共同利用研究会
福島原発事故に起因するニホンザルと他の野生生物の保全問題の解決に向けた国際情報発信
シンポジウムタイトル
Radiation Monitoring and Conservation of Wildlife after Fukushima.
日時
2015年7月29日（水） 13:00 - 18:10
場所
札幌コンベンションセンター 中ホール
〒003-0006 札幌市白石区東札幌6条1丁目1-1
TEL: 011-817-1010
URL: http://www.sora-scc.jp
世話人
河村正二（東京大学）（代表）, Tomoko Y. Steen（Georgetown
University）,竹ノ下祐二 (中部学院大学),
川本芳（京都大学）,
仲谷淳（独立行政法人農業・食品産業 技術総合研究機構
中央農業総合研究センター）, 大井徹（石川県立大学）,
山田文雄（国立研究開発法人 森林総合研究所）
この共同利用研究会は2015年7月26日（日）-30日（木）に札幌市で開催される第５回国際野生生物管理会議のシンポジウムのひとつとして開催し, 英語で行います。
世話人代表者 河村正二（東京大学）
Tel: 04-7136-3683
E-mail: kawamura@k.u-tokyo.ac.jp
所内対応者 川本芳
Tel: 0568-63-0527
E-mail: kawamoto.yoshi.3s@kyoto-u.ac.jp
プログラム
13:00-13:05 Shoji Kawamoto (The University of Tokyo)
Lead organizer
15:35-15:45 Break
17:15-18:10 Discussion
Commentator Thimothy Mousseau (University of South Carolina)
Outline
Four years has passed since the accident at the Fukushima Daiichi Nuclear power plant. The event released and still continues to release ionizing radiation into the environment. Sporadic data on the exposure to ionizing radiation of wildlife have been produced over the years. However, the overall assessments of the actual condition and effective measures to manage and protect the future of wildlife in the area have not been developed, especially due to the limitations of scientists’ access to the area. In particular there is very limited knowledge on the biological effects of low level radiation and if threshold exposures exist. In this symposium, we report recent methods to monitor ionizing radiation developed individually by scientists working on specific wild animals namely, insects, birds, marine animals, and mammals including primates. We will also further our discussion to key issues on wildlife management. The Fukushima nuclear power plant accident and several subsequent events there have resulted in the accidental release of high levels of ionizing radiation on the soil, underground water, atmosphere, and ocean. The purpose of the symposium is to create a place to share, discuss and analyze future research plans for assessing, monitoring, and managing radioactive effects on wildlife in Fukushima and beyond, using multi-disciplinary approaches offered by experts in broad range of wildlife species. Commentator: Timothy Mousseau, University of South Carolina, Columbia, SC 29208, USA
International Research Needs for the Effects of Radiation on Non-Human Biota and Ecosystems.
Satoshi Yoshida
National Institute of Radiological Sciences
Most of the present systems of radiation protection have been developed to protect human health. However, increasing attention has been paid over the last two decades on the protection of the environment (i.e., non-human biota and ecosystems) from ionizing radiation. International organizations, such as International Commission on Radiological Protection (ICRP), International Atomic Energy Agency (IAEA) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), have organized meetings on environmental effect of radiation and published the up-to-date outcome as official reports. A series of European projects have played an important role in collecting scientific data currently available. However, they have also pointed out existing gaps of data. For example, data on the effect of exposed radiation dose (especially by chronic exposure) on biota is limited though essential for risk assessment. Many projects have attempted risk assessment in the contaminated areas of Chernobyl. Radiation exposure by the accident of Fukushima Daiichi Nuclear Power Plant in 2011 could be at a considerable level for non-human biota in highly contaminated areas, according to the derived consideration reference levels (DCRLs) proposed by ICRP. Although an extreme consequence, such as “red forests” seen in Chernobyl, has not been observed in Fukushima, several existing studies note possible effects of radiation exposure on some species in biota. This paper summarizes international and national efforts to protect non-human biota from ionizing radiation in the last two decades, and discusses research needs after the accident of Fukushima Daiichi Nuclear Power Plant.
Establishment of Animal Archives in and around the Ex-Evacuation Zone of the Fukushima Nuclear Power Plant Accident.
Manabu Fukumoto, Yusuke Urushihara, Masatoshi Suzuki, Yoshikazu Kuwahara
and Gohei Hayashi
Institute of Development Aging and Cancer, Tohoku University
We have been establishing an archive system composed of animal tissue,
grass and soil samples in and around the ex-evacuation zone of the Fukushima
Nuclear Power Plant (FNPP) accident. We intend to make use of it for the
assessment of radiation effects on ecosystem and the future radioprotection.
As of December 1, 2014, we collected samples from 301 cattle, 57 pigs and 162
Japanese macaques. Four years after the accident, among radionuclides
attributable to the accident, only radiocesium was detectable. Radiocesium
concentration in each organ was proportional to that in peripheral blood and
the highest in the skeletal muscle among organs examined irrespective of
animal species. However, we have not observed abnormal findings in animals in
and around the ex-evacuation including the leukocyte count in peripheral blood
of Japanese macaques. Some of anti-oxidant activities examined were
significantly correlated with the blood radiocesium level in cattle. These
observations suggest that animals affected by the FNPP accident are under a
stressful environment. However, we need a long-term follow-up study for
decades to conclude whether the notions above are correct and how irradiation
is involved in them.
Hematological Characteristics and Muscle Radiocesium Concentrations in Wild Japanese Monkeys after Fukushima Disaster.
Takuya Kato
Nippon Veterinary and Life Science University
The objective of this study is to monitor concentration of radiocesium
Cs-134 and Cs-137 over time in the muscle of Japanese monkeys (Macaca fuscata)
inhabiting Fukushima City located 70 km from the Fukushima Daiichi Nuclear
Power Plant (NPP), and their health effect due to exposure to radioactive
materials using the blood data. Cesium concentration in the muscle of monkeys
was 6,000-25,000 Bq/kg in April 2011 and decreased over 3 months to around
1,000 Bq/kg. However, the concentration increased again to 2,000-3,000 Bq/kg
for some individuals during winter period before returning to 1,000 Bq/kg in
April 2012. In 2012, we carried out a one-year hematological study on a
population of Fukushima City (n = 61) and the Shimokita Peninsula (n = 31)
located approximately 400 km from the NPP as a control. Total muscle cesium
concentration in Fukushima monkeys was in the range of 78-1778 Bq/kg, whereas
the level of cesium was below the detection limit in all Shimokita monkeys.
Compared to Shimokita monkeys, Fukushima monkeys had significantly low white
and red blood cell counts, hemoglobin, and hematocrit. In Fukushima immature
monkeys the white blood cell count showed a significant negative correlation
with muscle cesium concentration. These results suggest that the exposure to
some form of radioactive material contributed to hematological changes in
Fukushima monkeys.
The Pale Grass Blue Butterfly in Fukushima.
Joji Otaki, Atsuki Hiyama, Wataru Taira, Chiyo Nohara, Mayo Iwasaki, Seira
Kinjo and Masaki Iwata,
University of the Ryukyus
To fully understand what has happened to organisms living in the radiation
polluted areas, long-term monitoring of the biological impacts on organisms is
required. We investigated spatial and temporal changes of the abnormality rate
(AR) in both field-caught adult and laboratory-reared offspring populations of
the pale grass blue butterfly, Zizeeria maha. They have generation time of
approximately one month. We monitored 7 localities in and around Fukushima
Prefecture every spring and fall over 3 years between 2011 and 2013 (n = 1,713
for field caught; n = 9,663 for offspring). The adult ARs peaked in the fall
of 2011, while no AR increase was observed in non-contaminated localities.
Among offspring, the total ARs, which include deaths at premature stages and
morphological abnormalities at the adult, peaked either in the fall of 2011 or
in the spring of 2012. The AR level was much higher than those of the parent
field populations for those periods, suggesting that the similarly high level
of deaths and abnormalities might have occurred also among the field
populations. Importantly, the elevated ARs in the field and offspring came
back to normal by the fall of 2012 and by the spring of 2013, respectively.
These results demonstrate an occurrence and an accumulation of adverse
physiological and genetic effects in early generations, followed by their
decrease in AR and recovery to the normal. The study provides one of the most
comprehensive records of biological dynamics after a nuclear accident
available today.
Effects of Radioactive Contamination around Fukushima Daiichi on the Morphology and Genetics on Aphids.
Shin-ichi Akimoto and Izumi Yao
Graduate School of Agriculture, Hokkaido University
To evaluate the impact of fallout from the Fukushima Daiichi Nuclear Power
Plant accident on organisms, the morphology and viability of the gall-forming
aphid Tetraneura sorini were compared between a Fukushima population and seven
populations from non-contaminated areas. The present study focused on first-instar
gall formers derived from the first sexual reproduction after the accident. Of
164 first instars from T. sorini galls collected 32 km from Fukushima Daiichi
in spring 2012, 13.2% exhibited morphological abnormalities, including 4
conspicuously malformed individuals (2.4%). In contrast, in the control
populations, first instars with abnormal morphology accounted for 0.0-5.1% (on
average, 3.8%). The incidence of abnormalities was significantly higher in
Fukushima than in the control populations. We morphologically compared first
instars of the first generation (hatching from eggs on the bark surface and
inducing galls) with those of the second generation ("clones" of the
first generation and produced parthenogenetically in the galls as larvae). Of
543 second-generation first instars in the Fukushima population, only 0.37%
had abnormalities. This result suggests that radioactive contamination had
deleterious effects on embryogenesis in eggs deposited on the bark surface,
but a negligible influence on the second generation produced in closed galls.
Analysis of samples collected in spring 2013 indicated that the viability and
healthiness of the aphids were recovered compared to those in the 2012
samples. Thus, a reduced level of radiation may have led to the recovery of
viability and healthiness of the Fukushima population.
Research on Breeding of Ural Owl Using Nest-Boxes in Fukushima.
Isao Nishiumi
National Museum of Nature and Science
Birds of prey are top level consumers in terrestrial ecosystems and are
known to be less abundant with increasing levels of radiation around Chernobyl
and Fukushima. Causes of the declining predators in radioactively contaminated
areas are assumed to be both the ecological concentration of radioactive
substances and reduced abundance of the prey. The Ural Owl Strix uralensis is
one of the top predators in the forest of Fukushima, and is known as an
opportunistic predator, namely opportunistically hunts any rodents, moles
and/or small birds which is abundant and easy to catch in their territory. We
can easily investigate the contents of their food by setting video cameras in
the nest, by collecting the remnant of the nest after breeding (composed of
the pellet of chicks) or even by directly collecting their food because they
often keep the food in the nest during early stage of their nestling period. I
set 81 nests in total: 42 nest-boxes in Iitate village as highly contaminated
areas, where air radiation dose is from 0.8 to 4.0 μSv/h; 23 nests in
Tsuchiyu-onsen as low contaminated areas of 0.2 to 0.3 μSv/h; and 16 nests in
Aizu as control areas of 0.06 to 0.15 μSv/h. I will report the results of our
on-going investigation on how much the breeding of predatory species is
influenced by radiation exposure. Nest-boxes of Ural Owl would provide us with
an excellent monitoring window to evaluate the effect of radiation to
terrestrial ecosystem.
The Effects of Radiation for Non-Human Biota in Marine Environment since the Fukushima NPS Accident.
Tatsuo Aono
National Institute of Radiological Sciences
Monitoring and surveying of radioactivity in seawater, sediments and biota in the marine environment around the eastern Japan in the Pacific were carried out for understanding the dispersion of artificial radionuclides after the Fukushima Daiichi Nuclear Power Station (FD1NPS) accident. The Fukushima-derived radionuclides in the ocean were not only the release of the high level contaminated water from FD1NPS but also the deposition directly from atmosphere. The maximum of Cs-137 concentrations at the FD1NPS were about 70,000 Bq /L on March, 2011 and then the activity of Cs-137 in seawater had decreased gradually to 1-2 mBq /L in a few months after this accident, approaching the pre-accident levels. However, the Cs-137 activity variation in marine environment differed among seawater, sediments and marine biota. The monitoring was reported only on the gamma-emitting radionuclides iodine-131 and radioactive cesium (Cs-134 and Cs-137) in the marine environment after this accident. It is well known that marine biota concentrates elements in their organ. The observed artificial gamma emitter radionuclides include not only I and Cs but also Ag-110m in marine biota. It is necessary to clarify the effects of the Fukushima-derived radionuclides in marine biota off Fukushima. The aim of the study is to examine the temporal and spatial variation of radioactivity in marine biota after this accident. Studies on the effects of radiation on marine biota off Fukushima will be presented with some assessment models.
Studying Immunological Effects of Ionizing Radiation through Microbiome.
Tomoko Steen
Georgetown University
Since the nuclear power plant accidents of Chernobyl and of Fukushima, the main concern has been the biological effects of ionizing radiation on organisms including humans and wild animals resident in affected areas. It has been very difficult, however, to assess the actual short- and long-term effects of radiation on organisms accurately. Ionizing radiation is invisible, and the level of some isotope such as strontium cannot be assessed using a standard Geiger counter. Radioactive isotopes released by the nuclear accidents have long half-lives, thus they continue to expose organisms and accumulate in their bodies. Biological accumulation differs from simple physical assessments of isotopes and further complicates measurement of biological effects. In searching of a reliable tool to assess the health effects of radiation on organisms, I have been investigating the use of the microbial commensals found with every animal - the microbiome. Recent advances and sequencing cost reductions have significantly improved studies on microbiome composition. Recent studies clearly show that the composition of the gut microbiome changes to reflect an organisms’ health, age, and immune system status. In some cases, the use of microbiome as treatment of patients in the form of fecal transplant shows success. In this talk, I will discuss possibilities of using the gut microbiome to investigate minute effects of ionizing radiation on wild animals and potential use of the system to aid ecosystem recovery.