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Journal Articles

Plastic-associated metal(loid)s in the urban river environments of Mongolia

Battulga, B.; Atarashi-Andoh, Mariko; Koarashi, Jun; Bolormaa, O.*; Kawahigashi, Masayuki*

Ecotoxicology and Environmental Safety, 261, p.115100_1 - 115100_10, 2023/08

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

The widespread distribution of plastic debris in the riverine environment is one of the major concerns of environmental pollution because of its potential impact on the aquatic ecosystem. In this study, we investigated accumulation of metal(loid)s on polystyrene foam (PSF) plastics collected from the Tuul River shore of Mongolia. Sorbed metal(loid)s on plastics have been extracted from collected PSF by sonication after peroxide oxidation. Size-dependent association of metal(loid)s indicated that PSFs act as vectors for the pollutants in the urban river environment. In addition, images from scanning electron microscopy (SEM) indicated not only the degraded surface of plastics showing fractures, holes, and pits, but also adhered mineral particles and microorganisms on PSFs. Interaction of metal(loid)s with plastics may be facilitated by altered surface physical and chemical properties of the plastics through photodegradation followed by an increase in surface area by size reduction and/or biofilm development in the aquatic environment. Enrichment ratio (ER) of metals on PSF samples suggested continuous accumulation of heavy metals on plastics. Our results demonstrate that the widespread plastic debris could be one of the carriers for hazardous chemicals in the environment. Since the influences of plastic debris on environmental health are major concerns to be solved, the fate and behavior of hetero-aggregates of plastics in aquatic environments should be continuously studied.

Journal Articles

Thirty-year prediction of $$^{137}$$Cs supply from rivers to coastal waters off Fukushima considering human activities

Ikenoue, Tsubasa; Shimadera, Hikari*; Nakanishi, Takahiro; Kondo, Akira*

Water (Internet), 15(15), p.2734_1 - 2734_18, 2023/08

 Times Cited Count:0 Percentile:0

The Fukushima Daiichi Nuclear Power Plant accident caused an accumulation of $$^{137}$$Cs in coastal sediment. The $$^{137}$$Cs supply from rivers to the ocean can affect the long-term fate of $$^{137}$$Cs in coastal sediment. Since the Fukushima coastal river basins include large decontaminated and evacuation order areas, considering the decontamination work and resumption of agriculture is important for predicting the $$^{137}$$Cs supply. We conducted a 30-year prediction of the $$^{137}$$Cs supply from the Fukushima coastal rivers to the ocean using a distributed radiocesium prediction model, considering the effects of human activities. In river basins with decontaminated and evacuation order areas, human activities reduced the total $$^{137}$$Cs outflow from agricultural lands, urban lands, and forest areas to the rivers and the $$^{137}$$Cs supply to the ocean by 5.0% and 6.0%, respectively. These results indicated that human activities slightly impacted the $$^{137}$$Cs outflow and supply. The $$^{137}$$Cs supply from rivers impacted by the accident to the coastal sediment was estimated to correspond to 11-36% of the total $$^{137}$$Cs in the coastal sediment in the early phase of the accident. Therefore, the $$^{137}$$Cs supply from rivers to the ocean is important for the long-term behavior of $$^{137}$$Cs in coastal sediment.

Journal Articles

Tracking the behavior and characteristics of microplastics using a multi-analytical approach; A Case study in two contrasting coastal areas of Japan

Battulga, B.; Atarashi-Andoh, Mariko; Matsueda, Makoto; Koarashi, Jun

Environmental Science and Pollution Research, 30(31), p.77226 - 77237, 2023/05

 Times Cited Count:0 Percentile:0(Environmental Sciences)

The global survey for the presence of microplastics (MPs) in aquatic environments has attracted widespread scientific attention over the past decade. This study demonstrates a multidimensional analytical approach, including isotopic and thermogravimetric analyses to evaluate characteristics and behavior of MPs in the environment. The MP samples were collected in two contrasting coastal areas of Japan. The $$delta$$$$^{13}$$C values of field-collected polyethylene (PE), polypropylene (PP), and polystyrene (PS) MPs were ranged from -25.6 to -31.4, -23.4 to -30.9, and -27.3 to -28.6 per mil, respectively. The differences in $$delta$$$$^{13}$$C signature between MPs with the same polymer types (i.e., PE and PP) but different colors. Through thermal analysis, the single-step endothermic process was observed for environmental PE and PS-MPs. The results reveal that degradation may play a significant role in the behavior and characteristics of MP debris in the aquatic environment.

Journal Articles

Effect of radioactive cesium-rich microparticles on radioactive cesium concentration and distribution coefficient in rivers flowing through the watersheds with different contaminated condition in Fukushima

Tatsuno, Takahiro*; Waki, Hiromichi*; Kakuma, Minato*; Nihei, Naoto*; Takase, Tsugiko*; Wada, Toshihiro*; Yoshimura, Kazuya; Nakanishi, Takahiro; Ote, Nobuhito*

Journal of Environmental Management, 329, p.116983_1 - 116983_13, 2023/03

 Times Cited Count:0 Percentile:0(Environmental Sciences)

Journal Articles

A New approach to extracting biofilm from environmental plastics using ultrasound-assisted syringe treatment for isotopic analyses

Battulga, B.; Atarashi-Andoh, Mariko; Nakanishi, Takahiro; Koarashi, Jun

Science of the Total Environment, 849, p.157758_1 - 157758_11, 2022/11

 Times Cited Count:1 Percentile:35.39(Environmental Sciences)

Characterizing plastic-associated biofilms is key to the better understanding of organic material and mineral cycling in the "Plastisphere"-the thin layer of microbial life on plastics. In this study, we propose a new method to extract biofilms from environmental plastics, in order to evaluate the properties of biofilm-derived organic matter through stable carbon ($$delta$$$$^{13}$$C) and nitrogen ($$delta$$$$^{15}$$N) isotope signatures and their interactions with radionuclides especially radiocesium ($$^{137}$$Cs). After ultrasound-assisted separation from the plastics, biofilm samples were successfully collected via a sequence of syringe treatments. Biofilm-derived organic matter samples (14.5-65.4 mg) from four river mouths in Japan showed $$^{137}$$Cs activity concentrations of $$<$$75 to 820 Bq kg$$^{-1}$$ biofilm (dw), providing evidence that environmental plastics, mediated by developed biofilms, serve as a carrier for $$^{137}$$Cs in the coastal environment. Significant differences in the ($$delta$$$$^{13}$$C and $$delta$$$$^{15}$$N signatures were also obtained for the biofilms, indicating the different sources, pathways, and development processes of biofilms on plastics.

Journal Articles

Cesium-rich microparticles runoff during rainfall; A Case study in the Takase River

Tatsuno, Takahiro*; Waki, Hiromichi*; Kakuma, Minato*; Nihei, Naoto*; Wada, Toshihiro*; Yoshimura, Kazuya; Nakanishi, Takahiro; Ote, Nobuhito*

Radiation Protection Dosimetry, 198(13-15), p.1052 - 1057, 2022/09

 Times Cited Count:1 Percentile:35.78(Environmental Sciences)

JAEA Reports

Survey on the radioactive substance in the coastal areas near Fukushima Prefecture in FY2019 (Contract research)

Misono, Toshiharu; Tsuruta, Tadahiko; Nakanishi, Takahiro; Sanada, Yukihisa; Shiribiki, Takehiko; Miyamoto, Kenji*; Urabe, Yoshimi*

JAEA-Research 2020-008, 166 Pages, 2020/10

JAEA-Research-2020-008.pdf:13.11MB
JAEA-Research-2020-008(errata).pdf:0.92MB

After the accident at TEPCO Fukushima Daiichi Nuclear Power Station (1F), marine monitoring survey on radioactive substances have been conducted with financially supported by the Nuclear Regulatory Agency from FY2019. Results obtain in the project in FY2019 are presented in this report. Based on scientific grounds, the concept necessary for "progress of sea area monitoring" was arranged for the future medium- to long-term investigation of radiocesium concentrations. As basic information of survey frequency revise, a seabed topography and sediment distribution survey was conducted, and an attempt was made to understand the relationship between the seabed topography and the grain size distribution of bottom sediment. A columnar core sample was collected in the coastal area and analyzed for radioactive cesium concentration. In order to understand the dynamics of radioactive cesium contained in suspended matter flowing in from a river, suspended solids was collected using a sediment trap and the concentration of radioactive cesium was measured. We re-analyzed the towed monitoring data that had been implemented since 2013, and tried to improve the accuracy of the radioactive cesium distribution estimation map in the coastal area.

Journal Articles

Radiocesium distribution in the sediments of the Odaka River estuary, Fukushima, Japan

Hagiwara, Hiroki; Nakanishi, Takahiro; Konishi, Hiromi*; Tsuruta, Tadahiko; Misono, Toshiharu; Fujiwara, Kenso; Kitamura, Akihiro

Journal of Environmental Radioactivity, 220-221, p.106294_1 - 106294_9, 2020/09

 Times Cited Count:0 Percentile:0(Environmental Sciences)

Journal Articles

Key factors controlling radiocesium sorption and fixation in river sediments around the Fukushima Daiichi Nuclear Power Plant, 1; Insights from sediment properties and radiocesium distributions

Tachi, Yukio; Sato, Tomofumi*; Akagi, Yosuke*; Kawamura, Makoto*; Nakane, Hideji*; Terashima, Motoki; Fujiwara, Kenso; Iijima, Kazuki

Science of the Total Environment, 724, p.138098_1 - 138098_11, 2020/07

 Times Cited Count:13 Percentile:59.22(Environmental Sciences)

To understand and predict radiocesium transport behaviors in the environment, highly contaminated sediments from Ukedo and Odaka rivers around the Fukushima Daiichi Nuclear Power Plant were investigated systematically focusing on key factors controlling radiocesium sorption and fixation, including particle size, clay mineralogy and organic matter.

Journal Articles

Key factors controlling radiocesium sorption and fixation in river sediments around the Fukushima Daiichi Nuclear Power Plant, 2; Sorption and fixation behaviors and their relationship to sediment properties

Tachi, Yukio; Sato, Tomofumi*; Takeda, Chizuko*; Ishidera, Takamitsu; Fujiwara, Kenso; Iijima, Kazuki

Science of the Total Environment, 724, p.138097_1 - 138097_10, 2020/07

 Times Cited Count:9 Percentile:45.41(Environmental Sciences)

To understand and predict radiocesium transport behaviors in the environment, sorption and fixation behaviors of radiocesium on river sediments from Ukedo and Odaka rivers around the Fukushima Daiichi Nuclear Power Plant were investigated systematically focusing on Cs sorption and fixation mechanisms and their relationship with Cs concentrations and sediment properties including clay mineralogy and organic matter.

Journal Articles

Comparative analysis of water contamination of the Shagan river at the Semipalatinsk Test Site with heavy metals and artificial radionuclides

Gorlachev, I.*; Kharkin, P.*; Dyussembayeva, M.*; Lukashenko, S.*; Gluchshenko, G.*; Matiyenko, L.*; Zheltov, D.*; Kitamura, Akihiro; Khlebnikov, N.*

Journal of Environmental Radioactivity, 213, p.106110_1 - 106110_10, 2020/03

 Times Cited Count:8 Percentile:52.93(Environmental Sciences)

The main goal of the presented research activities is to determine the degree of water contamination of the largest waterway of the STS, the Shagan river, with heavy elements and artificial radionuclides. Such approach made it possible to identify the most significant elements-contaminants typical for the selected object, to determine the most dirty points of the Shagan riverbed, to compare the degree of water contamination with heavy metals and artificial radionuclides, and to calculate the complex indices of water contamination with heavy metals. According to the obtained data, the recommendations can be made for application of Shagan's water for household purpose.

Journal Articles

Transport and redistribution of radiocesium in Fukushima fallout through rivers

Taniguchi, Keisuke*; Onda, Yuichi*; Smith, H. G.*; Blake, W.*; Yoshimura, Kazuya; Yamashiki, Yosuke*; Kuramoto, Takayuki*; Saito, Kimiaki

Environmental Science & Technology, 53(21), p.12339 - 12347, 2019/11

 Times Cited Count:63 Percentile:94.9(Engineering, Environmental)

Journal Articles

Repeatability and reproducibility of measurements of low dissolved radiocesium concentrations in freshwater using different pre-concentration methods

Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 322(2), p.477 - 485, 2019/11

 Times Cited Count:2 Percentile:22.31(Chemistry, Analytical)

We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the $$^{137}$$Cs results were within $$pm$$2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.

Journal Articles

Calculation of tritium release from driver fuels into primary coolant of research reactors

Ho, H. Q.; Ishitsuka, Etsuo

Physical Sciences and Technology, 5(2), p.53 - 56, 2019/00

Increasing of tritium concentration in the primary coolant of the research and test reactors during operation had been reported. To check the source for tritium release into the primary coolant during operation of the JMTR and the JRR-3M, the tritium release from the driver fuels was calculated by MCNP6 and PHITS. It is clear that the calculated values of tritium release from fuels are as about 10$$^{7}$$ and 10$$^{6}$$ Bq for the JMTR and JRR-3M, respectively, and that calculated values are about 4 order of magnitude smaller than that of the measured values. These results show that the tritium release from fuels is negligible for both the reactors.

Journal Articles

Characteristics of radiocesium contamination of dry riverbeds due to the Fukushima Daiichi Nuclear Power Plant accident assessed by airborne radiation monitoring

Azami, Kazuhiro*; Otagaki, Takahiro*; Ishida, Mutsushi; Sanada, Yukihisa

Landscape and Ecological Engineering, 14(1), p.3 - 15, 2018/01

 Times Cited Count:2 Percentile:12.53(Biodiversity Conservation)

JAEA Reports

Compilation of information on uplift of the last hundred thousand years in the Japanese Islands

Nomura, Katsuhiro; Tanikawa, Shinichi*; Amamiya, Hiroki; Yasue, Kenichi

JAEA-Data/Code 2016-015, 49 Pages, 2017/03

JAEA-Data-Code-2016-015.pdf:2.88MB

The uplift of the last hundred thousand years in the Japanese Islands has been acquired mainly using marine and river terraces. We arranged information regarding the uplift in a table. This data is one of the useful information for the development of the investigation technology of uplift and for the research of the landform evolution in Japanese islands.

Journal Articles

Behavior of accidentally released radiocesium in soil-water environment; Looking at Fukushima from a Chernobyl perspective

Konoplev, A.*; Golosov, V.*; Laptev, G.*; Namba, Kenji*; Onda, Yuichi*; Takase, Tsugiko*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya

Journal of Environmental Radioactivity, 151(Part 3), p.568 - 578, 2016/01

 Times Cited Count:75 Percentile:92.16(Environmental Sciences)

JAEA Reports

Consideration for modeling studies of migration of accidentally released radionuclides in a river watershed

Matsunaga, Takeshi; Monte, L.; Tsuzuki, Katsunori; Yanase, Nobuyuki; Hanzawa, Yukiko; Ueno, Takashi

JAERI-Review 2003-039, 150 Pages, 2004/01

JAERI-Review-2003-039.pdf:11.12MB

Concerning radionuclides that might be released in an event of an accident from a nuclear facility, much attention has been paid to the migration pathways including the inflow to surface water bodies since the Chernobyl accident. In order to have discussions related to the current development of a mathematical model of the behavior of radionuclides in a river watershed, JAERI invited a guest scientist specializing in mathematical modeling of radioecology, Luigi Monte of Italian National Agency for New Technologies Energy and the Environment (ENEA: Ente per le Nuove tecnologie,L'Energia e l'Ambiente) of Italy, from May 22 to June 20 of 2003. This report is a summary of presentations and discussion made at the occasion of the visit of Dr. Monte at JAERI and also at relevant institutions of Japan involved in this study field. As a result of these discussions, distinct advantages and key problems of a mathematical model for prediction of the migration of radionuclides in a river watershed have been identified and analyzed.

Journal Articles

Construction of river transfer models for MOGRA

Hayashi, Hiroko*; Matsuoka, Shungo*; Takahashi, Tomoyuki*; Amano, Hikaru

JAERI-Conf 2003-010, p.122 - 130, 2003/09

Two dynamic compartment models were constructed as basic river models for MOGRA (Migration Of GRound Additions), an environmental-load effect predicting code. One is 1 component river model, in which radionuclides in particulate form and dissolved form are considered to be in equilibrium in the river water. Another one is 2 component river model, in which particulate form and dissolved form are considered to be different component and are separately compartmentalized. In each model the river sediment is set in a compartment, and the sedimentation of particulate form and resuspension of radionuclides in the river sediment are taken into account.To verify the analysis function of the constructed models, calculation conditions were set using data of Cs-137 concentration in the river water derived from Kuji river, Japan, and analysis was carried out. Comparing two models, almost no difference is seen when sedimentation velocity is low, while there is apparent difference when sedimentation velocity is high.

Journal Articles

Association of Am with humic substances isolated from river waters with different water quality

Nagao, Seiya*; Fujitake, Nobuhide*; Kodama, Hideki*; Matsunaga, Takeshi; Yamazawa, Hiromi

Journal of Radioanalytical and Nuclear Chemistry, 255(3), p.459 - 464, 2003/03

 Times Cited Count:7 Percentile:45.92(Chemistry, Analytical)

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