Re[2]: info

["Charles Potter" <CAPOTTE@sandia.gov>]

     Certainly personal air sampling is a much better method of plutonium 
     detection than any type of bioassay.  The sensitivity of the detection 
     of activity on the filter itself is quite low, combined with the 
     intake retention fraction equal to the sample pump flow rate divided 
     by reference man's breathing rate.  With the 20 l/m breathing rate, 
     this would result in an IRF of 0.1 for a 2 l/m sample pump rate.  
     Compare this to orders of 10^06 or less for urinalysis.  Fecal 
     analysis is much better, although much less pleasant, but, I 
     understand, is now being implemented at some sites.  Also, the IRF for 
     lung counting is greater than 0.1, but the MDA's can be as high as 100 
     nCi, almost useless for bioassay purposes.
     
     The other advantage of personal air sampling is that, properly used, 
     it can be a much more timely method of detection.  Any alpha spec on 
     excreta samples usually takes 3 days or more on an emergency basis.  A 
     contract laboratory may take up to 60 days to complete the analysis 
     and report the results.  Personal air samples can be analyzed weekly, 
     providing a timely indication of intake.  Using repetative alpha 
     counting to account for the radon componant, they can even be analyzed 
     daily, if necessary.
     
     Here ends the lesson.
     
     Gus Potter
     Sandia National Laboratories
     CAPOTTE@sandia.gov
     (505) 844-2750


______________________________ Reply Separator _________________________________
Subject: Re: info
Author:  stabin@esper.com at hubsmtp
Date:    7/17/96 6:33 PM


>We are examining the possibility of replacing a 24 hour composite urine 
>sample with a single grab sample for plutonium bioassay.  Can a single 
>grab sample at one point during the day be scaled up to a full day?  Does 
>anyone use this value to determine body burden?  Physicians scale urine 
>sample results by the creatinine level.  Can we also use creatinine?  Does 
>plutonium excretion follow a diurnal cycle that would make one void, 
>perhaps the first morning, more representative of the entire day?????
>
>--
     
Well, everyone, for any nuclide, scales up partial day samples to simulated 
24-hr values, using either urine volume (and an assumed volume for the 
individual, either standard - 1000/1400 ml/day for females/males - or 
perhaps typical values for the individual) or creatinine.  I don't have 
specific experience with Pu, but in general, there is much variability in 
the excretion of radionuclides throughout the day, so I always recommend 
that people use true 24-hr samples where possible with the 24-hr IRFs that 
are available.  There is also the "last at night first in the morning" 
simulated 24-hr sample that Kathren and others published a short article 
about recently.  I don't have the reference handy, but I can get it if Ron 
doesn't post it here himself.  The bottom line, IMO, is that it can 
certainly be done but that true 24 hr is best.
     
Mike Stabin
Oak Ridge