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Matsuda K, Yamamoto S, Miyamoto K. Comparison of 137Cs uptake, depuration and continuous uptake, originating from feed, in five salmonid fish species. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 222:106350. [PMID: 32745886 DOI: 10.1016/j.jenvrad.2020.106350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 06/25/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
The origin of 137Cs contamination, contamination levels, and its effective ecological half-life can differ among fish species, but until recently it was unknown whether interspecific differences in radiocaesium metabolism existed. We compare the trophic transfer of 137Cs in five salmonid species under controlled conditions. Fish were fed a diet containing 200 Bq kg-1 wet wt concentration of 137Cs for a fixed period of time. While there were almost no differences in contamination levels among individual fish within a species during fixed periods, the rate of 137Cs uptake was statistically different among the species examined, for which the effective half-life of 137Cs ranged 49-84 days. No significant difference in rate of decline in the quantity of 137Cs was apparent among species in two experiments after correcting for differences in growth. The effective half-life was shortest in Oncorhynchus mykiss and O. masou-two species exhibiting the best growth rate in both experiments-indicating an influence of the dilution effect associated with growth. When continuously fed 200 Bq kg-1 wet wt concentration of 137Cs for a period of 209-294 days, contamination levels in the five species ranged 216-240 Bq kg-1 wet wt, and reached a steady state value. Our results indicate metabolic rate, although accompanying a change of body size, did not affect 137Cs contamination levels in fish, which implies that contamination levels in the diet strongly determined contamination levels in fish.
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Affiliation(s)
- Keishi Matsuda
- National Research Institute of Fisheries Science, Nikko Station, Japan Fisheries Research and Education Agency, Nikko, Tochigi, 321-1661, Japan.
| | - Shoichiro Yamamoto
- National Research Institute of Fisheries Science, Nikko Station, Japan Fisheries Research and Education Agency, Nikko, Tochigi, 321-1661, Japan.
| | - Kouta Miyamoto
- National Research Institute of Fisheries Science, Nikko Station, Japan Fisheries Research and Education Agency, Nikko, Tochigi, 321-1661, Japan.
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Suzuki K, Watanabe S, Yuasa Y, Yamashita Y, Arai H, Tanaka H, Kuge T, Mori M, Tsunoda KI, Nohara S, Iwasaki Y, Minai Y, Okada Y, Nagao S. Radiocesium dynamics in the aquatic ecosystem of Lake Onuma on Mt. Akagi following the Fukushima Dai-ichi Nuclear Power Plant accident. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 622-623:1153-1164. [PMID: 29890584 DOI: 10.1016/j.scitotenv.2017.12.017] [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: 10/02/2017] [Revised: 11/27/2017] [Accepted: 12/02/2017] [Indexed: 06/08/2023]
Abstract
Understanding ecosystem dynamics of radionuclides is necessary to ensure effective management for food safety. The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on March 11, 2011 released large amounts of radiocesium (134Cs and 137Cs) and contaminated the environment across eastern Japan. In this study, we aimed to elucidate the temporal dynamics of 137Cs in the aquatic ecosystem of Lake Onuma on Mt. Akagi. The effective ecological half-life (Teff) of 137Cs in fishes, western waterweed (Elodea nuttallii), seston (phytoplankton and zooplankton), and lake water was estimated using survey data of 137Cs concentration collected from 2011 to 2016, and single- and two-component decay function models (SDM and TDM, respectively). The decay processes of 137Cs concentrations in wakasagi (Hypomesus nipponensis), pale chub (Zacco platypus), phytoplankton, and total 137Cs concentrations of the water column (WC) in the lake were well suited by the TDMs. The Teff in the fast component of the TDMs in these samples ranged from 0.49 to 0.74years. The Teff in the slow component of the TDMs could converge towards the physical half-life of 137Cs. Nearly five and a half years after the FDNPP accident, we concluded that 137Cs concentrations approached a state of dynamic equilibrium between some aquatic organisms (wakasagi, pale chub, and phytoplankton) and the environment (lake water). However, the decay processes of 137Cs concentrations in Japanese dace (Tribolodon hakonensis), western waterweed, zooplankton, and particulate- and dissolved-forms in the WC were better predicted for the SDM. The total 137Cs concentrations in inflowing river and spring waters were one to two orders of magnitude lower than lake water under normal flow conditions. However, particulate 137Cs contamination level in the river water was high after heavy rains. Overall, 137Cs contamination levels have significantly decreased in Lake Onuma, but monitoring surveys should be continued for further understanding of the reduction processes.
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Affiliation(s)
- Kyuma Suzuki
- Gunma Prefectural Fisheries Experiment Station, Japan.
| | - Shun Watanabe
- Gunma Prefectural Fisheries Experiment Station, Japan
| | - Yumi Yuasa
- Gunma Prefectural Fisheries Experiment Station, Japan
| | | | - Hajime Arai
- Gunma Prefectural Fisheries Experiment Station, Japan
| | - Hideki Tanaka
- Gunma Prefectural Fisheries Experiment Station, Japan
| | | | - Masanobu Mori
- Faculty of Science and Technology, Kochi University, Japan
| | - Kin-Ichi Tsunoda
- Graduate School of Science and Technology, Gunma University, Japan
| | | | - Yuichi Iwasaki
- Research Centre for Life and Environmental Sciences, Toyo University, Japan
| | | | - Yukiko Okada
- Atomic Energy Research Laboratory, Tokyo City University, Japan
| | - Seiya Nagao
- Low Level Radioactivity Laboratory, Kanazawa University, Japan
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Seasonal variation in food web-based transfer factors of radiocesium in white-spotted char (Salvelinus leucomaenis) from headwater streams. LANDSCAPE AND ECOLOGICAL ENGINEERING 2017. [DOI: 10.1007/s11355-016-0324-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Wada T, Tomiya A, Enomoto M, Sato T, Morishita D, Izumi S, Niizeki K, Suzuki S, Morita T, Kawata G. Radiological impact of the nuclear power plant accident on freshwater fish in Fukushima: An overview of monitoring results. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 151 Pt 1:144-155. [PMID: 26454695 DOI: 10.1016/j.jenvrad.2015.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 09/07/2015] [Accepted: 09/17/2015] [Indexed: 06/05/2023]
Abstract
Radionuclide ((131)I, (134)Cs, and (137)Cs) concentrations of monitored freshwater fish species collected from different habitats (rivers, lakes, and culture ponds) in Fukushima Prefecture during March 2011-December 2014 (total 16 species, n = 2692) were analyzed to present a detailed description of radionuclide contamination after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, and to elucidate species-specific spatiotemporal declining trends of (137)Cs concentration for their respective habitats. Low concentrations of (131)I (≤24 Bq kg(-1)-wet) were detected from only 11 samples collected during March-June 2011, demonstrating that (131)I transferred to freshwater fish were not intense. In river and lake fishes, a more gradual decrease and higher radiocesium ((134)Cs, (137)Cs) concentrations were observed than in culture pond fishes, which strongly implied that radiocesium in freshwater fish species was mainly bioaccumulated through the food web in the wild. During 2011-2014, percentages above the Japanese regulatory limit of 100 Bq kg(-1)-wet for radiocesium in river and lake fish (14.0% and 39.6%, respectively) were higher than in monitored marine fish (9.9%), indicating longer-term contamination of freshwater fish species, especially in lakes. Higher radiocesium concentrations (maximum 18.7 kBq kg(-1)-wet in Oncorhynchus masou) were found in the northwestern areas from the FDNPP with higher deposition. However, radiocesium contamination levels were regarded as 1-2 orders of magnitude less than those after the Chernobyl accident. Lagged increase of (137)Cs concentration and longer ecological half-lives (Teco: 1.2-2.6 y in the central part of Fukushima Prefecture) were observed in carnivorous salmonids (O. masou, Salvelinus leucomaenis), whereas a rapid increase and decrease of (137)Cs concentration and shorter Teco (0.99 and 0.69 y) were found in herbivorous and planktivorous osmerids (Plecoglossus altivelis, Hypomesus nipponensis) with younger age at maturity. Comparison of Teco among salmonids, osmerids, and cyprinids suggests that, in addition to the fish feeding habits and life-cycles, hydraulic conditions in rivers and lakes (e.g., turnover time), which are expected to affect radiocesium concentration in prey items, are an important factor affecting the (137)Cs decreasing rate of freshwater fish.
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Affiliation(s)
- Toshihiro Wada
- Institute of Environmental Radioactivity at Fukushima University, Fukushima, Fukushima 960-1296, Japan.
| | - Atsushi Tomiya
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Masahiro Enomoto
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Toshiyuki Sato
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Daigo Morishita
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Shigehiko Izumi
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Kouji Niizeki
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Shunji Suzuki
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
| | - Takami Morita
- National Research Institute of Fisheries Science, Fisheries Research Agency, Yokohama, Kanagawa 236-8648, Japan
| | - Gyo Kawata
- Fukushima Prefectural Inland Water Fisheries Experimental Station, Inawashiro, Fukushima 969-3283, Japan
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Takahara T, Endo S, Takada M, Oba Y, Nursal WI, Igawa T, Doi H, Yamada T, Okuda T. Radiocesium accumulation in the anuran frog, Rana tagoi tagoi, in forest ecosystems after the Fukushima Nuclear Power Plant accident. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2015; 199:89-94. [PMID: 25638689 DOI: 10.1016/j.envpol.2015.01.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/23/2015] [Accepted: 01/24/2015] [Indexed: 06/04/2023]
Abstract
Amphibians are key components in forest food webs. When examining radioactive contamination in anurans, it is important to understand how radiocesium transfer occurs from lower to higher trophic levels in forest ecosystems. We investigated the activity concentration of radiocesium ((134)Cs and (137)Cs) in Tago's brown frog (Rana tagoi tagoi) captured on the forest floor approximately 2.5 years after the Fukushima Nuclear Power Plant (FNPP) accident. We collected 66 R. tagoi tagoi at different distances from the FNPP. Radiocesium accumulation showed positive correlations with the air radiation dose rate and litter contamination but not with distance from the FNPP. Whole-body radioactivity showed no correlation with body mass or length. Our results suggest that differences in the available food items result in large variability in individual contamination. Contamination level monitoring in terrestrial and aquatic amphibian is necessary for clarifying the processes and mechanisms of radiocesium transfer through forest food webs.
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Affiliation(s)
- Teruhiko Takahara
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan.
| | - Satoru Endo
- Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | - Momo Takada
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Yurika Oba
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Wim Ikbal Nursal
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Takeshi Igawa
- Graduate School of International Development and Cooperation, Hiroshima University, 1-5-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8529, Japan
| | - Hideyuki Doi
- Institute for Sustainable Sciences and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Toshihiro Yamada
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Toshinori Okuda
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
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