Tuesday, July 24, 2012

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?


m a x l i said...

MEXT=Ministry of Extermination

Anonymous said...

Not that I'd believe it, but did anyone offer an explanation of why this was not released throughout the past 16 months? It seems that monthly data were being collected even before March 2011, How long did it take for them to release March 2010's data? How late is this new data in comparison? Why? Who made that decision? What jail is he or she being sent to?

Nancy said...

Where did you get the Chernobyl numbers for comparison? I have never seen any stronium numbers for Chernobyl so I am curious what they looked like. Anyone have an idea what the stronium 90 to cesium ratios were for Chernobyl for comparison against these MEXT numbers?
Bits of information keep coming out that hint the official readings are lower than what they really are.

arevamirpal::laprimavera said...

Nancy, I'm referring to the levels in Japan at the time of the Chernobyl accident - the spike in the chart around 1986-87.

Anonymous said...

If the Quake and tsunami damaged the sensors fine but why didn't they immediately repair or replace them? Once again we are left guessing because of the purpose built fragility of the detection network.

Anonymous said...

Nancy, the ratio of cesium to strontium in total releases after Chernobyl was around 15 to 1. After being transported 5000 miles, the ratio detected in Japan in 1986 seems to be around 10~50 to 1. Just check the database.

Laprimavera, I don't know if the journalists at asahi shimbum are scientifically illiterate or they just want to minimize the results, but I have encountered a lot of people that can't interpret a graph using the logarithmic scale.

Anonymous said...

Here, No one teaches logarithmic functions anymore..its all using your calculator...sad..

Anonymous said...

What was the mortality rate in the early 60's when strontium was at higher levels. What can we infer from that data about likely mortality from Fukushima strontium?

Anonymous said...

What can we infer from the government late publication of strontium contamination?
What infer from food analysis being done on cesium only?
What can we infer from Tepco profits and our food contamination?

Anonymous said...

What can we infer from MEXT not telling us exactly where they detected the highest levels the published? In Tokyo ok, but where exactly?
Has any other measurement being done after April 2011?
Is strontium being measured in driking water, considering that it is highly soluble?

Anonymous said...

@anon 3:50 PM:

Both the mortality and child mortality rates have been decreasing while life expectancy have been increasing steadily in Japan since the 50s, I don't think you would find anything there.

Maybe some increase for some kinds of cancer, but the effect on the overall demographic data is null.

Anonymous said...

9/11 too had a practically null effect on US demographics

Anonymous said...

I would like to point out the graph spikes in 1970, 1974 and 1977-79 were probably due to The Chinese and French reluctance to stop atmospheric testing when the US and USSR did in 1963 (LTBT). France continued atmospheric testing until 1974 and the Chinese until 1980. The 1981 spike was probably from China's last atmospheric test.

There were also some nuclear accidents in 1981 the most serious was an INES 3 accident at La Hague reprocessing plant I doubt it added much to the Chinese fallout burden but it is still and interesting bit of history.

La Hague Silo Fire:

Graphite elements had been burning for 24 hours in a waste silo. Uranium metal caught fire following a mechanical shock during operations. The maximum measured level of air contamination, 700 Bq/m3, was reached 10 hours after the beginning of the fire. The released activity is mainly due to caesium-137 and -134 (137Cs and 134Cs) and ranges between 740 GBq
and 1,850 GBq, thus 10 times of more the annual limit. The annual limit for the whole La Hague site is 74 GBq of caesium-137. Strontium-90 (90Sr) was detected in rainwater and the authorized limit of surface contamination was reached in 6 km distance from the site. A worker received in one day the annual admissible dose, 50 mSv. An off site health impact has not been carried out. This fire was considered a major accident and was rated later at level 3 of the International Nuclear Event

Source: [GRNC, GT-1, 1999; BSN, 1981]
and http://nucleaire.edf.fr



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