Long-term behavior of 137Cs and 3H activities from TEPCO Fukushima NPP1 accident in the coastal region off Fukushima, Japan
Decreasing trends of both 137Cs and 3H activity concentrations and an increasing trend of 3H/137Cs activity ratio at Fukushima Dai-ichi Nuclear Power Plant, FNPP1, were observed. Homogeneous distribution of 3H were observed off Fukushima and 3H activity concentrations ranged from 60 to 200 Bq m−3 in 2014. Contribution by relatively 3H rich water from surrounding rivers might be larger source of 3H rather than flux of 3H from FNPP1. Possibilities of observed high and variable 3H/137Cs activity ratio close to FNPP1 site may be evaporation of 3H or sporadic release of 3H rich/poor water from the site.
Keywords137Cs 3H Fukushima accident Activity ratio River water
The author thanks Rika Hozumi for her extraction work of caesium from seawater samples, Tomoni Onda for her work to prepare database and tables used in this study and Junkho Inomata, Kenji Watanabe and Azusa Goto for their support to collect seawater samples at Tomioka since June 2014. The author also thanks Satoshi Nakamura for collecting seawater samples at Hasaki at the research pier of Hazaki Oceanographical Research Station of the Port and Airport Research Institute since April 2011. The authors also thanks Yasunori Hamajima for his contribution to measure extracted caesium samples at Ogoya, Yukiko Suda for her work to handle spectra data of measured extracted caesium. A part of this work was supported by JSPS KAKENHI Grant Number JP15K00520 and by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan, (KAKENHI No. #24110005. A part of coastal observations at Tomioka and Hasaki presented in this article was supported by EC 7th Framework project COMET-FRAME (COordination and iMplementation of a pan-Europe instrumenT for radioecology) (Grant Agreement Number 604974) and a Marine Project of Institute of Environmental Radioactivity, Fukushima University, Japan. This article is based on two presentations and discussions, “IA-520 [Invited Talk] Long Term Behavior of TEPCO Fukushima NPP1 Accident Radiocaesium in the Coastal Region of Japan and the North Pacific Ocean, Past and Present: A Review” and “A-022 Radiocaesium in Surface Water Observed in Winter 2015/2016 in Both Coastal Regions of Japan and the Western North Pacific Ocean” at APSORC 17–6th Asia–Pacific Symposium on Radiochemistry held at ICC Jeju, Jeju Island, Korea on 17–22 September 2017.
- 1.The-2011-Tohoku-Earthquake-Tsunami-Joint-Survey-Group (2011) Nationwide field survey of the 2011 off the Pacific Coast of Tohoku Earthquake Tsunami. J Jpn Soc Civ Eng Ser B2 67(1):63–66. https://doi.org/10.2208/kaigan.67.63
- 3.Aoyama M, Kajino M, Tanaka TY, Sekiyama TT, Tsumune D, Tsubono T, Hamajima Y, Inomata Y, Gamo T (2016) 134Cs and 137Cs in the North Pacific Ocean derived from the March 2011 TEPCO Fukushima Dai-ichi Nuclear Power Plant accident, Japan. Part two: estimation of 134Cs and 137Cs inventories in the North Pacific Ocean. J Oceanogr 72(1):67–76. https://doi.org/10.1007/s10872-015-0332-2
- 5.Aoyama M, Hamajima Y, Hult M, Uematsu M, Oka E, Tsumune D, Kumamoto Y (2016) 134Cs and 137Cs in the North Pacific Ocean derived from the March 2011 TEPCO Fukushima Dai-ichi Nuclear Power Plant accident, Japan. Part one: surface pathway and vertical distributions. J Oceanogr 72(1):53–65. https://doi.org/10.1007/s10872-015-0335-z
- 7.Povinec PP, Aoyama M, Biddulph D, Breier R, Buesseler K, Chang CC, Golser R, Hou XL, Ješkovský M, Jull AJT, Kaizer J, Nakano M, Nies H, Palcsu L, Papp L, Pham MK, Steier P, Zhang LY (2013) Cesium, iodine and tritium in NW Pacific waters—a comparison of the Fukushima impact with global fallout. Biogeosciences 10(8):5481–5496. https://doi.org/10.5194/bg-10-5481-2013 CrossRefGoogle Scholar
- 8.Tsumune D, Aoyama M, Hirose K, Tsubono T, Misumi K, Tateda Y (2017) Estimations of direct release rate of 137Cs, 90Sr and 3 h from the Fukushima Dai-ichi Nuclear Power Plant for four-and-half years. In: Proceedings of the 4th international conference on environmental radioactivity, pp 24–28Google Scholar
- 10.Aoyama M, Hirose K (2008) Radiometric determination of anthropogenic radionuclides in seawater. In: Pavel PP (ed) Analysis of environmental radionuclides. Radioactivity in the environment, vol 11, 1st edn. Elsevier, Hungary, pp 137–162. https://doi.org/10.1016/s1569-4860(07)11004-4
- 11.Aoyama M (2018) Guideline of ocean observations, natural and artificial radioactivity. Guideline of ocean observations, vol 9, 2nd edn. The Oceanographic Society of Japan, TokyoGoogle Scholar
- 18.Galeriu D, Melintescu A (2011) Tritium: radionuclide. In: Encyclopedia of inorganic and bioinorganic chemistry. Wiley, New York. https://doi.org/10.1002/9781119951438.eibc0413
- 19.Nishihara K, Iwamoto H, Suyama K (2012) Estimation of fuel compositions in Fukushima-Daiichi Nuclear Power Plant(福島第一原子力発電所の燃料組成評価). JAEA-Data/Code 18:1–190Google Scholar
- 20.Chino M, Terada H, Nagai H, Katata G, Mikami S, Torii T, Saito K, Nishizawa Y (2016) Utilization of 134Cs/137Cs in the environment to identify the reactor units that caused atmospheric releases during the Fukushima Daiichi accident. Sci Rep 6:31376. https://doi.org/10.1038/srep31376 CrossRefPubMedPubMedCentralGoogle Scholar