Five months after the large Tohoku earthquake the cities of Nikko and Munich appear to have comparable levels of ground contamination with radioactive Cesium 137. Not a significant concern in Munich, people live normally, just no one eats local mushrooms and wild animals any more.
Image credit: antrix
Comparison table
| Place | Value | Source |
| Nikko and vicinity (2011) | 10.000 - 60.000 Bq/m 2 | Ground contamination map |
| Munich and vicinity (1996) | 19.000 - 80.000 Bq/m 2 | German health authority |
| Planetwide (before 1986) | ~ 4000 Bq/m 2 | from nuclear bomb testing, according to German health authority |
Ground contamination map, Cs 137, 134
文部科学省及び栃木県による航空機モニタリングの結果 （文部科学省がこれまでに測定してきた範囲及び栃木県南部におけるセシウム134、137の蓄積量の合計）
The Ministry of Education, Culture, Sports, Science & Technology in Japan published this monitoring report on 2011 July 27. The document focuses on Tochigi prefecture with Nikko city. This map shows elevated ground contamination levels for radioactive cesium in North East Japan. Depending at which level the line is drawn and what mitigation and decontamination techniques can be used, a lot of space may be declared uninhabitabe for generations.
Image source: page 08 from PDF by mext.go.jp 2011-07-27
retrieved 2011-08-11
Asahi Shimbun printed this map in better resolution, together with a chronicle of events and wind spread March 14-15 and March 20-23, Asahi Shimbun Kanagawa issue, 2011-08-11, page 5.
Why I trust the official measurements
On March 15 before noon, I observed a few hours of peak dosage around 0.6µSv/h on my Geiger counter system that normally shows around 0.12 µSv/h in Yokohama. This correlated with official sources such as SPEEDI . With a simple Geiger counter tube (Aware Electronics RM-60), even if backed by measurement software, I am not equipped to measure ground contamination or even food. However, such low levels, which at the time may have been mostly from iodine nuclides, do not concern me, not even for my children. This same Geiger counter showed 3 µSv/h for most of the duration of a flight to Europe.
Cesium is the main contaminant that stays and may find its way into the food chain (cosmic radiation during a flight does not stay in the body). If enough is eaten, it can add to the health hazards present in our environment. So how do we know we are below the "enough"? Indeed, one main concern in Japan is how to ensure no foodstuff contaminated beyond the legal limits finds is way into the food chain. A lot of measuring programs are being set up, but 100% certainty is not attainable, as always in life.
The nuclear debate
It is not about pro or con any more, although we can still hear fantastic arguments on both sides of the debate. It is more valuable now to discuss what is cheaper and safer and bring the bouquet of alternative energy technologies on-grid, soon. And:
We need to teach our children to be smarter than we are.
Gunter Pauli, entrepreneur and author of 36 fables
If you think I or someone else can help with that, please let me know in the comments below. Thank you.
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