Should the public be allowed to see the radio-contamination map ?

We are publishing the most recent map of the soil contamination made by the “Fukuichi area environmental radiation monitoring project“.



Tomioka soil constamination map M


富岡町土壌マップ M


We have published several soil contamination maps of the “Fukuichi area environmental radiation monitoring project” in this blog (see maps of Namie, Minamisoma 1 & 2 ). Normally, the government should carry out the measurements, but the government relies on the air radiation dose measurements at the expense of the radio-contamination measurements found on the surface and in the air (in terms of the volume of radioactive substances). To fulfill the lack of this essential information for the radioprotection of the population, civil groups conduct soil measurements.

このブログで紹介してきた「ふくいち周辺環境放射線モニタリングプロジェクト」の土壌汚染マップですが(浪江町南相馬市 1 & 2 )、もともと国や地方自治体が実施すべき測定です。しかし、政府は空間線量率の測定のみを優先し、表面(土壌を含む)や空間の汚染密度をニグレクトしています。そのため住民の放射線防護に不可欠の情報が欠如しています。この情報不備を補完するため、市民団体が測定を 実行しているのが現状です。

rice field

bord de route


Normally, both the air radiation dose rate and the soil contamination density are necessary to define the evacuation zones. Indeed, in the crippled TEPCO Fukushima Daiichi nuclear power plant, the radioprotection of the workers is staged according to the combination of the radiation dose, the surface contamination density, and the concentration of radioactive substances in the air. (See Forest fire in the exclusion zone in Fukushima: why monitoring the radiation dose is not enough for radioprotection)

避難指示区域の設定には空間線量率とともに土壌汚染密度が必須のはずです。実際、福島第1原発内では作業者の放射線防護対策には空間線量率(Sv/unit of time)、表面汚染密度(Bq/m2)、空気中放射性物質の濃度(Bq/m3)の三者の組み合わせを考慮しています。

Yet, for ordinary people, under the current Japanese government, only the air radiation dose rate is taken into account, disregarding the risk of internal radiation exposure (Note 1). The evacuation orders are lifted, and the inhabitants without a manual, nor professional radioprotection training are encouraged to return, including babies and pregnant women, to be exposed in the very highly radio-contaminated environment.

In this situation, what will be the use of the soil contamination maps created by civil groups? How will the local administrations deal with them? Will they make use of them at all?


このような状況の中で、市民団体が作成する土壌汚染マップ はどのように役立っているのでしょうか?地方行政による扱いはどのようなものでしょうか?行政は市民団体作成の地図を役立てることがあるのでしょうか?

Mr Yoichi Ozawa of the “Fukuichi area environmental radiation monitoring project” has given comments on this subject.




On December 14, we went to the city halls of Namie and of Tomioka, as well as to the firefighter headquarters of the Futaba district to present and offer free of charge an A0 size (841mm x 1189mm) print of the soil contamination map. We had already been to Namie town hall, but we had just showed the data without offering the map. Our purpose is to put the map in public places. In Tomioka, it was the assistant manager of the decontamination work section under the department of the reconstruction promotion who received us. We went to the firefighter headquarters of Futaba district to share the information about the scattering of radioactive particles in the case, for example, of the forest fire in Namie.

12月14日、浪江町と富岡町役場、そして、双葉地方広域消防本部にA0サイズ841mm x 1189mm)に拡大印刷した土壌汚染マップを無償提供し、詳しい説明をしてきました。 浪江町役場は、以前資料を見せるだけ見せて帰ってきましたが、やはり、提示してもらわなければ意味がありません。富岡町では対応窓口は復興推進課除染対策係長です。双葉地方広域消防本部には、浪江町の山火事や放射能の舞い上がりを知らせるのが目的です。

Both in Namie and in Tomioka, they spared about 15 minutes and they listened attentively to our presentation. They also wanted to receive the map. The firefighters showed interest, too. We told them that it is important to have a map at hand that shows the general view of the radio-contamination in case of further nuclear or natural disasters.

浪江町も富岡町も15分ほど話を聞いてくれて、マップも欲しいと言ってくれました。 双葉地方広域消防本部も関心を示してくれました。今後起こるかもしれない原発関連や自然災害のために、全体の汚染状況を見ることができるマップがあった方が良いですよ、と説明しました。

We have the impression that the local governments show more interest and are more open compared to the prefectural government, for they are themselves directly concerned with the problem of radioprotection. However, we really don’t know if they will put the map in public view or use it in any practical way. Our effort will be in vain if the map remains out of reach of the public. We really hope that they will make an effort to communicate this important information to the public.


End quote


As we can see from Mr. Ozawa’s comments, the local governments perhaps do not seem that enthusiastic to make use of the contamination map, although they seem to be more open than the prefectural government. However, it is impossible to achieve the radioprotection without the cooperation of the local government. The local civil servants are themselves exposed to the radiation risk. We do hope that they will collaborate with civil groups to present and publicize the contamination map, which will also be good for themselves and their families.



Note 1: In opposition to the external radiation exposure which occurs when the human body is exposed to an external source, the internal radiation exposure is an exposure from inside the body due to the incorporation of radioactive particles through ingestion, inhalation or adhesion to skin.

注1 :  放射線を発するもの源が体の外にあって、外から放射線が体に当たって被ばくする外部被ばくと異なり、内部被ばくの場合、体の中で発射された放射線で被ばくをします。放射性原子を吸い込んだり食べたり、または皮膚から吸収することによって、体の中に取り入れてしまい、体の中で放射線が発射されます。

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