Infant Radiation Dose Over 30 km From Plant May Be Over 100 Millisieverts

[tekisui]

Source: Kyodo News

The radiation dose received by one-year-old infants outside of a 30-kilometer radius of the Fukushima Daiichi nuclear plant since Saturday's explosion at the plant may have exceeded 100 millisieverts, a computer simulation conducted by the government showed Wednesday.

''There are some cases in which they could have received more than 100 millisieverts of radiation, even if they're outside the 30-kilometer radius and in the event that they spent every day outdoors since the explosion at the Fukushima nuclear plant,'' Chief Cabinet Secretary Yukio Edano told a news conference.

Haruki Madarame, chairman of the Nuclear Safety Commission of Japan, told reporters, ''The figure represents the level that one-year-old infants would have received and accumulated in their thyroids by midnight Wednesday since the explosion.''

(snip)

People exposed to a radiation dose of 100 millisieverts are required to take potassium iodide, Madarame said. An annual radiation dose of 100 millisieverts is believed to be associated with an increased risk of cancer.

more: http://english.kyodonews.jp/news/2011/03/80575.html

1 in 200 Infants in certain areas outside the 30km radius exposed to LETHAL radiation

What does that mean, exposure to 100 "millisieverts"?

Well, according to the EPA document here, the "nominal cancer fatality coefficient" is .05 /Sv. What this means is that for every dose of 1 Sv (sievert) of radiation, the chances of contracting a FATAL cancer is 5%.

This puts to light information where the workers at the Fukushima plant are subjected to 500 mSv (.5) per HOUR. In just 2 hours would be 1 Sv of radiation. In 20 hours at the same rate would be 10 Sv (50% chance of cancer fatality). This has been going on for over a week.

Apart from the workers, the Japanese Nuclear Safety Commission's own simulation put areas OUTSIDE 30 km from the plant to have an infant dose of 100 mSv. 100 mSv = .1 Sv (10% of 1 Sv). And according to the article, this is radiation they would have received up until "midnight Wednesday since the explosion."

So if 1 Sv has a 5% chance of contracting fatal cancer (meaning 1 in 20 people exposed will get fatal cancer), with .1 Sv you have 1 in 200 getting fatal cancer. That means in certain areas (they don't specify) OUTSIDE the 30km radius of the Fukushima accident, 1 in 200 infants will get fatal cancer from radiation exposure...as of Wed night. Every day they are there increases this risk, with more and more infants, children, and adults getting cancer.

http://libradex.com/viewArticle.aspx?id=125

[xchrom]

1. The next wave of the disaster. Nt

[uppityperson]

2. waiting for

a particular DUer to show up with a chart and lecture that this is no problem.

[tekisui]

3. There certainly are a fair share of 'Baghdad Bobs' around this disaster.

[PoliticAverse]

4. Ridiculous, unrec'd.

The portion of your post that comes from libradex is apparently written by someone that doesn't know much about radiation levels:

"This puts to light information where the workers at the Fukushima plant are subjected to 500 mSv (.5) per HOUR. In just 2 hours would be 1 Sv of radiation. In 20 hours at the same rate would be 10 Sv (50% chance of cancer fatality). This has been going on for over a week.".

If someone got 10 Sieverts of radiation in 20 hours they likely wouldn't be worrying about getting cancer as they'd be in the hospital suffering from radiation
poisoning.

See: http://en.wikipedia.org/wiki/Acute_radiation_syndrome

And: http://xkcd.com/radiation/

[spanone]

5. where have i seen that chart before....hmmmmm?

read the very last sentence on that chart - at the very bottom


IF YOU'RE BASING RADIATION SAFETY PROCEDURES ON AN INTERNET PNG IMAGE AND THINGS GO WRONG, YOU HAVE NO ONE TO BLAME BUT YOURSELF

[PoliticAverse]

6. So you think a person that received 10 Sieverts of radiation in 20 hours would be in fine health...

but might get cancer some time in the future ?

And did you miss the first link in my post to the Wikipedia article on Acute Radiation Syndrome:
http://en.wikipedia.org/wiki/Acute_radiation_syndrome
?

[uppityperson]

7. Yah know, it really makes me wonder

same link and stupid chart, same tactics of not answering but attacking differently. Odd, isn't it?

[PoliticAverse]

8. The chart indicates an 8 Sievert dose of radiation is fatal, do you disagree with that? n/t

[uppityperson]

9. aren't your feet cold? nt

[spanone]

10. you dispute the EPA's findings?

[PoliticAverse]

11. What I disputed was what I mentioned in my post...

The originally posted idea that the reactor workers have been subjected 500mSv/hour of radiation for an entire week.

[intaglio]

14. Like to put your profile details up? Or

Are you just here whilst the Nuclear industry needs supporting?

[Yo_Mama]

12. This information is SO MISLEADING

Look, almost everyone in the world receives over 2 millisieverts a year. A millisievert is a thousandth of a sievert.

Once you get over one sievert in exposure, the risk becomes that of death and acute radiation sickness (ARS) rather than cancer.

If you got 6 grays (6 sieverts) exposure, your risk of death within a month or two is very high indeed. 4.5 S is considered a 50/50 survival rate.

And as for cancer, there are actually a bunch of differentials that go into risk. The stuff we have data for is really medical doses (X-rays, CAT scans). Here is an example of how that is calculated:
http://www.hps.org/publicinformation/ate/q4773.html

We don't have good risk information for natural exposures, because natural exposures vary quite widely depending on the local geography (natural ground radiation, altitude).

Most people in the world receive between 3-6 millisieverts a year. But it as far as epidemiology can now verify, smaller dosage increases from background radiation don't seem to cause additional cancers the way medical radiation appears to do. It may be because medical radiation is very penetrating and because the higher dosage occurs in sudden impacts. Or may have something to do with general health.

Anyway, here's a dose chart so most US people can figure out their exposures.
http://www.new.ans.org/pi/resources/dosechart/

100 millirems = 1 millisievert

And here's a dosage chart for various types of exposures:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Radiation.html

As to workers at Fukushima getting 500 millisieverts an hour, that isn't happening. The maximum dose so far (total) is 180 millisievert as measured by a dosimeter. Workers at Fukushima are not supposed to be going over 150 millisieverts, total exposure.

You will note in the chart that 100 millisieverts IN A SINGLE DOSE is considered to give a 1% higher risk of developing cancer. And here I'm going to quote from the first link about calculations of medical exposure risk:

But, let's use these numbers to estimate your possible cancer risk. If we use the highest effective dose for the lumbar spine x rays that were taken when you were a child, then we would estimate the risk to be 12.6 mSv x 0.1 percent increase in risk/10 mSv (assuming double the risk). The increased cancer risk from these x rays would then be estimated to be about 0.13 percent.

The estimate of risk from the other x-ray studies you had as an adult would be (.37 mSv + 10 mSv) x 0.05 percent/10 mSv which equals 0.0685 percent.

Adding it all up, we get about a 0.2 percent increase in cancer risk.

To put that in perspective, the American Cancer Society estimates that about 33 percent of us will get a cancer and about 20 percent of us will die from a cancer. So, with no radiation exposure, you have a 33 percent chance of getting cancer. Adding in the estimated risk from the x rays, your risk today is now 33.2 percent. A small increase.

[Yo_Mama]

13. But, having written all that

The fact is that infants around Iitate have received doses equivalent to 100 milliS for adults. This is a total dose calculation, and it is mainly from the effect of Iodine 131.

And it is criminal that this was permitted to happen; I have been watching the monitoring points every day, and there was one small slice NW of the plant where measurements just kept running very much higher than in the other areas. This could have been prevented very simply by an early evacuation.

They are using a conversion factor of 3X dose to compare to adult equivalents.

In general risk factors for this type of lower exposure are said to be double that of an adult for children under ten. Since they are already converting the doses, you can use the adult risk factor. For 100 milliSieverts, the risk of cancer is increased by 1% for those infants. But that really is not a good figure, because most of the exposure was not through direct radiation, but through Iodine 131.

Specific thyroid risk can best be compared to Chernobyl studies:
http://chernobyl.cancer.gov/studies/ukram.php?lev=1&page=21
The above link is to a very high quality study.

It found a linear relationship of 1.91 excess risk/Gray. 1 Gray=1 absorbed Sievert.

Thus the 100 milliS estimate is one tenth of a sievert or an approximate increased risk of half a percent. In the Belarus study for doses below 5 Gray (this was mostly iodine exposure, not whole body exposure), the calculated excess risk was very similar at 2.15.
http://chernobyl.cancer.gov/studies/belam.php?lev=1&page=22

Thyroid cancer is one of the most common cancers. In the US, about 1 out of every 110 persons is expected to be diagnosed with thyroid cancer at some point in the person's lifetime.

Thus, at the exposure rate given, it seems likely that incidence rates of thyroid cancer among the children with the highest levels would rise from about 1% to about 1.5%.

This is a long but helpful article about radiation exposures and risks. Note that the risks of cancer from direct exposures are lower than those used in the US (UK health officials estimate life time increased risk from 250 millisieverts at 1%).
http://www.bbc.co.uk/news/health-12722435

[flamingdem]

15. Background radiation justifications are BS, the issue is inhalation or consumption

that is how the damage happens with nuke radiation.

Otherwise it's external as in an airplane flight.

That information has been used for decades to reduce public fear over radiation and it's pure hogwash.

Very few cases of cancer come from background radiation vs. inhaled or consumed radiation from a nuke accident.

[Yo_Mama]

16. Yes, ingested is much worse

Of course it is dose-dependent, but it's not the direct radiation that generally causes civilian casualties. It's the radioisotopes that make into food or water that cause damage to the average radiation victim.

That's why I think the Chernobyl studies are most relevant.