RE: Ra, 25 mrem/y

["Otto G. Raabe" <ograabe@ucdavis.edu>]

At 04:02 PM 12/10/1999 -0600, Paul Frame wrote:

>Table 7.17 in NCRP 94 attributes (to the soft tissues - so
>we can forget the bone's weighting factor):
> 3 uSv from Ra-226, 7 uSv from Rn-222, and 140 uSv from Pb-210 - Po-210.
>This is roughly 150 uSv or 15 mrem. Not, in my book, a very small fraction
>of 39. 

December 11, 1999
Davis, CA

These values look okay to me, but in my discussion I separated radon
exposures (with their complex exposure relationships) from intake of radium
into the body. The internal dose from world-wide exposure to
radium-226 may include 3 uSv/y (0.3 mrem/y) to soft tissue, but I consider
this as part of the negligible dose to which I was referring for internally
deposited Ra-226 and is a very small fraction of 39. I discussed the radon
issue separately, and the internal dose from radon depends on inhalation of
decay products and living in an atmosphere containing radon gas.

I think Paul and I are looking at the same information with somewhat
different perspectives.



		*****************************************************
		Prof. Otto G. Raabe, Ph.D., CHP
              Institute of Toxicology & Environmental Health (ITEH)
		   (Street address: Building 3792, Old Davis Road)
		University of California, Davis, CA 95616
		Phone: 530-752-7754  FAX: 530-758-6140
		E-mail ograabe@ucdavis.edu
              *****************************************************
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html