RE: Natural vs. Man-made - Uranium

["MacLellan, Jay A" <jay.a.maclellan@pnl.gov>]

Ron Kathren descretely questioned me off-line about my uranium absorption and
organ distribution numbers.  I got the absorption number out of ICRP 30 Part 1,
pg 102.  The discussion gives a number for dietary intake of about 20% for
non-occupationally exposed persons.  That is for extremely low levels of intake
of uranium which is probably in an organically complexed form.  I realize that
is much higher than the normal f1 values of 5% for water-soluble inorganic
compounds  and 0.2% for relatively insoluble compounds.  I got the organ
fractions by a quick check of the model used in the CINDY computer code.  I did
make a mistake there.  The numbers I gave were actually the clearance half-times
from the blood, and not the fractions reaching the specified organ.  Instead of
25% each, the fractions should have been 22% to bone, 12% to the kidneys, and
12% to other organs.  The fraction reaching the organ from the transfer
compartment (blood) is a much higher number than the fraction of an intake in
the organ at any time.  Ron, thanks for keeping an eye on me.  As always, I need
all the help I can get.

Jay A. MacLellan, CHP
Radiation and Health Technology
Pacific Northwest National Laboratory
Phone:  509-376-7247
Fax:      509-376-2906
Email:   jay.a.maclellan@pnl.gov



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