Slashdot Mirror
Elevated Radiation Claimed At Tokyo 2020 Olympic Venues
An anonymous reader writes "A citizens' group in Tokyo claims to have found elevated levels of radioactivity at 39 sporting venues earmarked for the 2020 Olympic Games. Expert and organizers are cautious about the findings but see no problem, as the levels do not pose an immediate threat to human health. From the article: '"It is difficult to have this debate unless we know for sure whether this radiation is from Fukushima or whether it is naturally occurring background radiation," said Pieter Franken, founder of the Japan office of the environmental monitoring organization Safecast."
randall munroe actually put up a fairly insightful chart of radiation levels: http://xkcd.com/radiation/
Somewhat amusingly, he typoed the one relevant box in there - "Extra dose to Tokyo in weeks following Fukushima accident" should probably be 40uSv (not 40mSv) if he means per person (and even then it sounds a bit high), or be in the orange chart if he means the total dose delivered to all of Tokyo.
This appears to be the letter and the data that started all this:
http://olympicsokuteikai.web.fc2.com/encontents.html
Perhaps the most crucial part of the letter is this:
"Just before the Fukushima power plant accident, the mean value of the atmospheric radiation in Tokyo was estimated as 0.04 Sv/h, and radioactive Cesium was almost non-existent. Therefore, atmospheric radiation value above this level can be regarded as the effect of the nuclear accident."
Is that a valid assumption?
The pools didn't break during a 9.0 magnitude earthquake. The fifth most fierce ever on earth. Why should they break during a lesser earthquake?
Because magnitude doesn't correspond all that well to forces felt at the surface.
The Christchurch, New Zealand earthquake of September 2010 was a 7.1, and the peak acceleration was 1.26g. The Feb 2011 at the same location much less energetic at "just" a 6.3, yet its peak acceleration was 2.2g (among the highest recorded in an urban area) due to most of that energy being released over just 12 seconds.
The 9.0 Fukushima earthquake OTOH was spread out over 6 minutes, so its peak acceleration was 2.99g despite it being thousands of times more energetic than Christchurch's Feb quake.
There is no such thing as "safe" radiation, so eliminating all man-made causes is a good thing, even if the levels are lower than background in some areas.
Citation please? I give you mine:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663584/
In many places where the background radiation is higher but still at "safe" levels it doesn't seem to be killing people faster. In fact in some places they seem to live longer! Yes it could be due to other factors (diet, lifestyle), but it just shows that at those levels the radiation no longer significantly reduces your lifespan.