The story so far: Nine years ago, on November 11, 2004, Yasser Arafat died. That he could have died from natural causes or some “lifestyle disease” was too unpalatable for his followers so they came up with a rather bizarre theory that he was poisoned with Polonium-210. After decomposing in Ramallah for eight years his wife and followers dug up his corpse to try to prove it.
As far as anyone knows there has been one detected and recorded deliberate case of Polonium-210 poisoning (from the rather authoritative Royal Society of Chemistry in the UK):
Polonium-210 is reported to have caused the fatal poisoning of former Russian spy, Alexander Litvinenko. Litvinenko died on the evening of Thursday 23 November  at University College Hospital, London, UK. He fell ill on 1 November within hours of meetings in a central London hotel and, later, a sushi bar. Chemistry World asked John Emsley, author of Elements of murder: a history of poison, what is known about polonium-210 poisoning.
The poisoning and subsequent death of Litvinenko occurred in London not far from me. He actually died in a hospital across the street from the office I was then working in. I spent a few days walking past the massed ranks of the world’s media or eating lunch alongside them in Pret a Manger.
But that’s not my only experience with radiation. You see I have a Physics PhD (admittedly in another branch of physics) but I did study medical physics at university.
Low activity suite
So here’s how you measure infinitesimally low amounts of radiation: amounts so low that they are usually drowned out by what we call “background radiation”.
Background radiation is like the noise when you’re standing on a street. If someone is standing next to you, talking to you, you can probably hear them. Detecting low levels of radiation is like listening to a whisper on a busy street. Best if you listen to the whisper in a quiet room.
Detecting Polonium 210 after 8 years is like trying to hear someone whispering on a busy street in New York. While you’re standing in London.
So if you are serious about detecting very low levels of radiation you need something called a “low activity” room. This is not a place with comfortable chairs and soothing music.
We had such a room at the hospital in Sheffield where I studied this. It was a room in the basement and within that room was a smaller room. The small room was made entirely out of battle ship plate armour steel: the walls were up to 2ft thick. The door was massive and resembled that of a safe.
The steel came from a battleship that was forged before 1945. That is critically important. The steel had to have been made before July 16, 1945.
Just like the noise on a street, steel makes a radioactive noise. Steel made before the dawn of man’s explosive nuclear experimentation is measurably quieter than steel made since. So if you want to hear the whisper of a truly tiny sample of something radioactive, you need both a thick piece of steel to keep the background noise out and that steel to be very quiet too.
That is what a low activity room or suite is.
What is this Polonium stuff?
Again from the Royal Society of Chemists:
How would one get hold of polonium-210?
With difficulty, unless you had access to a nuclear facility or were an authorized user, such as those who use it to generate thermoelectric power. (Polonium-210, half life 138 days, releases a lot of heat energy and a gram of the element can reach a temperature of 500 Celsius, which is why it has been used as an energy source in space). Around 100 grams a year of polonium-210 are manufactured in nuclear reactors, and this is done by bombarding bismuth with neutrons.
How much constitutes a fatal dose?
The maximum safe body burden of polonium is only 7 picograms. Polonium occurs naturally in the environment due to radioactive decay of radon, and we all have traces of polonium in us. Polonium-210 is regarded as one of the most dangerous substances known because it ejects alpha-particles, which are helium nuclei, and these wreak havoc with every organ of the body in which the polonium resides. (Inside a living cell they can trigger cancer if they damage DNA.)
In theory, a mere microgram of polonium-210, which is no larger than a spec of dust, would deliver a fatal dose of radiation. Polonium is only slowly excreted – it has a biological half life of around a month – and this ensures its alpha-particles continue to wreak havoc.
A gram of it, sitting in a box will be at 500℃ so clearly nobody has a gram of it sitting around. And if you did have a gram of this stuff, 138 days later you’d have something like half a gram (with the rest of it having turned into a little less than ½ gram of lead). That’s what a “half life” of 138 days means.
So if you gave someone a microgram (1/1,000,000th of a gram), after 138 days there would be a grand total of ½ a microgram left in him (actually there’d be even less because some of it would have been excreted during the time the victim was still living).
How much would be left after 8 years? Well take 8 * 365 = 2920 days. Divide by 138 to get 21 half lives.
If we start with 1/1,000,000 of a gram and divide by 2, 21 times… I’ll spare you the effort. your calculator will give up and tell you it’s nearly(*) nothing.
Realistically speaking there might be an atom or two(*) but we’re down in the depths of very small quantum things so it doesn’t take a Heisenberg to tell you finding this is uncertain. The only certainty is you won’t be able to detect it above background, even in a low activity room.
So what does this stuff turn into? Mostly something called Lead-206 − 206Pb. Now what a lab might have done is look to see if Arafat had more of this than would be expected, but considering the poisoning dose of Polonium-210 is so low to start with, that would also be impossible. We all have a bit of lead in us, especially those people who were alive back in the days of lead in gasoline!
With the most amazing measuring equipment, in the most physically shielded room possible, you couldn’t find a piece of radioactive Polonium-210 eight years after it was made. Looking for some in an exhumed body or belongs is astonishing.
The decay products of Polonium-210 are not uncommon enough to look for either.
There’s no way on earth this lab found anything scientifically significant in the corpse of Arafat (hence their very cagy language).
Arafat died of natural causes, Aids or something else: releasing an unedited version of his medical records would go a long way to solving this little mystery. Certainly that would do more than a pseudo-sicence dance in Switzerland. No matter what his widow and his adoring terrorist friends would like to think.
(*) Commenters have pointed out that in the first version I described the amount of material remaining from the decay of 1 microgram of PO-210 as “a few atoms” and this isn’t strictly true. The amount remaining would be around 1.3 billion atoms. The issue is most people don’t fully grasp how tiny atoms are or how many of them there are around and in us.
1,373,961,022 – atoms of PO-210 remaining
7,000,000,000,000,000,000,000,000,000 – atoms in a 70kg person.
So if we consider those remaining atoms of PO-210 are not in a single clump (they shouldn’t be) I hope it’s not too much of a stretch for people to believe that describing 1.3 billion atoms as “nearly nothing” is OK.