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東日本大震災における被災動物対応の現状と今後の課題―放射性物質汚染への対応を考える―
The Current Situation Concerning the Handling of Animals Affected by theGreat East Japan Earthquake - Considering Responses to Radioactive Material
Contamination
学校法人 北里研究所 理事／北里大学 獣医学部 学部長・伊藤 伸彦

Nobuhiko ITO, Director, Kitasato Institute, Dean, School of Veterinary Medicine, Kitasato University
Good morning everybody. Thank you very much forworking on the problems there. At least, that is how I

taking the trouble to attend this workshop from such

am reconfirming my situation.

an early hour.
Currently I am teaching at Kitasato University in
A little later, under the theme of “The Current Situation

Tokyo, where I serve as the Dean of the School ofConcerning the Handling of Animals Affected by the

Medicine. My specialties include therapeutic radiology

Great East Japan Earthquake - Considering Responses

and radiodiagnostics, and for a long time I haveto Radioactive Material Contamination,” two of ouralso researched environmental radiology. As you

speakers will be talking about small animal and farmknow, Aomori Prefecture is the site of a nuclear fuelanimal cases respectively. Even between us, it will be

reprocessing plant. Construction of the plant began

impossible to comprehensively cover such a broad-soon after I started working at Kitasato University and I

based theme so if any of you among the audience would

began to measure environmental background radiation

like to add your opinion, suggestion, or commentseven before it became operational. Ever since, I havebased on your own experience, please do not hesitate tocontinued taking these environmental measurements.

join in. We have allowed for approximately half an hour

Recently, I was told that my work is not an academic

at the end and we’d like to use that time to develop

subject and is of no value to the world. And while I

active discussions.

would prefer that such work never need become usefulI am now having to push myself to face this (radioactive

Please allow me to begin by telling you a little bit

contamination) problem in the closing years of my life.

about myself. I was born in Fukushima Prefecture but
moved to Sendai when I was five years old. Soon afterNow, I would like to introduce today’s lecturers. Ourthat I moved again to Tokyo. Until recently, I was not

first speaker will be Mr. Jun Kawamata a veterinarianvery conscious of where I had spent my earliest days.

who works at the Chiba Small Animal Clinic in

Indeed I had almost completely forgotten. But after

Fukushima City. In addition to being active in numerous

the earthquake and having to make frequent visits toother roles, he is currently serving as Chairman of the

Fukushima, I realized again that my parents’ roots were

Fukushima Veterinary Medical Association’s Great Eastin that prefecture. My mother comes from Aizu andJapan Earthquake Disaster Animal Rescue Task Force,

my father comes from Hara-no-Machi in Minamisoma.

so he is deeply engaged in dealing with this problem. I

I remember that, as a young child, I was often taken

believe he will be talking to us from that perspective.

to Hara-no-Machi to go swimming in the sea. Next
year I will reach retirement age and I feel that Fate

Our second speaker will be Mr. Toshihiro Sato, Head ofis once again drawing me there to grapple with thethe Medical Care Division in the Production Department

terrible problems. I had been expecting to live a quietof Fukushima Prefecture Dairy Farming Association.

life of retirement but it seems I must actively continue

A graduate of Azabu University, he has worked as a

2nd Live Love Animals International Conference on Animal Care in Kobe 201259

veterinarian at the Association for 23 years. For thethe No.3 reactor. The other reactors seem to havefirst ten years his medical practice work centered on

suffered meltdowns, with their fuel rods melting anddairy cattle, and since 1999 he has been involved inradioactive materials being released into the peripheral

making rounds and instructing farming families whileenvironment.

working at the Association’s Headquarters. Since theissue of handling animals affected by he earthquake

This is a photograph of people measuring radioactivity.

disaster not only encompasses relationships between

The Geiger counter shows quite a high reading ofpeople and animals but also touches on a variety of

300 microsieverts per hour. I don’t think anybody is

problems such as food problems, etc., I expect Mr. Satoliving around here but if somebody did stay here for awill also be talking about those topics.

year, I calculate they would receive about 26 sievertsof radiation. So you can see that this is a place where

This is a photograph of some newspapers. I took it inpeople would risk a lot of radiation exposure. Actually,a newsagents inside the evacuation zone when I hadlater on we found many places with higher radiation

permission to enter. I noticed how these undelivered

exposure levels than this. Particularly around thenewspapers were all piled up and took some photos

reactor buildings, there were places where the radiationof them. This is a newspaper dated March 12th, thelevels were pretty high. I imagine cleaning up that messday after the earthquake. There had been the tsunami,

must be very hard work.

of course. These photos show the situation inside theevacuation zone. Even large boats were swept inland

Often we measure the concentration of radioactiveby the tsunami and in many places they had not yet

substances with an instrument called a survey meter,

been removed. The photo at the bottom shows that the

but when we want to measure a sample precisely, wetsunami had passed through the building interior.

use a germanium semiconductor detector. Each type ofradioactive nuclide produces its own characteristic typeThis is the interior of a building close to the station.

of gamma ray emission with a specific energy level. We

I took a shot of the inside from the outside throughcan use this to simultaneously measure radiation both

the glass. I think the room had remained in the same

quantitatively and qualitatively. These are the figures

disordered state since the people who lived here

we measured on April 10th. At that time point, theevacuated on the day after the earthquake.

amount of radioactive contamination adhering to thegrass and trees was greater than the amount in the soil.

Since the damage caused by the tsunami was on such

This is a line-up of spectra from grass, soil and milka large scale, we tend to forget about the earthquake

samples, which were measured at the same time. I wasitself. But as this photo shows, there were lots ofasked to measure milk, pasture grass and fodder forold buildings that suffered either partial (first floor)

cattle by residents of Date City, and we performed thesecollapses or total (first and second floor) collapses.

measurements on April 10th. These spectra are fromthe samples we collected there. Radioactivity was not

This is a newspaper dated March 13th. On the 12th,

detected in the drinking water or milk.

there had been the hydrogen explosion in Fukushima.

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If this had not occurred, the situation would have been

Among the soil and pasture grass samples, the grassdifferent. I forget which is the No.1 reactor, but the

samples yielded higher radioactivity levels than thereactors here are lined up in order from No.1 to No.4.

soil. The grass subsequently died and fell flat. However,

It seems that the chemical environment inside thewhen the new grass for the next year came up, thereactor buildings made it easy to produce hydrogensituation reversed and the soil now has higher levels

and that this resulted in the explosion. First thereof radioactivity. Once radioactive particles get into thewas an explosion at the No.1 reactor, on March 12th,

soil they remain in place and will hardly wash away

and then the same thing happened on the 14th at

at all. Then eventually farm animals browse on the

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

contaminated pasture, and the radioactivity moves up

decontamination also. From my previous experience

the food chain, eventually reaching people.

with radiation therapy I felt that, essentially, there islittle difference between people and dogs or cats when

I wrote that animals are always victims in theseit comes to the effects of radioactivity. So we posted

situations and this photograph of a dead animal sadly

this on the Japan Veterinary Medical Association’s

illustrates the point. Cats will enter the area so we thenwebsite. Basically, it states in a nuanced way that we

come to a situation in which wild animals and feral

should treat companion animals in the same way as

dogs have eaten the flesh of dead cattle and pigs.

people. Because it was a tentative statement, although
it instructs vets to use a survey meter, it doesn’t

There is a video of some ostriches and watchingspecify which type of survey meter should be used,

it saddens me but I’ll just show a bit of it to you.

or under what conditions it should be used. It justNormally, this is a peaceful landscape with only the

explains how to wash the entire surface of an animal’ssound of birdsong. So the ostriches must be puzzled bybody, etc. At that time, we were considering only bodythe situation. I think they creatures were captured after

surface contamination. Even for people, we had little

the video was taken.

recognition about radioactive particles entering the
body and internal exposure. I will talk more about thisSome house pets were evacuated together with theirpoint later.

owners or keepers, but a lot of people had their hands
totally full with evacuating themselves and had to leave

Regarding farm animals used for food, on May 12th,

their animals behind. Those that were released werePrime Minister Naoto Kan, as the Head of the Nuclear

able to forage and many did survive, but others wereEmergency Response Headquarters, ordered Fukushima

left tied up and died of starvation or thirst. I’m sure thePrefecture to euthanize all living farm animals inside

owners expected to be able to come back soon but werethe evacuation zone after obtaining the agreement of

unable to. Many surviving animals still remain inside

the animals’ respective owners.

the evacuation zone.
The main targets for this order were dairy cows, beef
I took this information partially from the Ministry ofcattle and pigs. Abandoned chickens had already died of

the Environment’s website. The contents show the

starvation or thirst. And yesterday, I heard from Keikoactivities we carried out on May 11th. According toYamazaki of the Companion Animal Study Group “Go”

this, the animal rescue activities started soon afterthat all the animals kept in schools in the evacuation

the earthquake struck, but it proved very difficult tozone were dead. Sadly, many animals left behind in thecapture the animals. Mr. Kawamata will be talking

zone died totally neglected.

about this later on.
However, not all of the farm animals could be
As of April 1st, we posted this statement on the Japaneuthanized and the problem of escaped farm

Veterinary Medical Association’s website. Dr. Masahiro

animals including cows, remains. These animals are

Natsuhori of the Japan Animal Referral Medical Center

gradually turning feral such that the usual humanand I were also involved in its formulation, so I havecontrol methods are ineffective and the animals aresome responsibility there too. Around March 15th,

now becoming dangerous. Another problem is that

we started to talk about what to do. We had to decideunneutered male calves have now grown into bulls andan animal decontamination standard but at the time

begun to impregnate cows. A lot of of new calves havethere was no such standard, not even for people.

been born and the animals have now formed into herds.

However, the National Institute of Radiological Sciences

The bulls’ horns have grown larger for protecting theircame to announce some decontamination guidelines

herds and some of them are dangerous to approach.

which we decided to follow for companion animal

Now, compared to escaped dairy cows, escaped beef

2nd Live Love Animals International Conference on Animal Care in Kobe 201261

cattle are now more numerous. Mr. Sato will be talking

this raccoon dog was quite high, it was low in theabout beef cattle later on.

case of other raccoon dogs. So I think these figuresreflect the degree of contamination in the locations

This shows the situation faced by some pigs. The pig

where the individual animals were living. The figures

pens were locked and all the pigs left inside died anddiffer markedly from one individual animal to another.

their decomposing bodies congealed into a sticky

Please note that the figures here are presented using

mess. However, many were also released or escapeda modified scale that omits highly contaminatedfrom farms and subsequently became feral, forming

individuals like the raccoon dog I showed you just now.

themselves into groups. I don’t know whether the

These figures show Japanese serows, badgers, martens,

animals in this photo escaped or were released. Thereand masked palm civets. And this is a raccoon dog thatis a little piglet here, although it is difficult to see. I

had a low degree of contamination.

tried to get close in order to take a better shot of it,
but the mother moved in front to hide it. Next moment

We discussed how much these animals reflect thea boar also came out and threatened us so we quickly

contamination in the locations where they lived. But

retreated. It seems these pigs had broken into a grainwith the Japanese serows, because they range over astorage warehouse and had fed on the rice there. That’s

wide area, we felt that their readings do not necessarily

how they survived.

reflect the contamination situation of a given location.
What we focused on was the overall condition of theI have some photographs of horses that were caught

mountain areas. Contamination adheres firstly to theup in the tsunami and died. As you can imagine, theyleaves and bark of trees, so forests tend to capture

are too miserable to show so I won’t burden you withradioactive particles fairly easily. Once radioactivity

them today. However, many others did survive andadheres to organic materials it is not easily dislodged.

were basically treated in the same way as companion

These organic materials eventually fall to the groundanimals. The injured ones would receive medical

and accumulate in the soil where they decay overtreatment and be taken out of the evacuation zone.

time, eventually becoming covered by fresh material.

But even after all that, there was still another problem.

But they are not very deeply buried so other plants

They had been grazing on grass within the evacuation

growing in the soil easily absorb them. It is due to thiszone and had ingested radioactive particles. Radioactive

circulation between plants and soil that radioactive

cesium was detected in their feces and urine. So whencontamination in mountain forests can continue for a

attempts were made to move them to other places, they

very long time.

were not accepted. The result is that they remain andtheir keepers have to ensure they do not eat the local

When rain falls, radioactive cesium does initially flow

grass. This is Minamisoma Baji-Koen Equestrian Park,

through the surface soil layers but after some time

and the horses here seem to be lacking energy too.

has passed the flow becomes less. For this reason itis said that, apart from the physical attenuation due

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Finally, I’d like to talk about wild animals. When I wasto radioactive decay stemming from the half-life oftaking radiation measurements of wild animals in theradiocesium of about 30 years, the immobilization

early period after the earthquake (around April andprocess will reduce the bioavailability of cesium after aMay), the Fukushima Wildlife Rehabilitation Centeryear or two. I am not absolutely certain, but I suppose

sent us many different items which I measured. As wethat about two-thirds of the Fukushima Prefecture

also had to measure body surface contamination ofarea consists of mountain forests. Accordingly, awild animals we collected road kill and checked theconsiderable part of the prefecture will be in a fairly

levels of cesium 143 and 137, finding similar levels

contaminated situation. That radioactive materials haveof both nuclides present. Please note that, althoughbuilt up in the forests is quite well known, but detailed

the concentration of cesium in the muscle tissue of

research has not yet been undertaken. That’s the

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

current situation regarding the forest environment.

discussed.

It is said that wild boar territories tend to be small.

Now, let us consider radioactive contamination in

These animals live in a certain small area for a certain

muscle tissue. For the muscle as a whole, we obtain fineperiod. They do sometimes move to a new location but

positional information using precise instrumentation

will return to their original area again. When feeding

and then we perform dose-rate conversion. The muscle

they dig down into the soil and eat the things they find.

results show us the air dose rate in the area where theChecking their stomach contents tells us that they also

animal lived. Accordingly, we know that we can grasp

eat leaf mold. So the readings we have obtained fromthe contamination situation in the relatively small

wild boar correlate well with the level of radiation

zone where, for example, an individual boar is caught

contamination in the locations in which they live.

by measuring the levels of radioactivity in the boar’s muscle and organ tissues. We are now applying forThis map shows the 20km and 30km zones surrounding

research funding so that this research can be carried

the nuclear power plant as well as the area outside

out on a continuous basis. However, competition forthem. When nuisance animals in the Minamisoma,

funds is very intense because many researchers not

Soma and Nihonmatsu districts were exterminated we

previously been involved in radioactivity studies are

obtained samples of the local wildlife. This slide shows

now entering the field and taking advantage of thethe contamination situation in these areas. We asked

opportunity provided by the current nuclear situation.

Fukushima Wildlife Rehabilitation Center to send us
some samples, and we measured a variety of things

We have obtained some data from the survey weincluding body surface contamination.

began. For instance, it has been established that when
livestock farmers provide contaminated livestock withAir dose rates are measured at a height of 1m above

clean feed, the previous contamination is excreted andthe ground. We checked the relationship between

the livestock have no subsequent problems. This is a

air dose rates and degree of contamination in animal

study undertaken to see whether the data we gatheredbodies found at specific locations. This shows how theis of use in this context. This photograph was taken

level of radioactivity on the body surface overlaps within the Kodaka district of Minamisoma, which is inside

the concentration of radioactivity in the muscle tissue

the evacuation zone. This is a farmhouse not currently

on which we later performed precision analysis. Thereoccupied because the residents have been evacuated.

seems to be an overall correlation, but some of the body

Our plan was to house some contaminated cattle

surface measurements turned up negative figures. Thison this farm and provide them with clean feed. The

means that it is problematic to evaluate contamination

situation was that dozens of cattle had been captured

inside the body merely by measuring the body surface.

and were waiting to be euthanized. When we visited,
we were told that the cattle would be euthanized overThis slide shows the results of measuring

the course of several days beginning the next day. So

gastrointestinal contents. As to whether ambient air

we asked the handlers to let us use the cattle for ourdose rates and figures obtained from feces correlate

research instead which they agreed to. The cost of thisor not, since what an animal eats is excreted as feces

research was covered by a budget for various researchin a rather short time, one might assume that feces

projects obtained by Dr. Yamane, President of the Japan

contamination levels would reflect air dose rates.

Veterinary Medical Association. So we decided to begin

But in fact we found no strong correlation. However,this research with JVMA cooperation. And because thisgastrointestinal and stomach contents consist of theresearch has several data-gathering goals useful forfood an animal has eaten quite recently, so we know

livestock rearing, we are also joining with researchersthat they must have quite a high correlation coefficient,from several universities.

although this matter has not yet been sufficiently

2nd Live Love Animals International Conference on Animal Care in Kobe 201263

At the end of October, the hygiene conditions at theorgans take up not only cesium but also nuclides of

farmhouse were poor, and people were only going there

other elements.

occasionally. The farmhouse owners who had originally
lived there came to help only once every three days. We

After studying everything in greater detail, we expect

visited and worked there every few days but conditions

to be able to complete our data compilation andcan only be described as miserable. The cattle wereannounce our results to the public in May. We will

sometimes eating PVC and their feces was just left toattempt to summarize the data so that it will be useful

fester. Even when there was fresh feed it had just beenin regenerating the local livestock raising industry inrolled in and left on top of the feces, and the cattle

the future.

were left to eat it with no control. Because the place
was being managed in this haphazard way the cattle’That concludes my talk. Next I would like to call on Mr.

s nutrition status was quite poor and we would not be

Kawamata.

able to use them for research in that state. Unless thehygiene in the keeping areas and the cattle’s nutrition
status could be improved, we would not be able tocollect usable data. We would only be making the cattle
suffer for the sake of research. So having been kept
like this, after about six weeks, we began to supply
them with clean food that was imported and measured
and we optimized the nutritional balance by mixing
American and Australian feed. We started our research
while improving the cattle’s nutrition in this way. A
total of ten veterinarians were involved in the work.
From around Christmas time we switched the cattle toordinary feed and, one month after that, at the end ofJanuary, we performed autopsies on some of them andmeasured the extent of radioactive contamination.
Our results indicated that radioactive contamination
attenuated faster than we had expected. Over several
months it had attenuated at a faster rate than theradioactive half lives of the nuclides would lead one
to expect. We have been continuing this researchby dividing the cattle into four groups including one
group to which we administer Prussian blue as adecontamination aid.
As for cesium, we had expected to find it distributed
almost evenly throughout the body in the same
way as potassium, but when we performed theactual measurements we found that radioactivity
concentrations differ significantly between different
muscles. We also found that the distribution results are
reproducible and that there are no differences between
individual animals. In addition, we found that certain

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りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012