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Better cesium maps of the area around the accident site in Japan

Dear Reader,

MEXT and the US DOE have done some very good work, they have used aircraft to survey the cesium levels on the ground near to the accident site. They have made a series of maps which can be seen at the following site.


The yellow on the Cs-137 map is for land which has at least 1 MBq of cesium-137 per square meter, this will work out as 1 TBq per square kilometer. If we now convert this into curies it will work out as 27 curies per square kilometer. This is a high level of cesium contamination.

Page 22 of the IAEA report on the Cs-137 accident in Brazil (http://www-pub.iaea.org/MTCD/publications/PDF/Pub815_web.pdf) gives some important data for Cs-137. Using this data I have been able to estimate the gamma dose one meter above the ground due to Cs-137 when the ground is contaminated with 1 MBq of Cs-137 per square meter as being 1.6 microSv per hour, this will work out as 14 mSv per year.

You may want to look at the cesium map for the area around Chernobyl to allow you to compare the two events. Do bear in mind that the colour code on the Chernobyl map is different to the one on the Fukushima map.


Another map is present at the following site.


In the second Chernobyl map the areas which have more than 40 curies of Cs-137 are classed as closed zones, in modern units this translates into 1.48 TBq per square kilometer.

I suspect that the cesium level may have a very profound effect on farming for some years to come. One thing which the farmers of that part of Japan could do is to change to a new non-food crop.


Here is some advice which is given out by the UN regarding the people who live in the cesium contaminated areas in the former Soviet Union



3 Responses

  1. The IAEA as a “good” source for radiation maps of Fukushima?

    Is this the same IAEA which says, 32 people died by Chernobyl?
    The same IAEA who says, “Chernobyl was a small accident”?
    The same IAEA which says low radiation is harmless?
    The same IAEA which gags the W.H.O. witt the gag agreement WHA 12-40 since 1959?
    The same IAEA which advertises atomic power all around the planet? And so directly pushes the production of Plutonium and atomic bombs?
    The same IAEA which ignores ALL Fukushima and Chernobyl children – and sees them as a threat?
    The same IAEA which does not accept INES 7 for Fukushima and says “It’s INES 5”?

    (comment edited for reasons of bevity)

    Dr Mark Foreman replies, I see a series of problems with what you have written. What evidence do you have to support your claims.

    1. The IAEA did not publish the cesium map for Japan, that was done by the US DOE and MEXT (Ministry of Education, Culture, Sports, Science and Technology) were responsible for the cesium measurements in Japan. While the IAEA can provide advice on how to handle an accident site, they do not normally take responsibility for an accident. It is normally members of the UN (other nations) and organisations within the country where the accident occurred who make safe the site, deal with the injured and do the clean up.

    2.The IAEA estimate for the number of persons killed by Chernobyl is higher than 32. I know that among the plant worker, fire-fighters and other emergency workers that about 35 deaths occurred in the months after the accident, but this is not the total death toll from the accident. Please do provide me with a copy of the IAEA document which you cite.

    3.The IAEA do not regard Chernobyl as a small accident, when they set up the international scale for nuclear accidents they choose Chernobyl as an example of the worst type of accident possible. Please show me where they state that Chernobyl was a ‘small accident’.

    4.From my reading of the advice given by the IAEA to radiographic workers it does appear that the IAEA take a view that small doses of radiation are not harmless, please do show me where the IAEA state that small doses of radiation are harmless.

    5.The ‘gag agreement’ you talk about, if a government or international body (such as the UN) need to address something then it is often irresponsible and a waste of tax payer’s money for two different departments to do exactly the same work. Please could you show me some evidence that the agreement between the IAEA and the WHO is something sinister rather than a simple agreement to optimise the use of tax payer’s money?

    6.The IAEA does not promote the production or ownership of atom bombs, the IAEA was given a Nobel peace prize (2005) for its efforts to prevent the military use of nuclear technology.

    7.Please show me some evidence to suggest that the IAEA regards the children from the areas near Chernobyl as a threat.

    8.Please show me some evidence that the IAEA tried to keep the rating low on the accident scale. The level which many commentators ranked the accident at did go up during the accident. When the Japanese NISA raised the level of the accident to 7 the IAEA did accept this change. (See the IAEA press release on the 12th of April, http://www.iaea.org/newscenter/news/2011/fukushima120411.html)

  2. […] which included this above mentioned one, on blogger Mark Foreman’s May 17, 2011 blogpost: Better cesium maps of the area around the accident site in Japan.  Combined with the the UNEP’s detailed map of Cesium 137 & 134 fallout from Chernobyl […]

    • Nice maps, I am glad to see that you have had a go at redrawing the colours on the different maps.

      I will comment in detail on your blog entry later, but I will say something final point about the study in Sweden. The Swedish study which you mentioned is a study which from what I know does disagree with the majority of the scientific community think about the effects of Cs-137 contamination in Sweden.

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