Last week, one of the THJ guys, Murooka-san, brought along a handheld geiger counter up to Fukushima. There’s a 6-8 week waiting list for them in Japan these days but it had finally arrived. In Tokyo before we left it was reading around 0.15 microSieverts/hour, which seems to be around average. It’s hard to find data on the web that isn’t provided by the nuclear companies but according to Wikipedia, the average individual background radiation dose is 0.23μSv/h (0.00023mSv/h); 0.17μSv/h for Australians and 0.34μSv/h for Americans. (scroll down to the bit about hourly dose examples here)
Up at the volunteer centre in Iwaki City which is about 50 kms from the reactor, it was reading about 0.25 microSieverts/hour. When we got to the cleanup location a bit further North just under 40kms from the reactor and where people are still living, it read between 0.25 and 0.42, and peaked at 0.57 microSieverts/hour as the rain came down. We'll check again this weekend but basically, what we saw agreed with the official readings available online.
To extrapolate the per-hour readings to per-year values, you’d think just multiply the hourly reading by 24, then multiply by 365, but sometimes the figure is adjusted down because people spend a lot of time indoors sleeping etc where the levels are lower than outdoors. Some say the max recommended level is 1 milliSievert per year, some say it’s 5 milliSieverts per year, others say it’s up to 20. Either way, looking at our worst case exposure, the max we saw of 0.57 microSieverts/hour works out to an annual dose of 5 milliSieverts per year. That’s a full year of standing outside, 24 hours a day, less than 40kms from the plant. Since we’re only up there for 7-hours once a week or so, we got much, much less.
On the way home, I started thinking about my annual health check. Unusually for the rest of the world, in Japan most company health-checks include a barium meal, probably because stomach cancer is the most common cancer in Japan. The readings I found online for a barium meal varied from 2 milliSieverts on the NHS site to a whopping 15 milliSieverts on a private page written by what could have been the dubiously named Dr.Geoff Pain. Not knowing who to believe, again, I checked with the Medical Centre where I had my annual checkup only a few weeks ago. The nurse there was very helpful but had no idea and disappeared for 10 minutes to look up how many milliSieverts was in one dose.
She came back looking shocked saying it was actually between 10 and 20 milliSieverts (10,000 and 20,000 microSieverts) in one hit! Dr Pain was right on the money. Whether it was 10 or 20 varied depending on your body type and how long your body took to get rid of it.
Although one big concentrated hit of radiation is not the same as prolonged exposure at a much lower level, depending on what Fukushima reading you took, and depending on how your body handles it, one medical checkup packed the equivalent punch of standing outside, 24 hours a day, less than 40kms from the nuclear plant, for between 2 to 10 YEARS!! And I’ve had four of the buggers!
They’re not even that reliable. A friend of mine had a barium meal in February 2010 and got the all-clear. He was then diagnosed with stomach cancer three months later and had to have ¾ of his stomach removed. Luckily he’s over it now and fitter than me these days.
Stomach camera option for me next year!
A guy I work with showed me this site yesterday: microsievert.net
Best to look at the animation on the live site then use the screenshot below for a basic translation.
A brilliantly simple way to represent all these numbers being thrown at us everywhere we look, even at the end of the weather forecast.
The top row starts with the worldwide normal average on the left, increasing up to RUN AWAY! on the right. The bottom two rows show the actual current readings at main cities in the various prefectures in East Japan including at the exclusion limit around the reactor. I live closer to Shinjuku than Chigasaki, but between those two.
I've checked the data against a few other sources and everything seems to tie up. No need to divide some obscure number by the number of hours in a year any more, or convert micros to millis, just check it's still only pitter-pattering between here and Fukushima... and run to the hills if it starts snowing.
Currently drier than average though.
Last Sunday, Tepco announced that radiation levels at the No. 2 reactor were around ten million times that of a normal reactor core. They later corrected the information, saying the actual level was only a hundred thousand times higher than normal!
The Japanese government immediately came out and slammed Tepco. Why? Because they thought erroneous announcements were unacceptable!
Hang on, isn't being a hundred thousand times over the limit also cause for a bollocking??
It’s like getting pulled over for speeding on a 100km/hr limit stretch of road, and the cops let you off with a warning for claiming you were going at the speed of light, when you were only really going ten thousand times the speed of sound.
Actually, the additional bollocking was over and above the current standing bollocking that Tepco are under from almost everyone here at the moment, it just grated to see them only slammed for making incorrect announcements.
A bit flippant perhaps, but I was wondering how many of those who have left Tokyo recently, remembered to stock up on duty-free smokes at the airport on their way out?
Just wondering...
Mild Heaven headstone in Kamakura.
Despite having learned a lot more than I ever wanted to about radiation levels in microSieverts and now radioactive Iodine (I-131) and Cesium-137 levels in Becquerels per litre or kilo, my favourite scientist is still this guy.
For some this will be a naive post, and the fact that I first saw the Hydrogen Technology Applications guys on this clip from Fox News doesn't help their credibility, but this promotional clip for their HHO gas is a bit less sensationalist.
The News on their website hasn't been updated since 2009 so does that mean they were wrong and the energy required to split the water molecules and create Oxyhydrogen really does exceed the energy recouped by burning it? Or did darker forces intervene?
Maybe I need more sleep but is it really naive to think this won't work? Is using water for fuel as elusive as perpetual motion?
How many links could I fit into one short blog post?
What does blog stand for anyway?
Just some of the things I was thinking about on my way back from the supermarket carrying two 5-litre bottles of just-in-case drinking water.
“Interesting” times up here in Tokyo. Power cables have now been connected to all six reactors and Libya is been pushed up to lead-story status on BBC-World. even so though, the radiation levels are still a concern. I have friends who have left and friends who have stayed, but it seems pointless to divide them into two camps like this article tries to do, even if most of his article and particulalry his last paragraph is spot on. Depsite recent rants on the hype put out by the overseas-press, the local press can appear to go the other way and give the devil an easy ride. There’s always going to be a few hear-no-evil types who would stay and go down with the ship, but I hope staying doesn’t become a matter of pride.
For some people, I fully understand that leaving is a no-brainer. Having kids for one thing would certainly change your outlook and everyone has to do what they feel is best for their own and their family’s circumstances. Who was right or wrong to leave or stay is a pointless discussion.
I’ve now got a few websites bookmarked that give information on radiation levels close to where I live, as well as info on the water supply. I never ate much spinach anyway.
If I did want to get out, I’d be heading down to Sydney where we’re lucky enough to have a place to stay. I might lose some of you here but I’ve learned more about microSieverts per hour lately than I ever really wanted to. Anyway, a 10-hour flight to Sydney from here would rack up about 60 microSieverts at what seems to be a universally accepted 6 microSieverts/hour. No-one told me about this amount of exposure to radiation while flying till now though, I wonder if the flight attendants are clearly told about it? I’ve never met one who seemed too concerned.
According to this pdf in Japanese from the NIRS (National Institute of Radiological Sciences) at the bottom of the page , the average annual exposure worldwide per year is 2,400 microSieverts/year. In Brazil and India, it gets up to 10,000/yr.
Currently the nearest measuring point to me for environmental radiation is in Kawasaki. For water monitoring it’s in Shinjuku but both are close enough.
In Kanagawa the current real-time monitoring reading (bottom #5 above) at 21:30 on March 22 is 0.149uSv/hr and has been rising from 0.1244 earlier today but still below average. I expect it’ll keep rising for a while. At this level I’d get the same radiation fix after 16 days here as I would on the flight to Sydney.
The Iodine I-131 in the Shinjuku water supply is currently reading 5.3 becquerels/kg when the limit is 300. This is the stuff with the half-life of 8 days. The Cesium-137 is nastier as it has a half-life of 30 years but it’s at 0.22 becquerels/kg today when the limit is 200.
Also got the above cross-reference for radiation readings and water readings in Shinjuku from MEXT here (The Ministry of Education, Culture, Sports, Science and Technology)
With all these sites bookmarked, after getting up and checking that Libya is still the lead story on BBC, it looks like checking these sites will be the new routine for a while.
