Indexed: 12/05/2022] Open
Abstract
The Fukushima Daiichi nuclear power plant accident caused serious radiocesium (137Cs) contamination of the soil in multiple terrestrial ecosystems. Soil is a complex system where minerals, organic matter, and microorganisms interact with each other; therefore, an improved understanding of the interactions of 137Cs with these soil constituents is key to accurately assessing the environmental consequences of the accident. Soil samples were collected from field, orchard, and forest sites in July 2011, separated into three soil fractions with different mineral–organic interaction characteristics using a density fractionation method, and then analyzed for 137Cs content, mineral composition, and organic matter content. The results show that 20–71% of the 137Cs was retained in association with relatively mineral-free, particulate organic matter (POM)-dominant fractions in the orchard and forest surface soil layers. Given the physicochemical and mineralogical properties and the 137Cs extractability of the soils, 137Cs incorporation into the complex structure of POM is likely the main mechanism for 137Cs retention in the surface soil layers. Therefore, our results suggest that a significant fraction of 137Cs is not immediately immobilized by clay minerals and remains potentially mobile and bioavailable in surface layers of organic-rich soils.
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Affiliation(s)
- Jun Koarashi
- 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.,Tono Geoscience Center, Japan Atomic Energy Agency, Gifu, 509-5102, Japan
| | - Mariko Atarashi-Andoh
- 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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22
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Almahayni T, Beresford NA, Crout NMJ, Sweeck L. Fit-for-purpose modelling of radiocaesium soil-to-plant transfer for nuclear emergencies: a review. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 201:58-66. [PMID: 30776579 DOI: 10.1016/j.jenvrad.2019.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
Numerous radioecological models have been developed to predict radionuclides transfer from contaminated soils to the food chain, which is an essential step in preparing and responding to nuclear emergencies. However, the lessons learned from applying these models to predict radiocaesium (RCs) soil-to-plant transfer following the Fukushima accident in 2011 renewed interest in RCs transfer modelling. To help guide and prioritise further research in relation to modelling RCs transfer in terrestrial environments, we reviewed existing models focussing on transfer to food crops and animal fodders. To facilitate the review process, we categorised existing RCs soil-to-plant transfer models into empirical, semi-mechanistic and mechanistic, though several models cross the boundaries between these categories. The empirical approach predicts RCs transfer to plants based on total RCs concentration in soil and an empirical transfer factor. The semi-mechanistic approach takes into account the influence of soil characteristics such as clay and exchangeable potassium content on RCs transfer. It also uses 'bioavailable' rather than total RCs in soil. The mechanistic approach considers the physical and chemical processes that control RCs distribution and uptake in soil-plant systems including transport in the root zone and root absorption kinetics. Each of these modelling approaches has its advantages and disadvantages. The empirical approach is simple and requires two inputs, but it is often associated with considerably uncertainty due to the large variability in the transfer factor. The semi-mechanistic approach factorises more soil and plant parameters than the empirical approach; therefore, it is applicable to a wider range of environmental conditions. The mechanistic approach is instrumental in understanding RCs mobility and transfer in soil-plant systems; it also helps to identify influential soil and plant parameters. However, the comlexity and the large amount of specific parameters make this approach impractical for nuclear emergency preparedness and response purposes. We propose that the semi-mechanistic approach is sufficiently robust and practical, hence more fit for the purpose of planning and responding to nuclear emergencies compared with the empirical and mechanistic approaches. We recommend further work to extend the applicability of the semi-mechanistic approach to a wide range of plants and soils.
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Affiliation(s)
- Talal Almahayni
- Biosphere Impact Studies Unit, The Belgian Nuclear Research Centre, Boeretang 200, Mol, Belgium.
| | - Nicholas A Beresford
- NERC Centre for Ecology and Hydrology, CEH Lancaster, Lancaster Environment Centre, Library Av., Bailrigg, Lancaster, LA1 4AP, UK.
| | - Neil M J Crout
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK.
| | - Lieve Sweeck
- Biosphere Impact Studies Unit, The Belgian Nuclear Research Centre, Boeretang 200, Mol, Belgium.
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Itthipoonthanakorn T, Dann SE, Crout NMJ, Shaw G. Nuclear weapons fallout 137Cs in temperate and tropical pine forest soils, 50 years post-deposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 660:807-816. [PMID: 30743966 DOI: 10.1016/j.scitotenv.2019.01.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 06/09/2023]
Abstract
Following nuclear releases to the environment, 137Cs (half-life 30 years) is a long-term contaminant of many ecosystems, including forests. We recently sampled soils under pine forests in temperate and tropical climates to test the hypothesis that migration of 137Cs, 50 years after nuclear weapons fallout, is coupled with organic matter (OM) accumulation in these soils. Depth profiles of 137Cs, naturally-occurring 210Pb and weapons-derived 241Am were measured. After 50 years, migration of 137Cs into the temperate and tropical soils is limited to half-depths of 7-8 cm and 2-3 cm, respectively. At both locations, most 137Cs is associated with OM that accumulated from the early to mid-1960s. Illite, which immobilises radiocaesium, was undetectable by X-ray diffraction in the layer of peak 137Cs accumulation in the temperate forest soil, but apparent in the zone of peak concentration in the tropical soil. Data indicate that long-term (50 year) fate of 137Cs in organic-rich, temperate forest soil is coupled with OM accumulation; fixation of 137Cs by illite is more important in the tropical forest soil where OM is rapidly decomposed. Models of long-term radiocaesium migration in forest soils should explicitly account for the role of OM, especially when considering forests under contrasting climatic regimes.
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Affiliation(s)
| | - S E Dann
- Department of Chemistry, Loughborough University, Loughborough LE11 3TU, UK
| | - N M J Crout
- School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - G Shaw
- School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK.
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Ogasawara S, Eguchi T, Nakao A, Fujimura S, Takahashi Y, Matsunami H, Tsukada H, Yanai J, Shinano T. Phytoavailability of 137Cs and stable Cs in soils from different parent materials in Fukushima, Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 198:117-125. [PMID: 30605858 DOI: 10.1016/j.jenvrad.2018.12.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/20/2018] [Accepted: 12/23/2018] [Indexed: 06/09/2023]
Abstract
Weathered micaceous minerals (micas) are able to release potassium ion (K+) and fix caesium-137 (137Cs), both of which reduce soil-to-plant transfer of 137Cs. Among micas, trioctahedral micas such as biotite is expected to have a stronger ability to supply nonexchangeable K+ and a higher amount of Cs fixation sites than dioctahedral micas such as illite. Although biotite is predominant in granitic soils (G soils), illite is mainly dominant in sedimentary rock soils (S soils). Therefore, we hypothesized that G soils have a lower 137Cs transfer risk than S soils because of this difference in mineralogy. The objective of the present study was to determine the transfer factor (TF) of 137Cs and stable Cs (SCs) and to elucidate the determinant factors of TFs for G and S soils in Fukushima, Japan. Pot experiments were carried out with rice (Oryza sativa L. cv. Hokuriku 193) in G and S soils to determine the TF of 137Cs (TF-137Cs) and stable Cs (TF-SCs) under K-deficient conditions. TF-137Cs and TF-SCs were highly correlated, and both were significantly lower for G soils than for S soils. Higher TF values were shown for soils with lower amounts of exchangeable and nonexchangeable K or with higher percentages of exchangeable 137Cs (ex137Cs). The percentage of ex137Cs was negatively correlated with the amount of Cs fixation sites, represented by the radiocaesium interception potential. Thus, we concluded that smaller TF values for G soils were caused by a stronger ability to supply nonexchangeable K+ and a higher amount of Cs fixation sites. These findings will contribute to the establishment of soil screening techniques based on 137Cs transfer risk in Fukushima prefecture.
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Affiliation(s)
- Sho Ogasawara
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522, Japan; Japan Society for the Promotion of Science, 102-0083, Tokyo, Japan.
| | - Tetsuya Eguchi
- Tohoku Agricultural Research Centre, NARO, Fukushima, 960-2156, Japan
| | - Atsushi Nakao
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522, Japan
| | - Shigeto Fujimura
- Tohoku Agricultural Research Centre, NARO, Fukushima, 960-2156, Japan
| | | | - Hisaya Matsunami
- Tohoku Agricultural Research Centre, NARO, Fukushima, 960-2156, Japan
| | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, 960-1296, Japan
| | - Junta Yanai
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522, Japan
| | - Takuro Shinano
- Tohoku Agricultural Research Centre, NARO, Fukushima, 960-2156, Japan
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Fujii K, Yamaguchi N, Imamura N, Kobayashi M, Kaneko S, Takahashi M. Effects of radiocesium fixation potentials on 137Cs retention in volcanic soil profiles of Fukushima forests. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 198:126-134. [PMID: 30605859 DOI: 10.1016/j.jenvrad.2018.12.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/06/2018] [Accepted: 12/23/2018] [Indexed: 05/26/2023]
Abstract
Radiocesium is well-known to be stabilized by clay minerals in soils, while volcanic soils could typically be poor in micaceous clays that fix 137Cs effectively. We investigated 137Cs fixation potentials [radiocesium interception potential (RIP)] and depth distribution of 137Cs stocks in volcanic soils to analyze effects of clay content and mineralogy on soil retention and migration of 137Cs after the Fukushima nuclear accident. Clay minerals of the volcanic soils were dominated by hydroxy-interlayered vermiculite (HIV) and short-range-order minerals, irrespective of bedrocks. The soil RIPs were positively correlated with mass of clay fraction among the HIV-dominated volcanic soils, but RIP per clay content in the HIV-dominated volcanic soils were lower than in the soils rich in illite or vermiculitic clays. The small RIPs in the organic horizons resulted in rapid 137Cs migration from the organic horizons and their accumulation in the upper 0-5 cm mineral soil. Although RIPs of the studied volcanic soils fall within the lower class among major soil types, vertical 137Cs migration in the mineral soil is small unless RIP is less than 300-400 mmol kg-1 due to the low clay contents and shortage of illite or vermiculite.
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Affiliation(s)
- Kazumichi Fujii
- Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan.
| | - Noriko Yamaguchi
- National Institute for Agro-Environmental Sciences, Tsukuba, 305-8604, Japan
| | - Naohiro Imamura
- Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan
| | - Masahiro Kobayashi
- Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan
| | - Shinji Kaneko
- Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan
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26
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Chae JS, Kim TH, Lee MY, Song BC, Koh SH. Distributions of 137Cs in sediments of a crater lake: results from Baengnokdam of Mt. Halla, Jeju Island. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-018-6394-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Low 137Cs retention capability of organic layers in Japanese forest ecosystems affected by the Fukushima nuclear accident. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06435-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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28
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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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Škrkal J, Pilátová H, Rulík P, Suchara I, Sucharová J, Holá M. Behaviour of 137Cs in forest humus detected across the territory of the Czech Republic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 593-594:155-164. [PMID: 28343036 DOI: 10.1016/j.scitotenv.2017.03.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 06/06/2023]
Abstract
The activity concentration of 137Cs in samples of coniferous forest humus collected across the territory of the Czech Republic in 1995 and 2005 was analysed, and it was found significantly correlated with the surface deposition caused by the Chernobyl accident. The effective (12.8 y) and environmental (22.3 y) half-lives of radiocaesium in humus were calculated and compared with those in spruce bark. The impact of important forest stand factors, that is, precipitation, content of organic matter, age of trees and pH, on the behaviour of 137Cs in humus was studied. It was observed that humus samples with a higher proportion of organic matter, higher pH(H2O) and pH(CaCl2) contained higher amounts of 137Cs. Conversely, with the age of trees, the activity concentration of 137Cs in humus is decreasing. Higher precipitation and humus acidity decrease the reduction rate of the 137Cs in humus. These stand factors increase bioavailability of 137Cs in humus. The transfer and retention of available 137Cs in biomass of organisms living in humus for a long time can satisfactorily explain the longer residence time of 137Cs in humus affected by the studied factors.
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Affiliation(s)
- Jan Škrkal
- SÚRO (National Radiation Protection Institute), Bartoškova 28, CZ-140 00 Praha 4, Czech Republic.
| | - Helena Pilátová
- SÚRO (National Radiation Protection Institute), Bartoškova 28, CZ-140 00 Praha 4, Czech Republic.
| | - Petr Rulík
- SÚRO (National Radiation Protection Institute), Bartoškova 28, CZ-140 00 Praha 4, Czech Republic.
| | - Ivan Suchara
- VÚKOZ (Silva Tarouca Research Institute for Landscape and Ornamental Gardening), Květnové náměstí 391, CZ-252 43 Průhonice, Czech Republic.
| | - Julie Sucharová
- VÚKOZ (Silva Tarouca Research Institute for Landscape and Ornamental Gardening), Květnové náměstí 391, CZ-252 43 Průhonice, Czech Republic.
| | - Marie Holá
- VÚKOZ (Silva Tarouca Research Institute for Landscape and Ornamental Gardening), Květnové náměstí 391, CZ-252 43 Průhonice, Czech Republic.
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Negishi JN, Sakai M, Okada K, Iwamoto A, Gomi T, Miura K, Nunokawa M, Ohhira M. Cesium-137 contamination of river food webs in a gradient of initial fallout deposition in Fukushima, Japan. LANDSCAPE AND ECOLOGICAL ENGINEERING 2017. [DOI: 10.1007/s11355-017-0328-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Koarashi J, Atarashi-Andoh M, Matsunaga T, Sanada Y. Forest type effects on the retention of radiocesium in organic layers of forest ecosystems affected by the Fukushima nuclear accident. Sci Rep 2016; 6:38591. [PMID: 27974832 PMCID: PMC5156898 DOI: 10.1038/srep38591] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/08/2016] [Indexed: 11/16/2022] Open
Abstract
The Fukushima Daiichi nuclear power plant disaster caused serious radiocesium (137Cs) contamination of forest ecosystems over a wide area. Forest-floor organic layers play a key role in controlling the overall bioavailability of 137Cs in forest ecosystems; however, there is still an insufficient understanding of how forest types influence the retention capability of 137Cs in organic layers in Japanese forest ecosystems. Here we conducted plot-scale investigations on the retention of 137Cs in organic layers at two contrasting forest sites in Fukushima. In a deciduous broad-leaved forest, approximately 80% of the deposited 137Cs migrated to mineral soil located below the organic layers within two years after the accident, with an ecological half-life of approximately one year. Conversely, in an evergreen coniferous forest, more than half of the deposited 137Cs remained in the organic layers, with an ecological half-life of 2.1 years. The observed retention behavior can be well explained by the tree phenology and accumulation of 137Cs associated with litter materials with different degrees of degradation in the organic layers. Spatial and temporal patterns of gamma-ray dose rates depended on the retention capability. Our results demonstrate that enhanced radiation risks last longer in evergreen coniferous forests than in deciduous broad-leaved forests.
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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
| | - Takeshi Matsunaga
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki 319-1195, Japan
| | - Yukihisa Sanada
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 975-0036, Japan
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Koarashi J, Nishimura S, Nakanishi T, Atarashi-Andoh M, Takeuchi E, Muto K. Post-deposition early-phase migration and retention behavior of radiocesium in a litter-mineral soil system in a Japanese deciduous forest affected by the Fukushima nuclear accident. CHEMOSPHERE 2016; 165:335-341. [PMID: 27664523 DOI: 10.1016/j.chemosphere.2016.09.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/12/2016] [Accepted: 09/12/2016] [Indexed: 06/06/2023]
Abstract
The fate of radiocesium (137Cs) derived from the Fukushima nuclear accident and associated radiation risks are largely dependent on its migration and retention behavior in the litter-soil system of Japanese forest ecosystems. However, this behavior has not been well quantified. We established field lysimeters in a Japanese deciduous broad-leaved forest soon after the Fukushima nuclear accident to continuously monitor the downward transfer of 137Cs at three depths: the litter-mineral soil boundary and depths of 5 cm and 10 cm in the mineral soil. Observations were conducted at two sites within the forest from May 2011 to May 2015. Results revealed similar temporal and depth-wise variations in 137Cs downward fluxes for both sites. The 137Cs downward fluxes generally decreased year by year at all depths, indicating that 137Cs was rapidly leached from the forest-floor litter layer and was then immobilized in the upper (0-5 cm) mineral soil layer through its interaction with clay minerals. The 137Cs fluxes also showed seasonal variation, which was in accordance with variations in the throughfall and soil temperature at the sites. There was no detectable 137Cs flux at a depth of 10 cm in the mineral soil in the third and fourth years after the accident. The decreased inventory of mobile (or bioavailable) 137Cs observed during early stages after deposition indicates that the litter-soil system in the Japanese deciduous forest provides only a temporary source for 137Cs recycling in plants.
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Affiliation(s)
- Jun Koarashi
- 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
| | - Takahiro Nakanishi
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, Fukushima 970-8026, Japan
| | - Mariko Atarashi-Andoh
- 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
| | - Kotomi Muto
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki 319-1195, Japan
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33
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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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Aung HP, Mensah AD, Aye YS, Djedidi S, Oikawa Y, Yokoyama T, Suzuki S, Dorothea Bellingrath-Kimura S. Transfer of radiocesium from rhizosphere soil to four cruciferous vegetables in association with a Bacillus pumilus strain and root exudation. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 164:209-219. [PMID: 27517724 DOI: 10.1016/j.jenvrad.2016.07.006] [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: 04/17/2016] [Revised: 07/03/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
This study was carried out to assess the effect of Bacillus pumilus on the roots of four cruciferous vegetables with different root structures in regard to enhancement of 137Cs bioavailability in contaminated rhizosphere soil. Results revealed that B. pumilus inoculation did not enhance the plant biomass of vegetables, although it increased root volume and root surface areas of all vegetables except turnip. The pH changes due to rhizosphere acidification by B. pumilus inoculation and root exudation did not affect the bioavailability of 137Cs. However, concentrations of 137Cs in plant tissues and soil-to-plant transfer values increased as a result of the larger root volume and root surface area of vegetables due to inoculation. Moreover, leafy vegetables, which possessed larger root volume and root surface areas, had a higher 137Cs transfer value than root vegetables.
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Affiliation(s)
- Han Phyo Aung
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Akwasi Dwira Mensah
- Department of International Environmental and Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Yi Swe Aye
- Department of International Environmental and Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Salem Djedidi
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Yosei Oikawa
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Tadashi Yokoyama
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Sohzoh Suzuki
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
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35
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Arai T. Temporal and spatial variations of radioactive cesium levels in Northeast Japan following the Fukushima nuclear accident. ECOTOXICOLOGY (LONDON, ENGLAND) 2016; 25:1514-1522. [PMID: 27619688 DOI: 10.1007/s10646-016-1703-1] [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] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
Radioactive emissions into the environment from the Fukushima Daiichi Nuclear Power Plant accident led to global contamination. Radionuclides such as 131I, 134Cs, and 137Cs were further transported to North America and Europe. Thus, the Fukushima Daiichi Nuclear Power Plant accident is a global concern for both human health and the ecosystem because a number of countries ban or impose restrictions the import of Japanese products. In the present study, three-year (May 2011 to May 2014) fluctuations and accumulations of Cs, 134Cs, and 137Cs in two salmonid fish, white-spotted char and masu salmon were examined in Northeast Japan. The total Cs, 134Cs, and 137Cs levels in the fish gradually decreased throughout the three-year studied period after the Fukushima Daiichi Nuclear Power Plant accident; however, higher levels (more than 100 Bq kg-1) were still detected in the Fukushima prefecture and neighboring prefectures in Japan 3 years after the Fukushima Daiichi Nuclear Power Plant accident. Spatial radiocesium levels gradually decreased with increasing distance from the Fukushima Daiichi Nuclear Power Plant (Fukushima prefecture). The radiocesium levels facing the Pacific Ocean area were generally higher than those facing the Sea of Japan area. These results suggest that radionuclides from Fukushima Daiichi Nuclear Power Plant are still widely distributed and remain in the natural environment in Northeast Japan.
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Affiliation(s)
- Takaomi Arai
- Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE, 1410, Brunei Darussalam.
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36
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Hashida SN, Yoshihara T. Disparate radiocesium leaching from two woody species by acceleration of litter decomposition using microbial inoculation. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 162-163:319-327. [PMID: 27323212 DOI: 10.1016/j.jenvrad.2016.06.010] [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: 01/08/2016] [Revised: 06/10/2016] [Accepted: 06/12/2016] [Indexed: 06/06/2023]
Abstract
Studies focusing on the migration of radionuclides in the forest floor have demonstrated that the ecological half-life of radiocesium on organic layer containing the debris of plant litter with various fungi and microorganisms is shorter than that in the deeper soil zone, suggesting that the litter decomposition affects radiocesium mobilization. Here, we showed the involvement of lignin, one of the major cell wall components of plant litter, in the fate of contaminated radiocesium during the process of fungal litter decomposition. In this study, litter decomposition of two different woody species, broadleaf deciduous Japanese cherry consisted of hardwood lignin and coniferous evergreen Japanese cedar with softwood lignin, were accelerated by in vitro fungal inoculation. In vitro inoculation exhibited 1.93- to 2.59-times faster decomposition than field experiment. Then, the cherry litter lost approximately 25% of initially contaminated radiocesium within 1 month of in vitro decomposition, whereas the cedar litter kept initial level at least for 6 month. The retention of radiocesium correlated with thioglycolate lignin content in cedar litter but not in cherry litter. Consequently, the behavior of radiocesium contaminated in litter fall may vary depending on the contamination pathway or the manner of nutrient mobilization at the stage of abscission between evergreen and deciduous trees.
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Affiliation(s)
- Shin-Nosuke Hashida
- Plant Molecular Biology, Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), Abiko 1646, Abiko-shi, Chiba, Japan.
| | - Toshihiro Yoshihara
- Plant Molecular Biology, Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), Abiko 1646, Abiko-shi, Chiba, Japan
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37
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Vertical distributions of global fallout 137Cs and 14C in a Japanese forest soil profile and their implications for the fate and migration processes of Fukushima-derived 137Cs. J Radioanal Nucl Chem 2016. [DOI: 10.1007/s10967-016-4938-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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38
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Suchara I, Sucharová J, Holá M, Pilátová H, Rulík P. Long-term retention of (137)Cs in three forest soil types with different soil properties. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 158-159:102-113. [PMID: 27085039 DOI: 10.1016/j.jenvrad.2016.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 04/06/2016] [Accepted: 04/06/2016] [Indexed: 06/05/2023]
Abstract
Current (137)Cs activity concentrations were studied at three localities in individual soil horizons of Stagnosol, Arenic Podzol and Haplic Cambisol soil units in soil blocks with dimensions of 20 × 20 × 40 cm situated below pine canopies (n = 3) and spruce canopies (n = 3), and below small canopy gaps, at least 15 × 15 m in area (n = 3 + 3), which have probably endured since 1986. The main zone of (137)Cs accumulation in all the localities was found to be in the organic horizons (H and F). No significant transport and accumulation of (137)Cs into illuvial soil horizons (Bm, Bs or Bhs, Bv and Bv/IIC) was found. The estimated current total (137)Cs activity concentrations in the soil blocks 40 cm in depth were only slightly higher below the coniferous canopy than they were below nearby canopy gaps. The inventory of (137)Cs in the soils was found to be in accordance with the estimated (137)Cs inputs from the Chernobyl fallout and from global fallout. The low amounts of (137)Cs found accumulated in the aboveground biomass (mosses, grasses, needles) did not substantially bias the studied radiocaesium balance in the soils. The vertical migration rate of (137)Cs in soils (cm/year) had a tendency to be higher below canopies than below canopy gaps and below pine canopies than below spruce canopies. We expected the current (137)Cs activity concentrations in the individual soil horizons to be related to the studied soil parameters: pH (H2O), pH (CaCl2), content of organic matter and mineral portion and portion of humic and fulvic acid contents (Q4/6). However, this was not confirmed. Similarly, we observed a weak tendency toward higher (137)Cs activity in soils below the canopy than in soils below canopy gaps. The available gaps used in our study may have been too small, and they may have been affected by an accumulation of litter and humus containing (137)Cs from the surrounding plots situated below neighbouring canopies.
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Affiliation(s)
- Ivan Suchara
- Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Květnové náměstí 391, CZ-252 43 Průhonice, Czech Republic.
| | - Julie Sucharová
- Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Květnové náměstí 391, CZ-252 43 Průhonice, Czech Republic.
| | - Marie Holá
- Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Květnové náměstí 391, CZ-252 43 Průhonice, Czech Republic.
| | - Helena Pilátová
- National Radiation Protection Institute, Bartoškova 28, CZ-140 00 Praha 4, Czech Republic.
| | - Petr Rulík
- National Radiation Protection Institute, Bartoškova 28, CZ-140 00 Praha 4, Czech Republic.
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Ota M, Nagai H, Koarashi J. Modeling dynamics of (137)Cs in forest surface environments: Application to a contaminated forest site near Fukushima and assessment of potential impacts of soil organic matter interactions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 551-552:590-604. [PMID: 26897402 DOI: 10.1016/j.scitotenv.2016.02.068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/09/2016] [Accepted: 02/09/2016] [Indexed: 06/05/2023]
Abstract
A process-based model for (137)Cs transfer in forest surface environments was developed to assess the dynamic behavior of Fukushima-derived (137)Cs in a Japanese forest. The model simulation successfully reproduced the observed data from 3year migration of (137)Cs in the organic and mineral soil layers at a contaminated forest near Fukushima. The migration of (137)Cs from the organic layer to the mineral soil was explained by the direct deposition pattern on the forest floor and the turnover of litter materials in the organic layer under certain ecological conditions. Long-term predictions indicated that more than 90% of the deposited (137)Cs would remain within the top 5cm of the soil for up to 30years after the accident, suggesting that the forest acts as an effective long-term reservoir of (137)Cs with limited transfer via the groundwater pathway. The model was also used to explore the potential impacts of soil organic matter (SOM) interactions on the mobility and bioavailability of (137)Cs in the soil-plant system. The simulation results for hypothetical organic soils with modified parameters of (137)Cs turnover revealed that the SOM-induced reduction of (137)Cs adsorption elevates the fraction of dissolved (137)Cs in the soil solution, thereby increasing the soil-to-plant transfer of (137)Cs without substantially altering the fractional distribution of (137)Cs in the soil. Slower fixation of (137)Cs on the flayed edge site of clay minerals and enhanced mobilization of the clay-fixed (137)Cs in organic-rich soils also appeared to elevate the soil-to-plant transfer of (137)Cs by increasing the fraction of the soil-adsorbed (exchangeable) (137)Cs. A substantial proportion (approximate 30%-60%) of (137)Cs in these organic-rich soils was transferred to layers deeper than 5cm decades later. These results suggested that SOM influences the behavior of (137)Cs in forests over a prolonged period through alterations of adsorption and fixation in the soil.
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Affiliation(s)
- Masakazu Ota
- Research Group for Environmental Science, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
| | - Haruyasu Nagai
- Research Group for Environmental Science, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Jun Koarashi
- Research Group for Environmental Science, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
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Kothamasi D, Wannijn J, van Hees M, Nauts R, van Gompel A, Vanhoudt N, Cranenbrouck S, Declerck S, Vandenhove H. Rhizophagus irregularis MUCL 41833 can colonize and improve P uptake of Plantago lanceolata after exposure to ionizing gamma radiation in root organ culture. MYCORRHIZA 2016; 26:257-262. [PMID: 26467250 DOI: 10.1007/s00572-015-0664-1] [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: 06/10/2015] [Accepted: 10/04/2015] [Indexed: 06/05/2023]
Abstract
Long-lived radionuclides such as (90)Sr and (137)Cs can be naturally or accidentally deposited in the upper soil layers where they emit β/γ radiation. Previous studies have shown that arbuscular mycorrhizal fungi (AMF) can accumulate and transfer radionuclides from soil to plant, but there have been no studies on the direct impact of ionizing radiation on AMF. In this study, root organ cultures of the AMF Rhizophagus irregularis MUCL 41833 were exposed to 15.37, 30.35, and 113.03 Gy gamma radiation from a (137)Cs source. Exposed spores were subsequently inoculated to Plantago lanceolata seedlings in pots, and root colonization and P uptake evaluated. P. lanceolata seedlings inoculated with non-irradiated AMF spores or with spores irradiated with up to 30.35 Gy gamma radiation had similar levels of root colonization. Spores irradiated with 113.03 Gy gamma radiation failed to colonize P. lanceolata roots. P content of plants inoculated with non-irradiated spores or of plants inoculated with spores irradiated with up to 30.35 Gy gamma radiation was higher than in non-mycorrhizal plants or plants inoculated with spores irradiated with 113.03 Gy gamma radiation. These results demonstrate that spores of R. irregularis MUCL 41833 are tolerant to chronic ionizing radiation at high doses.
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Affiliation(s)
- David Kothamasi
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium.
- Laboratory of Soil Biology and Microbial Ecology, Department of Environmental Studies, University of Delhi, Delhi, 110 007, India.
| | - Jean Wannijn
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium
| | - May van Hees
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium
| | - Robin Nauts
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium
| | - Axel van Gompel
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium
| | - Nathalie Vanhoudt
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium
| | - Sylvie Cranenbrouck
- Earth and Life Institute, Applied Microbiology, Mycology, Mycothèque de l'Université catholique de Louvain (MUCL), Université catholique de Louvain, Croix du Sud 2, bte L7.05.06, B-1348, Louvain-la-Neuve, Belgium
| | - Stéphane Declerck
- Earth and Life Institute, Applied Microbiology, Mycology, Université catholique de Louvain, Croix du Sud 2, bte L7.05.06, B-1348, Louvain-la-Neuve, Belgium
| | - Hildegarde Vandenhove
- Biosphere Impact Studies Unit, Belgian Nuclear Research Center (SCK•CEN), Boeretang 200, 2400, Mol, Belgium
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Teramage MT, Onda Y, Kato H. Small scale temporal distribution of radiocesium in undisturbed coniferous forest soil: Radiocesium depth distribution profiles. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 170:97-104. [PMID: 26803260 DOI: 10.1016/j.jenvman.2016.01.014] [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: 11/18/2015] [Revised: 01/08/2016] [Accepted: 01/12/2016] [Indexed: 06/05/2023]
Abstract
The depth distribution of pre-Fukushima and Fukushima-derived (137)Cs in undisturbed coniferous forest soil was investigated at four sampling dates from nine months to 18 months after the Fukushima nuclear power plant accident. The migration rate and short-term temporal variability among the sampling profiles were evaluated. Taking the time elapsed since the peak deposition of pre-Fukushima (137)Cs and the median depth of the peaks, its downward displacement rates ranged from 0.15 to 0.67 mm yr(-1) with a mean of 0.46 ± 0.25 mm yr(-1). On the other hand, in each examined profile considerable amount of the Fukushima-derived (137)Cs was found in the organic layer (51%-92%). At this moment, the effect of time-distance on the downward distribution of Fukushima-derived (137)Cs seems invisible as its large portion is still found in layers where organic matter is maximal. This indicates that organic matter seems the primary and preferential sorbent of radiocesium that could be associated with the physical blockage of the exchanging sites by organic-rich dusts that act as a buffer against downward propagation of radiocesium, implying radiocesium to be remained in the root zone for considerable time period. As a result, this soil section can be a potential source of radiation dose largely due to high radiocesium concentration coupled with its low density. Generally, such kind of information will be useful to establish a dynamic safety-focused decision support system to ease and assist management actions.
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Affiliation(s)
- Mengistu T Teramage
- Hawassa University, College of Agriculture, P.O.Box 5, Hawassa, Ethiopia; Institute of Radioecological and Nuclear Safety (IRSN), PRP-ENV/SERIS/L2BT, Cadarache, 13115 Saint-Paul-lez-Durance, France.
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki, 305-8572, Japan
| | - Hiroaki Kato
- Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki, 305-8572, Japan
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Hasegawa M, Kaneko S, Ikeda S, Akama A, Komatsu M, Ito MT. Changes in radiocesium concentrations in epigeic earthworms in relation to the organic layer 2.5 years after the 2011 Fukushima Dai-ichi Nuclear Power Plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 145:95-101. [PMID: 25890129 DOI: 10.1016/j.jenvrad.2015.03.015] [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: 09/09/2014] [Revised: 03/02/2015] [Accepted: 03/12/2015] [Indexed: 06/04/2023]
Abstract
We reported previously that radiocesium ((137)Cs) concentrations in earthworms increased with those in litter and/or soil in Fukushima Prefecture forests 0.5 y after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. This study provides further results for 1.5 and 2.5 y after the accident and discusses temporal changes in (137)Cs concentrations and transfer factors (TF) from litter to earthworms to better understand the mechanisms by which (137)Cs enters soil food webs. The concentration of (137)Cs in accumulated litter on the forest floor rapidly decreased, and the concentration in soil (0-5-cm depth) increased over time from 0.5 to 1.5 y, but changed only moderately from 1.5 to 2.5 y. The concentration of (137)Cs in earthworms consistently decreased during the study period; values 2.5 y after the accident were 18.8-68.5% of those 0.5 y after the accident. The TFs from accumulated litter to earthworms decreased over time: 0.24 ± 0.08 (mean ± SD) at 0.5 y and 0.16 ± 0.04 at 2.5 y. This decrease may be a result of decreases in the bioavailability of (137)Cs in litter and the surface soil layer. Changes in (137)Cs bioavailability should be continuously tracked to determine any changes in the relationship between radiocesium concentrations in earthworms and that in accumulated litter or soil.
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Affiliation(s)
- Motohiro Hasegawa
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
| | - Shinji Kaneko
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
| | - Shigeto Ikeda
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
| | - Akio Akama
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
| | - Masabumi Komatsu
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
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Nakao A, Takeda A, Ogasawara S, Yanai J, Sano O, Ito T. Relationships between Paddy Soil Radiocesium Interception Potentials and Physicochemical Properties in Fukushima, Japan. JOURNAL OF ENVIRONMENTAL QUALITY 2015; 44:780-788. [PMID: 26024258 DOI: 10.2134/jeq2014.10.0423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The radiocesium interception potential (RIP) of bulk soil (RIP) can reliably be used to predict the magnitude of soil-to-plant radiocesium transfer. There has been some controversy about which soil properties control the RIP, although the RIP is theoretically proportional to the amount of frayed edge sites in micaceous clay minerals. The RIP was determined for 97 paddy soils in three regions (Hama-dori, Naka-dori, and Aizu) in Fukushima Prefecture, Japan, and the relationships between selected physicochemical properties and the RIP were analyzed. The mean (± standard deviation) of the RIP for the 97 soils was 1.67 (±0.87) mol kg, and the range was 0.34 to 5.36 mol kg. Pearson correlation analysis revealed that the RIP positively correlated best ( < 0.01) with the clay fraction K content as a mass fraction of the bulk soil (clay-K) and negatively correlated with the total C content and the phosphate absorption coefficient ( < 0.05). Therefore, clay-K, an indicator of the amount of micaceous clay minerals in a soil, was confirmed as being useful for estimating the magnitude of the RIP for paddy soils in Fukushima. The RIP was invariably low if either the total C content exceeded 6.0% or the phosphate absorption coefficient exceeded 1500 mg kg, suggesting that these parameters could be useful for screening soils with particularly low RIP values.
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García MA, Alonso J, Melgar MJ. Radiocaesium activity concentrations in macrofungi from Galicia (NW Spain): Influence of environmental and genetic factors. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 115:152-158. [PMID: 25700093 DOI: 10.1016/j.ecoenv.2015.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 01/30/2015] [Accepted: 02/04/2015] [Indexed: 06/04/2023]
Abstract
Radiocaesium ((137)Cs) is an artificial radionuclide that can be captured from the soil through the mycelium of fungi. However, in Spain there are few data on its presence in edible mushrooms. (137)Cs activity concentrations were determined using 54 samples of wild and cultivated mushrooms and 18 samples of soil, all of them collected in Galicia (NW Spain) during 2010. Samples were analyzed by gamma spectroscopy with a High-Purity Germanium (HPGe) detector. The average activity concentration of (137)Cs in wild mushrooms was 249.2Bqkg(-1) dry weight (dw) and about 24.9Bqkg(-1) fresh weight (fw). Genetic factors (species) influenced the uptake of (137)Cs, highlighting Hydnum repandum as the greatest accumulator of all wild species (1016.4Bqkg(-1) dw), while cultivated species showed much lower levels (1.6Bqkg(-1) fw). Accumulation was also favored by fungal mycorrhizal ecology, whose mycelium was distributed in contaminated soil horizons. The mean levels detected in soils were 14Bqkg(-1) fw. Although some species behaved as bioexclusors of radiocaesium, the transfer factors (TF) suggest that mushrooms preferentially bioaccumulate (137)Cs. No sample reached the limit of 600Bqkg(-1) fw (about 6000Bqkg(-1) dw) indicated in the European legislation. In conclusion, the consumption of mushrooms harvested from the investigated areas poses no toxicological risk to human health due to radiocaesium.
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Affiliation(s)
- M A García
- Department of Toxicology, Faculty of Veterinary Science. University of Santiago de Compostela, 27002 Lugo, Spain
| | - J Alonso
- Department of Toxicology, Faculty of Veterinary Science. University of Santiago de Compostela, 27002 Lugo, Spain; Centro Tecnológico Agroalimentario de Lugo (CETAL), 27002 Lugo, Spain
| | - M J Melgar
- Department of Toxicology, Faculty of Veterinary Science. University of Santiago de Compostela, 27002 Lugo, Spain.
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Teramage MT, Onda Y, Patin J, Kato H, Gomi T, Nam S. Vertical distribution of radiocesium in coniferous forest soil after the Fukushima nuclear power plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2014; 137:37-45. [PMID: 24998747 DOI: 10.1016/j.jenvrad.2014.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 06/06/2014] [Accepted: 06/17/2014] [Indexed: 06/03/2023]
Abstract
This study deals with the description of the vertical distribution of radiocaesium ((137)Cs and (134)Cs) in a representative coniferous forest soil, investigated 10 months after the Fukushima radioactive fallout. During soil sampling, the forest floor components (understory plants, litter (Ol-) and fermented layers (Of)) were collected and treated separately. The results indicate that radiocesium is concentrated in the forest floor, and high radiocesium transfer factor observed in the undergrowth plants (3.3). This made the forest floor an active exchanging interphase for radiocesium. The raw organic layer (Ol + Of) holds 52% (5.3 kBq m(-2)) of the Fukushima-derived and 25% (0.7 kBq m(-2)) of the pre-Fukushima (137)Cs at the time of the soil sampling. Including the pre-Fukushima (137)Cs, 99% of the total soil inventory was in the upper 10 cm, in which the organic matter (OM) content was greater than 10%, suggesting the subsequent distribution most likely depends on the OM turnover. However, the small fraction of the Fukushima-derived (137)Cs at a depth of 16 cm is most likely due to the infiltration of radiocesium-circumscribed rainwater during the fallout before that selective adsorption prevails and reduces the migration of soluble (137)Cs. The values of the depth distribution parameters revealed that the distribution of the Fukushima-derived (137)Cs was somewhat rapid.
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Affiliation(s)
- Mengistu T Teramage
- Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan.
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan
| | - Jeremy Patin
- Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan
| | - Hiroaki Kato
- Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan
| | - Takashi Gomi
- Department of International Environmental and Agriculture Science, Tokyo University of Agriculture and Technology, Fuchuu, Tokyo 183-8509, Japan
| | - Sooyoun Nam
- Department of International Environmental and Agriculture Science, Tokyo University of Agriculture and Technology, Fuchuu, Tokyo 183-8509, Japan
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Koarashi J, Atarashi-Andoh M, Takeuchi E, Nishimura S. Topographic heterogeneity effect on the accumulation of Fukushima-derived radiocesium on forest floor driven by biologically mediated processes. Sci Rep 2014; 4:6853. [PMID: 25358420 PMCID: PMC4215300 DOI: 10.1038/srep06853] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 10/10/2014] [Indexed: 11/19/2022] Open
Abstract
The accident at the Fukushima Daiichi nuclear power plant caused serious radiocesium (137Cs) contamination of forest ecosystems located in mountainous and hilly regions with steep terrain. To understand topographic effects on the redistribution and accumulation of 137Cs on forest floor, we investigated the distribution of Fukushima-derived 137Cs in forest-floor litter layers on a steep hillslope in a Japanese deciduous forest in August 2013 (29 months after the accident). Both leaf-litter materials and litter-associated 137Cs were accumulated in large amounts at the bottom of the hillslope. At the bottom, a significant fraction (65%) of the 137Cs inventory was observed to be associated with newly shed and less degraded leaf-litter materials, with estimated mean ages of 0.5–1.5 years, added via litterfall after the accident. Newly emerged leaves were contaminated with Fukushima-derived 137Cs in May 2011 (two months after the accident) and 137Cs concentration in them decreased with time. However, the concentrations were still two orders of magnitude higher than the pre-accident level in 2013 and 2014. These observations are the first to show that 137Cs redistribution on a forested hillslope is strongly controlled by biologically mediated processes and continues to supply 137Cs to the bottom via litterfall at a reduced rate.
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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
| | - 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
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Navas A, López-Vicente M, Gaspar L, Palazón L, Quijano L. Establishing a tracer-based sediment budget to preserve wetlands in Mediterranean mountain agroecosystems (NE Spain). THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 496:132-143. [PMID: 25064720 DOI: 10.1016/j.scitotenv.2014.07.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 06/03/2023]
Abstract
Mountain wetlands in Mediterranean regions are particularly threatened in agricultural environments due to anthropogenic activity. An integrated study of source-to-sink sediment fluxes was carried out in an agricultural catchment that holds a small permanent lake included in the European NATURA 2000 Network. More than 1000 yrs of human intervention and the variety of land uses pose a substantial challenge when attempting to estimate sediment fluxes which is the first requirement to protect fragile wetlands. To date, there have been few similar studies and those that have been carried out have not addressed such complex terrain. Geostatistical interpolation and GIS tools were used to derive the soil spatial redistribution from point (137)Cs inventories, and to establish the sediment budget in a catchment located in the Southern Pyrenees. The soil redistribution was intense and soil erosion predominated over soil deposition. On the areas that maintained natural vegetation the median soil erosion and deposition rates were moderate, ranging from 2.6 to 6 Mg ha yr(-1) and 1.5 to 2.1 Mg ha yr(-1), respectively. However, in cultivated fields both erosion and deposition were significantly higher (ca. 20 Mg ha yr(-1)), and the maximum rates were always associated with tillage practices. Farming activities in the last part of the 20th century intensified soil erosion, as evidenced by the 1963 (137)Cs peaks in the lake cores and estimates from the sediment budget indicated a net deposition of 671 Mg yr(-1). Results confirm a siltation risk for the lake and provide a foundation for designing management plans to preserve this threatened wetland. This comprehensive approach provides information useful for understanding processes that influence the patterns and rates of soil transfer and deposition within fragile Mediterranean mountain wetlands subjected to climate and anthropogenic stresses.
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Affiliation(s)
- Ana Navas
- Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza, Spain.
| | - Manuel López-Vicente
- Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza, Spain.
| | - Leticia Gaspar
- School of Geography, Earth and Environmental Science, Plymouth University, Plymouth, Devon PL4 8AA, UK.
| | - Leticia Palazón
- Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza, Spain.
| | - Laura Quijano
- Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza, Spain.
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Yoshimura M, Yokoduka T. Radioactive contamination of fishes in lake and streams impacted by the Fukushima nuclear power plant accident. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 482-483:184-192. [PMID: 24657366 DOI: 10.1016/j.scitotenv.2014.02.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/19/2014] [Accepted: 02/25/2014] [Indexed: 06/03/2023]
Abstract
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011 emitted radioactive substances into the environment, contaminating a wide array of organisms including fishes. We found higher concentrations of radioactive cesium ((137)Cs) in brown trout (Salmo trutta) than in rainbow trout (Oncorhynchus nerka), and (137)Cs concentrations in brown trout were higher in a lake than in a stream. Our analyses indicated that these differences were primarily due to differences in diet, but that habitat also had an effect. Radiocesium concentrations ((137)Cs) in stream charr (Salvelinus leucomaenis) were higher in regions with more concentrated aerial activity and in older fish. These results were also attributed to dietary and habitat differences. Preserving uncontaminated areas by remediating soils and releasing uncontaminated fish would help restore this popular fishing area but would require a significant effort, followed by a waiting period to allow activity concentrations to fall below the threshold limits for consumption.
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Affiliation(s)
- Mayumi Yoshimura
- Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyuutaro 68, Momoyama, Fushimi, Kyoto 612-0855, Japan.
| | - Tetsuya Yokoduka
- Tochigi Prefectural Fisheries Experimental Station, Sarado 2599, Ohtawara, Tochigi 324-0404, Japan
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Škrkal J, Rulík P, Fantínová K, Burianová J, Helebrant J. Long-term ¹³⁷Cs activity monitoring of mushrooms in forest ecosystems of the Czech Republic. RADIATION PROTECTION DOSIMETRY 2013; 157:579-584. [PMID: 23838098 DOI: 10.1093/rpd/nct172] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This paper reports on results of activity mass concentration analyses performed in various forest mushrooms in the Czech Republic within 1986 and 2011. The estimated effective half-life of (137)Cs and its environmental half-life (i.e. the effective half-life minus the effect of physical decay) were found to be 5.6 ± 0.6 and 6.9 ± 0.7 y, respectively. Non-homogeneity in (137)Cs surface contamination over the country's territory and fungus species-based (137)Cs accumulation capacity then account for a span of up to 4 orders of magnitude in activity mass concentrations measured each year after the Chernobyl accident. The highest geometric activity mass concentration (Bq kg(-1) of dry weight) means of (137)Cs (obtained from samples between years 2004 and 2011) were measured in Suillaceae (1050 Bq kg(-1)) and Boletus badius (930 Bq kg(-1)), the lowest in Agaricus (1 Bq kg(-1)). The geometric mean of all mushrooms amounted to 230 Bq kg(-1), being 440 Bq kg(-1) in Boletales, 150 Bq kg(-1) in Russulales and 21 Bq kg(-1) in Agaricales. Geometric standard deviation levels were generally high. The highest Cs accumulation capacity was observed in Boletales (namely in Suillaceae), while the lowest in Agaricales, being over 3 orders of magnitude lower than in Suillaceae.
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Affiliation(s)
- J Škrkal
- SÚRO (National Radiation Protection Institute), Bartoškova 28, 140 00 Praha, Czech Republic
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Petrović J, Ćujić M, Đorđević M, Dragović R, Gajić B, Miljanić Š, Dragović S. Spatial distribution and vertical migration of (137)Cs in soils of Belgrade (Serbia) 25 years after the Chernobyl accident. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2013; 15:1279-1289. [PMID: 23681090 DOI: 10.1039/c3em00084b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this study, the specific activity of (137)Cs was determined by gamma-ray spectrometry in 72 surface soil samples and 11 soil profiles collected from the territory of Belgrade 25 years after the Chernobyl accident. Based on the data obtained the external effective gamma dose rates due to (137)Cs were assessed and geographically mapped. The influence of pedogenic factors (pH, specific electrical conductivity, cation exchange capacity, organic matter content, soil particle size and carbonate content) on the spatial and vertical distribution of (137)Cs in soil was estimated through Pearson correlations. The specific activity of (137)Cs in surface soil samples ranged from 1.00 to 180 Bq kg(-1), with a mean value of 29.9 Bq kg(-1), while in soil profiles they ranged from 0.90 to 58.0 Bq kg(-1), with a mean value of 15.3 Bq kg(-1). The mean external effective gamma dose at 1 m above the ground due to (137)Cs in the soil was calculated to be 1.96 nSv h(-1). Geographic mapping of the external effective gamma dose rates originating from (137)Cs revealed much higher dose rates in southern parts of Belgrade city and around the confluence of the Sava and Danube. Negative Pearson correlation coefficients were found between pH, cation exchange capacity and (137)Cs specific activity in surface soil. There were positive correlations between organic matter and (137)Cs specific activity in surface soil; and between specific electrical conductivity, organic matter, silt content and (137)Cs specific activity in soil profiles.
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Affiliation(s)
- Jelena Petrović
- University of Belgrade, Institute for the Application of Nuclear Energy, Banatska 31b, 11080 Belgrade, Serbia.
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