Research Overview

　Department of International Cooperation and Collaborative Research was established to promote collaborative study with national and international scientist from April 2020. The IREM has been established in order to develop unprecedented approaches, such as health management in nuclear facilities and medical facilities for radiation exposure throughout all of Japan and train expert human resources who can respond to accidents of nuclear exposure in case of an emergency. We have been pursuing pioneering and advanced research in a wide range of natural sciences, mainly radiation science. It has been accredited as one of Joint Usage / Research Center advocating the “Environmental Radioactivity Research Network Center” from 2019. We will further promote collaborative research and use that as a new resource to develop more diverse and widespread radiation science research. We will focus on activities that contribute to the development of young researchers and social contribution through internship programs, Nuclear Researchers Exchange Program.

Laboratory Organization

• • Professor　Dr. Masahiro Hosoda (concurrent)
• • Associate Professor Hirofumi Tazoe
• • Assistant Professor Chutima Kranrod
• • Specially Appointed Assistant Professor Anderson Donovan
• • Visiting Research Associate　Taeko Shinonaga
• • Visiting Research Associate　Yosuke Amano
• • Visiting Research Associate　Masatoshi Yamada

Current Research Themes

A.Development of new analytical methods of radionuclides

1. Development of analytical methods for radioactive material in biological samples and study on the evaluation of internal exposure doses
2. Development of new analytical methods for radionuclides using the triple quadrupole inductively-coupled plasma mass analysis method, and understanding the status of pollution from the Fukushima Daiichi Nuclear Power Plant accident.
3. Development of automatic analysis system for Sr-90

B.Study of distribution and behavior of radionuclides in the environment

1. Study on the behavior of radionuclides in Ukedo river basin in Namie town, Fukushima prefecture
2. Accumulation of background data of artificial long-lived radionuclides in the environment

C.Study of isotope geochemistry in the oceanic environment

1. Geochemical study for lithogenic element using Neodymium (Nd) and Radium (Ra) isotopes

D.Study of Radon, Thoron and Their Progeny

1. Radon, Thoron and Their Progeny Level in Dwellings at Mae-Chaem District, Chiang Mai, Thailand
2. Radon and Its Progeny Assessments in Dwellings and Water at Doi-Lor District, Chiang Mai, Thailand
3. Environmental Radioactivity Survey on Radon, Thoron and Their Progeny in the northern and the central regions of Thailand
4. Preliminary characterization studies of Rn-222 progeny calibration chamber (India)
5. Evaluate the conversion factor of Rn-Tn progeny by alpha-track detector for their progeny concentration in the dwellings (Thailand)
6. Study on the migration law of radioactive aerosol (China)

Experimental/equipment

Recent Projects

1. Hirofumi Tazoe (research contributor), Grants-in-Aid for Scientific Research (B),　Study for the bottom water circulation using radioactive cesium and strontium, (2019-2021)
2. Hirofumi Tazoe (research representative), Grants-in-Aid for Scientific Research (B), Reconstruction of bioavailable Cs-137 in river water just after the accident of the Fukushima Daiichi Nuclear Power Plant from record on biological hard tissue, (2018-2020)
3. Hirofumi Tazoe (research contributor), Grants-in-Aid for Scientific Research (B), Establishment of habitat history estimation method for migratory fish by using advanced geochemical analysis method　(2016-2018)
4. Hirofumi Tazoe (research representative), Grants-in-Aid for Scientific Research (C), Quantitative measurement of radioactive strontium by the micro-chemical chip online-concentration ICPMS (2014-2016)
5. Hirofumi Tazoe (research contributor)，Grant-in-Aid for Scientific Research on Innovative Areas, Investigation for mixing and geochemical cycle in the Okhotsk and Bering Seas. (2017-2019)
6. Hirofumi Tazoe (research contributor)，Grants-in-Aid for Scientific Research (C),　 Test to improvement for absorption efficiency and stability decontamination effect of radioactive cesium, (2016-2019)
7. Hirofumi Tazoe (research representative), Academic collaborative research of the Atmosphere and Ocean Research Institute, University of Tokyo, Establishment of an estimation approach of migration routes using neodymium isotope ratio analysis of marine fish vertebra (2015)
8. Hirofumi Tazoe (research contributor), Grant-in- Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Understanding the status of distribution of radioactive materials in the ocean and ocean floor (2012-2016)

Recent published papers

1. Hegedus, M., Shiroma, Y., Iwaoka, K., Hosoda, M., Suzuki, T., Tamakuma, Y., Yamada, R., Tsujiguchi, T., Yamaguchi, M., Ogura, K., Tazoe, H., Akata, N., Kashiwakura, I., Tokonami, S. Cesium concentrations in various environmental media at Namie, Fukushima Journal of Radioanalytical and Nuclear Chemistry. 323(1), 197-204 (2020).
2. Tazoe, H., Yamagata, T., Tujita, K., Nagai, H., Obata, H., Tsumune, D., Kanda J., Yamada, M. Observation of Dispersion in the Japanese Coastal Area of Released 90Sr, 134Cs, and 137Cs from the Fukushima Daiichi Nuclear Power Plant to the Sea in 2013. International Journal of Environmental Research and Public Health. 16 (21), 4094 (2019)
3. Zhao, L., Tanaka, K., Tazoe, H., Iizuka, T., Kubota, K., Sugihara, M.N., Shirai, K. Determination of the geographical origin of marine mussels (Mytilus spp.) using 143Nd/144Nd ratios, Marine Environmental Research, 148, 12-18 (2019)
4. Kritsananuwat, R., Kranrod, C., Chanyotha, S., Ploykrathok, T., Sriploy, P., Natural radionuclides in agricultural plants from nouthern Thailand. Radiation Protection Dosimetry. 184(3-4):397-9 (2019).
5. Janik, M., Tokonami, S., Iwaoka, K., Karunakara, N., Trilochana, S., Mohan, M.P., et al. Comparison of Radon and Thoron Concentration Measuring Systems Among Asian Countries. International Journal of Environmental Research and Public Health, 16(24) (2019).
6. Yang, G, Hu, J., Tsukada, H., Tazoe, H., Shao, Y., Yamada, M. Vertical distribution of 129I and radiocesium in forest soil collected near the Fukushima Daiichi Nuclear Power Plant boundary. Enironmental Pollution, 250, 578−585 (2019)
7. Yang, G, Rahman, M.S., Tazoe, H., Hu, J., Shao, Y., Yamada, M. ²³⁶U and radiocesium in river bank soil and river sediment in Fukushima Prefecture, after the Fukushima Daiichi Nuclear Power Plant accident. Chemosphere, 225, 388−394 (2019)
8. Shao, Y., Yang, G., Xu, D., Yamada, M., Tazoe, H., Luo, M., Cheng, H., Yang, K., Ma, L. First report on global fallout ²³⁶U and uranium atom ratios in soils from Hunan Province, China. Journal of Environmental Radioactivity 197, 1−8 (2019)
9. Amakawa, H., Yu, TL., Tazoe, H., Obata, H., Gamo, T., Sano, Y., Shen, C.C., Suzuki, K. Neodymium concentration and isotopic composition distributions in the southwestern Indian Ocean and the Indian sector of the Southern Ocean. Chemical Geology 511, 190-203 (2019)
10. Shao, Y., Yang, G., Tazoe, H., Yamada, M., Ma, LL., Xu, D. A review of measurement methodologies and their applications to environmental Sr-90.. Journal of Environmental Radioactivity 192, 321-333 (2018)
11. Yang, G., Tazoe, H., Yamada, M. Improved approach for routine monitoring of I-129 activity and I-129/I-127 atom ratio in environmental samples using TMAH extraction and ICP-MS/MS. Analytica Chimica Acta, 1008, 66–73 (2018)
12. Yang, G. S., Y. Kato, H. Tazoe, M. Yamada: Applying an improved method to measure ¹³⁴Cs, ¹³⁵Cs, and ¹³⁷Cs activities and their atom ratios in marine sediments collected close to the Fukushima Daiichi Nuclear Power Plant. Geochemical Journal, 52, 219-226 (2018)
13. Tazoe, H., H. Obata, M. Tomita, S. Mamura, J. Nishioka, T. Yamagata, Z. Karube, M. Yamada: Novel method for low level Sr-90 activity in seawater by combining oxalate precipitation and chelating resin extraction. Geochemical Journal, 51(2), 193-197 (2017) DOI:10.2343/geochemj.2.0441
14. Yang, G., Tazoe, H., Yamada, M. Can ¹²⁹I track ¹³⁵Cs, ²³⁶U, ²³⁹Pu, and ²⁴⁰Pu apart from ¹³¹I in soil samples from Fukushima Prefecture, Japan? Scientific Reports DOI:10.1038/s41598-017-15714-w (2017)
15. Yang, G., Tazoe, H., Kazuhiko, H., Kumiko, O., Yamada, M. Isotopic compositions of ²³⁶U, ²³⁹Pu, and ²⁴⁰Pu in soil contaminated by the Fukushima Daiichi Nuclear Power Plant accident. Scientific Reports DOI: 10.1038/s41598-017-13998-6 (2017)
16. Yang, G. S., H. Tazoe, M. Yamada: Determination of ²³⁶U in environmental samples by single extraction chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry. Analytica Chimica Acta, 944, 44-50 (2016) DOI: 10.1016/j.aca.2016.09.033
17. Yang, G. S., H. Tazoe, M. Yamada: ¹³⁵Cs activity and ¹³⁵Cs/¹³⁷Cs atom ratio in environmental samples before and after the Fukushima Daiichi Nuclear Power Plant accident. Scientific Reports, 6, 24119 (2016) DOI: 10.1038/srep24119
18. Chanyotha, S., Kranrod, C., Pengvanich, P., Sriploy, P., Determination of radon in natural gas pipelines. Journal of Radioanalytical and Nuclear Chemistry. 307(3):2095-9 (2016).
19. Tazoe, H., H. Obata, T. Yamagata, Z. Karube, H. Nagai, M. Yamada: Determination of strontium-90 from direct separation of yttrium-90 by solid phase extraction using DGA Resin for seawater monitoring. Talanta, 152, 219-227 (2016) DOI:10.1016/j.talanta.2016.01.065
20. Chanyotha, S., Kranrod, C., Kritsananuwat, R., Lane-Smith, D., Burnett, W.C., Optimizing laboratory-based radon flux measurements for sediments. Journal of Environmental Radioactivity. 158:47-55 (2016).
21. Yang, G. S., H. Tazoe, M. Yamada: Rapid determination of 135Cs and precise 135Cs/137Cs atomic ratio in environmental samples by single-column chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry. Analytica Chimica Acta, 908, 177-184 (2016) DOI: 10.1016/j.aca.2015.12.041
22. Chanyotha, S., Kranrod, C., Pengvanich, P., Systematic apporch to characterization of NORM in Thailand. Radiation Protection Dosimetry. 167(1-3):15-21 (2015).
23. 20. Sorimachi, A., Tokonami, S., Kranrod, C., Ishikawa, T., Preliminary Experiments Using a Passive Detector for Measuring Indoor 220Rn Progeny Concentrations with an Aerosol Chamber. Health Physics. 108(6):597-606 (2015)
24. Pornnumpa, C., Tokonami, S., Sorimachi, A., Kranrod, C., Characteristics of indoor radon and its progeny in a Japanese dowelling while using air appliances. Radiation Protection Dosimetry. 167(1-3):87-91 (2015).
25. Kranrod, C., Chanyotha, S., Pornnumpa, C., Kritsananuwat, R., Sriploy, P., BASELINE DATA OF NATURALLY OCCURRING RADIONUCLIDES IN SOME NATIVE VEGETABLES AND FRUITS IN SOUTHERN THAILAND. Radiation Protection Dosimetry. 167(1-3):270-5 (2015).