Current Tokyo radiation readings from personal geiger counters

[flamingdem]

http://falloutphilippines.blogspot.com/



When obtaining a radiation reading, it's always helpful to consider that figure with a yearly time-frame in mind so you can properly gauge your maximum permissible dose. In the case above, it's helpful to keep in mind:

* .218μSievert per hour yields an annual dose of 191 mrem
* Normal background levels in Tokyo prior to the Daichi incident were at 0.04μSv/h, so these readings are still about 5x higher than usual
* The source contributing to these higher readings are not cosmic sources as they would be during air travel; they are from radioactive fission products that will enter the body and deposit themselves in bone, tissue
* The isotope breakdown in air is very difficult to ascertain, even when keeping track of released numbers from government agencies. For example, how much Cs-137 contributes to the 5x reading vs Cs-134 or I-131

These doses are actually tolerable and probably wouldn't bump an adult above his/her recommended MPD, but if i had a baby and kids, it would be quite disconcerting to continually expose them to radiation levels that have fission products as a primary source. This is the exact trepidation with most Japanese who have relocated to areas with lower readings.

You can check out this guys facebook page here:


http://www.facebook.com/pages/Tokyo-Radiation-Levels/196845207013685

Tokyo Radiation Levels
‎2011-04-16 7:22: 21 micro-Roentgens/h (~21 cpm). 0.218 micro-Sieverts/h. Location: Kita-ku, Tokyo. Weather: partly cloudy, winds from the south. Safe.

[jimlup]

1. Actually this really sucks

In my opinion there is not safe dose and thus you try to minimize and weigh your exposure. All things being equal, I'd avoid flying but since it gets me there so much faster I'm willing to risk the small incremental increase in my cancer probability. The same goes for eating a banana (0.1 μSv). But to have to live in an area with this high a background would suck a lot. I hope that it isn't permanent or even very long term. They've got to get this thing "capped".

[flamingdem]

3. All this talk about bananas

are those seriously taken into consideration when determining yearly safe dosage?

[jimlup]

4. I think it is just a useful way of explaining background radiation...

1 banana is 0.1 microSieverts which is 1.0 nanomort (according to the Wiki article from which I lifted this data). 1.0 nanomort means that eating a banana increases your chances of getting cancer by 1 in 1,000,000,000. So by statistics, if 1 billion people each eat one banana, one will die from the cancer it caused them.

According to the U.S. Department of Agriculture, the annual per capita
consumption of bananas (in pounds) in the U.S. from 1976 to 2003 was
as follows:

1976 --19.3
1977 --19.2
1978 --20.2
1979 --21.0
1980 --20.8
1981 --21.5
1982 --22.5
1983 --21.3
1984 --22.2
1985 --23.5
1986 --25.8
1987 --25.0
1988 --24.3
1989 --24.7
1990 --24.4
1991 --25.0
1992 --27.1
1993 --26.6
1994 --27.8
1995 --27.1
1996 --27.6
1997 --27.2
1998 --28.0
1999 --30.7
2000 --28.4
2001 --26.6
2002 --26.8
2003 --26.2

Is the US per capita banana consumption in pounds. I'm just guessing about ~50 bananas per person. Let's assume a population of 200 million for rounding purposes that would mean that 10 people die of in the US each year from cancer caused by consumption of bananas.

No, I'm not worried about eating banana's but it does help illustrate why there is no safe dose of radiation. All this stuff about a few microSv's being just a little above annual background is misleading to most people.

Another example is living in the mountains. I'd like very much to live in the mountains of Colorado but the excess radiation that I would receive as a result of moving there is something that I would take in to consideration before I decided to make the move.

[flamingdem]

5. Great banana info!

I'm eat them everyday. Hmmm. Somehow they look less appetizing now even with the odds in may favor by many millions. I learned that if you grow up in those areas with high background radiation, rather if you're from a family of many generations in one of those areas you will acquire some immunity. It's radon I believe.

Somehow it seems like Colorado living would be healthful regardless especially if you live in an urban and smoggy area. Maybe try Vermont?

[franzia99]

6. Plus cesium doesn't exist naturally.

[Yo_Mama]

27. Not really

First, you should be able to eat as much bananas as you can hold without incurring radiation damage. It is true that bananas are high in natural radiation, but the increase is from Potassium 40. P-40 is a radioactive isotope of potassium.

Because your body preserves your potassium levels (eat more, some gets flushed out, eat less, less gets excreted), you would be unlikely to get any additional radiation from eating bananas unless the bananas in question had been contaminated with another radiation isotope capable of accumulating in your body.

Given that naturally higher radiation levels don't seem to be correlated well to excess human morbidity, I think it's a good bet that there IS some "safe" level of natural radiation.

All the epidemiological evidence is that low chronic (approaching observed natural levels of radiation exposure) radiation dosage doesn't increase death rates.

The regulatory approach is to use the LNT hypothesis, but that's because it is the no-risk choice. When trying to avoid unnecessary risks, that's the correct method. But every prediction I have ever looked at that used the LNT hypothesis to predict cancer rates from low chronic exposures has been disproven where evidence has been able to be collected.

You can believe the reverse if you wish, but there is no evidence for your belief. If you think you have some, please post it. I would be interested.

[jimlup]

28. I'm not an expert nor to I claim to be...

I am educated as a physicist not an epidemiologist. Your ideas are a welcome addition to my knowledge base. I'm not really concerned about bananas, I'm just trying to find a way to quantify a microSv. I suppose the interesting question would be what do the epidemological studies of people living at altitude show? Does living in Denver (which isn't really all that high) actually increase your baseline risk of cancer? Does living in Leadville (essentially twice as high but I don't know how much more radiation one would receive) increase your risk still further?

Do you know the answers to any of these questions? I'd be interested.

[marions ghost]

2. thanks

informative

[franzia99]

7. "Radiation levels in Tokyo surged to 23 times normal on Tuesday...levels of .809 micro sieverts"

http://www.marketwatch.com/story/tokyo-radiation-levels-23-times-normal-officials-2011-03-15-04540

HONG KONG (MarketWatch) -- Radiation levels in Tokyo surged to 23 times normal on Tuesday, according to reports that cited readings released by the Tokyo metropolitan government. Radiation levels of .809 micro sieverts were recorded in central Tokyo at 10.00 a.m. local time (9.00 p.m. U.S. Eastern time), reports said. Southerly winds are believed to be pushing a radioactive plume from the Fukushima Daiichi nuclear power plant, which lies about 150 miles north of Tokyo.

[Art_from_Ark]

8. That article is from March 15, for crying out loud!

Here are the Tokyo Metropolitan Government's official radiation data for the past 10 days-- all readings are NORMAL LEVELS!!!!!!!!

http://ftp.jaist.ac.jp/pub/emergency/monitoring.tokyo-eiken.go.jp/monitoring/hourly_data.html

[franzia99]

29. Just pointing out that annualizing the current readings isn't the whole story. Additional radioactiv

e emissions could cause it to spike up pretty high again. We have cause to worry about additional emissions for the next 6-9 months or so if you take TEPCO execs at their word and/or listen to independent nuclear physicists on this.

[Art_from_Ark]

31. The spike was from a hydrogen explosion

There was a sharp spike in measured radiation values as a result, but they quickly fell back.

[franzia99]

33. Where'd the tens of thousands of tons of radioactive water go?

[Art_from_Ark]

34. Some of was released into the atmosphere.

Some of it was released into the ocean. They say that the most highly radioactive water is being stored at the site. News programs have been showing diagrams of water storage facilities at the site. I don't know if anyone has accurate figures about the proportions/amounts of each type of storage/release.

[Art_from_Ark]

9. Official Tokyo readings

0.0749μGy (=0.0749 microsieverts) per hour, as of 1 hour ago

http://ftp.jaist.ac.jp/pub/emergency/monitoring.tokyo-eiken.go.jp/monitoring/hourly_data.html

[Bonobo]

10. Apparently people that rec this don't give one shit about truth. nt

[Art_from_Ark]

12. It's really ANNOYING, isn't it?

All this bullshit being posted from SuperReliableBlog.com and Bulgarian Make-up-your-own-shit News Service and the Washington ""We never got it right during the bu$h era but we're experts on Japan" Post, ad nauseum :argh:

[ChibaResident]

11. Thank you, Art-from-Ark, for your comments.

I can't imagine what you guys are going through up there! Even here in Chiba, the aftershocks and the stress levels are out-of-this-world, not to mention the major liquefaction damages around Tokyo Bay and, of course, worries about Fukushima.

But you are in a much worse position than I, clearly farther north than I am and nearer to the disaster areas (hopefully not IN the disaster areas by the sea? My friends have travelled North to help (I could not, because I can't take my daughter with me obviously, but I wish I could...they've been helping out in Miyagi-ken), and you continue to post informative and honest assessments of the situation. I've been lurking on Democratic Underground since the disaster struck, thirsting for information (I have a six year old I'm trying to protect!), and many have contributed good info (Bonobo has been great!), but you are right in the heart of things and have helped to give me some perspective here in Chiba, Japan through this ongoing disaster!

I thank you, sir. And I wish you well and hope you are okay! がんばってね！　日本一！！！！　

[Art_from_Ark]

14. Thank you

I am in an "affected area" but luckily not a "disaster area", and far enough from the sea that a tsunami would not pose a problem. We've had a bit of damage here, and lots of nerve-wracking aftershocks, but places just north of me have been hit harder, as have coastal areas (apparently the entire Ibaraki coast was hit hard).

I understand a bit about the liquefaction problem-- there was a recent TV program about the problem in Urayasu, and it apparently occurred in Asahi City and other places as well. I was talking about that with a chemical engineer last night who spends a lot of time in the Hasaki-Kashima area of Ibaraki just across the Tone River from Choshi.

がんばって日本!

[Art_from_Ark]

17. For my area, this is the main type of damage

to private property (blue tarps are covering damaged roofs):

[ChibaResident]

19. I see. Lots of damage to roofs and other "typical" damage, I would guess...

Thankfully you escaped any tsunami horrors there!

(by "typical" I definitely don't mean "minor" or anything of the sort! I just mean "regular", as in the regular sort of damage one might expect from any earthquake! the liquefaction thing in my area is more "atypical" is all I meant by my comment about the roofs damage in your area!)

The situation in Tokyo Bay is much the same, but the liquefaction damage so far from the epicenter is worrisome, to say the least (on March 11th, it was a horror show although no comparison to the tsunami).

Here's some photos from Urayasu...though beyond the obvious, the water was out for many weeks in many homes (no showers, no toilets!), along with other difficulties with gas and other hardships. We (personally) were very lucky not to lose water for more than a couple of days, but some have said the situation in Urayasu for some was even slightly worse than the situation for some up north since they got much more immediate red cross and other disaster relief help in comparison (again, NOT comparable as far as devastation or loss of lives obviously, but the hardships are comparable for some in the city of Urayasu and other parts of Tokyo Bay...surprising to many since Tokyo proper was not badly hit).

[Art_from_Ark]

23. Those are some pretty shocking pictures

We did not have anything like that here, thank goodness. I had heard two or three weeks ago from some TV program that 20% of the households of Urayasu were still without water. I don't know what the situation is like there now, though.

Urayasu is built on reclaimed ground, which contributed to the liquefaction. I heard that Tokyo Big Site is also built on reclaimed land, but it doesn't seem to have been damaged as much as Urayasu.

[ChibaResident]

26. The situation in Urayasu is still bad BUT

I've seen some improvement over the weeks. It's true, some people still don't have water (my wife saw a woman washing her hair in a hotel lobby bathroom last week!).

Not ALL of Urayasu is reclaimed, but a good portion is. But some was built well (like Disneyland) and some was built on the cheap (like shin-urayasu and the surrounding areas).

All of Tokyo Bay was pretty hard hit, though. Surprising and shocking, so far from the epicenter. I dread a large aftershock in the region at this point!

[Art_from_Ark]

32. Thanks for the information about Urayasu

It looks like it will take a while to get everything cleaned up.
I was told that there was some liquefaction in Tsuchiura, but I haven't seen it for myself.

[ChibaResident]

13. Bonobo and Art, I tried to send you guys an email here.

I couldn't figure out how. I guess it's because I'm a new member. But I wanted to get in touch with others living in Japan!

I hope to hear from you both, I guess through topics (I can't figure how the instant message thing works on this site!).

It's been a rocky road for all of us, especially for Art! (though I can understand Bonobo's crisis too, since I'm sort of in-between, not hit terribly hard (certainly NOTHING compared to up North, though the damage is real), and my friends and family are all okay, but still the stress is horrible as this disaster unfolds AND I have friends in Osaka and Okinawa who are telling me the same thing about how devastated WE all are!).

[Art_from_Ark]

15. I think there might be a minimum # of posts required

before you can send personal messages. But you're always welcome to send me a personal message when you are able to :hi:

[Bonobo]

16. Hi ChibaResident.

Everything is fine here. We just had a great Sakura Matsuri and we all talked alot about this.

Everyone is grateful for the support, but Japanese residents are expressing surprise at the exaggerated overseas news.

They are really getting mixed signals. On the one hand, they are glad for all the support and proud of the fact that foreigners recognize that the Japanese are tough and resilient, but they are puzzled as to why the foreign press is blowing things out of balance with their reporting.

Well, it is one of the things I love about the Japanese, and as I told them, if 9/11 had happened in Japan, they would have rebuilt the towers within a year and moved on.

Americans and the West have some kind of death complex -and they are welcome to it.

[ChibaResident]

18. Glad things are fine there Bonobo!

We had some nice Cherry Tree festivals here in Chiba too!

But, obviously things are dire in many parts of Japan (even including parts of Chiba, particularly the hard hit areas of Tokyo Bay, and most particular Urayasu City, which is home of Tokyo Disneyland but has been struck badly by liquefaction), I do hope the foreign media focuses on the truly hard hit areas (and that INCLUDES the evacuation zones of Fukushima where so many lost their homes!). Sensationalism is a media staple, but the important thing is to realize that Japan is still in a deep crisis and many people are displaced and have lost loved ones or homes!

And folks like Art further north are also experiencing more aftershocks (none today that I felt, so hopefully that will keep up!).

[Art_from_Ark]

20. There were a few aftershocks here in southern Ibaraki

but they were not so bad today. I could hear that now-sickening rumbling that is usually the sign of shaking to come, but then there was just a thud or two, a quiver, and then it was over. We even had a little shaking a few minutes ago from an earthquake that was centered near the reactors. There were even a couple of earthquakes recorded for NE Chiba today as well.

http://typhoon.yahoo.co.jp/weather/jp/earthquake/?c=3

[ChibaResident]

21. Honestly, it's hard to know what's an aftershock and what's not these days...

I'm sort of suffering from motion sickness or something.

I sit in my chair, and I feel like it's rocking and I think "earthquake", but it's just my body shaking.

Then, of course, aftershocks come too.

It's stressful to say the least.

[Art_from_Ark]

22. I know exactly how you feel

If I feel myself shaking, I also often wonder if it's just me, or if it's another earthquake. The way I make sure is, NHK will usually have some sort of announcement right after an actual earthquake.

[ChibaResident]

24. Aside from the TV early warnings (creepy, but important), I

usually look up at my hanging light. If it's moving, it's a quake (the thing was rocking like crazy on March 11, as you know!). If not, it's me.

Better than before though here, not so constant these days. I'm fearing the predicted 8.0 though, I fear it may strike in Tokyo Bay and cause tsunami!

[Art_from_Ark]

35. Chiba Resident, did you feel the earthquake about 15min ago?

Magnitude 5.0, came without warning. All of a sudden Wham! Epicenter southern Ibaraki. It felt like it was right under my house.

[Yo_Mama]

25. There is nothing here to worry about

Someone posted Japanese stats already. Those should be right:
http://ftp.jaist.ac.jp/pub/emergency/monitoring.tokyo-eiken.go.jp/monitoring/hourly_data.html
That is already converted to grays which should account correctly for isotopes.

First, anyone remember the Japanese guy who was sitting in his apartment with his Geiger counter? Remember his readings back then? These are very comparable.

Converting from a Geiger counter CPM to microSieverts isn't simple, and that's where the problem may lie. You have to know the isotopes:
http://www.blackcatsystems.com/GM/converting_CPM_mRhr.html

But let's take the numbers as given above. I think they come from this observation post:
http://metropolis.co.jp/quake/quake-2011-03/tokyo-atmospheric-radiation-levels/

I'm going to take about the highest measurement shown there and convert it into yearly exposure:
8766 hours per year x .25 microSieverts/hr = 2.191.5

2,191.5 microsieverts = 2.2 milliSieverts.

Average US yearly exposure to radiation is 310 milliRem = 3.1 milliSieverts.
http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html

This is not something to worry about. A lot of areas in both the US and northern Europe have higher natural background levels, and in some areas in the world, natural background levels are over 50 per year.

Based on what is reported, you would cut your infant's radiation exposure by moving from Boulder, CO (500> millirem annually) to Tokyo right now:
http://www.colorado.edu/EHandS/hpl/RADHandbook/Introduction.html

[Name removed]

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