[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Thorium in urine







I don


?t have ICRP-54 nor an extensive library.  However, it is true that FGR 11

lists the DCF for class W Th-232 as 4.43E-4 Sv/Bq while ICRP 68 is 4.2E-5 Sv/Bq

for 1 um AMAD.  For Class Y, the FGR 11 DCF is 3.11e-4 Sv/Bq and the ICRP 68

value is 2.3E-05.



For class Y, this is partially offset by a reduction in the IRF from

NUREG/CR-4884 to ICRP 78.  The 5 day 24-hour urine IRF in NUREG/CR-4884 is

4.22E-06 whereas the ICRP 78 IRF is 1.4E-06.



I would like to see some insight from those who are closer to the actual

research.



Again, all thoughts are entirely my own.



Brian Keele



















"Christoph Hofmeyr" <Christoph_Hofmeyr@NNR.CO.ZA> on 04/04/2001 09:57:46 AM



Please respond to "Christoph Hofmeyr" <Christoph_Hofmeyr@NNR.CO.ZA>

                                                                                

                                                                                

                                                                                





                                                              

                                                              

                                                              

 To:      radsafe@list.vanderbilt.edu                         

                                                              

 cc:      (bcc: Brian Keele/Contract/SWEC)                    

                                                              

                                                              

                                                              

 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













************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.