Talk:Polonium-210/Archive 1

How toxic is Po-210?
I had a look at the inconsistencies in the figures given for a "lethal dose" of Po-210

In Death by Polonium-210 by Robin B. McFee, & Jerrold B. Leikin (https://www.researchgate.net/publication/24206298_Death_by_polonium-210_Lessons_learned_from_the_murder_of_former_Soviet_spy_Alexander_Litvinenko/link/58188c4b08aee7cdc685a640/download) they say:

"Estimates suggest one gram of 210-Po could kill 50 million individuals and sicken another 50 million, and less than a microgram of Polonium could have caused Litvinenko’s death."

McFee and Leikin quote Kaplan K, Maugh TH: “A restless killer radiates intrigue.” The Los Angeles Times. Jan. 1, 2007. http://www.mjwcorp.com/rad_dose_ assessments_poloniumarticle.php https://www.latimes.com/archives/la-xpm-2007-jan-01-sci-polonium1-story.html

"Pound for pound, polonium-210 is at least a million times more toxic than hydrogen cyanide, the poison used to execute prisoners in gas chambers, according to medical toxicology books. Radiation safety experts calculate that a single gram of polonium could kill 50 million people and sicken another 50 million."

Two things; why are McFee and Leikin quoting Kaplan and Maugh in the LA Times and not a better source? And the microgram dose for Litvinenko is not in the LA Times article.

Anyhow, if 1 g is capable of killing 50 million; that implies that 0.02 ug would kill one person. I guess you could say that is "less than a microgram" but that is an odd way to describe 0.02 ug. Like saying 2 cents is "less than a dollar".

There is another inconsistency. The LA Times says "polonium-210 is at least a million times more toxic than hydrogen cyanide" (HCN) but then it is reported as 250 000 times more toxic than HCN. That latter figure comes from Ahmed et al:

International Journal of Environmental Research and Public Health Health Risk of Polonium 210 Ingestion via Drinking Water: An Experience of Malaysia Minhaz Farid Ahmed, Lubna Alam, Che Abd Rahim Mohamed, Mazlin Bin Mokhtar and Goh Choo Ta Int. J. Environ. Res. Public Health 2018, 15, 2056; doi:10.3390/ijerph15102056 www.mdpi.com/journal/ijerph

"Alam and Mohamed [5] also reported Po-210 is about 250,000 times more toxic than hydrogen cyanide" who quote Alam, L.; Mohamed, C.A.R. Polonium. Radionuclides in the Environment; Atwood, D.A., Ed.; John Wiley & Sons Ltd.: Chichester, UK, 2010; pp. 149–154, which I can't access.

According to https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+165 the lethal does for HCN is 50 mg.

Maybe 50 mg is not the only figure for HCN lethal dose, and the two sources use different figures.
 * 50 mg / 250 000 = 0.2 ug (Ahmed et al, quoting Alam and Mohamed)
 * 50 mg / 1 000 000 = 0.05 ug (Kaplan and Maugh, and this is an upper figure as they say Po is "at least a million times more toxic")
 * From Kaplan and Maugh, 0.02 ug would allow 1 g to kill 50 million
 * Only McFee and Leikin quote "less than a microgram"

All a bit confusing! Ewen (talk) 11:21, 30 July 2019 (UTC)

More digging:

According to this site: http://www.3rd1000.com/elements/Polonium.htm#Overview

"the oral LD50 for 210Po is about 50 ng compared to about 250 mg for Hydrogen Cyanide" which means it is "around 5 million times more toxic than Hydrogen Cyanide, HCN". This would be 1 million times if the HCN figure were 50 mg

The https://en.wikipedia.org/wiki/Poisoning_of_Alexander_Litvinenko#210Po_content_in_the_body_of_Litvinenko article quotes the Lancet as

"post-mortem samples were used to estimate intake as 4.4 GBq"

I calculate:

4.4 GBq x half life * molar mass / (Avogadro's number x ln(2)) 4.4 GBq x 138.37 days x 24 x 60 x 60 * 209.98 / (6.022 x 10^23 x 0.693) = 26 ug (1 GBq of Po-210 is 6 ug)

Updated list of figures for a "lethal dose" of Po-210:


 * 0.05 ug (50 ng) (www.3rd1000.com)
 * 1.0 or 0.2 ug (using 250 mg or 50 mg figures for HCN) (Ahmed et al, quoting Alam and Mohamed)
 * 0.25 or 0.05 ug (Kaplan and Maugh, and this is an upper figure as they say Po is "at least a million times more toxic")
 * From Kaplan and Maugh, 0.02 ug would allow 1 g to kill 50 million
 * Only McFee and Leikin quote "less than a microgram" and actually it was about 26 micrograms that murdered Litvinenko (35 ug of PoCl2 if that's what was used).

Ewen (talk) 12:06, 30 July 2019 (UTC)


 * I see; though I only realize it now, no one seems to agree even on the LD50 for hydrogen cyanide, much less the LD50 of 210Po. I did, though, find another source for 250,000 times more toxic, as well as some for 1 million. It also is important to note that some sources compare 210Po to hydrocyanic acid (HCN dissolved in water). Perhaps the text can be amended to incorporate these sources, or say something along the lines of "at least 250,000 times more toxic..." - what do you think of this? ComplexRational (talk) 15:32, 30 July 2019 (UTC)


 * Thanks for helping with the digging! Yes, that's another one for "250,000 times" and an LD50 of 1 ug for Po-210 (by implication, putting the LD50 of HCN at 250 mg). I wonder if Alam & Mohamed are singing from the same source? I couldn't get their full text.


 * So, we have two (250 mg and 50 mg) figures for HCN and anywhere from 1.0 ug to 0.02 ug for Po-210. Dividing one substance's LD50 by the other's gives a range of 50,000 to 12,500,000. I guess the 250,000 and 1 million times figures are in the right range, but it's quite a range!


 * Ewen (talk) 16:19, 30 July 2019 (UTC)


 * Glad to help - though unfortunately I also cannot access the full text of Alam, 2010. Nevertheless, it is indeed quite a wide range given that these are reliable sources. Additionally, I also saw a few mentions of 250 billion, which is well outside this range and is inconsistent with all of the LD50 figures. One was in reference to hydrocyanic acid, so I can't assume its equitable with the rest. As I said, though, I feel a mention of this variation (at least 250,000 to a million) is needed if we're sure these sources are accurate. ComplexRational (talk) 17:19, 30 July 2019 (UTC)