Uncertanty of the correct Dose Conversion Factor for I-131
Hello,
Thanks again for all your work measuring and posting the results of your rain water tests. I don't see anyone else doing this. I think most of us here from the forum are interested in the potential biological effects of the concentrations that you measured. Accurately understanding this seems to hinge on the conversion from curies to rems.
Specifically for Radioactive Iodine-131, you posted a DCF of 68.49 millirem/microcurie
http://www.nuc.berkeley.edu/node/1897
This equates to 1.85e-08 Sv/Bq correct? It seems that you derived the this value from a NRC publication here:
http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/appb/Iodine-13...
I don't understand why you had to derive this value. Can you explain? I don't see where the NRC states its limits are 50 millirem / 730 Liters. Did you know that this DCF value is much lower than other published values
Dose Conversion Factor for Internal Exposure to I-131
| Authority | Sv/Bq |
| National Cancer Institute | 3.50E-08 |
| DOE (1988) | 4.90E-08 |
| EPA (1988) | 4.76E-08 |
| Killough, G.G | 4.50E-08 |
| you stated | 1.85E-08 |
All the original papers are sited in the footnotes of this document
http://web.engr.oregonstate.edu/~hambydm/papers/benke.pdf
Why is it that you need to derive the DCF from other NRC published values? Don't they release the DCF for I-131 in a table in one of their publications? Isn't it possible that you are understating the health risks due to using a DCF that is too low?
--
Raj
I-131 dose conversion factors
When estimating the thyroid dose from ingestion or inhalation of I-131, it is important to calculate the absorbed dose to the thyroid gland, not the so-called effective dose. The absorbed dose to the thyroid gland, per Bq intake, changes markedly, decreasing with increasing age at time of exposure.
The most recent publication that addresses the uncertainty in the thyroid dose conversion factor as a function of age and gender, is Apostoaei AI, Miller LF., Health Phys. 2004 May;86(5):460-82. Uncertainties in dose coefficients from ingestion of 131I, 137Cs, and 90Sr.
For the most sensitive members of the population, infants, the absorbed dose per Bq ingested is 4 microGy, 4 E-6 Gy per Bq, or 4 Gy per MegaBq (this dose conversion factor is the arithmetic mean of a 95% uncertainty interval estimated for a 1-year old child).
For infant girls, the risk of thyroid cancer in later life may approach or exceed one chance in ten-thousand per milligray to the thyroid gland (using the age and gender-dependent thyroid cancer risk coefficients in NRC/NAS BEIR VII (2006) and updating these BEIR VII risk coefficients with the most recent published baseline rates for thyroid cancer in the US).
In general, regarding radiation exposure of the thyroid gland, boys are less at risk than girls for thyroid cancer in later life, given the same thyroid dose. For the same amount (Bq) of I-131 ingested, thyroid doses and risks decrease markedly with increasing age at time of exposure. So far, there is very little evidence from epidemiology supporting a statistically significant increase in thyroid cancer when radiation exposures occur to an adult.
It is difficult for epidemiological studies to detect a statistically significant increase in the risk of thyroid cancer in later life when exposed cohorts receive thyroid doses much less than 100 mGy. But, this is merely a limit of epidemiological detection of statistically significant risk; it does not mean that doses much less than 100 mGy constitute a dose threshold, below which the risk of radiogenic thyroid cancer is zero.
Thanks also
I have a VERY specific concern that I'd love some guidance or advice about: I have an eleven-year-old daughter. She is in good health and is pretty hardy (she's a cheerleader, after all), but I am frankly scared to death about the likely doses she is and will probably continue to receive in the near future, most especially with regard to ingested / absorbed liquids and foods. As I've mentioned before, I do not have readily available, limitless financial resources with which to surround her, my wife and myself with an iron bubble of month-old canned goods, bottled water, and frozen foods; neither can I go back in time and pick up milk from, say, February 15. That ship has sailed; and I can't hide her from the sky, either. Nor can I completely insulate her from the rain. She is going to get dosed, pure and simple.
This is a very selfish, obnoxious, possibly antagonizing post, I know. We all have families and loved ones, and we are all concerned. But that being said, and with apologies for my bluntness, if there is anyone "out there" who can give me some direction / instruction and give me something to do -- no matter how small, inefficient or laughable -- that will put my mind somewhat at ease, that I have in fact managed to do SOMETHING to protect my little girl from these horrible times we are living in... Well, I would be very, very grateful. Sorry; this isn't appropriate. And certainly the UCB Lab staff has enough on their plates without giving credence to every single scared-stiff, possibly paranoid, even wigged-out middle-aged man (or woman) and responding to their particulars. But if there is ANYONE reading this, with genuine knowledge who would be so kind as to do me a mitzvah... Well, I would be very much in your debt, sir or ma'am.
Many thanks --
Rick Cromack.
Allen, Texas
www.facebook.com/lonestarplano
Sigh
In the exact same boat you are in, Rick. In the interest of complete disclosure, the ONLY reason we were able to afford to go buy a couple of boxes of powdered milk, a couple of boxes of canned foods and a small stock of cheddar to freeze was because we got our tax return JUST before this whole thing went down.
If you want to swap ideas, you can e-mail me at littlemaleficent@hotmail.com.
- Jen
Thanks, Jen...
You feel free to E-mail me, too. I put my addy at the bottom of this post.
Rick Cromack.
Allen, Texas
www.facebook.com/lonestarplano
RichardFCromackJr@gmail.com
Does this info change your calculations?
Professor Miller, does this post change your calculations at all? If so, how would you assess the risk in light of this information? Thank you.
Thanks...
...And, once again, you guys are putting your own lives out there as well, and those of your families, as your "bona fides" for the "calls" you're making. I'm personally sorry that you're put in this position, of basically having to justify your professional conclusions by way of reminding us of your PERSONAL lives... It's a pretty astonishing place for you to be in. (As this is for us all.)
Please, feel free to use my comments in your efforts to persuade other professionals and educators to contribute.
Rick Cromack.
Allen, Texas
www.facebook.com/lonestarplano
Why are you so worried if
Why are you so worried if you live in Texas? I am considering moving to Dallas from LA. I thought Dallas would get a lot less bad stuff. No?
Source For Good Info
The following website contains some good links for info on the radiation event at:
pstuph.wordpress.com/2011/03/31/fukushimatoolkit/
Also a good article on iodine in milk is here:
http://pstuph.wordpress.com/2011/03/31/radiationmilk/
To Protect Your Family/Children
R. Cromack,
I applaud you for putting your details out there and asking for help. I have found a lot of reassurance at these two or three sites.
http://doctorapsley.com/RadiationTherapy.aspx
The above explains some health things we can do to rid our bodies of radiation.
http://www.enviroreporter.com/2011/03/enviroreporter-coms-radiation-stat...
The above is where I got the first link and there is a great conversation of other protective parents.
http://www.radiationnetwork.com/
I check this everyday for peace of mind, so I may know the difference between any abnormal radiation versus the "normal" background radiation.
I hope this helps. I am still scared because my immune system has been compromised for years, but I am doing what I can.
CMH
Thank you
I've been perusing the advice of the "eclectic physician" and am planning on speaking with my primary care physician about some of his suggestions this week. It may be possible for me to pick up some of these supplements / medications for my family.
I am beginning to be overwhelmed by the enormity of it all. Frankly, I have dropped twelve pounds in six days... I am afraid to eat or drink. I have no appetite. I am not able to get to sleep at this point without medicinal "assistance". I'm just a mess.
The "disconnect", as I've mentioned elsewhere, between what I am learning online and what is being pumped out of the ignorant, blind, deaf and dumb media machine is more ominous than I can express. Idahoans, at the minimum, are apparently being irradiated more than anyone else in the continental United States, and the response of an uncaring Government is no better than a disinterested shrug. I am beginning to get VERY ANGRY; what falls in Idaho will eventually end up "downstream", here and everywhere. Not to mention, we're getting doses pretty good here, ourselves, I imagine, all on our own.
Hardly anyone seems to have the slightest idea -- let alone, concern -- about what we are facing. I have basically given up sounding warnings on my FB page, 99% or higher of my "Friends" have their heads in pillows and think I've become a raving nut. I now have some understanding of what it must have been like for people, all these years, who have been "outside looking in," futilely trying to gain the attention of the media, the Government, and the public on various health issues. (I wonder where all those folks are now? ...'Cause they're CERTAINLY not being heard, ANYWHERE.)
A helluva time to realize that the good folks I used to dismiss as paranoid fear-mongerers, were RIGHT ALL ALONG... And I fear my family and I will pay a very high price for my ignorance.
Rick Cromack.
Allen, Texas
www.facebook.com/lonestarplano
I also found some good links
I also found some good links at http://radiationfears.com/category/links/