The mind boggles at the recent passing of Alexander Litvinenko in London.  This poor sod was evidently dosed with some radiological hellbroth, possibly at a sushi bar. Crimony. Authorities found the radionuclide Polonium-210 in his urine.  According to the Radiological Health Handbook, US Department of Health, Education, & Welfare, January 1970, Po-210 is an alpha emitter (5.31 MeV) with a half-life of 138.4 days. It decays to Lead-206 which is stable. The specific activity of Po-210 is about 4,500 Curies per gram. 

This bad actor has a half-life long enough to handle, but short enough to be intensely radioactive.  Like the proverbial ice dagger, the evidence rapidly decays to the asymptote of the background.  And, alpha particles are more problematic in their detection, given their low penetration ability.  Not all survey counters will pick up alpha’s, so samples must be taken and prepared for analysis.  And, someone must first have cause to suspect radiological mischief. 

Obviously, this is the work of some fiendish mind. 

The decay table shows the decay events from Radium-226 to Lead-206.  The decay of Polonium-210 is the last decay in the series.  This graphic is from the Radiation Health Handbook.  Unfortunately, the 1970 edition of the Handbook does not give a target organ.  I have no clue as to common chemical forms of polonium compounds.  However, given it’s high specific activity, chemical toxicity may be negligable relative to the radiological insult. 

I show the decay table only because some might find it interesting to see where Po-210 comes from.  Hopefully, the health physics people who investigate this might find other nuclides that could give a hint as to the production source of the Po-210.

This reprehensible action reminds us that civilization is a veneer that is only a millimeter in thickness.  A radiological assault of this sort is especially sneaky in its execution and savage in its effects.

(*Weasel words- I am not a health physics person. My experience is limited to a semester course in radioisotope techniques and safety in grad school given by a radiation biology department.*)