Quote Originally Posted by Throbert McGee View Post
...the risk would be that as the sweat/urine/feces dry out on Litvinenko's clothing and bedsheets, particles of polonium dust could become airborne and then be inhaled by a hospital worker. Although the risk from a one-time inhalation might be negligible because the Po210 dose was so tiny, if the same worker were visiting Litvinenko's bedside several times a day over a period of two or three weeks, then the total amount of inhaled Po210 could, in theory, become high enough to put the worker at statistically greater risk of lung cancer or leukemia. (Which could translate into expensive legal liability for the hospital.)
For another reason entirely, I was looking up radiological medicine issues for several weeks, and found out that the radioactive heavy metals do not eliminate as readily as things like radioactive iodine. Iodine does eliminate as sweat, urine etc. Except for things like Tc99/Tc99m, the heavy metals do not behave so nicely, from the point of view of de-toxification. The heavy metal elimination profile starts off at about 1% the first day (feces/urine), and then rapidly falls off to less than ~0.1% vicinity. Large amounts are deposited on bone. This is on longer time lines. You can see from these kinds of things that the inhalation hazard is very low, to the point that you probably could not tell the difference from background. The fact that you can legally buy antistatic brushes containing Po210 should be telling you something.

Take a look at this radiation exposure chart. If you look at the lower right area of the chart, you can tell that a worker probably would not get an amount from Litvinenko that could be even linked to an increased chance of getting cancer. You have to do a little ball-park calculation, based on the low elimination rate, and dilution of dust, time in room,etc. If you assume that the fatal dose was ~8 Sv (or even much larger), then you can see that the ~1% elimination as feces/urine first day would allow only a tiny fraction of 1% as a possible dose. Estimate several hundred mL feces/urine, single digits volume mL drying would give thus 1% of 1% as a high estimate. Then to dust, and more dilution before a worker could inhale it. See where it is going? We would now be down below the mSv level, but more likely much less than that. A chest CT scan is list at 7 mSv. . http://blog.xkcd.com/2011/03/19/radiation-chart/
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Quote from IAEA "Po-210 can enter the body through eating and drinking of contaminated food, breathing contaminated air or through a wound. The biological half-time (the time for the level of Po-210 in the body to fall by half) is approximately 50 days. If taken into the body, Po-210 is subsequently excreted, mostly through faeces but some is excreted through urine and other pathways. People who come into contact with a person contaminated by Po-210 will not be at risk unless they ingest or inhale bodily fluids of the contaminated person. "
http://www.iaea.org/Publications/Fac...lonium210.html
When they say ingest of inhale, they mean amounts that get into several percent. Not really very possible. The 50 day bio-half life is including the decay in the body also at the 138 day radioactive half life. The elimination rate slows down a lot after the first few days, resulting in incorporation in bones. This behaviour is similar for Plutonium radium, etc.
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