Someone asked a few questions in the News for Tsukuba Residents Facebook group (if you live in Tsukuba, you should really consider joining this group) about radiation levels in Tsukuba. Here are my answers (according to my understanding, so feel free to disagree).
1. The radiation level is said to be very low (around 0.20 microSv/h), but what was the normal level before the earthquake? I couldn’t find that information anywhere.
Radiation levels fluctuate even within Tsukuba.
AIST: 0.06 µSv/h
NIMS: 0.1 µSv/h
KEK: 0.07 – 0.09 µSv/h
AIST: 0.17 µSv/h, 0.28 µSv/h (readings from two different places, but it says they have subtracted the background amounts from each)
NIMS: 0.24 µSv/h
KEK: 0.18 µSv/h
2. About iodine in tap water, the last value we have is 8.3 Bq/kg (source: http://www.pref.ibaraki.jp/20110311eq/pdf/0222.pdf), but if you take a look at it, this value is from March 24, and the other cities seem to have much higher values in the next few days (Ushiku = 76.2 Bq/kg on March 26, for example). Ushiku is very near from Tsukuba so…
My guess is that they tested the water in a bunch of different places and then they continued testing only at the places where they found readings above 100. Since the Tsukuba level was so low, they didn’t continue testing. That is just a guess though, not based on any special information that I have.
3. What should we do about tap water? Is it safe to take shower? Can we eat a nice ramen or udon without fearing the radioactivity of the soup water? Should we use mineral water to cook or can we use tap water?
We haven’t been told that the tap water is unsafe in Tsukuba, so we have the choice of assuming that we will be told if it does become unsafe and going about our daily business as usual, or guessing that maybe Tsukuba’s tap water is similar to the cities around us and acting accordingly. The cities around us, such as Tsuchiura, Ushiku, and Joso all have levels that are well below 300 Bq/kg of iodine and 200 Bq/kg of cesium, so my choice is to use the tap water as I would normally.
Tsuchiura – 16.7 Bq/kg of iodine, cesium not detectable (March 24)
Ushiku – 76.2 Bq/kg of iodine, 4.38 Bq/kg of cesium (March 26)
Joso – 50.1 Bq/kg of iodine, 2.78 Bq/kg of cesium (March 24)
4. What about the food? Can we eat everything? Should we avoid vegetables and milk?
Regarding food, watch the prefecture’s website for updates.
5. Should we avoid the rain?
It is okay to go out in the rain. (See: http://www.nisa.meti.go.jp/english/files/en20110323-2-5.pdf)
Another good source for Tsukubans: http://www.pref.ibaraki.jp/bukyoku/seikan/kokuko/en/ (Ibaraki prefectural government site)