ISET-R Newsletter
9/1/2016 Vol. 9, Issued By Onda Lab, University of Tsukuba
http://www.ied.tsukuba.ac.jp/hydrogeo/isetr/

IS ET- R

Grant-in-Aid for Scientiﬁc Research on Innovative Areas
the Ministry of Education, Culture, Sports, Science, and Technology Japan 2012.

Interdisciplinary Study on
Environmental Transfer of Radionuclides
from the Fukushima Daiichi NPP Accident

ISET-R Plenary Conference@Laboratory of Advanced Research A in University of Tsukuba
March 11-12, 2016

Five years have passed since FDNPP, the Fukushima Dai-ichi Nuclear Power Plant accident. 4th ISET-R
Plenary Conference was held on 11-12 March 2016. Ninety-four participants participated this conference andactive discussion have conducted .
On the first day, the head investigator, Prof. Yuichi Onda made an explanation on the objective and futureplans of the Plenary Conference, followed by presentations on recent progress on their reserach from theprincipal investigators of each research group. Discussions were held in each four research group (B01 :chemical status, B02 : forest, B03 : terrestrial environment to rivers, B04 : calculation of radiation exposure).
After the discussion, convivial gathering was held.
On the second day, discussions were held on how to complete the final report and what to do in the final year
for the project. Four sectional research groups are the projects dealing with four cross-sectoral themes which
are expected to create a new research in Grant-in-Aid for Scientific Research on Innovative Areas.
Coordination committiee focuses on those projects aiming to strengthen the collaboration between them, by
supporting holding a work shop and so forth.
All the public offering researches belong to one of four projects, aiming to consolidate a collaborative
research and to create a new research. The notable point of B04 is that this group collects all the research resultsof environmental transfer of radionuclides and carries out an evaluation of radiation exposure in a specific area
to make a feed back to the residents and ecosystem.

B01

B02

Estimation of deposition process of radionuclides
based on the investigation, analysis and clarificationof chemical status at the time of release and impact
assessment of transfer [A01, A03, A04]

Clarification of circulation process of radionuclides
in forest environment and modeling of the process[A01, A03, A04]

B03

B04

Clarification of transfer process of radionuclides
from terrestrial environment to marine environment
through river network [A02, A03, A04]

Calculation of locational radiation exposure basedon radionuclide behavior and transfer in theenvironment [A01, A02, A03, A04]

ISET-R Newsletter, Volume 9

Presentation on recent developments ofresearch by principle investigators of each research group
Group A01-1
Teruyuki NAKAJIMA , Japan Aerospace Exploration
Agency“Understanding the atmospheric transport modeling andtransfer process of fallout radionuclides”
Collaborative research with A01-2(Land atmosphere) for
grasping composition and form through sampling and observing
the concentration in the atmosphere, and another joint workwith coordination committee, A04-7(Chemical forms) andA04-8(Development of measurement Technology) have led to a further understanding of wet and dry
deposition flux, time change of density in atmosphere and its variation factor. We would like to associatewith A02-3(Ocean) and A02-4(Marine economics) for the study of deposition in the ocean and influenceon life, and with A03-5(Migration process at land) and A03-6(Terrestrial ecology) for the study ofdeposition in land and migration to soil and ground water.
Group A01-2
Yasuhito IGARASHI, Meteorological ResearchInstitute“Understanding atmospheric deposition, dispersion process,and land interaction of radionuclides”
Such research results have been improving as 1) systematiccollection and radioactivity analysis of air sample 2)
elucidation of primary release 3) elucidation of secondary
release 4) accuracy improvement of atmospheric model andmodeling re-entrainment process.
Cooperation with A01-1, 02-3, 03-5, 03-6, 04-7 and 04-8 is reflected on a model calculation. And we held
projects for fostering young researchers “collection method and electron microprobe analysis of air sample
using high volume sampler” and “writing thesis training” , and the latter one received favorable reviews.
Group A02-3
Masatoshi YAMADA, Hirosaki University“Understanding the distribution status of radionuclides in sea
and seafloor sediment”
So far, efforts have been put on grasping the dispersion ofradionuclides in the sea and seafloor sediments. We’ re aiming
at gathering a wide range of data and elucidating thecirculation process in the sea.
Clarification of the vertical transport process of radionuclides
to the seafloor sediment, and the released amount ofradionuclides other than 134Cs and 137Cs such as 90Sr, 129I, 239+240Pu are also required.

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ISET-R Newsletter, Volume 9Group A02-4
Jota KANDA, Tokyo University of Marine Science andTechnology“Understanding the migration and concentration of radioactive
materials in marine ecosystems”
Tokyo University of Marine Science and Technology has been
analyzing spatio-temporal distribution of radioactivity
concentration in the seawater, seafloor sediments, plankton, andbenthos since July 2011 in collaboration with Fukushima
Prefectural Fisheries Experiment Station, Fukushima University
Institute of Environmental Radioactivity, and National Institute for Quantum and Radiological Science andTechnology. This year, a research was conducted boarding a research training vessel, Oshoro-maru,
collaborating with Hokkaido University. High-dose particles were found in the plankton samples with highconcentration of 137Cs and settling particles. Therefore, we’ re studying on reasons why 137Cs concentrations
greatly differ from study to study, from samples to samples. New themes were raised as to possibility of transfer
of high-dose radiocesim particles to creatures, origin of high-dose particles, and transfer process to oceans.
Group A03-5
Yuichi ONDA, University of Tsukubae“Understanding the migration process of radionuclides
associated with water and sediment”
As a result of monitoring transfer of radionuclides in forest
catchments and rivers including Abukuma River and Nitta River,
together with modeling of such observations, we found that theland use has influence on radionuclide transfer. In verifying suchmodels, estimation based on each observation site is required toclarify how radionuclides flow down the river, accumulate, andreach the marine area.
As to cesium flux from rivers to oceans, it is crucial to estimate cesium transfer flux and its timing and to
identify a proper timing to grasp the cesium transfer.. We also need to keep working on a task about how weshould integrate a radiocesium concentration into a flux from many rivers including Niida River.
We are working on a study of cesium flux to the ocean and calculation of its timing (collaboration with
A03, A04 and A07), measurement of the ecosystem in the Cs deposited areas in the moderate level(collaboration with A06), influence evaluation including on decontamination effect, and understanding thewhole image of cesium flux(collaboration with A02, A06 and IRSN).

Group A03-6
Chisato TAKENAKA, Nagoya University“Understanding the radionuclide circulation process interrestrial ecosystem”
Various kinds of investigations have been conducted so far,and for the final year we are planning to set our goal of gaining
a general understanding of where, how long and what kind ofform radioactive Cs would exist in Setohachiyama (cedar,
Japanese red pine, broad leaved forest), conducting a future

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ISET-R Newsletter, Volume 9prediction using a model, and experiment on clarifying whether the model can be applied to a transfer ofwild life. And the themes that we should work on in future are studies on accuracy improvement onmodeling cedar trees, influence from decomposition on spherical cesium-bearing particles and its
localization, organizing both common and different point about kinetics of potassium and contribution of
mycorrhizal fungi in a root absorption into each tree species.
Group A04-7
Yoshio TAKAHASHI, Tokyo University“Development of microanalysis technology and chemical
form of radionuclides associated with migration”
What we have worked on is (1) develop and apply
high-sensitivity measurement that enables estimating
quantity of tiny amount of radionuclides (2) research on
existence form from macro to micro (including a method
development), and elucidation of element process andtransfer estimation. It is essential to clarify a change of Kd
affected by an ionic strength and increase of total Cs concentration in modeling adsorption and desorption
transfer of cesium into particle settled in the ocean. It could be possible that our analysis of stable isotope
ratio in spherical cesium-bearing particles enables isotope fractionation from Fe and Zn in anthropogenic
aerosol to identify an existence of volatilization process and estimation of volatile temperature.
Group A04-8
Atsushi SHINOHARA, Osaka University“Radionuclide measurement in various chemical forms anddevelopment of technology”
Our outcomes include developing and standardizing
radioactivity analysis method, developing chemical
pretreatment and measurement method and simulation onradioactive isotope release. In the simulation, we haveworked on an experiment on element release from dummyfuel under high temperature, a simulation on creating
insoluble particles that contain an amount of Cs, a research on bond behavior of aerosol in-reactor, and an
elucidation of composed behavior of aerosol in the environment to clarify cesium release fromradionuclides fuel or condition in reactor when the plants got a major damage by the massive damage.

At the end of the first day, a convivial gathering was held.
An active discussion was exchanged, and the participants
built intimacy between them.
In a project for fostering young researchers, who take alead in a study on environmental transfer of radionuclides
which is crucial theme of ISET-R, two participants wereawarded for attending programs in all fields.

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ISET-R Newsletter, Volume 9They were Kotaro Ochi (Meiji University) and Shota
Kanbayashi (Toyama University), who were granted acertification by the head investigator.
Mr.Ochi who got hired at Japan Atomic Energy Agency spokeof his aspiration as a leader of young researchers for a study
on environmental transfer of radionuclides.
On the second day, the conference started with a poster
presentaion. There were 34 presentations, and a productive
discussion was held, followed by a presentation and overall
discussion over what was discussed the previous day in the four research groups at 10am.
Such agendas as how to conclude the project, what to do for the final report and what themes should be focusedon were discussed.

B01 Chemical forms, Yasuhito IGARASHI

Themes we are working on involve chemical forms of insoluble cesium(cesium ball), of radioactive iodine and etc. Our major goal is to search
for the form in a radiation release. We keep working on experiments ofiodine and cesium although it’ s difficult to clarify and get a certain result
from a research on cesium. We are planning to indicate sampling sites on
a map to make a whole picture clearer for a further understanding.

B02 Forest, Chisato TAKENAKA

We consider that the goals of the study on cesium behavior in a forest
ecosystem are future estimation in the utilization of forest and wildlife
animals, and influence on agricultural lands. There are many tasks weshould deal with, but priorities are to be set on suggestions on forest
management/utilization based on types of vegetation and zoning by theamount of deposition. Moreover, we need to clarify the transfer of cesium
to the outside forest environment. We will summarize our five-year study
and show the overall view of what is essential in the study of forests and what happened to the radionuclides
deposited in the forests.

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ISET-R Newsletter, Volume 9

B03 From terrestrial environment to rivers, Yuichi ONDA

There are still many tasks to tackle such as discharge of radionuclides froma forest environment, behavior of radionuclides in rice paddy field andfarmland. The study on transfer of radionuclides from the upstream Niida
River in Fukushima to the ocean has just started and we found that the
sediment deposited near the mouth of the river is being eroded. In studying
river environment, it is essential to focus on temporal variation ofradionuclide concentration, identification of subjects to which radionuclides are attached, influence offlooding, estimation of flux, and desorption in sea water. The results of the study including river monitoringand effect of land use will be reflected in the article now being written.
B04 Calculation of radioactive exposure, Haruo TSURUTA

Estimation of internal exposure to radioactive materials via respiration in
short-term, mid-term and long-term (lifetime) after the FDNPP accident isa specific research agenda to examine. It is important to collect data on
material balance of radionuclides and their temporal variation in eachresearch field and to clarify the mechanism. Together with the collection
and discovery of database available to use, we will put efforts in building
such mechanism. Consolidation of data which are being published in articles should be proceeded.
At the end of the conference, encouraging comments were given from the advisors.
Professor Shibata: Where did the cesium deposited on mountains go? It has to be clarified by this group, so
please make efforts to draw a picture to visualize the research achievements.”
Professor Gamou: Research has been conducted from various angles and now is the time to wrap up theachievements of five years. Creating a database is a critical task.”
Professor Moriguchi: The study itself is scientifically interesting, but we have to be careful as to how weconvey the results. Efforts have to be made to announce an overall picture. The results obtained by the
projects will be beneficial especially to those who have been affected by the FDNPP accident.”<Subsequent conference>
On July 2, 2016, a subsequent ISET-R Plenary Conference was held at Yokohama Institute for Earth Sciences, JAMSTEC.
The materials are posted on our ISET-R website at http://www.ied.tsukuba.ac.jp/hydrogeo/isetr/member/160702General.html.
<Scheduled programs fostering young researchers>[A01-1] Theme: The Third Seminar on the simulation of radioactive contamination caused by FDNPP accident
Date: August 25 & 26, 2016 at Asano Section, Hongo Campus, University of Tokyo[A01-2] Theme: Training in collecting samples of atmospheric, rainfall radioactivity bioaerosol and in electron
microscopy observation
Date: Field training Sept. 1 & 2, 2016 or Sept. 12 & 13, at Namie-machi, Futaba-gun, Fukushima Pref. Electron
microscopy observation Sept. 30, 2016 at Meteorological Research Institute[A02-3] Theme: Analysis of radiocesium in sea water. Visit to the oceanographic research vessel “MIRAI” equippedwith large observational equipment and Mutsu Science Museum
Date: October 24 & 25 at Mutsu Institute for Oceanography, JAMSTEC[A03-5] Theme: Transfer of radionuclides with a forest and measurement method of air dose rate
Date: From Sept. 21 to 24, 2016, field training in Yamakiya District, Fukushima Pref. and lectures at Adatara
Fureai Center[A03-6] Introductory session to ecology of wildlife animals and measurement method of radioactive wild boars
Date: Nov. 25, 2016 at Center for Weed and Wildlife Management, Utsunomiya University
ISET-R（Coordination Committee） Center for Research in Isotopes and Environmental Dynamics
Office：1-1-1 A-405 Tennodai TSUKUBA, IBARAKI 305-8572
TEL＆FAX：+81-29-853-4226

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