Re: monitoring for tritium

["Frank E. Gallagher, III" <fegallag@uci.edu>]

At the University of California, Irvine, we have procedures for bioassay
that specify confirmatory bioassays (done to verify the adequacy of
radiation safety practices, not necessarily to measure internal doses) at
the following levels for processes which occur weekly:

Chemical forms		Adults			Declared Pregnant women/Minors
Borohydrides		200 mCi		20 mCi
Water			2 Ci			200 mCi
Nucleotides		20 Ci			2 Ci
Amino Acids		200 Ci			20 Ci

These confirmatory bioassays would be performed quarterly for adults and
monthly for declared pregnant women and minors under 18.

If the confirmatory bioassays indicate significant intakes, or the
quantities used are 10 or more times greater than in the table above, we
would do routine bioassays to characterize and measure internal doses.
These would be done more frequently, based on considerations of effective
half-life.  We have set every 2 weeks for adults and weekly for declared
pregnant women and minors.

The quantities should also be adjusted down for daily processes, and up for
monthly or less frequent experiments.

With these internal dosimetry procedures, we seldom need to perform
bioassays any more.

The Health Physics Society Standards Committee is reviewing a draft
standard, "Design of Internal  Dosimetry Programs--Minimum Acceptable
Requirements."   I was part of the working group which wrote the draft
standard.  The above numbers are loosely based on what (I hope) will be
included in the final standard when it FINALLY comes out in a few years
after MUCH, MUCH additional review.

I can mail you a copy of my 15 page bioassay procedure if you like.  It
includes levels for 25 additional radionuclides and equations for
determining the levels for any others of interest.


************************************************************
Frank E. Gallagher, III, CHP		  
Manager, Radiation Protection Section     	  
Radiation Safety Officer
=================================================
University of California, Irvine / Environmental Health & Safety
300 University Tower / Irvine, CA    92697-2725
fegallag@uci.edu / (949) 824-6904 / Fax (949) 824-8539
************************************************************

At 02:15 AM 06/10/1998 -0500, you wrote:
>Can you please give me an indication of at what levels of activity of
>tritium it would be prudent to recommend urinalysis.  Our two major uses
>are; common lab applications of tritium-labelled reagents eg H3-thymidine;
>and larger activities of tritiated water used in large animal experiments.
>Thanks,
>Stuart Prosser