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Elevated Radiation Claimed At Tokyo 2020 Olympic Venues

Posted by samzenpus on from the mutant-games dept.

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."

2 of 164 comments (clear)

  1. Some numbers for reference. by marcansoft · · Score: 5, Interesting

    Using my Safecast Onyx (hi Safecast folks!) I measure ~0.32 uSv/h in Dublin, next to a granite wall (granite is everywhere around here, and naturally radioactive). The article speaks of of 0.484 uSv/h, not much higher than that. On an airplane at cruising altitude I get about 2.0uSv/h. At home I might see 0.08uSv/h, and in the middle of the street somewhere around 0.15uSv/h. *

    I just visited japan and took the Safecast everywhere I went. At no point did it go significantly above what were normal background radiation readings in Dublin (not even when I was passing by Fukushima station, though admittedly that was on a high-speed train).

    Radiation is everywhere. Unless you can identify the source as the Fukushima disaster, it might be perfectly normal. Even if the source is Fukushima, at low levels, at some point you have to stop worrying about it and realize that plenty of other places on Earth have higher naturally occurring background radiation.

    * Rough numbers pulled from memory in CPM and converted to uSv/h using the conversion factor in the firmware source code, since my Onyx battery is dead at the moment. Take with a grain of salt.

    1. Re:Some numbers for reference. by marcansoft · · Score: 3, Interesting

      Interesting. I didn't stop at Fukushima station, but I went past it on the Shinkansen with my Onyx in the outer pocket of my backpack (obviously it won't be picking up any alpha radiation there, but still useful data). Looking closely at the logs it is possible that one spike correlates with roughly the time I'd have been in that area, though I really would have to check the times closely. The Onyx was set to log every 10 minutes so it's also possible that it just missed the interesting times. The peak readings were about 0.2uSv/h, and that wasn't near Fukushima. Tokyo averaged somewhere around 0.11 uSv/h, while Hakodate (where I stayed a couple of days) was around 0.07uSv/h.

      Interestingly, my return flight hit 3.0uSv/h, higher than the first flight (I just dumped the last chunk of the log which I hadn't done yet).

      These readings seem to be using the default calibration of the Onyx. I haven't delved into the details yet (the firmware is still WIP as far as I can tell), but AIUI they are supposed to come calibrated, so either the default calibration is spot on, or the firmware isn't using the calibration data, or my firmware upgrade wiped the calibration data, or the calibration data was never there. Either way, I assume the default conversion factor is good enough for rough measurements of background radiation.