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Processes affecting long-term changes in 137Cs concentration in surface sediments off Fukushima

  • Special Section: Original Article
  • Radionuclides in coastal sediments after the accident of Fukushima Daiichi Nuclear Power Plant
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Abstract

Temporal changes in cesium-137 (137Cs) concentrations in the surface (0–10 cm) layer of seabed sediment were quantified from continuous observation data at 71 stations within a 150-km radius of the Fukushima Daiichi Nuclear Power Plant, and the primary processes affecting temporal changes were identified. From March 2011 to the end of 2015, about 80% of the initially deposited 137Cs in the surface sediment in the coastal region (bottom depth ≤100 m) region has dissipated (radioactive decay is not included). Such a remarkable change in the 137Cs concentration was not observed in the offshore (>100 m) region. This paper focuses on the following three processes that affected the decrease in the 137Cs concentrations, and assesses their relative importance; (1) resuspension and transport of 137Cs-bound sediment, (2) desorption of 137Cs from the sediment, and (3) dilution of 137Cs by vertical mixing of sediment. Consequently, it was estimated that the first two processes together have potentially contributed to reduce the 137Cs inventory in the top 10 cm of the coastal region by at most 35%. Furthermore, by applying a pulse input sediment mixing model to the observed vertical distribution of sedimentary 137Cs, it was also estimated that more than 43% of the 137Cs in the surface sediment was transported to deeper sediment layers by vertical mixing of the sediment. This indicates that the decrease of 137Cs concentrations in coastal sediments was mainly affected by mixing of 137Cs-bound surface sediment with less contaminated sediment in the deeper layers.

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References

  • Abril JM, Fraga E (1996) Some physical and chemical features of the variability of k d distribution coefficients for radionuclides. J Environ Radioact 30:253–270

    Article  Google Scholar 

  • Adachi K, Kajino M, Zaizen Y, Igarashi Y (2013) Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident. Sci Rep 3:2554. doi:10.1038/srep02554

    Article  Google Scholar 

  • Ambe D, Kaeriyama H, Shigenobu Y, Fujimoto K, Ono T, Sawada H, Saito H, Miki S, Setou T, Morita T, Watanabe T (2014) Five-minute resolved spatial distribution of radiocesium in sea sediment derived from the Fukushima Dai-ichi Nuclear Power Plant. J Environ Radiact 138:264–275

    Article  Google Scholar 

  • Black EE, Buesseler KO (2014) Spatial variability and the fate of cesium in coastal sediments near Fukushima, Japan. Biogeosci 11:5123–5137

    Article  Google Scholar 

  • Buesseler KO, German CR, Honda MC, Otosaka S, Black EE, Kawakami H, Manganini SJ, Pike SM (2015) Tracking the fate of particle associated Fukushima Daiichi cesium in the ocean off Japan. Environ Sci Technol 49:9807–9816

    Article  Google Scholar 

  • Buesseler KO, Dai M, Aoyama M, Benitez-Nelson Charmasson S, Higley K, Medrich V, Masque P, Oughton D, Smith JN (2017) Fukushima Daiichi–derived radionuclides in the ocean: transport, fate, and impacts. Annu Rev Mar Sci 9:173–203

    Article  Google Scholar 

  • Cochran JK (1985) Particle mixing rates in sediments of the eastern equatorial Pacific: evidence from 210Pb, 239,240Pu and 137Cs distributions at MANOP sites. Geochim Cosmochim Acta 49:1195–1210

    Article  Google Scholar 

  • Comans RN, Haller M, De Preter P (1991) Sorption of cesium on illite: non-equilibrium behaviour and reversibility. Geochim Cosmochim Acta 55:433–440

    Article  Google Scholar 

  • Fukuda M, Aono T, Yamazaki S, Nishikawa J, Otosaka S, Ishimaru T, Kanda J (2017) Dissolved radiocaesium in seawater off the coast of Fukushima during 2013–2015. J Radioanal Chem. 311:1479–1484. doi:10.1007/s10967-016-5009-9

    Article  Google Scholar 

  • IAEA (2003) Collection and Preparation of bottom sediment samples for analysis of radionuclides and trace elements. IAEA TECDOC 1360, International Atomic Energy Agency, Vienna, pp 130

  • IAEA (2004) Sediment distribution coefficients and concentration factors for biota in the marine environment. IAEA Technical Report Series 422, International Atomic Energy Agency, Vienna, pp 95

  • Ikehara K, Irino T, Usami K, Jenkins R, Omura A, Ashi J (2014) Possible submarine tsunami deposits on the outer shelf of Sendai Bay, Japan resulting from the 2011 earthquake and tsunami off the Pacific coast of Tohoku. Mar Geol 349:91–98

    Article  Google Scholar 

  • Iwata K, Tagami K, Uchida S (2013) Ecological half-lives of radiocesium in 16 species in marine biota after the TEPCO’s Fukushima Daiichi Nuclear Power Plant accident. Environ Sci Technol 47:7696–7703

    Article  Google Scholar 

  • Kakehi S, Kaeriyama H, Ambe D, Ono T, Ito S, Shimizu Y, Watanabe T (2016) Radioactive cesium dynamics derived from hydrographic observations in the Abukuma River Estuary, Japan. J Environ Radioact 153:1–9

    Article  Google Scholar 

  • Kanda J (2013) Continuing 137Cs release to the sea from the Fukushima Dai-ichi Nuclear Power Plant through 2012. Biogeosci 10:6107–6113

    Article  Google Scholar 

  • Li YH, Gregory S (1974) Diffusion of ions in sea-water and in deep-sea sediments. Geochim Cosmochim Acta 38:703–714

    Article  Google Scholar 

  • MAFF (Ministry of Agriculture, Forestry and Fisheries), Japan (2016) Results of the monitoring on radioactivity level in fisheries products. http://www.jfa.maff.go.jp/e/inspection/index.html. Accessed 13 Mar 2017

  • Misumi K, Tsumune D, Tsubono T, Tateda Y, Aoyama M, Kobayashi T, Hirose K (2014) Factors controlling the spatiotemporal variation of 137Cs in seabed sediment off the Fukushima coast: implications from numerical simulations. J Environ Radioact 136:218–228

    Article  Google Scholar 

  • MOE (2016a) Results of the 2014 monitoring survey after the Great East Japan earthquake (in Japanese). http://www.env.go.jp/press/files/jp/102775.pdf. Accessed 13 Mar 2017

  • MOE (2016b) Results of the 2015 monitoring survey after the Great East Japan earthquake (in Japanese). http://www.env.go.jp/jishin/jishin/waste/101662/bessi_4.pdf. Accessed 20 Jan 2017

  • MOE (Ministry of the Environment), Japan (2013) Results of the monitoring survey after the Great East Japan earthquake (in Japanese). http://www.env.go.jp/jishin/monitoring/results_me.html. Accessed 13 Mar 2017

  • Murota K, Saito T, Tanaka S (2016) Desorption kinetics of cesium from Fukushima soils. J Environ Radioact 153:134–140

    Article  Google Scholar 

  • Nadaoka K, Tanaka N, Katoh K (1981) Field observation of local sand movements in the surf zone using fluorescent sand tracer. Port Harb Res Inst Rep 20:75–126

    Google Scholar 

  • NOAA (National Oceanic and Atmospheric Administration), US, (2006) 1-Minute gridded global relief data (ETOPO2v2). NOAA National Geophysical Data Center, Boulder

    Google Scholar 

  • NRA (Nuclear Regulation Authority), Japan (2016) Monitoring information of environmental radioactivity level. http://radioactivity.nsr.go.jp/en/list/205/list-1.html. Accessed 13 Mar 2017

  • Oikawa S, Takata H, Watabe T, Misonoo J, Kusakabe M (2013) Distribution of the Fukushima-derived radionuclides in seawater in the Pacific off the coast of Miyagi, Fukushima, and Ibaraki Prefectures, Japan. Biogeosci 10:5031–5047

    Article  Google Scholar 

  • Okamura H, Ikeda S, Morita T, Eguchi S (2016) Risk assessment of radioisotope contamination for aquatic living resources in and around Japan. Proc Natl Acad Sci USA 113:3838–3843

    Article  Google Scholar 

  • Ono T, Ambe D, Kaeriyama H, Shigenobu Y, Fujimoto K, Sogame K, Nishiura N, Fujikawa T, Morita T, Watanabe T (2015) Risk assessment of radioisotope contamination for aquatic living resources in and around Japan. Geochem J 49:219–227

    Article  Google Scholar 

  • Otosaka S, Kato Y (2014) Radiocesium derived from the Fukushima Daiichi Nuclear Power Plant accident in seabed sediments: initial deposition and inventories. Environ Sci Processes Impacts 16:978–990. doi:10.1039/c4em00016a

    Article  Google Scholar 

  • Otosaka S, Kobayashi T (2013) Sedimentation and remobilization of radiocesium in the coastal area of Ibaraki, 70 km south of the Fukushima Dai-ichi Nuclear Power Plant. Environ Monit Assess 185:5419–5433

    Article  Google Scholar 

  • Otosaka S, Nakanishi T, Suzuki T, Satoh Y, Narita H (2014) Vertical and lateral transport of particulate radiocesium off Fukushima. Environ Sci Technol 48:12595–12602

    Article  Google Scholar 

  • Saito K, Tanihata I, Fujiwara M, Saito T, Shimoura S, Otsuka T, Onda Y, Hoshi M, Ikeuchi Y, Takahashi F, Kinouchi N, Saegusa J, Seki A, Takemiya H, Shibata T (2015) Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident. J Environ Radioact 139:308–319

    Article  Google Scholar 

  • Santschi PH, Bower P, Nyffeler UP, Azevedo A, Broecker WS (1983) Estimates of the resistance to chemical transport posed by the deep-sea boundary layer. Limnol Oceanogr 28:899–912

    Article  Google Scholar 

  • Sawaragi T (1995) Coastal engineering—waves, beaches, wave-structure interactions. Elsevier, Amsterdam, p 478

    Google Scholar 

  • Seike K, Kitahashi T, Noguchi T (2016) Sedimentary features of Onagawa Bay, northeastern Japan after the 2011 off the Pacific coast of Tohoku Earthquake: sediment mixing by recolonized benthic animals decreases the preservation potential of tsunami deposits. J Oceanogr 72:141–149

    Article  Google Scholar 

  • Takata H, Hasegawa K, Oikawa S, Kudo N, Ikenoue T, Isono RS, Kusakabe M (2015) Remobilization of radiocesium on riverine particles in seawater: the contribution of desorption to the export flux to the marine environment. Mar Chem 176:51–63

    Article  Google Scholar 

  • Tateda Y, Tsumune D, Tsubono T (2013) Simulation of radioactive cesium transfer in the southern Fukushima coastal biota using a dynamic food chain transfer model. J Environ Radioact 124:1–12

    Article  Google Scholar 

  • Tateda Y, Tsumune D, Misumi K, Aono T, Kanda J, Ishimaru T (2017) Biokinetics of radiocesium depuration in marine fish inhabiting the vicinity of the Fukushima Dai-ichi Nuclear Power Plant. J Environ Radioact 166:67–73

    Article  Google Scholar 

  • Teal LR, Bulling MT, Parker ER, Solan M (2008) Global patterns of bioturbation intensity and mixed depth of marine soft sediments. Aquat Biol 2:207–218

    Article  Google Scholar 

  • TEPCO (Tokyo Electric Power Co.) (2016) Analysis results of radioactive materials obtained at each sampling location. http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/index-e.html. Accessed 13 Mar 2017

  • Wang C, Baumann Z, Madigan DJ, Fisher NS (2016) Contaminated marine sediments as a source of cesium radioisotopes for benthic fauna near Fukushima. Environ Sci Technol 50:10448–10455

    Article  Google Scholar 

  • Yagi H, Sugimatsu K, Kawamata S, Nakayama A, Udagawa T (2015) Bottom turbidity, boundary layer dynamics, and associated transport of suspended particulate materials off the Fukushima coast. In: Nakata K, Sugisaki H (eds) Impacts of the Fukushima nuclear accident on fish and fishing grounds. Springer, Tokyo, p 238

    Google Scholar 

  • Yamaguchi M, Kitamura A, Oda Y, Onishi Y (2014) Predicting the long-term 137Cs distribution in Fukushima after the Fukushima Dai-ichi nuclear power plant accident: a parameter sensitivity analysis. J Environ Radioact 135:135–146

    Article  Google Scholar 

Download references

Acknowledgements

The author is grateful to captains, crews and scientists of the R/V Tansei-Maru KT-11-27, KT-13-01, R/V Hakuho-Maru KH-11-07, R/V Shinsei-Maru KS-14-20, KS-15-13 (Univ. of Tokyo/JAMSTEC), and R/V Seikai (JAEA) cruises for their assistance in the fieldwork. The author is also grateful to J. Nishikawa, H. Narita, Y. Kato (Tokai Univ.), T. Aono, M. Fukuda (QST), M. Uematsu, H. Obata (Univ. Tokyo), H. Tazoe (Hirosaki Univ.), M.C. Honda (JAMSTEC), K.O. Buesseler (WHOI), S. Nagao (Kanazawa Univ.), T. Morita, T. Ono, H. Kaeriyama, D. Ambe (Natl. Res. Inst. Fish Sci., Japan), T. Kobayashi, H. Kawamura, T. Nakanishi, E. Takeuchi, M. Watanabe, Y. Kumagai, Y. Segawa, Y. Satoh, M. Nakano, T. Isozaki, M. Nemoto, K. Tobita, M. Nagaoka, M. Hirasawa, and K. Matsumura (JAEA) for their support in the field, laboratory work and their valuable comments. The manuscript was improved by two helpful reviews.

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  1. Research Group for Environmental Science, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan

    Shigeyoshi Otosaka

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Correspondence to Shigeyoshi Otosaka.

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Otosaka, S. Processes affecting long-term changes in 137Cs concentration in surface sediments off Fukushima. J Oceanogr 73, 559–570 (2017). https://doi.org/10.1007/s10872-017-0421-5

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  • DOI: https://doi.org/10.1007/s10872-017-0421-5

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