Thanks for all the great insights! But why was the Po-210 not dangerous in that vial of water?
It seems many people who got in touch with it got ill: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767288/
https://www.argonelectronics.com/blog/litvinenko-and-the-per...
Also, from the article:
> The UK Health Protection Agency, which is advising authorities on technical aspects of the case, characterises the contamination in all 12 cases as “not significant enough to result in any illness in the short term,” while “any increased risk in the long term is likely to be very small.”