[ RadSafe ] Guidance on Outdoor Gamma Dose Rates - Second Request

[Leo M. Lowe]

Dear Radsafers,

I previously sent the query below to Radsafe but I have received no 
responses (except for one on the potential hormetic effects of 
elevated background radiation levels).  To repeat, are there any 
reference levels on natural  background gamma radiation relative to 
new residential construction?

Feel free to respond to me directly.
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Do you know of any criteria/guidelines for outdoor gamma 
dose/exposure rates for natural background radiation; that is, given 
that many people live in areas resulting in annual doses greater than 
1, 2, 5 mSv/y or more, is there any guidance on a background dose 
rate above which people would be advised not to live?  This could be 
an issue, for example, if someone wanted to build a house in an area 
with some natural thorium or uranium mineralization.

I am aware of recommended limits for NORM in building materials (such 
as the European Commission in Radiation Protection 112),  reference 
limits for initiating action for existing situations (ICRP 2007 says 
that remedial action is not likely justified below 10 mSv/y) and of 
limits for indoor radon, but is there any specific guidance on the 
issue of outdoor natural gamma radiation relative to new construction?
_______________________________________________________________________________________

Leo M. Lowe, Ph.D., P.Phys.

SENES Consultants Limited
llowe at senes.ca
www.senes.ca
Tel:  905-764-9380
Fax: 905-764-9386

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