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RE: Thorium in urine
Chris,
I'm believe the ICRP 68 DAC for Thorium 232 Type S is 1.7 Bq/m^3 and 0.72
Bq/m^3 for type M.
Randy Redmond
BWXT Y-12 L.L.C.
Y-12 National Security Complex
Radiological Control Organization
Email: rxq@Y12.doe.gov
Phone: 865-574-5640
Fax: 865-574-0117
> -----Original Message-----
> From: Christoph Hofmeyr [SMTP:Christoph_Hofmeyr@NNR.CO.ZA]
> Sent: Wednesday, April 04, 2001 10:58 AM
> To: radsafe@list.vanderbilt.edu
> Subject: Re: Thorium in urine
>
>
> RADSAFERS,
> Isn't Thorium-232 one of the radionuclides which miraculously has lost a
> lot of its radio-toxicity between ICRP 54 and ICRP 68, a factor of almost
> 30, if I am not mistaken (ALI of 40 Bq for 50 mSv went to 470Bq for 20
> mSv)?
> Chris Hofmeyr
> chofmeyr@nnr.co.za
>
>
> Previous messages:
>
>
>
>
> brian.keele@SWEC.COM
>
> Sent by: To:
> radsafe@list.vanderbilt.edu
> owner-radsafe@list.vand cc: (bcc: Christoph
> Hofmeyr/CNS1)
> erbilt.edu Fax to:
>
> Subject: Re:
> Thorium in urine
>
>
> 2001/04/04 16:08
>
> Please respond to
>
> brian.keele
>
>
>
>
>
>
>
> The thorium in urine background is highly variable. The ICRP 23 value is
> 0.1
> ug/day.
>
> P.Roth et. al., Journal of Radioanalytical and Nuclear Chemistry, Vol.
> 226,
> 1997
> is a reference. They report:
>
> Background Urinary excretion of Th-232 average: 47+/-27 uBq/day with a
> range
> between 9 and 121 uBq/day. One person varied between 26 and 167 uBq/day
> over a
> 15 day period.
>
> P Roth also refers to several studies, including:
> H. Dang, Health Physics, 1989: 16+/-6 uBq/day
> Minoia, Sci. Tot. Environ., 1990: 0.35+/- 0.16 mBq/liter with a range
> from
> 0.04
> to 2.9 mBq/liter.
>
> From my own experience, I am reasonably certain that there are a number of
> individuals (in the U.S.) with much higher levels of ambient thorium in
> their
> urine and that the levels fluctuate for even more dramatically than what
> has
> been published.
>
> Of course, all thoughts are entirely my own and do not necessarily reflect
> that
> of my employer or clients.
>
> Brian Keele, CHP
>
>
>
> BLHamrick@AOL.COM on 04/03/2001 11:34:34 PM
>
> Please respond to BLHamrick@AOL.COM
>
>
> To: radsafe@list.vanderbilt.edu
>
> cc: (bcc: Brian Keele/Contract/SWEC)
>
>
> Subject: Thorium in urine
>
>
> Does anyone have a reference for an average (i.e., background value) of
> thorium in human urine?
>
> Thank you,
> Barbara L. Hamrick
> BLHamrick@aol.com
>
>
>
>
>
>
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