#Radioactive Strontium Was Detected in Monthly Fallout As Late As November Last Year in Chiba, Ibaraki, Ministry of Education's Data Shows

But the Ministry of Education (MEXT) doesn't think the strontium-90 fallout after May last year was of Fukushima origin.

Following up on the post about strontium-90 fallout last year that MEXT (Ministry of Education and Science) announced on July 24 this year, I found some interesting data in the Japan Chemical Analysis Center where I created the chart plotting the Sr-90 fallout for the past 50 years or so in Japan (reproduced here).

The 2011 monthly fallout data for strontium-90 at the Japan Chemical Analysis Center is easier to see than the MEXT PDF file pages (they are the same data). As I was browsing through the search result, I started to wonder:

When was the last month that strontium-90 was detected in the fallout for these ten prefectures?

So here it is, from the search result at the Japan Chemical Analysis Center's website, the last date when strontium-90 was detected in the monthly fallout in the cities/prefectures in Tohoku and Kanto in 2011:

Aomori City, Aomori: March 31
Morioka City, Iwate: September 10
Akita City, Akita: July 1
Yamagata City, Yamagata: July 1
Hitachinaka City, Ibaraki: November 1
Utsunomiya City, Tochigi: August 1
Maebashi City, Gunma: June 1
Saitama City (Sakura-ku), Saitama: August 1
Ichihara City, Chiba: November 1
Chiba City (Inage-ku), Chiba: November 1
Shinjuku-ku, Tokyo: August 1
Chigasaki City, Kanagawa: June 30

Of these results, MEXT doesn't seem to think the detection in Aomori had anything to do with the Fukushima nuclear accident, as the prefecture is excluded from the list by MEXT in the press release (see my previous post for the MEXT list). In addition, MEXT seems to think the fallout after the first two to three months of the accident (March through May, 2011) is due not to the Fukushima accident but to the past atmospheric nuclear testing because the measured amount did not exceed the amount prior to the Fukushima accident.

Outside Kanto and Tohoku regions, there are occasional detection of strontium-90 in:

Niigata City (Nishi-ku), Niigata: May 2
Imizu City, Toyama: April 1
Kakamigahara City, Gifu: July 1
Shizuoka City (Aoi-ku), Shizuoka: August 1
Yokkaichi City, Mie: May 2
Kyoto City (Fushimi-ku), Kyoto: April 1
Wakayama City, Wakayama: November 1
Okayama City (Minami-ku), Okayama: April 1
Ishii-cho (Myozai-gun), Tokushima: April 1
Takamatsu City, Kagawa: April 1
Matsuyama City, Ehime: April 1
Kochi City, Kochi: April 1

Likewise, none of the detections above is considered by MEXT as the result of the Fukushima accident.

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Now They Tell Us: Ministry of Education Says Strontium-90 of #Fukushima Origin Found in 10 Prefectures

It took about 15 to 16 months for the Ministry of Education and Science or MEXT (the very name is a joke at this point) to announce radioactive strontium (Sr-90) was widely dispersed from the broken reactors at Fukushima I Nuclear Power Plant last year in 10 prefectures in Kanto and Tohoku, to the levels last seen in the Chernobyl accident.

Caveat is that it excludes Fukushima and Miyagi, probably the two most contaminated with radioactive fallout from the Fukushima accident. MEXT's excuse is that the stations in these prefectures have been damaged by the earthquake/tsunami.

From the press release by Ministry of Education and Science on July 24, 2012, "Analysis of Strontium-90 in the monthly environmental radioactivity levels (fallout)" (in Japanese; labels added by me):

Asahi Shinbun has a chart that tries to put these numbers in perspective. The bump this time looks slightly bigger than the one after the Chernobyl accident. But Asahi, either in its scientific illiteracy or on purpose to minimize the latest bump, uses the normal scale on the Y-axis instead of a log scale which would make it easier to discern the fluctuations in smaller numbers:

Looking for a historical chart on a log scale, I went to the site maintained by the Japan Chemical Analysis Center. I searched the database, and the 2011 data is already in the database. Here's the chart I created using the graph function at the site. I added the thin red line later to compare the 2011 level with that after the Chernobyl accident. It does look it is ever so slightly higher. The chart is a log scale, and the data is from all prefectures:

I wonder what the levels would be if Fukushima and Miyagi's data were to be added. Back to the level during the atmospheric nuclear testing? Or would it exceed that level?

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Radiation in Namie-machi, Fukushima Almost Exceeded OSHA 90-Day Limit for Radiation Worker in 14 Days Last Year

The cumulative radiation dose at MP (monitoring post) 32 in Fukushima Prefecture from March 23 to April 4, 2011 was 11,630 microsieverts (or 11.63 millisieverts), almost exceeding the OSHA 90-day limit for radiation worker of 12,500 microsieverts in 14 days.

My guess is if the radiation had been measured from March 11, 2011, it would have surpassed that limit long before March 23, 2011.

From Enformable's digging of the NRC FOIA documents, 3-page email dated April 9, 2011 says on page 3:

MP32

The U.S. 50-mile radius adequately protects public health, but the Japanese 20-kilometer (12 mile) radius may not protect the health of the general public, pregnant female radiation workers, or radiation workers who remain longer than 2 weeks near MP32.

MP32 remained MP32 in the Ministry of Education and Science (MEXT) monitoring data, until April 11, 2011 when the location was finally named. It was Akougi District of Namie-machi in Fukushima. Why was the location finally named that day? Because that was the day the government announced the planned evacuation zone that included Akougi and most of Namie-machi that was not already inside the 20-kilometer no-entry zone.

Akougi is located at 31 kilometers northwest of Fukushima I Nuclear Power Plant, outside the no-entry zone. The district was finally declared planned evacuation zone on April 11, 2011, because the annual cumulative radiation dose was expected to exceed 20 millisieverts.

There was a evacuation shelter in Akougi, with people living there until March 30, 2011.

According to the MEXT data, as of March 26, 2012, the cumulative dose at MP32 since March 24, 2011 is 125,760 microsieverts, or 125.76 millisieverts.

Chuck Casto E-Mail - Pages From C141933-02BX-24

Here's the same information released by the Ministry of Education on April 6, 2011.

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