Wednesday, July 25, 2012

#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.


Little canary said...

Japanese sickness:

First they ignore it, then deny it and finally they do not take any responsabilities.

Western people have also similar symptoms in decission matters.

JAnonymous said...

Why do these dates strike me as odd ? Almost all strontium episodes are on end of month / start of month... Or is this due to the sampling period being once a month ?

A while ago, I saw the CTBT data posted somewhere (maybe here?) and extracted all data to plot them. Most importantly there were the Xe isotopes. I believe Sr90 was also one of them. I never thought anything of those graphs, especially because I used a log scale ;-)

I'll try to dig them up tonight.

Anonymous said...

Sorry I'm getting a little off the strontium topic, but...

I played with the DB and checked various isotopes. I live in Japan and I often hear people say: "Yeah of course, Fukushima is bad but it is nothing compared to what we got from nuclear testing in the past so we should be fine"

Well, we could consider this is kind of true for strontium by looking at the graphs you posted, but then looking at cesiums shows a very different story.

These are historical graphs of cesium deposition since 1957 (again, post accident Fukushima and Miyagi prefectures are NOT included).

Cesium 137:

Cesium 134:

Clearly, depositions of cesium 137 coming from the Fukushima NPP was/is more than ten times worse that what came from nuclear testing (graphs are log scale).

Anonymous said...


All the data I downloaded was organized by month (sampling start date on the first of the month and sampling stop date on the last day of the same month).
So when plotting this data it kind of look like vertical bars.

Chibaguy said...

Do these people really not understand where these fission ionizing radionuclides originate from? This makes me even more depressed. When did Japan forget science is the question.

Safety Products said...

its really very difficult to imagine about any type disaster am really get scared whenever i heard about such disaster news in nearby our area....

Atomfritz said...

My personal guess is that the Strontium contamination spreads via wind-transported "black dust", soil etc.

Anyway I am amazed how the MEXT has mastered highest degrees of wishful thinking, as they apparently fail to provide a plausible alternative explanation for this spike which even exceeds the Chernobyl spike.

Anonymous said...

.thanks for sharing

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