以下は稲葉政満教授（東京藝術大学大学院保存科学教室）からの寄稿である。

被曝した書類の取扱い 稲葉政満（東京藝術大学大学院保存科学教室）

●被曝量を減らす

1. 時間
2. 距離
3. 遮蔽する

線量率の高いものの側にできるだけ近づかない、あるいはその塊から離れて作業する。持ち運ぶ場合も柄杓のようなもので運び(小さい場合）、可能な限り体から離す。個別作業も、作業者間の距離を取れば、被曝量は減らせます。距離の二乗で被曝量は減ります。透過量の低い放射線は壁一枚でも大分違います。γ線などで遮蔽しにくいものは鉛の板で遮蔽できれば良い。大事なところを守る（鉛のエプロンで、腰周りを中心に）（指先などは比較的影響は少ない）

●内部被曝
体内に放射性物質を取り込まないようにマスクをする。

●外部被曝
作業着への付着量をサーベイメータで調べる。特に、作業終了後(休憩で飲食する前も含め）は全身をくまなくチェックして、体(服も含めて）に付けて持ち出さない。体に付着したままだと作業終了後も被曝してしまいます。あるいは、飲み込んで内部被曝する可能性もあります。

●モニターする
ガイガーカウンターで線量率を調べて、線量率の高いモノはできるだけ短時間に個人別の被曝量を測定する。その場ではポケット線量計が手軽です。リアルタイムで個人の被曝量をモニターできるので、ただし、精度はよくないので、別途フィルムバッジの後継タイプ(長瀬ランダウの場合はクイクセルバッジできちんと測っておく。（放射線作業者として業務を行う場合は、事前に講習を受け、身体検査、血液検査が必要）

●被曝量の管理
一般の方は年間１ｍSvです。一方、業務上作業するならば、下記のようになります。ただし、緊急時の値は100ｍSvから250ｍSVに引き上げられました。（遺伝的影響は子孫を残さなければ関係ないし、後発タイプのがんは20～30年後がピークですので、若い人よりも私が優先的にやるべきです。また、妊娠中、妊娠している可能性のある女性は、作業させない）

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

下記にあるように、法令により放射線業務従事者の被曝線量の限度（線量限度）が定められております。

放射線Q&A

線量限度は、被曝線量の上限を示したもので、これを超えるとすぐ人体に影響が現れるということではなく、あくまで放射線を安全に取り扱うための目安です。なお、自然放射線による被曝や診療による被曝は含まれないと取り決められています。実効線量限度100mSv/5年、かつ50mSv/1年5mSv/3ヶ月（女子）妊娠する可能性がないと診断されたもの及び妊娠中のものを除く等価線量限度。目の水晶体150mSv/1年皮膚500mSv/1年妊娠中の女子の腹部表面2mSv/妊娠と診断されてから出産までの間。

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

●何時処理するか
汚染されている放射線核種の半減期との関係例えば、ヨウ素113のように半減期が8日のモノの寄与が大きければ、80日間で線量率は1000分の1（2の10乗分の1）となるので、それまで冷凍保存してくと良い。一方、セシウム-137（半減期30.1年）であるので、除染を先にする。でしょうか

●溜める、広げない
除染したものを、外部に広げないように、溜めておく。可能であれば、濃縮処理して廃棄物量を減らす。

［編者注：上記文中、●被曝量の管理に、「若い人よりも私が優先的にやるべきです。」とある。この「私が」について再度、稲葉氏に尋ねた。文字通り、若い人達ではなく、氏ぐらいの年齢以上の人が優先的に応えるべきだという意味、との返信をいただいた。］

以下の文献は、AATS（American Association for the Advancement of Science）の雑誌 Science（ Vol. 263, No. 5144 , Jan. 14, 1994）が掲載した Christopher Anderson による DOE Finds Physics Archives　May Be Too Hot To Handle の抄訳である。戦時中のアメリカのマンハッタン計画（原爆開発）に関わった複数の科学者が残した膨大な記録（ノート、文書）、モノ資料など、放射能に汚染された資料はどのように「保存」処置が施されたかを述べている。

いま読むうえでの留意点がある。上述のように発表年は1994年。チェルノブイリ原発事故（1986年4月）の約10年後ではあるが、いまから遡ればすでに15年前の文献である。当時にあっても、比較的高い濃度の被曝物への扱いは最高のレベルで行われてはいるのだろうが、低濃度被曝物の取扱いは、現在（2010年）ならばいくつもの留保が必要かもしれない。例えば、手袋着用程度で放射線を発しているモノを扱えるものだろうか—というような。

であるにしても、類似の文献や事例が見当たらない今、ここで述べられている除染そしてコンテンツの移し替え（マイクロ化）というプロセスは、今後、二次汚染が予想される被曝資料を取扱わねばならない場合のヒントになるかもしれない。そういう事態にならないことを祈りつつ。

［2011/04/22　木部記]

マンハッタン計画を記した被曝ノートはどのように「保存」されたか –アメリカ国立公文書館などの取り組み　 ［島田 要 抄訳]

1.　先行事例は無く、二次被災のリスクがある

3月11日午後に東日本を襲った大地震と津波、それに続く福島原子力発電所の事故から約一ヶ月を経過した。しかし、今なお余震は続き、原発事故はどこに向かってどのように収束していくのか見当もつかない。

この困難な状況のなかで、被災した資料の救済に向けての動きが始まっている。しかし、有り体にいって、どこからどのように手をつけたらよいのか、手をこまねいているというのが現状ではないだろうか。地震と津波による被災だけでも未曾有の規模になることは間違いない。だが、それ以上に今回の被災は、かつて大災害による救済にあたった世界中のコンサーバターや、図書館・アーカイブの誰も経験したことのない難問を私たちに突きつけている。原発事故がもたらした/もたらしつつある放射能汚染と、それによる資料の被曝である。放射能汚染された資料(以下では被曝資料)は果たして救済することができるのだろうか？瓦礫の下から拾い上げることはできたとしても、その後の除染を含めたコンサベーション処置は可能か？

当社では海外のコンサーバターや保存科学者、図書館員やアーキビストに対して「被曝資料の取り扱い」について意見を求めた。それは可能か、可能だとすればどのような方法があるのか、救済事例は過去にあるのか…

約10日間ぐらいの間に、深甚なるお悔やみとお見舞いの言葉とともに、少なくない数の「回答」が欧米各国の方々から寄せられた。寄せられた意見は、本文の「3.質問と回答」にある。

このようにして衆知を集める中で、被曝資料をどう取り扱うかについての共通認識が浮かび上がってきた。すなわち–

これをいま少し敷延すれば以下のようになる。

被災現場からの拾い出しにしろ、その後の海水と泥の洗浄・乾燥にしろ、もしその資料があるレベルを超えた放射能汚染の可能性があるすれば、救済作業者の安全性確保は当然配慮されなければならない。これについては放射能の研究者や物理学者、医者の助けを必要とする。また、寄せられた意見の中には、低レベルでも繰り返し放射線にさらされることで、健康への潜在的なリスクがあることを考慮すべきだというものもあった。放射能汚染されたモノへの緊急的な処置が可能なのかさえ、否定的に考えざるを得ないという意見もあった。対処法を優先するのは近視眼的であり、汚染レベルの区分け、被曝に対する制御対策や救済処置を比較することに特段の意味は見いだせず、それよりも作業者への被曝のリスク（危険度）のみが問題なのであり、先ずこのことを理解することが先決であろう、と。

なお、被曝した文化財の救済処置に関して、文化財のコンサベーション文献データベースBCIN、AATAを検索したが、詳しく言及されたものは見つからなかった。先行する事例もないのが実情であり、現在の文化財保存科学や防災・救助対策の枠組みでは解決できない、未曽有の問題に直面しているといえる。

2.　なおかつ取り扱わねばならない場合の認識と準備

以上をふまえ、なおかつ被曝資料を取り扱うとすれば、どのような認識と準備が必要か。寄せられた回答を要約し列挙すると以下のようになる。

• 高度な専門施設・設備（放射線使用施設、貯蔵施設、廃棄施設等）が必須。 George Bailey (Senior Objects Conservator) Australian War Memorial, Australia

• 放射性物質/粒子が何であるかを知る必要がある、これは行う処置がどれくらい危険なものであるかの判断基準になる。 Susan Lee-Bechtold (chemist) National Archives, US

• ガイガーカウンターで常に放射線測定を行い、放射線値を可能な限り低く保ち、安全なレベル下で作業をする。同時に予防策も講じる必要があり人の健康に対する安全レベル、許容値を考えねばならない。 Valerie Tomlinson (Conservator) Auckland Museum, New Zealand

• 肌の露出をなくすこと。手袋、フィルターマスク、防護服などの適切な防護材を着用し、常にガイガーカウンターで被曝量を記録する。 Valerie Tomlinson (Conservator) Auckland Museum, New Zealand

• 作業にあたる人の防護服、除染処置で使用した材料は放射性廃棄物とする。 Valerie Tomlinson (Conservator) Auckland Museum, New Zealand

• 放射能に汚染されたモノは撮影しリフォーマットするのが普通である。そして汚染されたオリジナルと利用した機器は放射性廃棄物とする。 Susan Lee-Bechtold (chemist) National Archives, US

• 放射能汚染されたすべての資料は、ポリエチレン袋に密封する必要がある。適切な方法が見つかるまで、承認された場所に格納する。汚染物質を取り除こうとす る際、汚染されている人やもの、物体に近づいたりしたときに、放射線にさらされる状態になることがあり、さらなる二次被害に繋がることは必然である。 Susan Lee-Bechtold (chemist) National Archives, US

• 除染事業のためには財源が必要となる。それをどう調達し、償還していくかも重要事項である。 Dr. John Havermans (Scientist) TNO Build Environmental and Geosciences, Netherlands

[文責： 島田要 Kaname Shimada]

3.　質問と回答

From: Randy Silverman
Date: Thu, 31 Mar 2011
Subject: RE: From Japan:radiation contaminated library and archive material

Dear Mr. Kibe,
I am grateful for your shared information and will read it with interest and share it with colleagues. For better or worse, the lessons you learn from this experience may serve others in the future.
As an introduction, my chief book conservator, Tomomi Nakashima, is Japanese and a native speaker. If it is easier for you to communicate with us in Japanese please send messages through her and we will discuss your needs or concerns. I remain extremely sorry for your current situation and anxious to help in any way we can that would be useful.

Best wishes in all things,

Randy

Randy Silverman
Preservation Librarian University of Utah Marriott Library
295 South 1500 East Salt Lake City,
UT 84106-0860 ?USA
t. 01-801-585-6782 ?/ ?f. 01-801-585-3464

From: Valeria Orlandini
Date: Thu,31 Mar 2011
Subject: Response re: Japanese Materials Contaminated by Radiation

Dear Toru Kibe, Thanks a lot for your reply. After you message in the Conservation DistList, I inquired with some colleagues in The Netherlands, Argentina and Brazil. I encourage you to get in contact with them since these 3 labs do work with gamma radiation and are very aware how to protect the personnel and the archival material being treated with gamma rays.

?”Dr. Havermans, J.B.G.A. (John)”?,at TNO Build Environmental and Geosciences in Delf, The Netherlands ?”Ana Maria Calvo” ,at CNEA in Buenos Aires, Argentina? “Maria Fernanda Auada” ,at SENAI in Sao Paulo, Brazil

Hope this information will be helpful for you and others. I/We are praying for yours and hope that your family and friends and the Japanese people can be better soon. I am very sympathetic so do not hesitate to contact me if there is anything that you think I can do.

Very kind regards,
Valeria

—————- Forwarded message ——————————

From: Havermans,J.B.G.A. (John) ??
Date: Tue, Mar 29, 2011 at 3:14 AM
Subject: RE: Response re: Japanese Materials Contaminated by Radiation
To: Valeria Orlandini

Good morning Valeria,
I even discussed this matter with the board of directors at our institute. Although we do not have feeling on what should be done it might good to see what we can do. The less positive thing is, that we have no funds to work voluntary at the moment. But things can change.  About the problems of the paper heritage in Japan, I feel already that we have to solve the following issues:
・1 damage due to water, here disinfection and restoration is needed
・2 damage due to other factors, here mainly restoration is needed
・3 damage due to high dose radiation: if it is only radiated, materials may still be in a good condition. However we do not know the dose. Any dose higher than 10 kGy may deteriorate the materials significantly while dose higher than 50 may deteriorate the materials severe, this restoration is needed. It is well known that materials will not hold the radiation.
・4 damage due to the uptake of radioactive particles. Here more care has to be taken in order to remove these particles if possible.
So, a lot to do. And of course we , in our team, can be of help. But without funds were are getting nowhere. I will contact Hanako Hirano at Tokyo National Universityto see what is going on further Regards,

John

————————————————————

From: Valeria Orlandini
Sent: maandag 28 maart 2011
To: Havermans,J.B.G.A. (John)
Subject: Response re: Japanese Materials Contaminated by Radiation

Dear John,
Thus a lot for your prompt reply to my message. I am wondering if your research and contact could be of any help. I do not want tobother you but I was talking over the weekend with a friend/acquaintance that work in the NYC Department of Safety (explosives section) and his wife working for U.S. Homeland Security and he mentioned that the radia with this in radiation in those archival materials probably are gamma rays but a very high doses. Am aware that you, Ana Maria Calvo at CNEA in Buenos Aires, Argentina and Maria Fernanda Auada at SENAI in Sao Paulo, Brazil are working with gamma radiation for the treatments of mold infestations. Let me know if you and/or others in The Netherlands have anything to assist these colleagues with the aftermath of the Japanese Disasters. I have contacted AIC and they do not seem to know much about it because in America conservators and scientists do not use radiations to treat archival materials.

Have a great day! very kind regards,
Valeria

————————————————————

On Mon, Mar 28, 2011, Havermans, J.B.G.A. (John) ??

Good morning too Valeria,
It was indeed a fine weekend. Working under my house to improve the cables of my internet connection.
Indeed a serious item. We have to think about it what we can do for them. We will keep in touch
John

————————————————————

From: Valeria Orlandini
Sent: vrijdag 25 maart 2011
To: Havermans, J.B.G.A. (John)
Subject: Japanese Materials Contaminated by Radiation

Dear John,
Good morning! I read this post in the Conservation Distlist about Japanese Materials Contaminated by Radiation and thought that maybe you can help this conservator and others in Japan that are dealing with similar problems. Enclosed find an email of a colleague conservator Hanako Hirano in Tokyo.
Have a good weekend!
Best regards,
Valeria

Date: 29 Mar 2011
From: John Havermans
Subject: Library and archive material contaminated by radiation

I have been noticed about your questions recently by other colleagues on the contamination of library and archive materials.

In my team we do have ample experience with science for herritage, and I am specialised in the field of paper materials, including radiation.

Please feel free to discuss your problems with me and I can see if any help can be given from distance.

Unfortunately we do have lack of funds at the moment for doing additional research or for developing tools/methods that might helpful for you. However this might change.

So again, feel free for further discussions.

Also I recently made a forum, dedicated to radiation technology for herritage. This form can include discussions dedicated to your subject as well. It is an open forum having access easily.

Please do not hessitate to use this new forum as well.

http://radiation4herritage.createforum.net/index.php

I wish you sunshine, luck and strength

John Havermans

Date: 29 Mar 2011
From: Gary D. Saretzky
Subject:book and paper restoration

Are large freezers available to stabilize water damaged materials until they can be evaluated and treated? If there are no disaster recovery vendors available, check with food vendors or institutional cafeterias that may have large food freezers such as colleges and universities.

I have no experience with radiation contamination so regret that I cannot provide advice on that topic.

cordially,

Gary D. Saretzky, Archivist
Monmouth County Archives
125 Symmes Drive
Manalapan, NJ 07726

Date: 29 Mar 2011
From: florian szibor
Subject: cons-dist-list

Dear Mr. Kibe,
reading your question about handling contaminated material at const-dist-list. and seeing the terrible pictures from your country, brings me to the question, if there are enough people helping you saving cultural heritage or if there´s a need for conservators in japan in the moment. if so, i would gladly offer you my help. i´m about to finish my studies of restauration for meodern material/technical heritage in berlin. i would be glad if there would be any way to help.

yours sincerely

Florian Szibor

Date: 28 Mar 2011
From: Valerie Tomlinson
Subject: Library and archive material contaminated by radiation

Unless the material was at the centre of the nuclear disaster in the nuclear plant itself, the radiation levels of any contamination are likely to be quite low. The levels may be above “standard background” level, but there are many places around the world where the background radiation level are dozens of times standard background level just because of the natural composition of the minerals in the rocks and soil (and people have been living there for millennia). The radiation levels from contaminated material is likely too low to harm the material itself (very high levels might slightly increase aging of materials, or mean there is sufficient foreign material present to rate as “dirt”). The main issue with contamination is human health, specifically of anyone accessing the material. Ingestion of traces of contamination by mouth or breathing is the main concern here. Check the radiation levels of the material with a Geiger counter. If it is not significantly above standard background or the normal background levels for the area, then there is probably nothing to worry about. If you actually get a reading high enough to be of concern, then anyone handling the material should take contamination precautions (gloves, protective clothing/tyvek suit, respirator, no eating or drinking in the area, etc.). Protective clothing may need to be disposed of as “active waste” after use if contamination levels are high, so disposable clothing is preferred. The material should be sealed to prevent spreading the contamination around (sealing in plastic should be sufficient), after completing any necessary preservation treatment. If the radiation levels are very high (unlikely), you may want to enclose the material in a lead enclosure, or with a lead sheet in front of it. Don’t bother with the lead if the levels of radiation are low, the toxicity of lead becomes a greater health hazard than the radiation at very low levels. On the plus side, the isotopes that compose the contamination are likely to be ones with relatively short half lives, and the radiation levels will decay to safe levels relatively quickly (days, months, years, or even decades, but not likely centuries), so continue to monitor the radiation periodically with a Geiger counter, and remove the radiation precautions when the readings fall to safe levels (“safe” may still be dozens of times standard background level).

Valerie Tomlinson
Conservator
Auckland Museum
Tamaki Paenga Hira
The Domain
Private Bag 92018
Auckland 1142
New Zealand
+64 9 306 7068

Date: 26 Mar 2011
From: Rebekah Tabah
Subject: Library and archive material contaminated by radiation

The attached article may not give an exact answer to your question, but may point in the direction of others to contact.

Our heartfelt sympathies to you and all in Japan.

Rebekah Tabah

Rebekah Tabah , MA
Photo Preservationist
Arizona Historical Foundation
Hayden Library, Room 412
Arizona State University
Box 871006
Tempe , AZ 85287-1006
P: 480-965-3283
F: 480-965-5744
www.ahfweb.org

Science.pdf 390K?ダウンロード

Date: 25 Mar 2011
From: Randy Silverman
Subject: Library and archive material contaminated by radiation

You are very brave trying to address this catastrophic event. I sincerely wish there was something I could suggest. I have been dealing with disasters for 25 years and was able to get involved in recovery work in Mississippi following Hurricane Katrina which is the biggest event we have had in the U.S. in modern times. However, that hurricane and the accompanying storm surge and tornadoes pale compared with your current situation. So I have a very slight idea how terrifying the destruction must be. I can certainly help with drying wet books but undoubtedly that is not the issue at this point. There is no reasonable solution for radioactive books and paper that I am aware of. I am afraid I can offer no suggestions except to please be careful for the sake of your own health and that of your colleagues.

If you can think of any way I can help please contact me again. I very sincerely wish you the best under extremely difficult circumstances.

With warmest regards,

Randy

Randy Silverman
Preservation Librarian
University of Utah Marriott Library
295 South 1500 East
Salt Lake City, UT 84106-0860? USA
t. 01-801-585-6782? /? f. 01-801-585-3464 randy.silverman[at]utah.edu

Date: 25 Mar 2011
From: Valeria Orlandini
Subject: Library and archive material contaminated by radiation

Am a paper conservator in Washington D.C. and called this morning the Cultural Office of the Chinese Embassy to enquire about how they/we could assist you and the Japanese colleagues in charge of cultural heritage and library and archival materials contaminated by radiation.

Mr. Liu Dong, at the Chinese Embassy encouraged me to tell you to contact the Chinese Embassy in Tokyo and inform them about the problems you are having and then seek help from them re: materials’ contaminated by radiation.

Hope this could be useful. Also,? want you to contact colleagues in The Netherlands, Spain, Brazil and Argentina that deal with library and archives materials with gamma radiations since they might know what to do and how to collaborate.

“Dr. John Havermans” <john.havermans[at]tno.nl>, Delf, The Netherlands (scientist)

“Maria Carme Sistach” <csistach[at]telefonica.net>, Barcelona, Spain (scientist)

“Fernanda Auada” <labconservacao114[at]tsp.senai.br>, Sao Paulo, Brazil (paper conservator)

“Ana Maria Calvo” <calvo[at]cae.cnea.gov.ar>, CNEA ? Ezeiza, Buenos Aires, Argentina (paper conservator)

Please, reply and let me know that you received this message. Thank you!

Sincerely,

Valeria

Valeria Orlandini
Paper/ Photograph Conservator
Chevy Chase, Maryland
U.S.A.

Date: 25 Mar 2011
From: George Bailey
Subject: Library and archive material contaminated by radiation

Most of the library and archive material that has become contaminated with radiation will have done so by being covered with fallout (radioactive dust) that has settled upon the material. It is highly unlikely that the material itself has become radioactive. The fallout can be removed with appropriate safety systems set in place. Not knowing what the rules and regulations in Japan are for handling of radioactive material are, I can only give general advice. It may well be that only certified companies or persons may be authorised to decontaminate such material. If you are handling radiation contaminated material, you should be wearing appropriate protective clothing, e.g. nitrile gloves, dust mask or filtered respirator, protective clothing, and a dosimeter to record your exposure. You should limit your exposure by keeping the material as far away from your body as possible, keeping the time spent with the material to a minimum, and have shielding between you and the contaminated material. All archive / library material contaminated with radioactive fallout should be sealed in polyethylene bags and suitably labelled (i.e. with the internationally recognised Radiation Trefoil device), and should be stored in an approved location until a plan of action is developed and approved. Freezing water damaged contaminated items will have no effect on the radiation activity. Good luck, and remember to consider your own longevity before any archive or library material.

George Bailey
Senior Objects Conservator
Australian War Memorial

Date: 25 Mar 2011
From: Sue Lee-Bechtold
Subject: radiation contamination

I read your plea to the distlist, and thought of the problems we at the National Archives (US) have had.?I am a chemist, recently retired from there.? First you need to have a radiation monitor of some type, or the help of a health physicist who can tell you if particular records are indeed contaminated.?Much of the radiation produced has half lives that are short enough that it decays perceptibly before you can even get around to doing any kind of conservation treatment.? Also, you need to know what the contaminants are.?This will give you an idea of how dangerous what you are dealing with is, or will be in the future.?This is difficult, there are lots of handheld monitors to tell you how much radiation you have…but it takes more sophisticated equipment to tell you what is there that you really need your government’s specialists help. We have encountered a very few records contaminated with isotopes with such long half-lives that we considered them too much of a risk for the employees or public to handle.?But there are a number of nuclear plants in this country which have undertaken copying of records and bound volumes to preserve the information while the originals(and the copy machine) go into low level radioactive waste dump.? Sorry to say, I know of no way to remove radioactive isotopes completely from paper, without creating a larger volume of contaminated material.?You could try putting the paper upside down on your suction table and using flooding the back of the sheet, and checking to see if the radiation is reduced…but then you have contaminated your suction table…it seems inevitable that in trying to remove it, you just get more things contaminated.? But if you’re lucky, and the isotopes have short enough half lives, you can just shut them up in a lead lined room until decayed sufficiently to be safe for use.

Susan Lee-Bechtold

Date: 25 Mar 2011
From: Paul Sillitoe
Subject: Library and archive material contaminated by radiation

As an archivist I am not qualified to answer your question, but may I please express my sorrow at your nation’s dreadful difficulties, and very sincere best wishes for a recovery to normality as soon as possible. We cannot start to imagine the problems that you all face, in archival conservation and far beyond.

Paul Sillitoe
UK