Internal doses to the public in the Fukushima prefecture from the Fukushima Daiichi NPP accident

The article is devoted to the analysis of internal dosimetry in residents of Fukushima Prefecture due to the accident at the Fukushima-Daiichi NPP. On March 24-30, 2011, screening studies were conducted on measurements of  ¹³¹I content in thyroid gland of children in those municipalities where the Japanese program for assessing the radiological consequences of the radiation accident “SPEEDI” predicted doses in the thyroid of one-year children from 100 to 500 mSv. Among 1080 children measured, 55% had results below the background, and the maximum estimate of the equivalent dose in the thyroid was 43 mSv. Measurements of several dozen inhabitants with other instruments and methods confirmed low levels of  ¹³¹I in the thyroid. In total, the  ¹³¹I thyroid direct measurement database of Fukushima residents contains approximately 1300 individuals. 75% quartile of individual thyroid dose distributions was below 10 mSv, the median was from 0 to 3.7 mSv among children aged from 0 to 15 years in the five examined municipalities. The contribution of short-lived iodine radionuclides was estimated as 15% of the dose from  ¹³¹I for the main radioactive release on March 15. The effective dose of internal exposure to cesium radionuclides ( ¹³⁴Cs +  ¹³⁷Cs), estimated from 10 thousand whole body measurements for the first year after the accident, was below 0.1 mSv in 90% of the examined people. Whole body measurements of children 6-15 years old in the second year after the accident confirmed the values of the effective dose of internal exposure less than 0.1 mSv, while the estimates of the effective dose of external exposure in the same children with using individual dosimeters determined the median distribution as 0.66 mSv with a maximum value of 3.45 mSv . The measurement results do not provide any basis to expect a future increase in the incidence of thyroid cancer and other radiogenic diseases among the Fukushima residents. Preventive evacuation of the population before the radioactive release, stay in enclosed dwellings, strict radiation control of food products have effectively reduced the expected doses of internal exposure to residents. In the predictions of the radiological consequences of the accident, it is necessary to take into account the actually implemented measures to protect the population, and local characteristics of the style of life and living.

1. WHO. Preliminary dose estimation from the nuclear accident after the 2011 Great East Japan earthquake and tsunami. World Health Organization. Geneva, 2012.

2. WHO. Health risk assessment from the nuclear accident after the 2011 Great East Japan earthquake and tsunami based on a preliminary dose assessment. Draft report of the World Health Organisation. Geneva, February 2013. World Health Organisation. Geneva, 2013.

3. United Nation Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). Levels of effects of radiation exposure due to the nuclear accident after the 2011 Great East-Japan Earthquake and Tsunami, 2014. UNSCEAR 2013 Report Volume 1. Scientific Annex A: http://www.unscear.org/unscear/en/publications/2013_1.html (дата обращения: 21.06.2020)

4. Fukushima, one year later. Initial analyses of the accident and its consequences. Report IRSN/DG/2012-003 of March 12. Paris, 2012.

5. Golikov VYu, Zvonova IA. Dose assessments to residents of Japan. In the monograph: “Accident at the Fukushima-1 NPP”, Ed. Acad. RAMS G.G. Onischenko. Saint-Petersburg: NIIRG named after Prof. P.V. Ramzaev; 2012: 336. (In Russian).

6. United Nations Scientific Committee on the Effects of Atomic Radiation. UNSCEAR 2008 report Vol. II. Effects of ionizing radiation. Annex D: Health effects due to radiation from the Chernobyl accident. United Nations. New York, 2011.

7. Cardis E, Kesminiene A, Ivanov V, Malakhova IV, Shibata Y, Khrouch V, et al. Risk of thyroid cancer after exposure to 131I in childhood. Journal of the National Cancer Institute. 2005;97(10): 724-732.

8. Cardis E, Howe G, Ron E, Bebeshko V, Bogdanova T, Bouville A, et al. Cancer consequences of the Chernobyl accident: 20 years after. Journal of Radiological Protection. 2006;26: 127-140.

9. Likhtarev I, Kovgan L, Vavilov S, Chepurny M, Ron E, Lubin J, et al. Post-Chernobyl thyroid cancers in Ukraine, Report 2: Risk analysis. Radiation Research. 2006;166(2): 375-386.

10. Preston DL, Ron E, Tokuoka S, Funamoto S, Nishi N, Soda M, et al. Solid cancer incidence in atomic bomb survivors: 1958-1998. Journal of Radiation Research. 2007;168(1): 1-64.

11. Furukawa K, Preston D, Funamoto S, Yonehara S, Ito M, Tokuoka S, et al. Long-term trend of thyroid cancer risk among Japanese atomic-bomb survivors: 60 years after exposure. International Journal of Cancer. 2013;132(5): 1222-1226.

12. Nuclear Regulation Authority of Japan. Available from: http://www.nsr.go.jp/archive/nsc/mext_speedi/0312-0324_in.pdf [Accessed 21 June 2020].

13. Kim E, Kurihara O, Suzuki T, Matsumoto M , Fukutsu K , Fukutsu Yu , et al. Screening survey on thyroid expo sure for children after the Fukushima Daiichi nuclear power station accident (NIRS-M-252). In: Proceedings of the 1st NIRS Symposium on Reconstruction of Early Internal Dose in the TEPCO Fukushima Daiichi Nuclear Power Station Accident. Chiba, Japan; National Institute of Radiological Sciences; 2012: 59–66: http://www.nirs.go.jp/publication/irregular/pdf/nirs_m_252.pdf [Accessed 21 June 2020].

14. Hosokawa Y, Hosoda M, Nakata A, Kon M. Thyroid Screening Survey on Children after the Fukushima Daiichi Nuclear Power Plant Accident. Radiation Emergency Medicine. 2013;2(1): 82-86.

15. Tokonami S, Hosoda M, Akiba S, Sorimachi A, Kashiwakura I, Balonov M. Thyroid doses for evacuees from the Fukushima nuclear accident. Scientific Reports. 2012; 2: 507.

16. Matsuda N, Kumagai A, Ohtsuru A, Morita N, Miura M, Yoshida M, et al. Assessment of Internal Exposure Doses in Fukushima by a Whole Body Counter Within One Month after the Nuclear Power Plant Accident. Journal of Radiation Research. 2013;179: 663–668.

17. Ohtsuru A, Midorikawa S, Ohira T, Suzuki S, Takahashi H, Murakamiet M, et al. Incidence of Thyroid Cancer Among Children and Young Adults in Fukushima, Japan, Screened With 2 Rounds of Ultrasonography Within 5 Years of the 2011 Fukushima Daiichi Nuclear Power Station Accident. Journal of Otolaryngology – Head & Neck Surgery. 2019;145(1): 4–11.

18. Balonov MI, Anspaugh LR, Bouville A, Likhtarev IA. Contribution of internal exposures to the radiological consequences of the Chernobyl accident. Radiation Protection Dosimetry. 2007;127(1–4): 491–6. Epub 2007/11/06. doi: 10.1093/rpd/ncm301 PMID: 17977893.

19. Nagataki S, Shisume K, Nakao R. Thyroid Function in Chronic Excess Iodide Ingestion: Comparison of Thyroidal Absolute Iodine Uptake and Degradation of Thyroxine in Euthyroid Japanese Subjects. Journal of Clinical Endocrinology and Metabolism. 1967;27(5): 638-647.

20. Zvonova IA. Dietary intake of stable iodine and some aspects of radioidine dosimetry. Health Physics. 1989;57(3): 471-475.

21. ICRP, 1989. Age-dependent doses to members of the public from intake of radionuclides: Part 1. ICRP Publication 56. Ann. ICRP 20(2).

22. Kim E, Kurihara O, Kunishima N, Momose T, Ishikawa T, Akashi M. Internal thyroid doses to Fukushima residents—estimation and issues remaining. Journal of Radiation Research. 2016; 57: i118–i126.

23. Kim E, Yajima K, Hashimoto S, et al. Reassessment of Internal Thyroid Doses to 1,080 Children Examined in a Screening Survey after the 2011 Fukushima Nuclear Disaster. Health Physics. 2019;118(1): 1. DOI: 10.1097/HP.0000000000001125

24. Shinkarev SM, Kotenko KV, Granovskaya EO, Yatsenko VN, Imanaka T, Hoshi M. Estimation of the contribution of shortlived radioiodines to the thyroid dose for the public in case of inhalation intake following the Fukushima accident. Radiat. Prot. Dosimetry. 2015;164(1-2): 51–56. Doi:10.1093/rpd/ncu335.

25. Shinkarev SM, Samoilov AS, Granovskaya EO, Korneva EA, Kukhta BA, Androsova AA, et al. Comparative analysis of the contribution of short-lived iodine isotopes to the thyroid dose in the population after the Chernobyl and Fukushima accidents. Gigiena i sanitariya = Hygiene and sanitation. 2017; 96 (9): 827-832. (In Russian).

26. Balonov M, Kaidanovsky G, Zvonova I, Kovtun A, Bouville A, Luckyanov N, et al. Contributions of short-lived radioiodines to thyroid doses received by evacuees from the Chernobyl area estimated using early in vivo activity measurements. Radiation Protection Dosimetry. 2003;105(1–4): 593–599.

27. Gavrilin Yu, Khrouch V, Shinkarev S, Drozdovitch V, Minenko V, Shemiakina E, et al. Individual thyroid dose estimation for a case-control study of Chernobyl-related thyroid cancer among children of Belarus—Part I: 131I, short-lived radioiodines ( 132I, 133 I, 135I), and short-lived radiotelluriums (131mTe and 132Te). Health Physics. 2004;86: 565–585 .

28. Hosoda M., Tokonami Sh, Tazoe H, Sorimachi A, Monzen S, Osanai M, et al. Activity concentrations of environmental samples collected in Fukushima Prefecture immediately after the Fukushima. Scientific reports. 2013;3: 2283. DOI: 10.1038/srep02283.

29. Momose T, Takada Ch, Nakagawa T, Kanai K, Kurihara O. Whole-body Counting of Fukushima Residents after the TEPCO Fukushima Daiichi Nuclear Power Station Accident. (NIRS-M-252). In: Proceedings of the 1st NIRS Symposium on Reconstruction of Early Internal Dose in the TEPCO Fukushima Daiichi Nuclear Power Station Accident. Chiba, Japan. National Institute of Radiological Sciences; 2012: 67–82.

30. Takada C, Kurihara O, Tsujimura N, Kanai K, Nakagawa T, Miyauchi H, et al. Evaluation of Internal Exposure of the Workers and the Residents Caused by the Fukushima Nuclear Accident. 13th International Congress of International Radiation Protection Association (IRPA13) At: Glasgow, Scotland. – Available from: http://www.irpa13glasgow.com/information/downloads/, File P12.22.doc. [Accessed 21 June 2020].

31. Tsubokura M, Kato S, Morita T, Nomura S, Kami M, Sakaihara K, et al. Assessment of the Annual Additional Effective Doses amongst Minamisoma Children during the Second Year after the Fukushima Daiichi Nuclear Power Plant Disaster. PLoS ONE. 2015;10(6): e0129114. doi:10.1371/journal.pone.0129114.

32. Tsubokura M, Kato S, Nomura S, et al. Absence of internal radiation contamination by radioactive cesium among children affected by the Fukushima Daiichi nuclear power plant disaster. Health Phys. 2015;108: 39–43.