Veterans Affairs Committee on Feb. 26th, 2013

[The Vice-Chair, NDP, Peter Stoffer]

Good morning, everyone. Welcome back to the halls of Parliament.

We continue our study on depleted uranium and Canadian veterans. Today we're very pleased to have, from Atomic Energy Canada Limited, Mr. Nicholas Priest, the section leader for radiation biology and health physics.

Am I correct in that, sir?

[Nicholas Priest, As an Individual]

Yes, except I'm representing myself, not AECL, at this meeting.

[The Vice-Chair, NDP, Peter Stoffer]

Very good, sir.

Thank you very much for coming today. We look forward to your presentation. Afterwards we will have questions from both sides of the desk.

Again, sir, we thank you very much for being with us today.

[Nicholas Priest]

Thank you for inviting me.

It came as a bit of a surprise to be asked to give a presentation. I wasn't aware that I had to give an introduction, but I've made a few notes, and I just hope that's okay. If you have problems with it, please indicate and I'll clear it up.

I'm a toxicologist. I have a Ph.D. in medicine from the University of London. Following my Ph.D., I worked for 13 years for the National Radiological Protection Board in the U.K., where I studied toxicity and behaviour in the body of materials that deposit in the skeleton. That's most metals, including uranium, radium, plutonium, and all sorts of things like this.

I then for ten years was head of biomedical research at the United Kingdom atomic energy establishment at Harwell, which is the sister organization to where I work now, at Chalk River. It was started by the same people at the same time.

Then we had a reorganization, and the organization was effectively broken up. I left the UKAEA—or AEA Technology, as it was called then—and moved to a university chair in London, where I was a professor of environmental toxicology.

In 2007 I was approached by AECL in Canada and asked to come over and look after biological research at Chalk River Laboratories. I readily agreed, because after 10 years in the university, that was enough.

I think Joe Oliver is meant to give a talk, perhaps even this week, on the future of the Chalk River laboratory. I just hope that I don't get caught, the second time in my life, when a laboratory is broken up.... Never mind.

So I came out here and subsequently picked up additional responsibilities for radiation dose symmetry at Chalk River and also for environmental technologies.

In the context of my experience with uranium, which I guess is the major issue here, it started at the NRPB, where I undertook studies on the way in which uranium behaves in the body and also on the toxicity of uranium—specifically, forms of uranium that are radioactive, or the opposite end of the spectrum to depleted uranium, if you want to put it that way.

I also was asked by the BBC to go with them to do a two-week investigation of depleted uranium exposures in the Balkans. I was in both Bosnia and Kosovo collecting urine samples from the general population, bringing the samples back to the U.K., and then using the technique, an isotopic technique, to detect depleted uranium in the residents living there.

I found a very small amount. The amount of natural uranium they were excreting was larger, but about 20% of the uranium they were excreting at that time, which wasn't very long after the war, gave a signature that suggested it was depleted uranium.

I was invited back by the German army a couple of years later. I went back with them to Kosovo, and this time to Serbia. When I was in Kosovo, I went back to the original people I had measured and took more samples from them. I found that now there was no indication of any depleted uranium excretion in the population whatsoever, which to me indicated that the people had a small continuous exposure after the war and that they didn't have a significant body burden of uranium; otherwise, it would have been excreted when I went back the second time.

I was asked in 2001 to write a review for The Lancet, which I did, on the toxicity of uranium. I was asked as a consultant, or asked basically as an agent provocateur, to sort of criticize evidence that was being provided to the Royal Society in their review of depleted uranium following the Iraq war, the Gulf wars.

I was a member of the U.K. Ministry of Defence depleted uranium research review group, and the IAEA asked me to go out on a field expedition to Iraq to look at the situation with regard to depleted uranium. That never came up, because the security position in Iraq was always such that the mission couldn't be undertaken.

In the context of this report, I was approached by Pierre Morisset and asked if I would be prepared to review the report. I agreed only too happily. I reviewed it. I made some comments, most of which were picked up. So as far as you're concerned, then, I have no problem agreeing with the conclusions of that report.

Thanks.

[The Vice-Chair, NDP, Peter Stoffer]

Mr. Priest, thank you very much for your presentation.

The format, sir, is that we go back and forth between parties for a variety of questions. They're normally five minutes each, but we certainly won't cut any of your response time.

Obviously, you're aware of translation services.

[Nicholas Priest]

That's happening now. I'm swapping from French to English.

[The Vice-Chair, NDP, Peter Stoffer]

I just have to ask a personal question. What is your favourite football club in England?

[Nicholas Priest]

The Tottenham Hotspur.

[The Vice-Chair, NDP, Peter Stoffer]

Yes. You're a good man; we're going to get along fine. There are not many Hotspur fans in the world. It's nice to see one. Thank you, sir.

We'll start with Mr. Sylvain Chicoine, for five minutes.

[Sylvain Chicoine, NDP, Châteauguay—Saint-Constant, QC]

Thank you, Mr. Chair.

Mr. Priest, thank you for joining us today and for sharing your comments with us.

In your presentation, you said that you analyzed or looked at the blood samples of British soldiers, I believe, and that you detected traces of depleted uranium. Could you give us a little more details about that? We have mostly heard about uranium in urine. We have not heard about blood samples.

Could you tell us a bit more about those two ways—blood and urine—of analyzing traces of uranium?

[Nicholas Priest]

Thank you very much for the question.

No, I didn't actually analyze blood samples. I analyzed urine samples.

There are several ways of doing this. The way most normally used in North America, both in Canada and in the United States, is to measure the amount of total uranium in the urine sample and then compare it with the background levels of uranium excretion in the population, which can vary quite a lot.

I didn't use that method. I used a method that was used in the U.K. when they looked at their own forces. What we do there is measure the ratio of certain uranium isotopes in the urine. If we see an isotope ratio is typical of natural uranium, then all the uranium in the sample is natural. As we see the ratio shift towards depleted uranium signature, we can say how much of the uranium in the sample was depleted uranium and actually work out the fraction that is excreted as DU.

That's a very sensitive method. I think Matthew Thirlwall and I were the first to use it, but it was subsequently picked up and used to analyze those people in the British armed forces who actually wanted uranium measurements. They were offered the opportunity, and a significant fraction didn't actually want to have their urine analyzed.

So it wasn't blood, it was urine. But we used isotopics to identify depleted uranium in urine, rather than total uranium.

[Sylvain Chicoine, NDP, Châteauguay—Saint-Constant, QC]

Thank you.

You have used sampling a lot and you have made a lot of observations. With the Germans, your observation was that they had eliminated it all. Have you seen any samples with traces of depleted uranium, the way you did with the British soldiers in the study you briefly talked about? What did you find? Finally, were there some traces of uranium or none at all?

[Nicholas Priest]

Firstly, the people whom we measured in Bosnia, Kosovo, and Serbia were members of the public. We collected urine samples, and we had urine samples from everybody, from babies all the way up to senior citizens.

The amount of total uranium excreted by the people in the area was not too dissimilar from the levels found excreted by people in Ontario, Canada.

The next thing we found was that a small fraction, somewhere between 10% and 20%, of the uranium they excreted was from depleted uranium. Now, that wasn't present in the water supply, but the water supply was discontinuous at that time. At the time, I think in Bosnia there were about three tonnes of depleted uranium used as munitions fired by Warthog aircraft, and in Kosovo about 10 tonnes were used. When this happens a small amount of the uranium is vaporized and that would have gone into the atmosphere.

So the question is not whether people were exposed to DU but how much exposure they had to it and whether or not it was significant.

Our conclusions were that the amounts were insignificant. But we saw that signature and we wondered where they were getting it from, and it was probably because they were drinking from the rainwater running off their roofs. Also, they probably preserved a lot of vegetables and things like that, which were possibly subject to having materials deposited on them. They stored these vegetables over the winter and they would still have been eating them the next year, which would have tiny trace amounts of DU on them.

When uranium enters the body, about 80% to 90% of what gets into the blood is very rapidly excreted. So what we were measuring was that fraction of the uranium that was rapidly excreted following its entry into the blood.

We went back two years later and measured some of the same individuals. We actually found the same individuals in Kosovo we had measured two years previously. They provided us with some more samples then and when we measured them we could find no trace of depleted uranium. So we think this was a transitory, low-level exposure subsequent to the conflict.

It's interesting that of the British veterans who came back from the Gulf War, there was no real indication of any significant intake of depleted uranium by them. I think there were hundreds of people measured, again using this isotopic method. It rather bears out our suggestion that it was coming from food and rainwater and things like that because, quite clearly, that wasn't the source of food and water for the British army. Even though they're quite badly off sometimes, I don't think they resorted to using rainwater and locally stored foods for feeding the army.

So I think that's a reasonable suggestion.

[The Vice-Chair, NDP, Peter Stoffer]

Thank you, Mr. Priest.

Now we'll go over to Mr. Hayes for five minutes, please.

[Bryan Hayes, Conservative, Sault Ste. Marie, ON]

Thank you, Mr. Chair.

Welcome, sir.

You've touched on your past research and it's significant. I'm just curious how your findings compare with other international research. Is there consistency across the board in the findings with respect to depleted uranium? Or are there areas of disagreement in any way, shape, or form?

[Nicolas Priest]

I don't think there are any areas of disagreement. Certainly people will interpret the same data in different ways. For instance, in the United States the army chose to just measure total uranium, except in the individuals who were caught in friendly-fire incidents. None of the military personnel showed uranium excretion levels falling outside the normal distribution of those within the population. That's reasonable because depleted uranium is less toxic than natural uranium. If somebody is excreting levels of total uranium that are within the normal band, then you haven't got any cause for concern. It suggests that even if they were excreting DU, the toxicity level would be lower than within that normal band.

I don't think there's any real disagreement. There was some disagreement at first about the use of isotopic methods. There were some early studies that were not very good because the method was being worked out. There was resistance from some sources because they thought that if we used these methods, then we might find things that we don't want to find. In the end, as I said, in the U.K. we do those isotopic measurements, and Americans do them as well. It makes sense.

[Bryan Hayes, Conservative, Sault Ste. Marie, ON]

As for your peer review of this particular report, you made some comments, most of which were picked up, you said, and that you agreed with the conclusions. Did you at any point, while reviewing that report, have to challenge its findings at all?

[Nicolas Priest]

No. What I was doing was trying to add context.

I put in some things like the sort of levels of uranium that are found in Ontario. Most people have quite a low level of uranium intake because they're drinking town water supplies, which are controlled. People on well water can have huge concentrations of uranium from that water. Normally, you might have, oh, I don't know, but say 5 micrograms per litre, or even less. You can then find wells where there's 800 micrograms per litre. In Bosnia we found some wells that were between 2,000 micrograms and 3,000 micrograms per litre. There's a huge variation in the amount of uranium taken up within the population. Almost everybody in Finland, for instance, drinks water with more uranium in it than the standard set by the World Health Organization. Again, it's a consequence of the local geology and the fact that water contains a lot of natural uranium.

[Bryan Hayes, Conservative, Sault Ste. Marie, ON]

How's my time, Mr. Chair? I'm still okay.

Could you explain what experience you were referring to when you wrote in a 2001 article titled “Toxicity of depleted uranium” the following:

experience supports the claim that health effects produced by the radioactive decay of depleted uranium in the body are extremely unlikely....

What experience was that?

[Nicholas Priest]

That's a quote from my Lancet paper. If we start off with the fact that depleted uranium, chemically speaking, has identical toxicity to natural uranium and that radiologically it's less toxic, because most of the more radioactive isotopes are reduced in the uranium, then we can go back and look at the experience within industry where people have been working with uranium for years.

There were two large studies, one conducted in the United States with about 20,000 people and one conducted in the U.K. with about 20,000 people. The one in the United States looked at cancer and the one in the U.K. looked at all causes of death. The conclusion of both was that they could find no evidence of any adverse effects in those populations, even though in the early days of the nuclear industry when most of the exposures occurred people just threw uranium yellow cake around without taking very many precautions. People sometimes wore dust masks, sometimes they didn't wear a dust mask. So there were considerable exposures in those days, but there's no indication of any toxicity within those groups.

One or two studies suggest there might be a link with lung cancer, but the suggestion is very weak, and lung cancer studies are notoriously difficult to interpret because you have to control for smoking, and unless you know exactly what the smoking habits were of every one of the subjects, it's difficult to interpret.

If it were a more radioactive form of uranium, the more toxic one, and you asked me what I would expect, I would tell you that when that uranium is breathed in, it is breathed in as particles and goes into the lungs. About one-third of it is exhaled with the next breath. Most of the remainder is deposited on the airways of the lungs, and about 6%, depending on the size, is deposited in the deep lung, meaning the respiratory sacs, the alveoli, of the lung.

That which is on the airways rapidly comes up and is swallowed. So there is a flow of mucous up the respiratory tract, but you swallow it. So within one or two days that would have cleared. Then you have 6% left behind in the lung and that gradually dissolves. It can take a long time to dissolve. More insoluble forms of uranium can take months or years to dissolve in the bottom lung. While it's there it irradiates the lung. So one risk that we would associate with a highly radioactive form of uranium, like uranium-233, which is an isotope, is lung cancer.

When it gets into the bloodstream, the vast majority of it is excreted. While it's being excreted, some of it gets hung up in the kidney for a while. So you get a radiation dose to the kidney and might expect to get kidney tumours.

The other thing is that because uranium behaves in the body like calcium, it goes into the skeleton and some of it is in the skeleton. There you might expect to find bone tumours.

So the three tumours that you would be looking for within a population exposed to uranium would be lung tumours, bone tumours, and renal tumours. And those are not found, as I said—with the possible exception of lung cancer, but with a very big uncertainty associated with that. Some studies suggest there's an excess, some suggest there's no excess, and it depends critically on whether there's any smoking.

[Bryan Hayes, Conservative, Sault Ste. Marie, ON]

Thank you.

Thanks, Mr. Chair.

[The Vice-Chair, NDP, Peter Stoffer]

Thank you, Mr. Hayes.

Now we go over to Mr. Casey, sir, for five minutes.

[Sean Casey, Liberal, Charlottetown, PE]

Thank you, Mr. Chairman.

Dr. Priest, I want to ask you, first of all, about a section in the report that talks about the experience of uranium miners and the fact that they have a high incidence of lung cancer. The conclusion drawn by the authors of the report is that the major contributing factor in this cohort is radon and not uranium. I'm sorry if this sounds like a stupid question, but I'm not a scientist. Can you explain the relationship between radon and uranium?

[Nicholas Priest]

Okay. Uranium is radioactive, which means that its nucleus is unstable and at some point, depending on how unstable it is, it will decay away to another nucleus that is smaller. It will lose some of the nucleus. Then if that's stable, fair enough. If that is radioactive, it will decay away to another material, and you go down through a chain. We call that a daughter chain. So you start with a parent radionuclide like uranium and you get a succession of radioactive decays all the way down—in the case of uranium—through radium. Then radium decays to radon. Then there are more alpha particles and more radiations, until you come down to lead. When it gets to lead, it's now stable and there's no further radioactivity.

Radon is a gas, and whereas the uranium stays in the rocky material, the radon diffuses out. In the early days when the mines were poorly ventilated the concentrations of radon in the mines in Canada and elsewhere in the world were really very high, so the lung doses from the inhaled radon were very high. The amounts of uranium these people inhaled were very small. The bigger problem was actually inhalation of silica.

So yes, in that case, if you work it out and do the dose symmetry, asking how much of the radiation is coming from the uranium and how much of it is coming from radon and the daughters of radon, you find the dose from uranium is minuscule compared with the dose from both normal radon, which comes from uranium, and another radon isotope that we call thoron, that comes from thorium, which is present in the uranium deposits. Those two, and their daughters, contribute 99.9% of the dose when you work it out.

[Sean Casey, Liberal, Charlottetown, PE]

So radon is decayed uranium.