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Kurikami H, Sakuma K, Malins A, Sasaki Y, Niizato T. Numerical study of transport pathways of 137Cs from forests to freshwater fish living in mountain streams in Fukushima, Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 208-209:106005. [PMID: 31279227 DOI: 10.1016/j.jenvrad.2019.106005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 06/21/2019] [Accepted: 06/28/2019] [Indexed: 06/09/2023]
Abstract
The accident at the Fukushima Dai-ichi Nuclear Power Plant in 2011 released a large quantity of radiocesium into the surrounding environment. Radiocesium concentrations in some freshwater fish caught in rivers in Fukushima Prefecture in October 2018 were still higher than the Japanese limit of 100 Bq kg-1 for general foodstuffs. To assess the uptake of 137Cs by freshwater fish living in mountain streams in Fukushima Prefecture, we developed a compartment model for the migration of 137Cs on the catchment scale from forests to river water. We modelled a generic forest catchment with Fukushima-like parameters to ascertain the importance of three export pathways of 137Cs from forests to river water for the uptake of 137Cs by freshwater fish. The pathways were direct litter fall into rivers, lateral inflow from the forest litter layer, and lateral transfer from the underlying forest soil. Simulation cases modelling only a single export pathway did not reproduce the actual trend of 137Cs concentrations in river water and freshwater fish in Fukushima Prefecture. Simulations allowing a combined effect of the three pathways reproduced the trends well. In the latter simulations, the decreasing trend of 137Cs in river water and freshwater fish was due to a combination of the decreasing trend in the forest leaves/needles and litter compartments, and the increasing trend in soil. The modelled 137Cs concentrations within the forest compartments were predicted to reach an equilibrium state at around ten years after the fallout due to the equilibration of 137Cs cycling in forests. The model suggests that long term 137Cs concentrations in freshwater fish in mountain streams will be controlled by the transfer of 137Cs to river water from forest organic soils.
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Affiliation(s)
- Hiroshi Kurikami
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, 963-7700, Japan.
| | - Kazuyuki Sakuma
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, 963-7700, Japan.
| | - Alex Malins
- Japan Atomic Energy Agency (JAEA), Center for Computational Science & e-Systems, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa, Chiba, 277-0871, Japan.
| | - Yoshito Sasaki
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, 963-7700, Japan.
| | - Tadafumi Niizato
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, 963-7700, Japan.
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52
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Sakuma K, Nakanishi T, Yoshimura K, Kurikami H, Nanba K, Zheleznyak M. A modeling approach to estimate the 137Cs discharge in rivers from immediately after the Fukushima accident until 2017. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 208-209:106041. [PMID: 31494389 DOI: 10.1016/j.jenvrad.2019.106041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/15/2019] [Accepted: 08/27/2019] [Indexed: 06/10/2023]
Abstract
We developed a simple model to evaluate and predict the 137Cs discharge from catchments using a tank model and the L-Q equation. Using this model, the 137Cs discharge and discharge ratio from the Abukuma River and 13 other rivers in the Fukushima coastal region were estimated from immediately after the Fukushima accident up to 2017. The 137Cs discharge (and discharge ratio to the deposition inventory in the catchment) of the Abukuma River and 13 other rivers in the Fukushima coastal region during the initial six months after the accident were estimated to be 18 TBq (3.1%) and 11 TBq (0.79%), respectively. These values of 137Cs discharge ratio were 1-2 orders of magnitude higher than those observed after June 2011 in previous studies (Ueda et al., 2013; Tsuji et al., 2016; Iwagami et al., 2017a), indicating that the initial 137Cs discharge from the catchments through the rivers was significant. The simulated initial 137Cs discharge rates for the initial six months after the Fukushima accident were about 9-30 times larger in each catchment than those after that point until 2017, though initial 137Cs concentration in river water was derived from an extrapolation of data based on a two exponentially decreasing fitting. However, it was found that the impact on the ocean from the initial 137Cs discharge through the rivers can be limited because the 137Cs discharge from the Abukuma River and the 13 other rivers in the Fukushima coastal region (29 TBq) was two orders of magnitude smaller than the direct release from Fukushima Dai-ichi Nuclear Power Plant (FDNPP) into the ocean (3.5 PBq) and from atmospheric deposition into the ocean (7.6 PBq) (Kobayashi et al., 2013). This model is expected to be useful to evaluate and predict 137Cs discharge from catchments in future water management and in the estimation of 137Cs discharge into reservoirs and the ocean.
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Affiliation(s)
- Kazuyuki Sakuma
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima, 963-7700, Japan.
| | - Takahiro Nakanishi
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima, 963-7700, Japan
| | - Kazuya Yoshimura
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima, 963-7700, Japan
| | - Hiroshi Kurikami
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima, 963-7700, Japan
| | - Kenji Nanba
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, 960-1296, Japan
| | - Mark Zheleznyak
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, 960-1296, Japan
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53
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Delmas M, Garcia-Sanchez L, Onda Y. Factors controlling the variability of 137Cs concentrations in 5 coastal rivers around Fukushima Dai-ichi power plant. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 204:1-11. [PMID: 30946972 DOI: 10.1016/j.jenvrad.2019.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/08/2019] [Accepted: 03/10/2019] [Indexed: 06/09/2023]
Abstract
The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to the contamination by radiocesium (137Cs) of large drained areas. Cesium-137 concentrations in rivers result from complex transfer processes, depending on multiple forcings. Better knowledge of the factors controlling these concentrations is therefore a prerequisite to improve predictions of 137Cs transfers within river catchments. This study aimed at analyzing the spatial and temporal variability of 137Cs concentrations in rivers and identifying the key factors controlling their variability. Published values of 137Cs concentrations in rivers in the north of FDNPP were collected, characterizing 122 sampling sites from May 2011 to October 2014. It resulted in three datasets: dissolved concentrations CW (Bq/L), concentrations in suspended sediment CSS (Bq/kg) and total concentrations CT (Bq/L). The resulting database reflected a large variety of catchments and hydrological conditions. Observed 137Cs concentrations varied by 2-4 orders of magnitude and were poorly explained (R2 = 0.13-0.38) by the average contamination density. Indices summarizing the complex spatial and temporal properties of the catchments were proposed as candidate explanatory variables of concentrations in rivers. They were selected by stepwise regression for each dataset (CW, CSS, CT). For the three datasets, the selection and combination of 5-10 indices significantly better explained this variability (R2 = 0.69-0.83). Deposit indices were identified as first drivers of concentrations in rivers. A deposit index was selected for each dataset, indicating no effect of the contamination distribution for CW, whereas CT and CSS required considering the distribution of contamination and connectivity, as well as the presence of dams for CSS. The others selected variables significantly contributed to explain the concentration variability. This meta-analysis emphasizes the importance of structural (e.g. slope, land-cover) and functional (e.g. delay, season, rainfall) properties in the dissimilarities of catchments responses, stressing that assessments could be improved by including more these properties in models.
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Affiliation(s)
- M Delmas
- Laboratory of Research on Radionuclides Transfers in Terrestrial Ecosystems (LR2T), IRSN, Centre de Cadarache, Bât. 183, BP 3, 13115, Saint-Paul-lez-Durance, France.
| | - L Garcia-Sanchez
- Laboratory of Research on Radionuclides Transfers in Terrestrial Ecosystems (LR2T), IRSN, Centre de Cadarache, Bât. 183, BP 3, 13115, Saint-Paul-lez-Durance, France
| | - Y Onda
- Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba, Japan
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54
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Liu X, Machida M, Kurikami H, Kitamura A. Long-term simulations of radiocesium discharge in watershed with improved radioesium wash-off model: Applying the model to Abukuma River basin of Fukushima. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 203:135-146. [PMID: 30901741 DOI: 10.1016/j.jenvrad.2019.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/15/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
In order to simulate the long-term migration and distribution of radiocesium after the Fukushima accident, a numerical model, Soil and Cesium Transport (SACT) based on universal soil loss equation (USLE), has been developed in previous studies. Although the SACT model's results on radiocesium discharge in 2011 are in reasonable agreement with field measurements, it fails to capture the sharp decrease of radiocesium flux in subsequent years, especially in the case of Abukuma River. The present work aims to improve SACT by implementing new processes for radiocesium wash-off, in which the vertical migration, and long-term fixation of radiocesium in soil are taken in to account. To understand the vertical migration process, depth profile measurement results between 2011 and 2016 have been fitted by different distribution functions and analyzed statistically. A conceptual model has been developed to describe results from recent sorption experiments, which support long-term fixation of radiocesium in soil particles. For validation purpose, the annual average radiocesium concentration in sediments discharged from Abukuma river has been evaluated from measurement data. With these improvements, the new SACT model could achieve much better agreement with the measurement results without parameter tuning.
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Affiliation(s)
- Xudong Liu
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, 178-4-4 Wakashiba, Kashiwa, Chiba, 277-0871, Japan.
| | - Masahiko Machida
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, 178-4-4 Wakashiba, Kashiwa, Chiba, 277-0871, Japan.
| | - Hiroshi Kurikami
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan.
| | - Akihiro Kitamura
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan.
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55
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Johansen MP, Cresswell T, Davis J, Howard DL, Howell NR, Prentice E. Biofilm-enhanced adsorption of strong and weak cations onto different microplastic sample types: Use of spectroscopy, microscopy and radiotracer methods. WATER RESEARCH 2019; 158:392-400. [PMID: 31059933 DOI: 10.1016/j.watres.2019.04.029] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 03/29/2019] [Accepted: 04/13/2019] [Indexed: 06/09/2023]
Abstract
The adsorption of metals and other elements onto environmental plastics has been previously quantified and is known to be enhanced by surface-weathering and development of biofilms. However, further biofilm-adsorption characterisation is needed with respect to the fate of radionuclides. This study uses spectroscopy, microscopy and radiotracer methods to investigate the adsorption capacity of relatively strong and weak cations onto different microplastic sample types that were conditioned in freshwater, estuarine and marine conditions although marine data were limited. Fourier-transform infrared spectroscopy confirmed that surface oxidation chemistry changes induced by gamma irradiation were similar to those resulting from environmental exposures. Microscopy elemental mapping revealed patchy biofilm development, which contained Si, Al, and O, consistent with microbial-facilitated capture of clays. The plastics+biofilm of all sample types had measurable adsorption for Cs and Sr radiotracers, suggesting environmental plastics act broadly as a sink for the key pervasive environmental radionuclides of 137Cs and 90Sr associated with releases from nuclear activities. Adsorption onto high-density polyethylene plastic types was greater than that on polypropylene. However, in most cases, the adsorption rates of all types of plastic+biofilm were much lower than those of reference sediments and roughly consistent with their relative exchangeable surface areas.
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Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia.
| | - Tom Cresswell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Joel Davis
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Daryl L Howard
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria, 3168, Australia
| | - Nicholas R Howell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Emily Prentice
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia; University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia
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56
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Jaegler H, Pointurier F, Diez-Fernández S, Gourgiotis A, Isnard H, Hayashi S, Tsuji H, Onda Y, Hubert A, Laceby JP, Evrard O. Reconstruction of uranium and plutonium isotopic signatures in sediment accumulated in the Mano Dam reservoir, Japan, before and after the Fukushima nuclear accident. CHEMOSPHERE 2019; 225:849-858. [PMID: 30904765 DOI: 10.1016/j.chemosphere.2019.03.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/15/2019] [Accepted: 03/10/2019] [Indexed: 06/09/2023]
Abstract
The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in Japan resulted in a major release of radionuclides into the environment. Compared to other radionuclides, few studies have investigated the fate of actinides in the environment. Accordingly, this research investigates the Pu composition in soil samples collected in paddy fields before and after the accident. Furthermore, the vertical distributions of Pu and U isotopic signatures, along with 137Cs activities, were measured in a sediment core collected in the Mano Dam reservoir, in the Fukushima Prefecture. Changes in the relative contributions of the major actinide sources (global fallout or FDNPP derived fallout) were investigated in sediment deposited in the reservoir. The distinct peak observed for all Pu isotope ratios (240Pu/239Pu, 241Pu/239Pu and 242Pu/239Pu) and for 137Cs concentrations in the sediment core was attributed to the Fukushima fallout, and coincided with the maximum atomic contribution of only 4.8 ± 1.0% of Pu from the FDNPP. Furthermore, 236U/238U ratios measured in the sediment core remained close to the global fallout signature indicating there was likely no U from the FDNPP accident detected in the sediment core. More research is required on the environmental dynamics of trace actinides in landscapes closer to the FDNPP where there are likely to be greater abundances of FDNPP-derived Pu and U.
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Affiliation(s)
- Hugo Jaegler
- Laboratoire des Sciences Du Climat et de L'Environnement, LSCE/IPSL, UMR 8212 (CEA-CNRS-UVSQ), Université Paris-Saclay, F-91198, Gif-sur-Yvette Cedex, France
| | | | - Silvia Diez-Fernández
- Den - Service D'Etudes Analytiques et de Réactivité des Surfaces (SEARS), CEA, Université Paris-Saclay, F-91191, Gif sur Yvette, France
| | - Alkiviadis Gourgiotis
- Institut de Radioprotection et de Sûreté Nucléaire - PSE/ENV - SEDRE/LELI BP 17, Fontenay-aux-Roses, 92262, France
| | - Hélène Isnard
- Den - Service D'Etudes Analytiques et de Réactivité des Surfaces (SEARS), CEA, Université Paris-Saclay, F-91191, Gif sur Yvette, France
| | - Seiji Hayashi
- National Institute for Environmental Science, Fukushima Branch, 10-2 Fukasaku, Miharu, Tamura, Fukushima, 963-7700 Japan
| | - Hideki Tsuji
- National Institute for Environmental Science, Fukushima Branch, 10-2 Fukasaku, Miharu, Tamura, Fukushima, 963-7700 Japan
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba, Japan
| | | | - J Patrick Laceby
- Laboratoire des Sciences Du Climat et de L'Environnement, LSCE/IPSL, UMR 8212 (CEA-CNRS-UVSQ), Université Paris-Saclay, F-91198, Gif-sur-Yvette Cedex, France; Environmental Monitoring and Science Division, Alberta Environment and Parks, 3115 - 12 Street NE, Calgary, Alberta, Canada
| | - Olivier Evrard
- Laboratoire des Sciences Du Climat et de L'Environnement, LSCE/IPSL, UMR 8212 (CEA-CNRS-UVSQ), Université Paris-Saclay, F-91198, Gif-sur-Yvette Cedex, France.
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57
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Evrard O, Laceby JP, Ficetola GF, Gielly L, Huon S, Lefèvre I, Onda Y, Poulenard J. Environmental DNA provides information on sediment sources: A study in catchments affected by Fukushima radioactive fallout. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 665:873-881. [PMID: 30790760 DOI: 10.1016/j.scitotenv.2019.02.191] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/06/2019] [Accepted: 02/12/2019] [Indexed: 05/23/2023]
Abstract
An excessive supply of sediment is observed in numerous rivers across the world where it leads to deleterious impacts. Information on the sources delivering this material to waterbodies is required to design effective management measures, and sediment tracing or fingerprinting techniques are increasingly used to quantify the amount of sediment derived from different sources. However, the current methods used to identify the land use contributions to sediment have a limited discrimination power. Here, we investigated the potential of environmental DNA (eDNA) to provide more detailed information on the plant species found in sediment source areas as a next generation fingerprint. To this end, flood sediment deposits (n = 12) were collected in 2017 in two catchments impacted by the Fukushima radioactive fallout along differing river sections draining forests, cropland or a mix of both land uses. Conventional fingerprints (i.e. fallout radionuclides and organic matter properties) were also measured in these samples. The conventional fingerprint model results showed that most sediment samples contained a dominant proportion of subsoil material. Nevertheless, the eDNA information effectively discriminated the three above-mentioned groups of sediment, with the dominance of tree, shrub and fern species in sediment sampled in rivers draining forests versus a majority of grass, algae and cultivated plant species in sediment collected in rivers draining cropland. Based on these encouraging results, future research should examine the potential of eDNA in mixed land use catchments where the contribution of topsoil to sediment dominates and where the cultivation of land has not been abandoned in order to better characterize the memory effect of eDNA in soils and sediment.
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Affiliation(s)
- Olivier Evrard
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette, France.
| | - J Patrick Laceby
- Environmental Monitoring and Science Division (EMSD), Alberta Environment and Parks (AEP), Calgary, Alberta, Canada
| | - Gentile Francesco Ficetola
- Université Grenoble Alpes, CNRS, Laboratoire d'Écologie Alpine, Grenoble, France; Departement of Environmental Science and Policy, Università degli Studi di Milano, Milano, Italy
| | - Ludovic Gielly
- Université Grenoble Alpes, CNRS, Laboratoire d'Écologie Alpine, Grenoble, France
| | - Sylvain Huon
- Sorbonne Universités, UPMC Univ Paris 06, Institut d'Ecologie et des Sciences de l'environnement de Paris (iEES), Paris, France
| | - Irène Lefèvre
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette, France
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba, Japan
| | - Jérôme Poulenard
- Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, EDYTEM (Environnements, DYnamiques et TErritoires de la Montagne), Chambéry, France
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58
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Külahcı F, Bilici A. Advances on identification and animated simulations of radioactivity risk levels after Fukushima Nuclear Power Plant accident (with a data bank): A Critical Review. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06559-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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59
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Nishikiori T, Hayashi S, Watanabe M, Yasutaka T. Impact of clearcutting on radiocesium export from a Japanese forested catchment following the Fukushima nuclear accident. PLoS One 2019; 14:e0212348. [PMID: 30763401 PMCID: PMC6375618 DOI: 10.1371/journal.pone.0212348] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/31/2019] [Indexed: 11/19/2022] Open
Abstract
Changes in 137Cs export over time following clearcutting were investigated in a Japanese forested catchment affected by the Fukushima nuclear accident. A total of 13% of the catchment area was clear-cut 2 years after the accident. Annual suspended solids (SS) export at the catchment outlet increased 1.4 to 2.0 times after clearcutting; however, 137Cs export increased slightly (up to 1.1 times), corresponding to 0.21% to 0.30% of the 137Cs inventory in the catchment. The smaller change in 137Cs export than in SS export was due to a rapid decrease in the activity concentration following clearcutting. This decrease was likely caused by both natural attenuation and SS derived from sources with a low activity concentration in the clear-cut area. Monitoring of the sediment transport from hillslopes in small-scale experimental plots showed that the 137Cs yield in the skid trail was 3.6 to 21 times greater than those in clear-cut and unlogged forest floors. This significant 137Cs transport was due to greater soil erosion (by up to two orders of magnitude) along the skid trail, despite the lower activity concentration than those in the other plots. This indicates that while skid trails were involved in the rapid decrease of the activity concentration of SS, they were a potential source of the increased export of 137Cs and SS. Net 137Cs export increased by clearcutting (the export excluding the decrease accompanied by natural attenuation) was estimated to account for only 0.092% of the inventory in the catchment for 2.5 years. These results imply that the impact of clearcutting on 137Cs export was temporary in this catchment.
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Affiliation(s)
- Tatsuhiro Nishikiori
- Center for Regional Environment Research, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan
- Fukushima Prefectural Centre for Environmental Creation, Fukasaku, Miharu, Fukushima, Japan
| | - Seiji Hayashi
- Fukushima Branch, National Institute for Environmental Studies, Fukasaku, Miharu, Fukushima, Japan
| | - Mirai Watanabe
- Center for Regional Environment Research, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan
| | - Tetsuo Yasutaka
- National Institute of Advanced Industrial Science and Technology, Higashi, Tsukuba, Ibaraki, Japan
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60
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Pappalardo RR, Caralampio DZ, Martínez JM, Marcos ES. Hydration Structure of the Elusive Ac(III) Aqua Ion: Interpretation of X-ray Absorption Spectroscopy (XAS) Spectra on the Basis of Molecular Dynamics (MD) Simulations. Inorg Chem 2019; 58:2777-2783. [DOI: 10.1021/acs.inorgchem.8b03365] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - José M. Martínez
- Departmento de Química Física, Universidad de Sevilla, 41012 Sevilla, Spain
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61
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Paterne M, Evrard O, Hatté C, Laceby PJ, Nouet J, Onda Y. Radiocarbon and radiocesium in litter fall at Kawamata, ~ 45 km NW from the Fukushima Dai-ichi nuclear power plant (Japan). J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-6360-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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62
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Takahashi J, Onda Y, Hihara D, Tamura K. Six-year monitoring of the vertical distribution of radiocesium in three forest soils after the Fukushima Dai-ichi Nuclear Power Plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 192:172-180. [PMID: 29982001 DOI: 10.1016/j.jenvrad.2018.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 05/31/2018] [Accepted: 06/22/2018] [Indexed: 05/22/2023]
Abstract
After the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011, several studies showed that the downward migration of 137Cs from litter to mineral soil is more rapid in forests in Fukushima than in forests affected by the Chernobyl accident. Therefore, the downward migration within mineral soil layers is more important for predicting long-term dynamics of 137Cs in forest ecosystems in Fukushima. In the present study, we monitored the detailed vertical distribution of 137Cs in litter and soil layers for 6 y (2011-2017) following the previous study (2011-2012), and found that temporal changes in those distributions were different among mixed forest (MF), mature cedar (MC) and young cedar (YC) forests. The 137Cs concentrations and inventories in the litter layer exponentially decreased with time for all sites, with more than 80-95% of the deposited 137Cs on the forest floor distributed in mineral soil layers by 2017. The percentage of 137Cs inventory in the litter layer to the total 137Cs inventory in litter and mineral soil layers was well fitted by a single exponential equation with decreasing rate of 0.22-0.44 y-1. The slower migration was observed in the YC site, probably because of higher initial interception of 137Cs fallout by dense canopy. As the downward migration from litter to mineral soil progressed, the 137Cs concentration in the first few cm of mineral soil surface gradually increased and became higher than the 137Cs concentration in the litter within 2-3 y of the accident. The 137Cs concentration in mineral soil layers exponentially decreased with depth throughout survey period, and an exponential equation fitted well. The relaxation depth of 137Cs concentration in mineral soil layers estimated by the exponential equation were constantly increasing in the MC and YC sites with 0.08 cm y-1. In contrast, there was no temporal increase in the relaxation depth in the MF site, indicating little migration to subsurface soil layer from not only litter layer but also surface soil layer. Further studies are necessary to identify the forests prone to the downward migration of 137Cs and its factors regarding both forest and soil characteristics.
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Affiliation(s)
- Junko Takahashi
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Japan.
| | - Yuichi Onda
- 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
| | - Kenji Tamura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Japan
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Otosaka S, Satoh Y, Suzuki T, Kuwabara J, Nakanishi T. Distribution and fate of 129I in the seabed sediment off Fukushima. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 192:208-218. [PMID: 29982005 DOI: 10.1016/j.jenvrad.2018.06.025] [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: 03/20/2018] [Revised: 06/11/2018] [Accepted: 06/28/2018] [Indexed: 06/08/2023]
Abstract
In this study, seabed sediment was collected from 26 stations located within 160 km from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) during the 2 years which followed the FDNPP accident of March 2011 and the concentrations of 129I and 137Cs were measured. By comparing the distribution of these two radionuclides with respect to their different geochemical behaviors in the environment, the transport of accident-derived radionuclides near the seafloor is discussed. The concentration of 129I in seabed sediment recovered from offshore Fukushima in 2011 ranged between 0.02 and 0.45 mBq kg-1, with 129I/137Cs activity ratios of (1.9 ± 0.5) × 10-6 Bq Bq-1. The initial deposition of 129I to the seafloor in the study area was 0.36 ± 0.13 GBq, and the general distribution of sedimentary 129I was established within 6 months after the accident. Although iodine is a biophilic element, the accident-derived 129I negligibly affects the benthic ecosystem. Until October 2013, a slight increase in activity of 129I in the surface sediment along the shelf-edge region (bottom depth: 200-400 m) was observed, despite that such a trend was not observed for 137Cs. The preferential increase of the 129I concentrations in the shelf-edge sediments was presumed to be affected by the re-deposition in the shelf-edge sediments of 129I desorbed from the contaminated coastal sediment. The results obtained from this study indicate that 129I/137Cs in marine particles is a useful indicator for tracking the secondary transport of accident-derived materials, particularly biophilic radionuclides, from the coast to offshore areas.
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Affiliation(s)
- Shigeyoshi Otosaka
- Research Group for Environmental Sciences, Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan.
| | - Yuhi Satoh
- Department of Radioecology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho, Aomori, 039-3212, Japan
| | - Takashi Suzuki
- Research Group for Environmental Sciences, Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Jun Kuwabara
- AMS Management Section, Aomori Research and Development Center, Japan Atomic Energy Agency, 4-24 Minatomachi, Mutsu, Aomori, 035-0064, Japan
| | - Takahiro Nakanishi
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
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64
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65
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Johansen MP, Prentice E, Cresswell T, Howell N. Initial data on adsorption of Cs and Sr to the surfaces of microplastics with biofilm. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 190-191:130-133. [PMID: 29787932 DOI: 10.1016/j.jenvrad.2018.05.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 04/27/2018] [Accepted: 05/01/2018] [Indexed: 05/20/2023]
Abstract
The adsorption of radiocesium and radiostrontium onto a range of natural materials has been well quantified, but not for the new media of environmental plastics, which may have enhanced adsorption due to surface-weathering and development of biofilms. Microplastic samples were deployed in freshwater, estuarine and marine conditions, then characterised using infrared spectroscopy to document changes to the plastic surface (vs interior). Synchrotron elemental mapping data revealed surfaces that were well-covered by accumulation of reactive water solutes and sulphur, but, in contrast, had highly discrete coverage of elements such as Fe and Ti, indicating adhered mineral/clay-associated agglomerates that may increase overall adsorption capacity. Plastics that had been deployed for nearly five months adsorbed radionuclides in both freshwater and estuarine conditions with the highest Kd for cesium (Cs) in freshwater (80 ml g-1) and lowest for strontium (Sr) in estuarine conditions (5 ml g-1). The degree of Cs and Sr adsorption onto plastics appears to be approximately 2-3 orders of magnitude lower than for sediment reference values. While lower than for sediments, adsorption occurred on all samples and may indicate a significant radionuclide reservoir, given that plastics are relatively buoyant and mobile in water regimes, and are increasing in global aquatic systems.
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Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia.
| | - Emily Prentice
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia; University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia
| | - Tom Cresswell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Nick Howell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
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66
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Jaegler H, Pointurier F, Onda Y, Hubert A, Laceby JP, Cirella M, Evrard O. Plutonium isotopic signatures in soils and their variation (2011-2014) in sediment transiting a coastal river in the Fukushima Prefecture, Japan. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 240:167-176. [PMID: 29734077 DOI: 10.1016/j.envpol.2018.04.094] [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: 11/17/2017] [Revised: 04/03/2018] [Accepted: 04/21/2018] [Indexed: 06/08/2023]
Abstract
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in a significant release of radionuclides that were deposited on soils in Northeastern Japan. Plutonium was detected at trace levels in soils and sediments collected around the FDNPP. However, little is known regarding the spatial-temporal variation of plutonium in sediment transiting rivers in the region. In this study, plutonium isotopic compositions were first measured in soils (n = 5) in order to investigate the initial plutonium deposition. Then, plutonium isotopic compositions were measured on flood sediment deposits (n = 12) collected after major typhoon events in 2011, 2013 and 2014. After a thorough radiochemical purification, isotopic ratios (240Pu/239Pu, 241Pu/239Pu and 242Pu/239Pu) were measured with a Multi-Collector Inductively Coupled Mass Spectrometer (MC ICP-MS), providing discrimination between plutonium derived from global fallout, from atmospheric nuclear weapon tests, and plutonium derived from the FDNPP accident. Results demonstrate that soils with the most Fukushima-derived plutonium were in the main radiocaesium plume and that there was a variable mixture of plutonium sources in the flood sediment samples. Plutonium concentrations and isotopic ratios generally decreased between 2011 and 2014, reflecting the progressive erosion and transport of contaminated sediment in this coastal river during flood events. Exceptions to this general trend were attributed to the occurrence of decontamination works or the remobilisation of contaminated material during typhoons. The different plutonium concentrations and isotopic ratios obtained on three aliquots of a single sample suggest that the Fukushima-derived plutonium was likely borne by discrete plutonium-containing particles. In the future, these particles should be isolated and further characterized in order to better understand the fate of this long-lived radionuclide in the environment.
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Affiliation(s)
- Hugo Jaegler
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, Unité Mixte de Recherche 8212 (CEA-CNRS-UVSQ), Université Paris-Saclay, F-91198, Gif-sur-Yvette, France
| | | | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba, Japan
| | | | - J Patrick Laceby
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, Unité Mixte de Recherche 8212 (CEA-CNRS-UVSQ), Université Paris-Saclay, F-91198, Gif-sur-Yvette, France; Environmental Monitoring and Science Division, Alberta Environment and Parks, 3115 - 12 Street NE, Calgary, Alberta, Canada
| | | | - Olivier Evrard
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, Unité Mixte de Recherche 8212 (CEA-CNRS-UVSQ), Université Paris-Saclay, F-91198, Gif-sur-Yvette, France.
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67
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Funaki H, Yoshimura K, Sakuma K, Iri S, Oda Y. Evaluation of particulate 137Cs discharge from a mountainous forested catchment using reservoir sediments and sinking particles. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 189:48-56. [PMID: 29602059 DOI: 10.1016/j.jenvrad.2018.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/24/2018] [Accepted: 03/13/2018] [Indexed: 06/08/2023]
Abstract
The time and size dependencies of particulate 137Cs concentrations in a reservoir were investigated to evaluate the dynamics of 137Cs pollution from a mountainous forested catchment. Sediment and sinking particle samples were collected using a vibracorer and a sediment trap at the Ogaki Dam Reservoir in Fukushima, which is located in the heavily contaminated area that formed as a result of the Fukushima Dai-ichi Nuclear Power Plant accident of 2011. The inventory of 137Cs discharged into the reservoir during the post-accident period (965 days) was estimated to be approximately 3.0 × 1012-3.9 × 1012 Bq, which is equivalent to 1.1%-1.4% of the initial estimated catchment inventory. The particulate 137Cs concentration showed a decline with time, but the exponent value between the specific surface area and the 137Cs concentration for the fine-sized (<63 μm) particle fraction remained almost constant from the immediate aftermath of the accident. These quantitative findings obtained by reconstructing the contamination history of particulate 137Cs in reservoir sediments and sinking particles have important implications for the evaluation of 137Cs dynamics in mountainous forested catchments.
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Affiliation(s)
- Hironori Funaki
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan.
| | - Kazuya Yoshimura
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan
| | - Kazuyuki Sakuma
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan
| | - Shatei Iri
- West Japan Engineering Consultants, Inc., 1-1, 1-chome, Watanabe-dori, Chuo-ku, Fukuoka-shi, Fukuoka, 810-0004, Japan
| | - Yoshihiro Oda
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Fukushima, 963-7700, Japan
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68
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Long-Term Monitoring of Radiocesium Concentration in Sediments and River Water along Five Rivers in Minami-Soma City during 2012–2016 Following the Fukushima Dai-ichi Nuclear Power Plant Accident. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8081319] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Radiocesium monitoring in sediments and river water has been conducted along five rivers in Minami-Soma City during 2012–2016 to clarify the temporal changes of radiocesium contamination in these rivers. Sampling has been performed annually under normal flow conditions. Sediment and river water samples were collected from four or five sampling sites along each river. Gamma-ray measurements of sediments were performed using a low-background Ge detector and unfiltered river water was utilized to determine radiocesium concentration using a well-type Ge detector. The 137Cs concentration in sediments was highest at upstream sites and slowly decreased to downstream sites for all rivers reflecting the high radioactive contamination in the upstream area. Temporal decrease of the 137Cs concentration was observed in sediments and river water for each river. The effective half-lives were 1.3–2.1 y for sediments, and 0.9–2.1 y for river water from rivers with upstream dams. On the undammed river, the effective half-lives were 4.7 y and 3.7 y for sediment and river water, respectively. Much longer effective-half-lives might reflect the direct transfer of radiocesium from forests and plains to the river. The 137Cs concentration in riverbed was low in downstream areas, however, accumulation of 137Cs over the floodplain was observed. Rapid decrease of 137Cs contamination through rivers will put residents at ease, but high accumulation of radiocesium over floodplains should be noted for future river decontamination.
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69
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Sakuma K, Tsuji H, Hayashi S, Funaki H, Malins A, Yoshimura K, Kurikami H, Kitamura A, Iijima K, Hosomi M. Applicability of K d for modelling dissolved 137Cs concentrations in Fukushima river water: Case study of the upstream Ota River. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 184-185:53-62. [PMID: 29353199 DOI: 10.1016/j.jenvrad.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/25/2017] [Accepted: 01/04/2018] [Indexed: 06/07/2023]
Abstract
A study is presented on the applicability of the distribution coefficient (Kd) absorption/desorption model to simulate dissolved 137Cs concentrations in Fukushima river water. The upstream Ota River basin was simulated using GEneral-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) for the period 1 January 2014 to 31 December 2015. Good agreement was obtained between the simulations and observations on water and suspended sediment fluxes, and on particulate bound 137Cs concentrations under both base and high flow conditions. By contrast the measured concentrations of dissolved 137Cs in the river water were much harder to reproduce with the simulations. By tuning the Kd values for large particles, it was possible to reproduce the mean dissolved 137Cs concentrations during base flow periods (observation: 0.32 Bq/L, simulation: 0.36 Bq/L). However neither the seasonal variability in the base flow dissolved 137Cs concentrations (0.14-0.53 Bq/L), nor the peaks in concentration that occurred during storms (0.18-0.88 Bq/L, mean: 0.55 Bq/L), could be reproduced with realistic simulation parameters. These discrepancies may be explained by microbial action and leaching from organic matter in forest litter providing an additional input of dissolved 137Cs to rivers, particularly over summer, and limitations of the Kd absorption/desorption model. It is recommended that future studies investigate these issues in order to improve simulations of dissolved 137Cs concentrations in Fukushima rivers.
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Affiliation(s)
- Kazuyuki Sakuma
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan; Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
| | - Hideki Tsuji
- Fukushima Branch, National Institute of Environmental Studies, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan
| | - Seiji Hayashi
- Fukushima Branch, National Institute of Environmental Studies, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan
| | - Hironori Funaki
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan
| | - Alex Malins
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Kazuya Yoshimura
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan
| | - Hiroshi Kurikami
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Akihiro Kitamura
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Kazuki Iijima
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2, Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan
| | - Masaaki Hosomi
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan
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70
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Deposition density of 134Cs and 137Cs and particle size distribution of soil and sediment profile in Hibara Lake area, Fukushima: an investigation of 134Cs and 137Cs indirect deposition into lake from surrounding area. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-5809-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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71
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Zhao L, Liu D, Wang J, Du J, Hou X, Jiang Y. Spatial and vertical distribution of radiocesium in seawater of the East China Sea. MARINE POLLUTION BULLETIN 2018; 128:361-368. [PMID: 29571384 DOI: 10.1016/j.marpolbul.2018.01.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
The 137Cs activity in surface water of the East China Sea (ECS) was 0.66-1.36 Bq m-3 during May of 2011. The low activities were observed in the Changjiang Estuary and Zhejiang-Fujian coast and high activities were observed in the south offshore and Kuroshio Current pathway, suggesting that the influence from the current system in the ECS. The 134Cs were undetectable (<0.03 Bq m-3) and the contribution of the Fukushima accident to ECS is estimated to be below 3%; hence it is negligible during the investigation period. Using the vertical profiles of 137Cs in the ECS, the mass balance is obtained, which suggests that the oceanic input dominates the 137Cs source in the ECS. 137Cs is potentially useful to trace water mass movement in the ECS. Our study provides comprehensive baseline of 137Cs in the ECS for evaluation of the possible influence of the nuclear power plants in the future.
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Affiliation(s)
- Lijun Zhao
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Dantong Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jinlong Wang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Xiaolin Hou
- Xi'an AMS Center and KLLQG, Institute of Earth Environment, Chinese Academy of Science, Xi'an 710075, China
| | - Yifei Jiang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
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72
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Sakuma K, Malins A, Funaki H, Kurikami H, Niizato T, Nakanishi T, Mori K, Tada K, Kobayashi T, Kitamura A, Hosomi M. Evaluation of sediment and 137Cs redistribution in the Oginosawa River catchment near the Fukushima Dai-ichi Nuclear Power Plant using integrated watershed modeling. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 182:44-51. [PMID: 29190508 DOI: 10.1016/j.jenvrad.2017.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/23/2017] [Accepted: 11/21/2017] [Indexed: 06/07/2023]
Abstract
The Oginosawa River catchment lies 15 km south-west of the Fukushima Dai-ichi nuclear plant and covers 7.7 km2. Parts of the catchment were decontaminated between fall 2012 and March 2014 in preparation for the return of the evacuated population. The General-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) code was used to study sediment and 137Cs redistribution within the catchment, including the effect of decontamination on redistribution. Fine resolution grid cells were used to model local features of the catchment, such as paddy fields adjacent to the Oginosawa River. The simulation was verified using monitoring data for river water discharge rates (r = 0.92), suspended sediment concentrations, and particulate 137Cs concentrations (r = 0.40). Cesium-137 input to watercourses came predominantly from land adjacent to river channels and forest gullies, e.g. the paddy fields in the Ogi and Kainosaka districts, as the ground in these areas saturates during heavy rain and is easily eroded. A discrepancy between the simulation and monitoring results on the sediment discharge rate following decontamination may be explained by fast erosion occurring after decontamination. Forested areas far from the channels only made a minor contribution to 137Cs input to watercourses, total erosion of between 0.001 and 0.1 mm from May 2011 to December 2015, as ground saturation is infrequent in these areas. The 2.3-6.9% y-1 decrease in the amount of 137Cs in forest topsoil over the study period can be explained by radioactive decay (approximately 2.3% y-1), along with a migration downwards into subsoil and a small amount of export. The amount of 137Cs available for release from land adjacent to rivers is expected to be lower in future than compared to this study period, as the simulations indicate a high depletion of inventory from these areas by the end of 2015. However continued monitoring of 137Cs concentrations in river water over future years is advised, as recultivation of paddy fields by returnees may again lead to fast erosion rates and release of the remaining inventory.
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Affiliation(s)
- Kazuyuki Sakuma
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
| | - Alex Malins
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Hironori Funaki
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan
| | - Hiroshi Kurikami
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Tadafumi Niizato
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan
| | - Takahiro Nakanishi
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan
| | - Koji Mori
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Kazuhiro Tada
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Takamaru Kobayashi
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Akihiro Kitamura
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Masaaki Hosomi
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan
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73
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Takahashi J, Wakabayashi S, Tamura K, Onda Y. Downward migration of radiocesium in an abandoned paddy soil after the Fukushima Dai-ichi Nuclear Power Plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 182:157-164. [PMID: 29248741 DOI: 10.1016/j.jenvrad.2017.11.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 11/20/2017] [Accepted: 11/25/2017] [Indexed: 05/24/2023]
Abstract
After the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011, continuous monitoring of the detailed vertical distribution of radiocesium in soil is required to evaluate the fate of radiocesium and establish strategies for remediation and management of the contaminated land. It is especially important to investigate paddy soil because little knowledge has been accumulated for paddy soil and wetland rice is a major staple in Japan. Therefore, we monitored the vertical distribution of 137Cs in abandoned paddy soil in a planned evacuation zone from June 2011 to March 2016. The decontamination works (i.e., 5 cm of surface soil removal and re-covering with uncontaminated soil) were conducted by the government in 2015. As a result of monitoring, the 137Cs gradually migrated downward with time and the 137Cs concentration in the 0-10 cm soil was almost homogenous in October 2014, although it was non-cultivated. The liner relationship was obtained between the median depth, which is the thickness of a soil layer containing half of the total 137Cs inventory, and the time after the accident, indicating the migration rate was constant (1.3 cm y-1) before the decontamination works. After the decontamination works, the 137Cs concentration in the uppermost surface layer was reduced by 90%, however the total 137Cs inventory was reduced by only 50-70%. It was shown that the efficiency of 137Cs removal by the decontamination works decrease linearly over time in fields like the studied paddy, in which the homogenization of 137Cs concentration occurred. Conversely, the downward migration of 137Cs to subsurface layers deeper than 10 cm (i.e., plowpan layer) with low permeability rarely occurred. It is expected that these unique trends in distribution and migration of 137Cs would be found in abandoned paddy soils with properties similar to the studied soil, sandy loam but poorly drained because of the low permeable plowpan layer, although further validation is necessary.
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Affiliation(s)
- Junko Takahashi
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
| | - Shokichi Wakabayashi
- Tohoku Agricultural Research Center, National Agriculture and Food Research Organization, 50 Harajukuminami, Arai, Fukushima, Fukushima 960-2156, Japan
| | - Kenji Tamura
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
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74
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Leelőssy Á, Lagzi I, Kovács A, Mészáros R. A review of numerical models to predict the atmospheric dispersion of radionuclides. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 182:20-33. [PMID: 29179047 DOI: 10.1016/j.jenvrad.2017.11.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 11/03/2017] [Accepted: 11/06/2017] [Indexed: 06/07/2023]
Abstract
The field of atmospheric dispersion modeling has evolved together with nuclear risk assessment and emergency response systems. Atmospheric concentration and deposition of radionuclides originating from an unintended release provide the basis of dose estimations and countermeasure strategies. To predict the atmospheric dispersion and deposition of radionuclides several numerical models are available coupled with numerical weather prediction (NWP) systems. This work provides a review of the main concepts and different approaches of atmospheric dispersion modeling. Key processes of the atmospheric transport of radionuclides are emission, advection, turbulent diffusion, dry and wet deposition, radioactive decay and other physical and chemical transformations. A wide range of modeling software are available to simulate these processes with different physical assumptions, numerical approaches and implementation. The most appropriate modeling tool for a specific purpose can be selected based on the spatial scale, the complexity of meteorology, land surface and physical and chemical transformations, also considering the available data and computational resource. For most regulatory and operational applications, offline coupled NWP-dispersion systems are used, either with a local scale Gaussian, or a regional to global scale Eulerian or Lagrangian approach. The dispersion model results show large sensitivity on the accuracy of the coupled NWP model, especially through the description of planetary boundary layer turbulence, deep convection and wet deposition. Improvement of dispersion predictions can be achieved by online coupling of mesoscale meteorology and atmospheric transport models. The 2011 Fukushima event was the first large-scale nuclear accident where real-time prognostic dispersion modeling provided decision support. Dozens of dispersion models with different approaches were used for prognostic and retrospective simulations of the Fukushima release. An unknown release rate proved to be the largest factor of uncertainty, underlining the importance of inverse modeling and data assimilation in future developments.
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Affiliation(s)
- Ádám Leelőssy
- Department of Meteorology, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary.
| | - István Lagzi
- Department of Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111, Budapest, Hungary; MTA-BME Condensed Matter Research Group, Budafoki út 8, H-1111, Budapest, Hungary
| | - Attila Kovács
- Department of Meteorology, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary
| | - Róbert Mészáros
- Department of Meteorology, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary
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75
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Huon S, Hayashi S, Laceby JP, Tsuji H, Onda Y, Evrard O. Source dynamics of radiocesium-contaminated particulate matter deposited in an agricultural water reservoir after the Fukushima nuclear accident. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 612:1079-1090. [PMID: 28892848 DOI: 10.1016/j.scitotenv.2017.07.205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/23/2017] [Accepted: 07/23/2017] [Indexed: 06/07/2023]
Abstract
The Fukushima nuclear accident in Japan resulted in the deposition of radiocesium over forested and rural landscapes northwest of the power plant. Although there have been several investigations into the dynamics of contaminated river sediment, less attention has been paid to the sources of deposited particulate matter in dams and reservoirs. In the Fukushima Prefecture, there are 10 significant dams and over a 1000 reservoirs for both agricultural and surface water management. These reservoirs may have trapped a significant volume of radiocesium-contaminated sediment. Therefore, characterizing the sources of contaminated particulate matter is important for the ongoing management of contamination in the region. Accordingly, the composition of particulate matter deposited in the Mano Dam reservoir, approximately 40km northwest of the power plant, was investigated with the analyses and modelling of carbon and nitrogen stable isotope ratios (δ13C and δ15N), total organic carbon (TOC) and total nitrogen (TN) concentrations. Four sediment cores, with lengths ranging 29-41cm, were sampled in the Mano Dam. Source samples from 46 forest soils, 28 cultivated soils and 25 subsoils were used to determine the source contributions of particulate matter. Carbon and nitrogen parameters were analyzed on all samples and a concentration-dependent distribution modelling approach was used to apportion source contributions. Three of the four cores sampled in the Mano Dam reservoir had distinct radiocesium peaks representative of the initial post-accident wash-off phase. Cultivated sources were responsible for 48±7% of the deposited fine particulate matter whereas forests were modelled to contribute 27±6% and subsoil sources 25±4%. Ongoing decontamination of cultivated sources in the Fukushima region should result in a decrease of contaminated matter deposition in reservoirs.
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Affiliation(s)
- Sylvain Huon
- Sorbonne Universités UPMC Univ Paris 06, Institut d'Ecologie et des Sciences de l'environnement de Paris (iEES), case 120, 4 place Jussieu, 75 252 Paris cedex 05, France.
| | - Seiji Hayashi
- National Institute for Environmental Science, Fukushima Branch, 10-2 Fukasaku, Miharu, Tamura, Fukushima 963-7700, Japan
| | - J Patrick Laceby
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Centre de Recherche du CNRS - Bât. 12 - Avenue de la terrasse, 91 198 Gif-sur-Yvette, France
| | - Hideki Tsuji
- National Institute for Environmental Science, Fukushima Branch, 10-2 Fukasaku, Miharu, Tamura, Fukushima 963-7700, Japan
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Olivier Evrard
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Centre de Recherche du CNRS - Bât. 12 - Avenue de la terrasse, 91 198 Gif-sur-Yvette, France
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76
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Saito T, Zhang M, Kavthe RD, Akagi K, Nakayama KS, Adschiri T, Asao N. Dealloying-oxidation Technique as a Powerful Synthetic Tool for Sodium Titanate Nanowires with High Ion-exchange Ability. CHEM LETT 2017. [DOI: 10.1246/cl.170887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Teppei Saito
- Division of Chemistry and Materials, Graduate School of Science and Technology, Shinshu University, Ueda, Nagano 386-8567
| | - Man Zhang
- Division of Chemistry and Materials, Graduate School of Science and Technology, Shinshu University, Ueda, Nagano 386-8567
- Advanced Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577
| | - Rahul D. Kavthe
- Division of Chemistry and Materials, Graduate School of Science and Technology, Shinshu University, Ueda, Nagano 386-8567
| | - Kazuto Akagi
- Advanced Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577
| | | | - Tadafumi Adschiri
- Advanced Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577
- NICHe, Tohoku University, Sendai, Miyagi 980-8577
| | - Naoki Asao
- Division of Chemistry and Materials, Graduate School of Science and Technology, Shinshu University, Ueda, Nagano 386-8567
- Advanced Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577
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77
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Wakiyama Y, Konoplev A, Wada T, Takase T, Byrnes I, Carradine M, Nanba K. Behavior of 137Cs in ponds in the vicinity of the Fukushima Dai-ichi nuclear power plant. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:367-376. [PMID: 28797551 DOI: 10.1016/j.jenvrad.2017.07.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 07/19/2017] [Accepted: 07/26/2017] [Indexed: 06/07/2023]
Abstract
137Cs activity concentration in the water of four ponds, Suzuuchi (SU), Funasawa (FS), Inkyozaka (IZ), and Kashiramori (KM), that are within 10 km of the Fukushima Dai-ichi nuclear power plant were observed from April 2015 to August 2016. 137Cs inventories in soils surrounding SU, FS, IZ, and KM were 6.4, 2.9, 2.1, and 0.9 MBq m-2, respectively. 137Cs inventories in the bottom sediments of SU, FS, IZ, and KM were 13, 8.9, 1.6, and 1.1 MBq m-2, respectively. Higher 137Cs inventories in bottom sediment than those of soil in SU and FS suggest that 137Cs was delivered to and accumulated in these ponds. Mean total 137Cs activity concentrations in SU, FS, IZ, and KM were 41, 13, 9.5, and 1.4 Bq L-1, respectively. Particulate 137Cs concentration accounted for 71-90% of total 137Cs in the water samples, on average. The mean distribution coefficient, Kd, in SU, FS, IZ, and KM was 1.3 × 105, 2.1 × 105, 1.7 × 105, and 6.2 × 105 L kg-1, respectively. These Kd values were higher than the Kd values observed in the Chernobyl area by 1-2 orders of magnitude. Although no significant decreasing trends were found, dissolved 137Cs activity concentration tended to be low during winter in all four ponds. Dissolved 137Cs activity concentrations were proportional to K+ and DOC concentrations in all the ponds. The results from principal component analysis performed for 137Cs activity concentration and water chemistry data sets suggested that there were different mechanisms behind variability of dissolved 137Cs activity concentrations for each pond. Continuous monitoring is required to reveal temporal trends in 137Cs activity concentrations of these waters and controlling factors of such in closed water systems in Fukushima.
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Affiliation(s)
- Yoshifumi Wakiyama
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan.
| | - Alexei Konoplev
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan
| | - Toshihiro Wada
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan
| | - Tsugiko Takase
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan
| | - Ian Byrnes
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Matthew Carradine
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Kenji Nanba
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan
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78
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Murakami M, Saha M, Iwasaki Y, Yamashita R, Koibuchi Y, Tsukada H, Takada H, Sueki K, Yasutaka T. Source analysis of radiocesium in river waters using road dust tracers. CHEMOSPHERE 2017; 187:212-220. [PMID: 28850907 DOI: 10.1016/j.chemosphere.2017.08.095] [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: 03/31/2017] [Revised: 07/28/2017] [Accepted: 08/18/2017] [Indexed: 06/07/2023]
Abstract
Following the Fukushima Dai-ichi Nuclear Power Station accident, regional road dust, heavily contaminated with radiocesium, now represents a potential source of radiocesium pollution in river water. To promote effective countermeasures for reducing the risk from radiocesium pollution, it is important to understand its sources. This study evaluated the utility of metals, including Al, Fe, and Zn as road dust tracers, and applied them to analyze sources of 137Cs in rivers around Fukushima during wet weather. Concentrations of Zn in road dust were higher than agricultural and forest soils, whereas concentrations of Fe and Al were the opposite. Concentrations of Zn were weakly but significantly correlated with benzothiazole, a molecular marker of tires, indicating Zn represents an effective tracer of road dust. Al, Fe, and Zn were frequently detected in suspended solids in river water during wet weather. Distribution coefficients of these metals and 137Cs exceeded 104, suggesting sorptive behavior in water. Although concentrations of Al, Fe, Zn, and 137Cs were higher in fine fractions of road dust and soils than in coarse fractions, use of ratios of 137Cs to Al, Fe, or Zn showed smaller differences among size fractions. The results demonstrate that combinations of these metals and 137Cs are useful for analyzing sources of radiocesium in water. These ratios in river water during wet weather were found to be comparable with or lower than during dry weather and were closer to soils than road dust, suggesting a limited contribution from road dust to radiocesium pollution in river water.
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Affiliation(s)
- Michio Murakami
- Department of Health Risk Communication, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, Fukushima, 960-1295, Japan.
| | - Mahua Saha
- Chemical Oceanography Division, National Institute of Oceanography, Council of Scientific & Industrial Research, Dona Paola-Goa 403004, India
| | - Yuichi Iwasaki
- Research Center for Life and Environmental Sciences, Toyo University, 1-1-1 Izumino, Itakura, Oura, Gunma, 374-0193, Japan
| | - Rei Yamashita
- Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, 3-5-8, Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Yukio Koibuchi
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima, 960-1296, Japan
| | - Hideshige Takada
- Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, 3-5-8, Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Keisuke Sueki
- Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Tetsuo Yasutaka
- Research Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology, 1-1-1, Higashi, Tsukuba, Ibaraki, 305-8567, Japan
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79
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Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan. Proc Natl Acad Sci U S A 2017; 114:11092-11096. [PMID: 28973919 DOI: 10.1073/pnas.1708659114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There are 440 operational nuclear reactors in the world, with approximately one-half situated along the coastline. This includes the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which experienced multiple reactor meltdowns in March 2011 followed by the release of radioactivity to the marine environment. While surface inputs to the ocean via atmospheric deposition and rivers are usually well monitored after a nuclear accident, no study has focused on subterranean pathways. During our study period, we found the highest cesium-137 (137Cs) levels (up to 23,000 Bq⋅m-3) outside of the FDNPP site not in the ocean, rivers, or potable groundwater, but in groundwater beneath sand beaches over tens of kilometers away from the FDNPP. Here, we present evidence of a previously unknown, ongoing source of Fukushima-derived 137Cs to the coastal ocean. We postulate that these beach sands were contaminated in 2011 through wave- and tide-driven exchange and sorption of highly radioactive Cs from seawater. Subsequent desorption of 137Cs and fluid exchange from the beach sands was quantified using naturally occurring radium isotopes. This estimated ocean 137Cs source (0.6 TBq⋅y-1) is of similar magnitude as the ongoing releases of 137Cs from the FDNPP site for 2013-2016, as well as the input of Fukushima-derived dissolved 137Cs via rivers. Although this ongoing source is not at present a public health issue for Japan, the release of Cs of this type and scale needs to be considered in nuclear power plant monitoring and scenarios involving future accidents.
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80
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Takahashi Y, Fan Q, Suga H, Tanaka K, Sakaguchi A, Takeichi Y, Ono K, Mase K, Kato K, Kanivets VV. Comparison of Solid-Water Partitions of Radiocesium in River Waters in Fukushima and Chernobyl Areas. Sci Rep 2017; 7:12407. [PMID: 28963532 PMCID: PMC5622054 DOI: 10.1038/s41598-017-12391-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/30/2017] [Indexed: 11/13/2022] Open
Abstract
Adsorption of radiocesium (RCs) on particulate matters in aquatic environment is important to understand its mobility and bioavailability. We here focused on factors controlling partition of RCs on particulate matters and sediments in Kuchibuto (Fukushima) and Pripyat (Chernobyl) Rivers, though RCs level in water was much smaller than WHO guideline. Moreover, Cs speciation and organic matter-clay mineral interaction were studied: (i) extended X-ray absorption fine structure showed that the contribution of outer-sphere complex of Cs on particulate matters is larger in Chernobyl than in Fukushima and (ii) scanning transmission X-ray microscope revealed larger association of humic substances and clay minerals in Chernobyl partly due to high [Ca2+] in the Pripyat River. Consequently, RCs is more soluble in the Pripyat River due to weaker interaction of RCs with clay minerals caused by the inhibition effect of the adsorbed humic substances. In contrast, particulate matters and sediments in the Kuchibuto River display high adsorption affinity with lesser inhibition effect of adsorbed humic substances. This difference is possibly governed by the geology and soil type of provenances surrounding both catchments (Fukushima: weathered granite; Chernobyl: peat wetland and carbonate platform) which leads to high concentrations of organic matter and Ca2+ in the Pripyat River.
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Affiliation(s)
- Yoshio Takahashi
- Department of Earth and Planetary Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113- 8654, Japan. .,Institute of Materials Structure Science, High-Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki, 305-0801, Japan.
| | - Qiaohui Fan
- Department of Earth and Planetary Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113- 8654, Japan.,Northwest Institute of Eco-Environment & Resources, CAS, 382 West Donggang Road, Lanzhou, Gansu, 730000, China
| | - Hiroki Suga
- Department of Earth and Planetary Systems Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Kazuya Tanaka
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Aya Sakaguchi
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Yasuo Takeichi
- Institute of Materials Structure Science, High-Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Kanta Ono
- Institute of Materials Structure Science, High-Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Kazuhiko Mase
- Institute of Materials Structure Science, High-Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Kenji Kato
- Department of Geosciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
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81
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Smith JN, Rossi V, Buesseler KO, Cullen JT, Cornett J, Nelson R, Macdonald AM, Robert M, Kellogg J. Recent Transport History of Fukushima Radioactivity in the Northeast Pacific Ocean. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10494-10502. [PMID: 28876047 DOI: 10.1021/acs.est.7b02712] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The large inventory of radioactivity released during the March, 2011 Fukushima Dai-ichi nuclear reactor accident in Japan spread rapidly across the North Pacific Ocean and was first observed at the westernmost station on Line P, an oceanographic sampling line extending 1500 km westward of British Columbia (BC), Canada in June 2012. Here, time series measurements of 134Cs and 137Cs in seawater on Line P and on the CLIVAR-P16N 152°W line reveal the recent transport history of the Fukushima radioactivity tracer plume through the northeast Pacific Ocean. During 2013 and 2014 the Fukushima plume spread onto the Canadian continental shelf and by 2015 and early 2016 it reached 137Cs values of 6-8 Bq/m3 in surface water along Line P. Ocean circulation model simulations that are consistent with the time series measurements of Fukushima 137Cs indicate that the 2015-2016 results represent maximum tracer levels on Line P and that they will begin to decline in 2017-2018. The current elevated Fukushima 137Cs levels in seawater in the eastern North Pacific are equivalent to fallout background levels of 137Cs that prevailed during the 1970s and do not represent a radiological threat to human health or the environment.
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Affiliation(s)
- John N Smith
- Bedford Institute of Oceanography , Fisheries and Oceans Canada, Dartmouth, Nova Scotia B2Y 4A2, Canada
| | - Vincent Rossi
- Mediterranean Institute of Oceanography (UM 110, UMR 7294), CNRS, Aix Marseille Université , Université Toulon, IRD, 13288 Marseille, France
- Climate Change Research Centre, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Ken O Buesseler
- Woods Hole Oceanographic Institute , Woods Hole, Massachusetts 02543-1050, United States
| | - Jay T Cullen
- University of Victoria , Victoria, British Columbia V8P 5C2, Canada
| | - Jack Cornett
- University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Richard Nelson
- Bedford Institute of Oceanography , Fisheries and Oceans Canada, Dartmouth, Nova Scotia B2Y 4A2, Canada
| | - Alison M Macdonald
- Woods Hole Oceanographic Institute , Woods Hole, Massachusetts 02543-1050, United States
| | - Marie Robert
- Institute of Ocean Sciences , Fisheries and Oceans Canada, Sidney, British Columbia V8L 4B2, Canada
| | - Jonathan Kellogg
- University of Victoria , Victoria, British Columbia V8P 5C2, Canada
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82
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Sources of 137Cs fluvial export from a forest catchment evaluated by stable carbon and nitrogen isotopic characterization of organic matter. J Radioanal Nucl Chem 2017. [DOI: 10.1007/s10967-017-5350-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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83
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Kurikami H, Malins A, Takeishi M, Saito K, Iijima K. Coupling the advection-dispersion equation with fully kinetic reversible/irreversible sorption terms to model radiocesium soil profiles in Fukushima Prefecture. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 171:99-109. [PMID: 28219041 DOI: 10.1016/j.jenvrad.2017.01.026] [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: 10/26/2016] [Revised: 01/25/2017] [Accepted: 01/29/2017] [Indexed: 06/06/2023]
Abstract
Radiocesium is an important environmental contaminant in fallout from nuclear reactor accidents and atomic weapons testing. A modified Diffusion-Sorption-Fixation (mDSF) model, based on the advection-dispersion equation, is proposed to describe the vertical migration of radiocesium in soils following fallout. The model introduces kinetics for the reversible binding of radiocesium. We test the model by comparing its results to depth profiles measured in Fukushima Prefecture, Japan, since 2011. The results from the mDSF model are a better fit to the measurement data (as quantified by R2) than results from a simple diffusion model and the original DSF model. The introduction of reversible sorption kinetics means that the exponential-shape depth distribution can be reproduced immediately following fallout. The initial relaxation mass depth of the distribution is determined by the diffusion length, which depends on the distribution coefficient, sorption rate and dispersion coefficient. The mDSF model captures the long tails of the radiocesium distribution at large depths, which are caused by different rates for kinetic sorption and desorption. The mDSF model indicates that depth distributions displaying a peak in activity below the surface are possible for soils with high organic matter content at the surface. The mDSF equations thus offers a physical basis for various types of radiocesium depth profiles observed in contaminated environments.
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Affiliation(s)
- Hiroshi Kurikami
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan.
| | - Alex Malins
- Japan Atomic Energy Agency (JAEA), Center for Computational Science & e-Systems, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa, Chiba 277-0871, Japan.
| | - Minoru Takeishi
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan.
| | - Kimiaki Saito
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 2-2-2 Uchisaiwai-cho, Chiyoda, Tokyo 100-8577, Japan.
| | - Kazuki Iijima
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan.
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84
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Sakuma K, Kitamura A, Malins A, Kurikami H, Machida M, Mori K, Tada K, Kobayashi T, Tawara Y, Tosaka H. Characteristics of radio-cesium transport and discharge between different basins near to the Fukushima Dai-ichi Nuclear Power Plant after heavy rainfall events. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 169-170:137-150. [PMID: 28161603 DOI: 10.1016/j.jenvrad.2016.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/19/2016] [Accepted: 12/17/2016] [Indexed: 06/06/2023]
Abstract
This paper describes watershed modeling of catchments surrounding the Fukushima Dai-ichi Nuclear Power Plant to understand radio-cesium redistribution by water flows and sediment transport. We extended our previously developed three-dimensional hydrogeological model of the catchments to calculate the migration of radio-cesium in both sediment-sorbed and dissolved forms. The simulations cover the entirety of 2013, including nine heavy rainfall events, as well as Typhoon Roke in September 2011. Typhoons Man-yi and Wipha were the strongest typhoons in 2013 and had the largest bearing on radio-cesium redistribution. The simulated 137Cs discharge quantities over the nine events in 2013 are in good agreement with field monitoring observations. Deposition mainly occurs on flood plains and points where the river beds broaden in the lower basins, and within dam reservoirs along the rivers. Differences in 137Cs discharge ratios between the five basins are explained by differences in the initial fallout distribution within the basins, the presence of dam reservoirs, and the input supply to watercourses. It is possible to use these simulation results to evaluate future radioactive material distributions in order to support remediation planning.
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Affiliation(s)
- Kazuyuki Sakuma
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan.
| | - Akihiro Kitamura
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Alex Malins
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Hiroshi Kurikami
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Masahiko Machida
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Koji Mori
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Kazuhiro Tada
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Takamaru Kobayashi
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Yasuhiro Tawara
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Hiroyuki Tosaka
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
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85
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Delmas M, Garcia-Sanchez L, Nicoulaud-Gouin V, Onda Y. Improving transfer functions to describe radiocesium wash-off fluxes for the Niida River by a Bayesian approach. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 167:100-109. [PMID: 27843066 DOI: 10.1016/j.jenvrad.2016.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/20/2016] [Accepted: 11/01/2016] [Indexed: 06/06/2023]
Abstract
This paper proposed methodological refinements of the generic transfer function approach to reconstruct radiocesium wash-off fluxes from contaminated catchments, by the integration of hydrological descriptors (passed volume of water, flow rate fluctuations and antecedent flow conditions). The approach was applied to the Niida River (Fukushima prefecture, Japan) for the period 03/2011-03/2015, for which daily flow rate (m3/s) and infrequent total radiocesium concentration (Bq/L) values were available from literature. Three models were defined, generic TF (Φ0), flow-corrected time variant (Φ1) and antecedent-flow corrected variant (Φ2). Calibration of these models' parameters was performed with a Bayesian approach because it is particularly adapted to limited datasets and censored information, and it provides parameters distributions. The model selection showed strong evidence of model Φ2 (indicated by marginal likelihood), which integrates current and recent hydrology in its formulation, and lower prediction errors (indicated by RMSE and ME). Models Φ1 and Φ2 better described wash-off dynamics compared to model Φ0, due to the inclusion of one or several hydrological descriptors. From March 2011 to March 2015, model Φ2 estimated 137Cs export from Niida catchment between 0.32 and 0.67 TBq, with a median value of 0.49 TBq, which represents around 0.27% of the initial fallout and could represent a significant source-term to the Ocean compared to the direct release from Fukushima Dai-ichi Nuclear Power Plant (FDNPP). Moreover the remaining 99% of the initial radiocesium fallout within the catchment may constitute a persistent contamination source for wash-off. Although the proposed methodology brought improvements in the assessment of wash-off fluxes, it remains an empirical interpolation method with a limited predictive power, particularly for recent low activities. To improve predictions, modelling approaches require more observed data (particularly more activity values corresponding to more hydrological conditions), and the inclusion of more hydrological descriptors.
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Affiliation(s)
- M Delmas
- Laboratory of Biogeochemistry, Bioavailability and Transfers of Radionuclides (L2BT), IRSN, Centre de Cadarache, bât. 183, BP 3, 13115 Saint-Paul-lez-Durance, France.
| | - L Garcia-Sanchez
- Laboratory of Biogeochemistry, Bioavailability and Transfers of Radionuclides (L2BT), IRSN, Centre de Cadarache, bât. 183, BP 3, 13115 Saint-Paul-lez-Durance, France
| | - V Nicoulaud-Gouin
- Radionuclide Transfers in the Environment Research Laboratory (LRTE), IRSN, Centre de Cadarache, bât. 159, St, Paul-lez-Durance, 13115, France
| | - Y Onda
- Center for Research in Isotopes and Environmental Dynamics (CRIED), Tsukuba University, Tsukuba, Japan
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86
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Buesseler K, Dai M, Aoyama M, Benitez-Nelson C, Charmasson S, Higley K, Maderich V, Masqué P, Morris PJ, Oughton D, Smith JN. Fukushima Daiichi-Derived Radionuclides in the Ocean: Transport, Fate, and Impacts. ANNUAL REVIEW OF MARINE SCIENCE 2017; 9:173-203. [PMID: 27359052 DOI: 10.1146/annurev-marine-010816-060733] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is appropriate to review what happened in terms of the sources, transport, and fate of these radionuclides in the ocean. In addition to the oceanic behavior of these contaminants, this review considers the potential health effects and societal impacts.
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Affiliation(s)
- Ken Buesseler
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543;
| | - Minhan Dai
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China;
| | - Michio Aoyama
- Institute of Environmental Radioactivity, Fukushima University, Fukushima 960-1296, Japan;
| | | | - Sabine Charmasson
- Institut de Radioprotection et de Sûreté Nucléaire, PRP-ENV, La Seyne/Mer 83507, France;
| | - Kathryn Higley
- School of Nuclear Science and Engineering, Oregon State University, Corvallis, Oregon 97331;
| | - Vladimir Maderich
- Institute of Mathematical Machine and System Problems, Kiev 03680, Ukraine;
| | - Pere Masqué
- School of Science, Edith Cowan University, Joondalup 6027, Australia;
- Departament de Física, Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelon, 08193 Bellaterra, Spain
| | - Paul J Morris
- Environment Laboratories, International Atomic Energy Agency, MC 98000, Monaco;
| | - Deborah Oughton
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences, Ås 1430, Norway;
| | - John N Smith
- Bedford Institute of Oceanography, Dartmouth B2Y 4A2, Canada;
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87
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Iwagami S, Onda Y, Tsujimura M, Abe Y. Contribution of radioactive 137Cs discharge by suspended sediment, coarse organic matter, and dissolved fraction from a headwater catchment in Fukushima after the Fukushima Dai-ichi Nuclear Power Plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 166:466-474. [PMID: 27475667 DOI: 10.1016/j.jenvrad.2016.07.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 07/09/2016] [Accepted: 07/19/2016] [Indexed: 06/06/2023]
Abstract
Radiocesium (137Cs) migration from headwaters in forested areas provides important information, as the output from forest streams subsequently enters various land-use areas and downstream rivers. Thus, it is important to determine the composition of 137Cs fluxes (dissolved fraction, suspended sediment, or coarse organic matter) that migrate through a headwater stream. In this study, the 137Cs discharge by suspended sediment and coarse organic matter from a forest headwater catchment was monitored. The 137Cs concentrations in suspended sediment and coarse organic matter, such as leaves and branches, and the amounts of suspended sediment and coarse organic matter were measured at stream sites in three headwater catchments in Yamakiya District, located ∼35 km northwest of Fukushima Dai-ichi Nuclear Power Plant (FDNPP) from August 2012 to September 2013, following the earthquake and tsunami disaster. Suspended sediment and coarse organic matter were sampled at intervals of approximately 1-2 months. The 137Cs concentrations of suspended sediment and coarse organic matter were 2.4-49 kBq/kg and 0.85-14 kBq/kg, respectively. The 137Cs concentrations of the suspended sediment were closely correlated with the average deposition density of the catchment. The annual proportions of contribution of 137Cs discharge by suspended sediment, coarse organic matter, and dissolved fraction were 96-99%, 0.0092-0.069%, and 0.73-3.7%, respectively. The total annual 137Cs discharge from the catchment was 0.02-0.3% of the deposition.
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Affiliation(s)
- Sho Iwagami
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 305-8577, Japan.
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 305-8577, Japan
| | - Maki Tsujimura
- Department of Sustainable Environmental Studies, Graduate School of Life and Environmental Sciences, University of Tsukuba, 305-8572, Japan
| | - Yutaka Abe
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 305-8577, Japan
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88
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De França EJ, De Nadai Fernandes EA, Miranda MVFES, Santos TO, Cantinha RS. Cesium accumulation in native trees from the Brazilian Cerrado. J Radioanal Nucl Chem 2016. [DOI: 10.1007/s10967-016-4943-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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89
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Laceby JP, Huon S, Onda Y, Vaury V, Evrard O. Do forests represent a long-term source of contaminated particulate matter in the Fukushima Prefecture? JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 183:742-753. [PMID: 27647133 DOI: 10.1016/j.jenvman.2016.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/02/2016] [Accepted: 09/03/2016] [Indexed: 06/06/2023]
Abstract
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in radiocesium fallout contaminating coastal catchments of the Fukushima Prefecture. As the decontamination effort progresses, the potential downstream migration of radiocesium contaminated particulate matter from forests, which cover over 65% of the most contaminated region, requires investigation. Carbon and nitrogen elemental concentrations and stable isotope ratios are thus used to model the relative contributions of forest, cultivated and subsoil sources to deposited particulate matter in three contaminated coastal catchments. Samples were taken from the main identified sources: cultivated (n = 28), forest (n = 46), and subsoils (n = 25). Deposited particulate matter (n = 82) was sampled during four fieldwork campaigns from November 2012 to November 2014. A distribution modelling approach quantified relative source contributions with multiple combinations of element parameters (carbon only, nitrogen only, and four parameters) for two particle size fractions (<63 μm and <2 mm). Although there was significant particle size enrichment for the particulate matter parameters, these differences only resulted in a 6% (SD 3%) mean difference in relative source contributions. Further, the three different modelling approaches only resulted in a 4% (SD 3%) difference between relative source contributions. For each particulate matter sample, six models (i.e. <63 μm and <2 mm from the three modelling approaches) were used to incorporate a broader definition of potential uncertainty into model results. Forest sources were modelled to contribute 17% (SD 10%) of particulate matter indicating they present a long term potential source of radiocesium contaminated material in fallout impacted catchments. Subsoils contributed 45% (SD 26%) of particulate matter and cultivated sources contributed 38% (SD 19%). The reservoir of radiocesium in forested landscapes in the Fukushima region represents a potential long-term source of particulate contaminated matter that will require diligent management for the foreseeable future.
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Affiliation(s)
- J Patrick Laceby
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Centre de Recherche du CNRS - Bât, 12 - Avenue de la terrasse, 91 198 Gif-sur-Yvette, France.
| | - Sylvain Huon
- Sorbonne Universités, UPMC Univ Paris 06, Institut d'Ecologie et des Sciences de l'Environnement de Paris (iEES), Case 120, 4 Place Jussieu, 75252 Paris Cedex 05, France
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Veronique Vaury
- Sorbonne Universités, UPMC Univ Paris 06, Institut d'Ecologie et des Sciences de l'Environnement de Paris (iEES), Case 120, 4 Place Jussieu, 75252 Paris Cedex 05, France
| | - Olivier Evrard
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Centre de Recherche du CNRS - Bât, 12 - Avenue de la terrasse, 91 198 Gif-sur-Yvette, France
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90
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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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91
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Kurikami H, Funaki H, Malins A, Kitamura A, Onishi Y. Numerical study of sediment and 137Cs discharge out of reservoirs during various scale rainfall events. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 164:73-83. [PMID: 27442257 DOI: 10.1016/j.jenvrad.2016.07.004] [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: 01/28/2016] [Revised: 06/24/2016] [Accepted: 07/03/2016] [Indexed: 06/06/2023]
Abstract
Contamination of reservoirs with radiocesium is one of the main concerns in Fukushima Prefecture, Japan. We performed simulations using the three-dimensional finite volume code FLESCOT to understand sediment and radiocesium transport in generic models of reservoirs with parameters similar to those in Fukushima Prefecture. The simulations model turbulent water flows, transport of sediments with different grain sizes, and radiocesium migration both in dissolved and particulate forms. To demonstrate the validity of the modeling approach for the Fukushima environment, we performed a test simulation of the Ogaki Dam reservoir over Typhoon Man-yi in September 2013 and compared the results with field measurements. We simulated a set of generic model reservoirs systematically varying features such as flood intensity, reservoir volume and the radiocesium distribution coefficient. The results ascertain how these features affect the amount of sediment or 137Cs discharge downstream from the reservoirs, and the forms in which 137Cs is discharged. Silt carries the majority of the radiocesium in the larger flood events, while the clay-sorbed followed by dissolved forms are dominant in smaller events. The results can be used to derive indicative values of discharges from Fukushima reservoirs under arbitrary flood events. For example the generic model simulations indicate that about 30% of radiocesium that entered the Ogaki Dam reservoir over the flood in September 2015 caused by Typhoon Etau discharged downstream. Continued monitoring and numerical predictions are necessary to quantify future radiocesium migration in Fukushima Prefecture and evaluate possible countermeasures since reservoirs can be a sink of radiocesium.
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Affiliation(s)
- Hiroshi Kurikami
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan.
| | - Hironori Funaki
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan.
| | - Alex Malins
- Japan Atomic Energy Agency (JAEA), Center for Computational Science & e-Systems, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa, Chiba 277-0871, Japan.
| | - Akihiro Kitamura
- Japan Atomic Energy Agency (JAEA), Sector of Fukushima Research and Development, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima 963-7700, Japan.
| | - Yasuo Onishi
- Yasuo Onishi Consulting, LLC, Richland, WA 99354, USA.
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92
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Yoshihara T, Matsumura H, Hashida SN, Nakaya K. Radiocesium contamination in living and dead foliar parts of Japanese cedar during 2011-2015. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 164:291-299. [PMID: 27537824 DOI: 10.1016/j.jenvrad.2016.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 07/27/2016] [Accepted: 08/07/2016] [Indexed: 06/06/2023]
Abstract
Radiocesium (137Cs) activity concentrations, mainly derived from the Fukushima accident of March 2011, were measured in green foliar parts without separation by age (bulk green foliar parts; GL) and litterfall (LF) of Japanese cedar (Cryptomeria japonica) from 2011 to 2015. In all samples, 137Cs concentrations decreased exponentially over time, but were always higher in LF (7.36-0.58 Bq g-DW-1) than in GL (2.10-0.06 Bq g-DW-1). The difference in the decreasing rate between GL and LF would reflect a difference in the dominant factor of the decrease between living and dead tissues (i.e., internal translocation and weathering, respectively). Over this same timeframe, potassium (K) concentrations in both GL and LF experienced repetitive periodical changes within a certain range (0.38-3.0 mg g-DW-1 for LF and 2.08-4.77 mg g-DW-1 for GL, respectively). Thus, there was no specific correlation between 137Cs and K concentrations in LF and GL. However, analyses of the age classified green foliar parts (GL-S) and dead foliar parts still retained on trees (DL) could indicate another view. The annual changes in residual rates of both 137Cs and K concentrations in GL-S demonstrated very similar two-phase reductions (i.e., a faster reduction in each expansion year than in the following years) and an obvious linear correlation between each other. Radiocesium concentration in DL were always higher than in any part of GL-S sampled at the same timing, but K concentrations showed the reverse relation. It is probable that 137Cs is basically translocated from older parts to the developing parts (as long as the former are alive) via a seasonal nutritional flow of K; however, a part of 137Cs translocation would cease considerably earlier than the cessation of K translocation.
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Affiliation(s)
- Toshihiro Yoshihara
- Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194, Japan.
| | - Hideyuki Matsumura
- Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194, Japan
| | - Shin-Nosuke Hashida
- Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194, Japan
| | - Ko Nakaya
- Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194, Japan
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93
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Evrard O, Laceby JP, Onda Y, Wakiyama Y, Jaegler H, Lefèvre I. Quantifying the dilution of the radiocesium contamination in Fukushima coastal river sediment (2011-2015). Sci Rep 2016; 6:34828. [PMID: 27694832 PMCID: PMC5046143 DOI: 10.1038/srep34828] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/21/2016] [Indexed: 11/13/2022] Open
Abstract
Fallout from the Fukushima Dai-ichi nuclear power plant accident resulted in a 3000-km2 radioactive contamination plume. Here, we model the progressive dilution of the radiocesium contamination in 327 sediment samples from two neighboring catchments with different timing of soil decontamination. Overall, we demonstrate that there has been a ~90% decrease of the contribution of upstream contaminated soils to sediment transiting the coastal plains between 2012 (median – M – contribution of 73%, mean absolute deviation – MAD – of 27%) and 2015 (M 9%, MAD 6%). The occurrence of typhoons and the progress of decontamination in different tributaries of the Niida River resulted in temporary increases in local contamination. However, the much lower contribution of upstream contaminated soils to coastal plain sediment in November 2015 demonstrates that the source of the easily erodible, contaminated material has potentially been removed by decontamination, diluted by subsoils, or eroded and transported to the Pacific Ocean.
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Affiliation(s)
- Olivier Evrard
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France)
| | - J Patrick Laceby
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France)
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba (Japan)
| | - Yoshifumi Wakiyama
- Institute of Environmental Radioactivity (IER), University of Fukushima, Fukushima (Japan)
| | - Hugo Jaegler
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France)
| | - Irène Lefèvre
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France)
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94
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Niizato T, Abe H, Mitachi K, Sasaki Y, Ishii Y, Watanabe T. Input and output budgets of radiocesium concerning the forest floor in the mountain forest of Fukushima released from the TEPCO's Fukushima Dai-ichi nuclear power plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 161:11-21. [PMID: 27131868 DOI: 10.1016/j.jenvrad.2016.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 04/14/2016] [Accepted: 04/16/2016] [Indexed: 06/05/2023]
Abstract
Estimations of radiocesium input and output concerning the forest floor within a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, northeast Japan, after a 2-3 year period following the TEPCO Fukushima Dai-ichi nuclear power plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at experimental plots installed on the forest floor of evergreen Japanese cedars and deciduous Konara oaks have been monitored. Despite the high output potential in the mountainous forest of Fukushima, the results at both monitoring locations show the radiocesium input to be 4-50 times higher than the output during the summer monsoon in Fukushima. These results indicate that the radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios (0.05%-0.19%). Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels, along with the subsequent reconstruction of life emphasized within the setting.
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Affiliation(s)
- Tadafumi Niizato
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 963-7700, Japan.
| | - Hironobu Abe
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 963-7700, Japan
| | - Katsuaki Mitachi
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 963-7700, Japan
| | - Yoshito Sasaki
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 963-7700, Japan
| | - Yasuo Ishii
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 963-7700, Japan
| | - Takayoshi Watanabe
- Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Fukushima 963-7700, Japan
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95
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Gallardo AH, Marui A. The aftermath of the Fukushima nuclear accident: Measures to contain groundwater contamination. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 547:261-268. [PMID: 26789364 DOI: 10.1016/j.scitotenv.2015.12.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/20/2015] [Accepted: 12/24/2015] [Indexed: 06/05/2023]
Abstract
Several measures are being implemented to control groundwater contamination at the Fukushima Daiichi Nuclear Plant. This paper presents an overview of work undertaken to contain the spread of radionuclides, and to mitigate releases to the ocean via hydrological pathways. As a first response, contaminated water is being held in tanks while awaiting treatment. Limited storage capacity and the risk of leakage make the measure unsustainable in the long term. Thus, an impervious barrier has been combined with a drain system to minimize the discharge of groundwater offshore. Caesium in seawater at the plant port has largely dropped, although some elevated concentrations are occasionally recorded. Moreover, a dissimilar decline of the radioactivity in fish could indicate additional sources of radionuclides intake. An underground frozen shield is also being constructed around the reactors. This structure would reduce inflows to the reactors and limit the interaction between fresh and contaminated waters. Additional strategies include groundwater abstraction and paving of surfaces to lower water levels and further restrict the mobilisation of radionuclides. Technical difficulties and public distrust pose an unprecedented challenge to the site remediation. Nevertheless, the knowledge acquired during the initial work offers opportunities for better planning and more rigorous decisions in the future.
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Affiliation(s)
- Adrian H Gallardo
- CONICET (Argentina National Scientific and Technical Research Council), San Luis National University, FCFMyN, Department of Geology, San Luis 5700, Argentina.
| | - Atsunao Marui
- AIST Geological Survey of Japan, Geo-Resources and Environment Institute, Groundwater Research Group, Ibaraki-ken, Tsukuba 305-8567, Japan
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96
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Miura S, Akazawa Y, Kurashige T, Tukasaki K, Kondo H, Yokota K, Mine M, Miyazaki Y, Sekine I, Nakashima M. The Nagasaki Atomic Bomb Survivors' Tumor Tissue Bank. Lancet 2015; 386:1738. [PMID: 26545440 DOI: 10.1016/s0140-6736(15)00698-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Shiro Miura
- Tissue and Histopathology Section, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Yuko Akazawa
- Department of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan; Department of Gastroenterology and Hepatology, Nagasaki University Hospital, Nagasaki, Japan
| | - Tomomi Kurashige
- Tissue and Histopathology Section, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Kunihiro Tukasaki
- Department of Hematology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan; Department of Hematology, National Cancer Center Hospital East, Chiba, Japan
| | - Hisayoshi Kondo
- Biostatistics Section, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Kenichi Yokota
- Biostatistics Section, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Mariko Mine
- Biostatistics Section, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Yasushi Miyazaki
- Department of Hematology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Ichiro Sekine
- Nagasaki Red Cross Blood Center, Japanese Red Cross Society, Nagasaki, Japan
| | - Masahiro Nakashima
- Tissue and Histopathology Section, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan; Department of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan.
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