RE: Basis for Reg. Guide 1.86 limits?

[Karin Gordon <KGordon@exchange.hsc.mb.ca>]

The Canadian AECB Advisory Committee on Radiological Protection published
a 1993 document entitled "ACRP-7 Report on Derived Working Limits for
Surface contamination. AECB INFO-0451(E)", which reviewed the theoretical
basis for contamination limits established by national and international
agencies (ICRP, IAEA, IATA,USNRC, UK and Canada). Many of the DWLs  are
based on  Sr-90 (long-lived, bone seeking, high energy beta emitter) as a
worst-case beta/gamma source of contamination.  

Appendix D of the document has two and a half pages devoted to tables of US
surface contamination limits from various references. 

The ACRP-7 document is quite useful, as it provides dose-based methods for
determining DWLs for various exposure scenarios - the DWL is selected using
the most restrictive pathway of exposure from inhalation, ingestion, skin
surface contamination, and uptake into the skin (retention) or through the
skin into the systemic circulation. It also delves into practical monitoring
implications. ACRP-7 further suggests that existing surface contamination
limits may be quite inappropriate or inapplicable for "radionuclides which
emit no beta radiation or low energy beta or electron radiation; or which
have short half-lives, and are in compounds with unusual surface behavioral
properties (examples tritium and Tc-99m)". This is illustrated in Appendix B
which provides a example of calculations that could be used to derive
surface contamination limits resulting in the same dose for two typical
radionuclides: Sr-90 (0.5 MBq per square metre) versus Tc-99m  (6.6 GBq per
square metre) - the difference between the two DWLs is quite remarkable.

This document and many others (ask for the AECB publications catalogue)are
available for free by contacting the AECB Communications Division, phone:
1-800-668-5284, e-mail: info@atomcon.gc.ca.  I don't believe this document
(because of it's age) is available for download from the AECB website
http://www.aecb-ccea.gc.ca/menu_e.htm

Hope this is helpful

Karin
************************************************************************

Karin Gordon RTR, RTNM, RTT
Radiation Safety Office 
Winnipeg Health Sciences Centre
GC-214, 820 Sherbrook Street
Winnipeg, Manitoba
CANADA, R3A 1R9

phone   (204) 787-2903
fax        (204) 787-1313
e-mail    kgordon@hsc.mb.ca
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Jjblute1@aol.com wrote:
> 
> Does anyone know what the original basis for the contamination limits in
Reg.
> Guide 1.86 was?  Some possibilities...
> 
> Dose Based?
> Detectability?
> Old Military, DOE, or DOD Standard?
> 
> I would love a reference that discusses this but would be glad to hear
> qualified opinions.
> 
> Thanks
> 
> Jim Blute
> Health Physicist
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information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html