English Japanese
Michio AOYAMA, Dr Sc.青山道夫
Visiting Professor

Institute of Environmental Radioactivity
Radioisotope Geoscience Division, Marine Radionucled Dynamics

Work experience and the main results

*32 years of experience in environmental radioactivity, assessment and evaluation (atmosphere and oceans) and in the development of analytical methods of radioactivity.
*39 years of experience in hydrography, assessment of long term trend of physical and biogeochemical parameters and in the development of establish standard materials and quality assurance of salinity and nutrients in seawater.
*Re-evaluation of total amount of the global fallout and confirm that a new estimate of 765 ± 79 PBq as global 137Cs fallout for the Northern Hemisphere is 1.4 times higher than that of 545 PBq in the UNSCEAR's estimate.
*Provide one of the best evaluation of total amount of released radiocaesium from Fukushima Dai-ichi Nuclear Power Plant accident in 2011 based on observations in the North Pacific Ocean and atmospheric and ocean dispersion model simulations. I obtained 12-15 PBq for the total atmospheric deposition of 137Cs released by the FNPP1 accident into the North Pacific Ocean. The combined input to the North Pacific Ocean (the corrected atmospheric contribution plus the direct discharge) was thus around 15-18 PBq. I also estimated the total amount of 137Cs released to the atmosphere to be 15-20 PBq, and the total amount of 137Cs released to the environment to be 19-24 PBq, respectively. Observed 134Cs to 137Cs activity ratio at the time of accident was close to 1 and extremely uniform, therefore, the total amount of 134Cs deposition in the North Pacific Ocean, that of released to the atmosphere, that of direct discharge to the ocean and that of released to the environment were the same as those of 137Cs.
*Evaluation of sources of radioactivity in the environment - global fallout, Chernobyl fallout, releases from nuclear installations (nuclear power stations, reprocessing plants).
* Development of certified reference material of nutrients in seawater in seawater matrix and its use in WOCE, CLIVAR and GO-SHIP cruises since 2003. SCOR-JAMSTEC logo CRMs of nutrients in seawater is available for the community since November 2016.
* Establish the offset table of IAPSO salinity standards and its application of global salinity data.
* Marine radioactivity monitoring and assessment - development and use of low-level 137Cs measurement in deep sea waters.
* Development of marine radioactivity database, a relational database, HAM database, for radioactivity in the world ocean.
* Organization of international workshops, national symposiums (5 international workshops and 6 national symposiums)

Other major international projects

WOCE WHP PC committee member (1995-2000)
IOCCP SSG member (2012- )
SCOR WG 147 Towards comparability of global oceanic nutrient data (COMPONUT) Co-Chair (2014- )
SCOR WG146 Radioactivity in the Ocean, 5 Decades Later (RiO5) full member (2014-)


Published 116 reviewed articles in international journals and books. Author and co-authors of 19 international and national reports and 8 data books

University degrees

1977Meteorological College
1999Kanazawa Univ. degree in Doctor of Science

Present post

Visiting Professor
Faculty of Life and Environmental Sciences, Univ. of Tsukuba

Visiting Professor
Institute of Environmental Radioactivity, Fukushima University

Previous posts

1984-1989Scientist, Geochemical Research Department, Meteorological Research Institute
1989-1993Senior Technical Officer, Nagasaki Marine Observatory
1993-1995Senior Scientist, Ocean Research Department, JAMSTEC
1995-2014Senior Scientist, Geochemical Research Department, Meteorological Research Institute, Japan Meteorological Agency
2014-2019Professor, Institute of Environmental Radioactivity, Fukushima University