Re: Kosov DU - New Scientist Report

[Kim Merritt <merritt9@llnl.gov>]

Just a guess, but IH limits would seem to be based upon toxicity and not
the dose limits of the HP world.  They are looking at more "measurable"
effects, such as kidney failure, rather than extrapolated guesses about
cancer incidence.

>Hi again Radsafers
>
>Sorry, but here's another DU question.
>
>According to the Rand report vol 7
>(http://www.gulflink.osd.mil/library/randrep/du/mr1018.7.chap1.html), the
>American Conference of Government Industrial Hygenists set the MPC for
>insol or soluble U at 200 microgram/ m3 air in 1993.
>
>Now if you take nat-U as 0.0254 Bq/microgram, a breathing rate of 1.2 m3/hr
>(ICRP reference man), an average dose coefficient of 3.3E-05Sv/Bq (English
>NRPB) and a 2000 hr working year, you obtain
>
>200 x 0.0254 x 3.3E-05 x 1.2 x 2000 =0.4 Sv/yr, ie. 400mSv per year.
>
>The dose limits are 1mSv/yr for members of the public and 20 mSv / yr for
>occupational dose. So there's clearly a discrepancy here.
>
>In fact, the 1mSv/yr limit corresponds to about 0.5 microgram/m3, and the
>20mSv/yr limit to 10 microgram/m3. If you do a similar calc. for DU it
>comes out a bit higher, 0.7 microgram/m3 for 1mSv/yr.
>
>Can anyone explain why the ACGIH set a figure of 200 microgram/m3? Have I
>made an error somewhere? Is there a misprint somewhere along the line?
>
>Keith Bradshaw Southampton University UK
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| | | |    Kim Merritt, RRPT
| | | |__  Physics Safety Support Officer
| | \___/  Lawrence Livermore National Labs
| \___/    merritt9@llnl.gov
\___/      Voice: (925)423-9668   Fax: (925)422-7160
	   "When the only tool you have is a hammer,
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