[ RadSafe ] Po-210 Lethal dose

[Dukelow, James S Jr]

Charles Ellars wrote:
-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Ellars, Charles
Sent: Monday, November 27, 2006 11:44 AM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Po-210 Lethal dose

I read in some account the amount of 5 Gy for this ex-spy which is
probably not based on anything and is a wild guess.  But for arguments
sake...  Since Table 1 of Appendix B 10 CFR 20 shows the oral ingestion
ALI (daily) as 3 uCi for Po-210, that suggests he would need to have
swallowed approximately 3 mCi of Po-210 to get that dose.  My question:
Is that a legitimate way to ball park the ingestion amount? Or is there
a more appropriate way to do it.  Thanks.

=====================

The Wikipedia entry for polonium-210 at  en.wikipedia.org/Polonium  has
toxicity and specific activity information.

Since polonium-210 has a 138 day half-life and almost the same atomic
weight as radium-226 with a 1600 year half-life, its specific activity
will be approximately 5000 times the 1 curie per gram specific activity
of radium-226.  The Wiki gives 5.14E-7 Sieverts per Becquerel for
ingested Po-210 and 2.54E-6 Sv/Bq for inhaled Po-210.  Polonium is quite
volatile for reasons not fully understood - perhaps alpha recoil
spalling of small particles off the surface of solid Po-210.  A
potentially fatal dose (ingestion) of 10 Sv would require 0.12
micrograms.  The Wiki asserts that Po-210 is 2.5E11 times as toxic as
hydrogen cyanide.

If the UK authorities seem to be thrashing around, it is probably
because they are trying to figure out how much Po-210 is out there and
whether it represents a threat to the public and to the medical staff
that will perform the autopsy.

Best regards.

Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
Jim.dukelow at pnl.gov

These comments are mine and have not been reviewed and/or approved by my
management or by the U.S. Department of Energy.