[ RadSafe ] Depleted Uranium Found In Urine 20 Years Later

Otto G. Raabe ograabe at ucdavis.edu
Mon Oct 29 10:17:43 CDT 2007

At 10:59 PM 10/28/2007, Roger Helbig wrote:
>I rather wonder if the test proves that DU is there or that uranium 
>is there -- I have asked Dr Parrish what steps he has taken to 
>preclude natural uranium being reported as being DU.  The "aerosol" 
>comment makes it sound like Parrish was not particularly unbiased 
>when he began this testing.
October 29, 2007

The sector field - inductively coupled plasma - mass spectrometry 
(SF-ICP-MS) and multiple collector - inductively coupled plasma - 
mass spectrometry (MC-ICP-MS) can provide incredibly accurate 
measurements of all uranium isotopes in urine including U-234, U-235, 
U-236, U-238. [I think that this method has also been applied to to 
plutonium isotopes, and it is far more accurate and precise that 
old-fashioned alpha particle energy spectra counting.]

The uranium isotope ratios can be measured in urine to an accuracy 
less than 5% even when the total uranium in urine is only a few 
ng/liter.  So a relatively small increase of U-238/U235 above the 
natural ratio of 137.88 can be readily determined.

If a statistically significant increase in U-238/U-235 is observed, 
that does nothing to inform the reason for that increase or the time 
of a possible intake of extra U-238. A recent tiny exposure in food 
could look like a larger inhalation exposure  twenty years ago.

Of course, U-238  is barely radioactive and a feeble poison. Neither 
radiation exposure nor chemical toxicity pose meaningful hazards for 
exposure to small amounts of U-238.


Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
University of California
One Shields Avenue
Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140

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