Hello Dr. Zoomie! There was something in the news again about a Russian guy, Alexander Litvinenko and how he was killed with radiation. I remember something about this from about ten years ago and didn’t quite understand what was happening. Can you tell me what’s going on? And was there any risk from this to anyone else?
Good question – and an interesting story! The short version is that Alexander Litvinenko was a Russian who was killed after drinking tea laced with polonium (specifically, Po-210). Extensive radiation surveys by the British found a fairly extensive trail of contamination around the city, and even on a number of commercial aircraft. But in spite of extensive contamination, nobody except for Litvinenko was harmed by the radioactivity. OK – that’s the short version; now let’s dig a little deeper.
First – Litvinenko was indeed given some polonium in his tea. Polonium-210 is a naturally-occurring radionuclide that comes from the decay of natural uranium (U-238) in the rocks and soils. Po-210 can also be manufactured in nuclear reactors, and this is where the material used to kill Litvinenko probably came from. This particular radionuclide emits only alpha radiation – alphas are highly damaging to living cells, but are too weak to penetrate the dead layer of skin cells that comprise our epidermis so as long as they stay on the outside of our bodies they can’t hurt us. But once inside, it doesn’t take much for an alpha-emitter to be dangerous – the amount of radioactivity administered to Litvinenkowas less than the weight of a single grain of salt, but it was enough to be fatal.
Once administered, the radioactivity has to get into the blood – in Litvinenko’s case it was absorbed from the digestive tract. In actuality, only about 10% of the polonium was absorbed and the rest passed out of his body, so that grain of salt amount of Po-210 was ten times as much as was needed to kill him. After he started feeling ill, Litvinenko went to the hospital, where they initially suspected radiation but then went on to look at other types of toxins. In fact, Litvinenko was hospitalized for a few weeks before the doctors realized he was poisoned with radioactivity; by that time it was too late to help him – we just don’t know how to keep people alive when they’ve received a high enough dose of radiation.
According to research performed by the Russians in the 1960s, polonium in the body tends to concentrate in the hair follicles and to come out in perspiration when we sweat. It’s also very mobile – in the laboratory polonium was known to move around readily, spreading contamination all over the place. This means that, as Litvinenko moved around London after he was poisoned and before he was admitted to the hospital, he was shedding contaminated hairs and perspiration and, once on the ground, the polonium was able to spread from the hairs to the ground. So when British radiation specialists started performing surveys, they were able to find traces of polonium wherever Litvinenko had traveled. Not only that, but they also found polonium on a number of commercial aircraft – presumably contamination from whoever it was that brought the polonium from Russia to London.
With all that contamination, there was a lot of worry about the effects of the contamination on the health of Londoners or travelers flying on the jets that were contaminated. Luckily, there simply wasn’t enough polonium to cause problems – in spite of the low levels needed to cause harm. The reason is that we are very good at detecting very low levels of radioactivity – the fact that scientists are able to detect radioactivity doesn’t necessarily mean that it’s present at harmful levels. For example, you might be able to see a single speck of dust on a table – but just because you can see it doesn’t mean that it’s harmful to you. One radiation scientist was asked by a reporter if simply flying on contaminated airplanes posed a health risk to passengers – he replied “Not unless you lick the seats,” which not only sums up the radiological hazards, but is probably good advice on any plane! When all was said and done, not only was polonium found in a number of locations in London, but over 50 other nations were involved as well – traces of polonium were found in some, and others had citizens who were exposed to the polonium in London and who had to be checked when they returned home.
One really important thing to mention here is the effect of all of this on the hospital staff. Remember – Litvinenko was in the hospital for a few weeks before anybody knew that he had radioactivity in his body, let alone that he was shedding it with every hair that fell out of his head or from his body. In spite of that, not a single hospital worker had a significant uptake of polonium when they were tested – at the very least, this is a testament to the typical precautions taken by hospital workers to keep themselves safe.
Interestingly, when Litvinenko first checked into the hospital blood samples were sent off to be analyzed for radioactivity. But they were checked for gamma radiation, and Po-210 is very nearly a pure alpha emitter – because the detector being used was only sensitive to gamma radiation, the polonium contamination was missed. It wasn’t until several weeks later that the samples were re-analyzed for alpha contamination that the polonium was recognized.
There’s a lot more to this story, but to go into more detail would take much more space than we have here. But out of all of this there are a few interesting points that are worth mentioning:
- Alpha radioactivity is not only dangerous in very small quantities, but is also hard to detect without the correct instrument,
- Radiation poisoning is not always easy for doctors to recognize,
- Routine medical precautions offer good protection from low levels of radioactive contamination,
- We can detect radioactivity at levels that are much lower than what can cause harm.
To the best of my knowledge, Litvinenko is the only person to be assassinated this way, although there are those who believe that Yasser Arafat might also have been killed in the same manner (although this is more conjecture than fact at this time). As far as we know, this was a unique event – a tragedy for Litvinenko and his family – that will hopefully not be repeated.