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152. Factors Controlling the Dissolved 137Cs Seasonal Fluctuations in the Abukuma River Under the Influence of the Fukushima Nuclear Power Plant Accident.

Author

Igarashi, Yasunori, Nanba, Kenji, Wada, Toshihiro, Wakiyama, Yoshifumi, Onda, Yuichi, Moritaka, Shota, and Konoplev, Alexei

Subjects
DISSOLVED oxygen in seawater, FUKUSHIMA Nuclear Accident, Fukushima, Japan, 2011, WATER temperature, POTASSIUM, ENTHALPY
Abstract

The 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released large amounts of radioactive materials into the environment. River systems play an important role in the terrestrial redistribution of FDNPP‐derived 137Cs in association with water and sediment movement. We examined the seasonal fluctuations in dissolved and particulate 137Cs activity concentrations and clarified the biological and physicochemical factors controlling 137Cs seasonality in the Abukuma River's middle course in the region affected by the FDNPP accident. The results showed seasonal fluctuations in the dissolved 137Cs activity concentration, with an increase in summer and a decrease in winter, although there was no clear seasonal change in the particulate 137Cs activity concentration. Water temperature and K+ concentration dominated the seasonality of the dissolved 137Cs activity concentration. The volumetric activity concentration of the organically bound 137Cs was found to be several orders of magnitude lower than that of the dissolved 137Cs. Therefore, we concluded that the 137Cs in organic matter is not a source of dissolved 137Cs in river water. The study also revealed the temperature dependence of Kd in riverine environments from a Van't Hoff equation. The standard reaction enthalpy of 137Cs in the Abukuma River was calculated to be approximately −19.3 kJ/mol. This was the first study to clearly reveal the mechanisms by which the dissolved 137Cs activity concentration and Kd are influenced by chemical and thermodynamic processes in the middle course of a large river, and it is expected to lead to an improved model of 137Cs dynamics in rivers. Plain Language Summary: The 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released large amounts of radioactive materials into the environment. River systems play an important role in the terrestrial redistribution of FDNPP‐derived 137Cs in association with water and sediment movement. The dissolved 137Cs activity concentration in the Abukuma River showed clear seasonal fluctuations, with an increase in summer and a decrease in winter, although there was no clear seasonal change in the particulate 137Cs activity concentration. Water temperature and K+ concentration dominated the seasonality of the dissolved 137Cs activity concentration. Previously, decomposition of 137Cs‐contaminated organic matter was thought to be the reason for the seasonality of the dissolved 137Cs activity concentration in rivers. However, in the middle course of the river, the organically bound 137Cs activity concentration is much lower than that of the dissolved 137Cs activity concentration, indicating that the decomposition of organic matter does not directly affect the dissolved 137Cs in the middle course. This study revealed that seasonal fluctuations in river temperature determine the seasonality of the dissolved 137Cs activity concentration in the middle course in the region affected by the FDNPP accident. Key Points: Dissolved 137Cs in the Abukuma River displays significant seasonal fluctuationsThe main factors determining the seasonality of dissolved 137Cs activity concentrations are water temperature and K+The standard enthalpy of 137Cs desorption from sediments was determined to be approximately −19.3 kJ/mol [ABSTRACT FROM AUTHOR]

Published
2022
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169. Temporal Change in Radiological Environments on Land after the Fukushima Daiichi Nuclear Power Plant Accident

Author

Saito, Kimiaki, primary, Mikami, Satoshi, additional, Andoh, Masaki, additional, Matsuda, Norihiro, additional, Kinase, Sakae, additional, Tsuda, Shuichi, additional, Sato, Tetsuro, additional, Seki, Akiyuki, additional, Sanada, Yukihisa, additional, Wainwright-Murakami, Haruko, additional, Yoshimura, Kazuya, additional, Takemiya, Hiroshi, additional, Takahashi, Junko, additional, Kato, Hiroaki, additional, and Onda, Yuichi, additional

Published
2019
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171. Factors controlling dissolved 137Cs concentrations in east Japanese Rivers

Author

Tsuji, Hideki, primary, Ishii, Yumiko, additional, Shin, Moono, additional, Taniguchi, Keisuke, additional, Arai, Hirotsugu, additional, Kurihara, Momo, additional, Yasutaka, Tetsuo, additional, Kuramoto, Takayuki, additional, Nakanishi, Takahiro, additional, Lee, Sangyoon, additional, Shinano, Takuro, additional, Onda, Yuichi, additional, and Hayashi, Seiji, additional

Published
2019
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175. Comparison of Concentration Methods for Low-level Radiocesium in Fresh Water

Author

YASUTAKA, Tetsuo, SHIN, Moono, ONDA, Yuichi, SHINANO, Takuro, HAYASHI, Seiji, TSUKADA, Hirofumi, AONO, Tatsuo, IIJIMA, Kazuki, EGUCHI, Sadao, OHNO, Koichi, YOSHIDA, Yukihiro, KAMIHIGASHI, Hiroshi, KITAMURA, Kiyoshi, KUBOTA, Tomijiro, NOGAWA, Norio, YOSHIKAWA, Natsuki, YAMAGUCHI, Hiroaki, SUEKI, Keisuke, TSUJI, Hideki, MIYAZU, Susumu, OKADA, Yukiko, KURIHARA, Momo, TARJAN, Sandor, MATSUNAMI, Hisaya, and UCHIDA, Shigeo

Abstract

A large amount of radiocesium was released from the accident at Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company. The determination of dissolved and particulate radiocesium concentrations in water is important, which can be used as basic information for understanding the long-term radiocesium dynamics in the environment and the transfer of radiocesium to crops. Conventional quantitative methods include the evaporative concentration to the dryness method and the AMP method. These methods need to concentrate about 20–200 L of water due to the low concentration of the dissolved radiocesium. After the accident, several new methods, such as the Prussian blue filter cartridge method and the solid-phase disk method, have been developed and put to practical use. In this study, we carried out an accuracy evaluation test to assess five methods (i.e., the evaporative concentration to dryness method, the AMP method, the Prussian blue filter cartridge method, the solid-phase disk method, and the ion-change resin method) using 3 types of water samples containing 0.01-1.0 Bq L−1 of dissolved radiocesium. Our results showed that the z-scores of over 80 % of the measured data were within ±2 and their CVs in the range of 8-13 %, indicating good reproducibility of these methods.

Published
2017

176. Potential of spectrocolorimetry to trace sediment sources in coastal catchments draining the main Fukushima radioactive pollution plume (2011-2018)

Author

Evrard, Olivier, Durand, Roxanne, Foucher, Anthony, Tiecher, Tales, Sellier, Virginie, Onda, Yuichi, Lefèvre, Irène, Cerdan, Olivier, Laceby, J., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochimie Des Impacts (GEDI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), Université de Tsukuba = University of Tsukuba, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Alberta Environment and Parks (AEP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Spectrocolorimetric properties provide a quick, low-cost and non-destructive alternative to the measurement of geochemical and organic matter parameters. Their potential to discriminate between forest, cultivated and subsoil sources was tested in soils and sediment collected in coastal catchments draining the main radioactive pollution plume of Fukushima Prefecture, Japan. Fifteen spectrocolorimetric properties were determined in potential source (n=37) and sediment (n=400) samples collected during 13 campaigns from 2011-2017 in two catchments (covering a total surface area of 450 km$^2$) draining the main radioactive pollution plume. Potential sources included topsoil from forest and cropland sources along with subsoil material originating from landslides, channel banks and the decontamination of cultivated areas. The optimum set of parameters used in the mixed linear model to calculate the sediment source contributions was obtained through the use of a range test, the Kruskal-Wallis H-test, and a linear discriminant analysis. Nine colour parameters correctly classified 100% of the source samples (forest, subsoil and cultivated sources). The results illustrate that cultivated landscapes were the main source of sediment to these river systems (mean 56%, SD 34%) followed by subsoil (mean 26%, SD 16%) and forest sources (mean 21%, SD 24%). However, these contributions strongly varied over time, with a peak of subsoil contributions (mean 57%, SD 17%) in Fall 2015, coinciding with the occurrence of a typhoon after the remediation works. These original results demonstrate that spectrocolorimetric measurements provide a powerful tool for the monitoring of the effectiveness of remediation works in this post-accidental context.

Published
2019

178. Quantifying the contribution of subsurface sediment sources using spectrocolorimetry: A case study in coastal catchments exposed to Fukushima radioactive fallout, Japan

Author

Evrard, Olivier, Durand, Roxanne, Sellier, Virginie, Laceby, J., Onda, Yuichi, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochimie Des Impacts (GEDI), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Tsukuba = University of Tsukuba, ANR-11-RSNR-0002,AMORAD,AMORAD1(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
[SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; The accident that occurred at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011 resulted in the formation of a radioactive pollution plume on soils of Northeastern Japan. Among the emitted radionuclides, radiocesium (including Cs-137) is the most problematic substance over the medium to long term, because of its abundance and its relatively long half-life. The soils heavily contaminated with Cs-137 are drained by several coastal rivers to the Pacific Ocean, and extensive soil erosion occurring during typhoons may lead to the significant redistribution of these particle-bound radionuclides. To prepare the return of the local populations in the most contaminated areas, the Japanese authorities carried out remediation works consisting in the removal of the 5-cm topsoil layer heavily contaminated with Cs-137. Accordingly, the application of an alternative sediment tracing technique based on the measurement of spectrocolorimetry parameters was investigated to quantify the effectiveness of remediation. These measurements were conducted using a portable diffuse reflectance spectrophotometer (Konica Minolta 2600d) between 360 and 740 nm, with a 10-nm resolution. Potential sources samples corresponded to (i) topsoil collected under forests or paddy fields before remediation works, and (ii) subsoil material originating from channel bank/landslide erosion, or collected in paddy fields after decontamination. Sediment samples consisted of fine material deposited in the main river channel after the main floods and were systematically collected at the same locations every six months, between 2011–2017, in the Mano and Niida River catchments, Fukushima Prefecture. The results showed that the contribution of subsoil to sediment strongly varied across space and throughout time, reflecting the significant impact of decontamination works and the continuous ‒ although minor ‒ contribution of landslides as a perennial source of material transiting rivers in this region of the world. The impact of particle size is discussed through the comparison of measurements conducted on both

Published
2018

179. Differences in leaching characteristics of dissolved radiocaesium and potassium from the litter layer of Japanese cedar and broadleaf forests in Fukushima, Japan

Author

Takada, Momo, Onda, Yuichi, Yasutaka, Tetsuo, and Momo, Takada

Abstract

Cesium is an element that belongs to the same group as K, and is known to show similar behaviour to that of K in plants. In this study, we conducted a serial leaching test for 120 h to compare the leaching characteristics of dissolved 137Cs and K in forest litter, obtained from Japanese cedar and deciduous broadleaf forests located 40 km from the site of the 2011 Fukushima Dai-ichi nuclear power plant accident. The litter was collected in 2018 and was divided into three groups according to the decomposition level. The cumulative leachable fraction of 137Cs at 120 h ranged from 0.3% to 3.3%, suggesting that most of the 137Cs in the litter was hardly leachable in water. The leachable fraction of 137Cs generally decreased with the decomposition level of the litter, implying that the easily leachable 137Cs eluted into the water during the first stage of decomposition. Meanwhile, the cumulative leachable fraction of K at 120 h was approximately 10 times greater than that of 137Cs and ranged from 22.7% to 54.8%. The leaching speeds of 137Cs and K decreased suddenly with elapsed time regardless of the tree species, decomposition degree, or element. Our findings contribute to the long-term understanding of the 137Cs cycle in forest ecosystems.

Published
2020

182. Tracing the sources and dynamics of contaminated sediment in coastal rivers draining the main Fukushima radioactive fallout plume using gamma-emitting radionuclides and carbon/nitrogen stable isotopes (2011-2017)

Author

Evrard, O., Laceby, J. Patrick, Onda, Yuichi, Hayashi, Seiji, Tsuji, Hideki, Huon, Sylvain, Lefèvre, Irène, Jaegler, Hugo, Landemaine, Valentin, Vandromme, Rosalie, Cerdan, Olivier, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochimie Des Impacts (GEDI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Alberta Environment and Parks (AEP), Université de Tsukuba = University of Tsukuba, National Institute for Environmental Science [Fukushima], Institut d'écologie et des sciences de l'environnement de Paris (iEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), ANR-11-RSNR-0002,AMORAD,AMORAD1(2011), ANR-11-JAPN-0001,TOFU,Traçage des conséquences environnementales du tsunami provoqué par le séisme de TOhoku et de l'accident de FUkushima(2011), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Evrard, Olivier, AMORAD1 - - AMORAD2011 - ANR-11-RSNR-0002 - RSNR - VALID, and Great Tohoku Earthquake - Traçage des conséquences environnementales du tsunami provoqué par le séisme de TOhoku et de l'accident de FUkushima - - TOFU2011 - ANR-11-JAPN-0001 - JAPON - VALID

Subjects
[SDE] Environmental Sciences, [SDE.MCG] Environmental Sciences/Global Changes, [SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences, [SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, [SDV.SA.SDS] Life Sciences [q-bio]/Agricultural sciences/Soil study, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Fieldwork was conducted every 6 months between 2011 and 2017 to monitor the dispersion of sediment contaminated with radionuclides in rivers draining the main Fukushima radioactive pollution plume (~500 km²). Fine sediment was systematically collected at the same locations (n=47) and analysed for gamma-emitting radionuclides (including 137Cs and 110mAg). A selection of samples was also analysed for carbon/nitrogen concentrations and isotopes. Organic matter analyses showed that paddy fields provided the main source of contaminated sediment to the rivers shortly after the accident. The spatial variations of the 110mAg:137Cs activity ratio in soils were used to demonstrate the very rapid export of sediment to the Pacific Ocean. However, this tool could only be used during the first campaigns, because of the quick decay of 110mAg. Overall, radiocesium concentrations measured in sediment deposits decreased by ~90% between 2011 and 2017. This may be explained by remediation works, by a massive export of material during typhoons and by the occurrence of landslides or channel bank erosion that supply material sheltered from the Fukushima fallout to the river network. Consequently, 6 years after the accident, most of the residual radioactive contamination is found in forests and in dam reservoirs. The analysis of sediment cores collected in a reservoir confirmed the significant storage of contaminated material in these lakes and that paddy fields provided their main source. Ongoing research focuses on the development of a soil erosion model and on the quantification of the impact of remediation works.

Published
2018

184. Reconstruction of uranium and plutonium isotopic signatures in sediment accumulated in the Mano Dam reservoir, Japan, before and after the Fukushima nuclear accident

Author

Jaegler, Hugo, primary, Pointurier, Fabien, additional, Diez-Fernández, Silvia, additional, Gourgiotis, Alkiviadis, additional, Isnard, Hélène, additional, Hayashi, Seiji, additional, Tsuji, Hideki, additional, Onda, Yuichi, additional, Hubert, Amélie, additional, Laceby, J. Patrick, additional, and Evrard, Olivier, additional

Published
2019
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192. Source contributions to radiocesium contaminated particulate matter deposited in a reservoir after the Fukushima accident

Author

Laceby, J., Huon, Sylvain, Hayashi, Seiji, Onda, Yuichi, Evrard, Olivier, Alberta Environment and Parks (AEP), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), National Institute for Environmental Science [Fukushima], Université de Tsukuba = University of Tsukuba, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochimie Des Impacts (GEDI), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Evrard, Olivier

Subjects
[SDE] Environmental Sciences, [SDE.MCG] Environmental Sciences/Global Changes, [SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences, [SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, [SDV.SA.SDS] Life Sciences [q-bio]/Agricultural sciences/Soil study, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; The Fukushima nuclear accident 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 1,000 reservoirs for both agricultural and surface water management. These reservoirs may have trapped a significant volume of radiocesium contaminated sediment, and understanding the sources of this material is important for the ongoing management of contamination in the region. Accordingly, the source of contaminated particulate matter (i.e. cultivated, forest and subsoils) deposited in the Mano Dam reservoir, Japan, was investigated with the analyses and modelling of carbon and nitrogen stable isotope ratios, total organic carbon and total nitrogen concentrations. Four sediment cores with lengths ranging from 29-41 cm were sampled in the Mano Dam, approximately 40 km northwest of the FDNPP. Source samples were taken from 46 forest soils, 28 cultivated soils and 25 subsoils in the region. Carbon-nitrogen parameters were analysed 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% (SD 7%) of the deposited fine particulate matter in the three cores with the radiocesium peaks, whereas forests were modelled to contribute 27% (SD 6%) and subsoil sources 25% (SD 4%). Ongoing decontamination of cultivated sources in the Fukushima region should result in a decrease of contaminated matter deposited in reservoirs. More research is required to understand the potential ongoing source contributions from forested landscapes in this post-fallout environment.

Published
2017

193. Release of Radionuclides from Natural River, Abukuma as Suspended Particulate Matter into Pacific Ocean

Author

YAMASHIKI, Yosuke, ONDA, Yuichi, IGARASHI, Yasuhito, WAKAHARA, Taeko, TACHIKAWA, Yasuto, SHIIBA, Michiharu, and MATSUURA, Yuki

Subjects
放射性物質, Ocean, 河川, Flux, フラックス, 519.9, Suspended particulate matter, 海洋, 懸濁物質, Radionuclides, River transport
Abstract

Most of radioactive material released from Abukuma River Basin, one of the largest stream near the contaminated zone of Fukushima, flowing most of the contaminated plane zone then flow into the Pacific Ocean, are in the suspended particulate form, being estimated more than 90 % in the upper stream and 70% near the river mouth. Most of radionuclides in particulate form are still trapped bottom sediment in the middle of the basin, however we find that significant amount are released during the heavy precipitation event. We also found that, at hydrological extremes the total loading increase more than 1000 times higher than the normal stream condition. The total flux of radiocesium into the Pacificic Ocean estimated at the Iwanuma Station from 10 August 2011 to 10 May 2012 become 9.11 Terabecquerel during 274 days for [137]Cs, and 6.81 Terabecquerel during 274 days for [134]Cs.

Published
2013

196. Discovery of Novel Pyrazole-Based Selective Aldosterone Synthase (CYP11B2) Inhibitors: A New Template to Coordinate the Heme-Iron Motif of CYP11B2

Author

Sakakibara, Ryo, primary, Sasaki, Wataru, additional, Onda, Yuichi, additional, Yamaguchi, Minami, additional, Ushirogochi, Hideki, additional, Hiraga, Yuki, additional, Sato, Kanako, additional, Nishio, Masashi, additional, Egi, Yasuhiro, additional, Takedomi, Kei, additional, Shimizu, Hidetoshi, additional, Ohbora, Tomoko, additional, and Akahoshi, Fumihiko, additional

Published
2018
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