[ RadSafe ] Re: Residential radon risk

[Otto G. Raabe]

At 09:23 PM 5/19/2005, niton at mchsi.com wrote:
>Dr. Raabbe (sic), Just for the record, I offer a SINGLE post on this 
>topic.  It appears no one
>else on the list will refute these baseless assertions (most likely for 
>fear of being flamed).
***************************************
May 27, 2005

Dear Bill:

Thanks for the nice summary of your position. I appreciate a your scholarly 
approach to this issue.

I base my opinion on controlled lifetime studies with beagles of internally 
deposited radionuclides that irradiate various organs of the body including 
the lung with alpha and beta radiation protracted in time. All these data 
show an effective threshold for radiation induced carcinogensis that is 
consistent with observations in uranium miners for radon. The dose-response 
relationship for lifetime exposures is markedly non-linear!

Unlike the epidemiological radon studies you cite, the laboratory studies 
involved careful dosimetry including routine external monitoring and 
bioassay to accurately determine the radiation dose (Gy and Sv) over time 
to each target tissue in each individual case.

None of the radon studies that you reference has any information about lung 
or bronchial dose to anyone! Therefore, it is hard to reach definitive 
conclusions with those data. Also, the influence of cigarette smoking and 
exposure to cigarette smoke clouds all of the information in a complex 
fashion. It is easy to show that lung cancer is significantly associated 
with cigarette smoking, but it is hard show a separate association for 
bronchial exposure to alpha radiation from radon and its decay products 
since there are no definitive data.

As B. Cohen has shown, no matter how you slice it, lung cancer rates in the 
U.S. tend to be lower where indoor radon levels tend to be higher. This is 
a robust observation that can be hypothetically explained away as caused by 
some complex confounding relationship, but what that relationship is, if it 
exists, seems to be a mystery.

Best regards,

Otto


**********************************************
Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
(Street Address: Bldg. 3792, Old Davis Road)
University of California, Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140
***********************************************