This is TALK OF THE NATION Science Friday. I'm Ira Flatow.

Later in the hour, we'll be talking about global warming and the new Congress, but first the strange case of death by radioactive poisoning. Sounds almost like a novel, doesn't it? Let me recap it a bit.

On Thanksgiving, a former KGB agent named Alexander Litvinenko died at a hospital in London. Now you remember that. The investigators determined that Litvinenko, who was an outspoken critic of the current Russian government died from radiation poisoning after being exposed to polonium 210. That's a radioactive, very lethal, radioactive heavy metal. And traces of radiation have since been found in the sushi restaurant where Litvinenko ate on November 1st, the day he first got sick. Radiation has also been detected at the hotel where he met with two former KGB colleagues. Earlier this week, British Airlines - British Airways - announced that small traces of radiation had been found on flights between Moscow and London.

Now polonium 210 is an unusual choice of poison, first because it's hard to come by, but also it ravages the body very quickly and it decays very fast and has to be handled by an expert. And we have an expert here to talk about it. Nick Priest is a former research scientist for the UK's National Radiological Detection Board. He holds a research chair in radial biology and environmental toxicology at Middlesex University in the UK. He's also a visiting professor at the Medical University of South Carolina.

Welcome to the program, Dr. Priest.

Dr. NICHOLAS PRIEST (Professor of Environmental Toxicology): Welcome. Thanks for inviting me.

FLATOW: This sounds just like a novel, doesn't it?

Dr. PRIEST: Yes, it sure does. And actually, I can bring you up to date a bit as well.

FLATOW: Please.

Dr. PRIEST: There's a second victim now. The Italian colleague of his has been confirmed, now, to have a significant degree of contamination in his body and the health protection agency in the UK are saying that the levels in his body are sufficient to be of immediate concern. So the story winds on and it gets more and more intriguing all the time.

FLATOW: Does that help the case - solve it - knowing about the second victim here?

Dr. PRIEST: No, it doesn't. It introduces some more uncertainties. Certainly we now have a issue of how this person got contaminated, though he was in the sushi restaurant with Mr. Litvinenko.

FLATOW: Do you think the case is anywhere close to being solved?

Dr. PRIEST: I would be surprised if it wasn't. I have no inside knowledge at all, but of course, there are CCTV coverage of the restaurant itself. There is the - obviously, they know which seats were contaminated in the aircraft. They have a passenger list for who was traveling on the aircraft. And I've unofficially heard from reporters which have been talking to me, that there are three Russian men and one Russian woman, at the moment, which are under some degree of suspicion. But other than that, I don't know. And to be honest, that's hearsay.

FLATOW: Yeah. Let's talk about polonium 210. Why would it be a good choice for poison?

Dr. PRIEST: Well, it's pretty unique in a couple of respects. I think a few things make it very good. First of all, it's absorbed from the gut. Most heavy metals would be very poorly absorbed from the guts and so you wouldn't get it going into the blood stream and causing a radiation dose. So that's one thing, OK.

Another thing is, is it's a pure alpha emitter, although at very low frequency, it produces some gamma rays. And this means and this means it can't be detected at airport scanners and things like this. You could pass right through without it being detected. So that's a second reason.

And then the third reason which makes it particularly good, is that unlike most of these heavy metals, polonium doesn't seem to concentrate particularly in any one organ of the body, so it circulates around in the blood and in the tissue fluids and gives a general dose to all tissues. So you get similar sorts of symptoms in Mr. Litvinenko that you would have if people had been exposed, say, to radiation from a nuclear bomb or from an accident (unintelligible) therapy accident or something like that.

FLATOW: And where would you find a source of this, if you were looking for it?

Dr. PRIEST: Right. You can get it from four places, really. The first place you could get it, is you could do it the same way as Marie Curie did it when she discovered it in about 1903. What she did is she extracted it from uranium ores, from the minerals, but I don't think she used tons of uranium ore to extract her polonium, and I don't think that's on(ph), feasibly.

So the next way you could do it is you could find what they call an orphan radium source. One of the old sources were produced in the 1920s, 1930s, and there are a few of those missing or being found in Russia, and it's capable - these, in theory, you could remove the polonium 210 from these. But again, that would be very difficult because you would be irradiated by the radium and that would cause big problems.

The third way, which has been speculated about, would be for the polonium to be extracted from anti-static devices which are used in the photographic industry. Now that would be about the right amount of polonium 210, but the difficulty is that you have to remove it from these anti-static devices - which isn't easy because they're designed to be more or less tamper-proof. And if you succeeded in, say, dissolving this sample up, you would dissolve other metals and you'd end up with a cocktail of materials which would be very difficult for somebody to swallow. It'd be pretty unpalatable.

So that leaves the fourth and most likely method, and that is it was produced as polonium 210 from a target made with bismuth in a nuclear reactor.

FLATOW: And would that be a medical reactor, or one - the kind where nuclear power is made?

Dr. PRIEST: No, it wouldn't be a nuclear power reactor. It would be a reactor which was used to make medical isotopes, or conceivably, also it could be a materials testing reactor which are used for the development of nuclear power.

FLATOW: How dangerous - I'll let you take a drink of water there, or something - how dangerous would somebody be, coming in contact with anybody who has been exposed to this kind of radiation?

Dr. PRIEST: Well, up to the point where this Italian gentleman - Italian friend of his - is being confirmed as being significantly contaminated, one would think that the chances of somebody becoming contaminated from him would be small. Now you have to reassess the position, slightly, because maybe the risk is greater than we thought, but probably more likely, they were both contaminated at the same time because they were both in the restaurant.

Being contaminated from aircraft seats and things like this, it really isn't incredibly likely at all, and it's difficult to imagine how anybody could be significantly contaminated from sorts of contamination which you'd find on door handles, on seats, on clothes and this sort of thing.

FLATOW: How were they able to - it has a very short half-life, does it not?

Dr. PRIEST: Well, it's not very short. It's about 138 days.

FLATOW: Right. So you could then go back to the seats and wherever these gentlemen were, and ostensibly in the airport, and find some traces of it?

Dr. PRIEST: Yes. It's a sort of forensic trail, which they're leaving. So the levels are described as trace. And certainly in the UK, and with the people who are involved, if they describe them as trace that they would mean that they were fairly close to the detection limits. And so that would be an incredibly small fraction of the material which was actually put in Mr. Litvinenko, which was probably a thousand, million, alpha disintegrations per-second, some sort of - about that sort of level.

FLATOW: What kind of forensic work do you think will crack this case?

Mr. PRIEST: Well, of course, it is a question of whether forensic will crack it. I'm a biologist, not a politician, but it doesn't take too much (unintelligible) to realize that there are a few political overtones in this. And it may be that people know exactly who did it but can't prove it and - or perhaps they don't want to get involved with the political fallout. And I think it's interesting that the British police haven't described it as a murder. They're still describing it as a suspicious death.

FLATOW: That would be politics, if you describe it...

Mr. PRIEST: Yeah, I think so.

FLATOW: a murder. To your knowledge is this the first case of poisoning by polonium?

Mr. PRIEST: Yeah.

FLATOW: It is the book title right there, you know.

Mr. PRIEST: It's probably the first case - it's certainly the first case I've heard of. It's the first case of anybody being killed with acutely, that's with an early death radiation type (unintelligible) syndrome. With an alpha emitter, other people have had intakes of other alpha emitters, like plutonium, and they may, especially in the Soviet Union, and they may have died 20 years later as a consequence of cancer. But somebody dying within a short time of acute radiation poisoning, I don't think has ever happened before unless they tried it out on somebody else beforehand.

FLATOW: What - I know you're not a doctor, I don't want you to speculate, but do you think that this Italian gentleman has high enough dosage that he might also be - his life might be in danger.

Mr. PRIEST: Yeah. Well certainly, what they're saying is that it's enough to be of immediate concern. And now clearly, he hasn't got the same amount of radioactivity in him as Mr. Litvinenko had because he's still alive, and I understand he's symptom-free and asymptomatic. Now, if it was being described as a significant amount, then I would have thought well, this is a large amount and that it could give rise to an increased risk of cancer in later life - particularly given the distribution of polonium in the body - of leukemia, perhaps five years down the line.

However, when they described it being of immediate concern, it may mean the levels are somewhat higher than this. In which case they might be worried about things like bone marrow (unintelligible) radiation knocking out the bone marrow. If that happened, then the person would lose his resistance to the disease.

FLATOW: (Unintelligible) one quick question, I have about 30 seconds: Does the fact that two people have been poisoned and there are traces on airplanes, does that mean that it was not botched but it wasn't really good professional hit?

Mr. PRIEST: Put it this way, if I was working in a national lab and I did - I get fired. However, we don't know. My guess is that the people who did it weren't people who were experts in using radioactive materials. However, the people that produced it probably were. So - and you can imagine, for instance, if it came from Moscow - and that has to be confirmed - but if it came from Moscow then something might have transferred it from one container to another container or something like that.

FLATOW: I've got to go. I want to thank you for taking time to be with us.

Mr. PRIEST: That's okay. I'm pleased to be with you.

FLATOW: Nick Priest, former science researcher at UK's National Radiological Detection Board. Stay with us. We'll be right back after this break. I'm Ira Flatow. This is TALK OF THE NATION: SCIENCE FRIDAY from NPR News.

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