Skip to playerSkip to main content
TV Hub
  • 2 days ago

Category

📺
TV
Transcript
00:00Tonight, Equinox reports on a startling discovery that has shaken the scientific establishment.
00:17For almost a century, it has struggled to understand the mysterious forces of nuclear
00:22radiation. Now, scientists working at the frontiers of knowledge have uncovered an
00:28unsuspected link between radiation and cancer, which could overturn fundamental assumptions
00:33about nuclear safety, and throw light on unsolved mysteries.
00:41Scientists don't know it all. Regulators don't know it all. We all do our best, but we don't
00:47know it all. And something comes along that upsets the apple cart, and in some areas it's
00:53back to square one. And this is true, I think, with alpha particles. We've got to go back
00:57right to the beginning and start analysing the effects of alpha particles on cells, as
01:04if nothing had been known.
01:13We live on a radioactive planet. As the industry likes to remind us, we are constantly exposed
01:19to natural radiation from Earth and sky. Cosmic rays from space. Radioactive elements like
01:26uranium in rocks and soil.
01:31But it's man-made radiation which strikes a chill. The fear of unknown forces.
01:39Inside a nuclear reactor, unstable atoms of uranium split apart. They give off huge amounts of energy,
01:47and turn into new radioactive chemicals, like plutonium. These elements are unstable.
01:54Their nuclei decay, spitting out radiation in different forms. Gamma rays, which are pure
02:00energy. Alpha and beta particles. Locked up in a reactor, that energy is harmless.
02:08But when radiation penetrates living tissue, it damages cells. It punches holes in chromosomes,
02:15which can kill the cell, or leave mutations, which may lead to cancer.
02:23That much we know from the atom bomb.
02:26A whole population was exposed to a single massive dose of radiation, and a time bomb was planted
02:44in the survivors. Their experience has become the benchmark for our beliefs about nuclear risk.
02:51Records of cancer deaths among survivors are used to fix safety levels, and to check scientific
02:57theories. To be accepted, any new theory must match Japan.
03:02First to be defeated by this benchmark, Dr. Alice Stewart, cast out of favour for proposing a link
03:09between childhood cancer and radiation.
03:11Up to that point, I'd actually been recognised as one of a group of people who would be invited
03:21to Medical Research Council committees. I'd done studies of tuberculosis, I'd done studies of
03:26things affecting children's growth, and other things. And was, if not a blue-eyed girl of the
03:33Medical Research Council, at least a respectable member. And you can now look at and see that from
03:38that date onwards, they never consulted me.
03:43Alice's undoing was the Oxford Survey. In the 50s, she carried out the first major study
03:48of childhood leukaemia. She gathered case notes on hundreds of sick children and compared them
03:54with healthy controls. Only one factor stood out, an event before birth.
04:03Leukaemia victims had received a radiation dose while still in the womb. Their mothers had been
04:08x-rayed while pregnant.
04:12I had many sleepless nights about this difference because, of course, it immediately suggested
04:16that a single x-ray could have a cancer effect, which, of course, was not thought of at the
04:22time. And, you know, people were saying, deserving of a Nobel Prize and that sort of thing. But
04:27very quickly, there was a reaction the other way.
04:32The case of bomb survivors contradicted the idea. There were many young victims. But babies
04:39born after the bomb didn't get leukaemia, though exposed to much higher doses of radiation in
04:44the womb.
04:47Well, that became a body blow to us because everybody had put great faith in the A-bomb
04:53survival study. And all my protestations to say, but surely you could only find us out if the
04:59mother had survived anyway. And, in fact, you could only find out if the mother and child
05:03had survived. And so, you have no idea what got buried in the rubble. However, nobody would
05:09allow that. And I think you could say that at that point people buried us. We were wrong.
05:17And in a radioactive world, it seems reasonable to assume that low-level radiation, like a
05:22single x-ray, must be low risk or we couldn't survive.
05:28We are constantly exposed to damage from low-dose radiation, like sunlight and cosmic rays, from
05:34conception to the grave. But most of the time, our bodies cope. Our cells have a natural repair
05:40mechanism, perhaps acquired through evolution.
05:46In 1984, another mystery that didn't seem to fit the facts. A television documentary announced
05:54an alarming discovery. An unexpectedly high number of childhood leukaemia victims in the
06:02village of Seascale, lying in the shadow of Sellafield. Incidence of leukaemia here is 10%
06:10times the national average.
06:16Ronald Marr became ill four years ago.
06:18Don't look at my hand. You're a cheater.
06:22I am.
06:25When we were going uptown with him, he was crying. My legs are tired, Mummy. My legs are sore.
06:30But you'd normally think that a child like that, they just want them carried. But it's got worse and
06:37worse. And it got to the point where he started to lose colour. He was going very, very pale.
06:42But he was whiter than white. And he couldn't move at all. And my doctor came and he says,
06:48I'm going to send him to a specialist I'm not happy with, Ronald.
06:52I won't.
06:54That was at 10 o'clock in the morning. And at quarter to eight that night, my specialist
06:59and doctor came out to tell me it was leukaemia.
07:04He's had to grow up in many ways for what he's suffered, the suffering he's gone through.
07:15And I find that very hard to accept. It's nearly four years now and he's holding his own.
07:23We feel that we're very, very lucky to still have Ronald. But we shouldn't have to feel that
07:29here. Ronald's dad started to work at Sellafield. And it just seems a coincidence that this has
07:47happened. He used to come home when he was contracting it, he was digging the foundations
07:51and that for the Thorpe site. He was covered from head to foot in like a brown dust. He was
07:57always fetching this dust into our house. They never got showered or anything there, so
08:02they weren't checked. So he came home in the clothes that he'd been working in. And the
08:08little and his babies do, they run to the daddy when they haven't seen them all day, cuddle
08:11his daddy, take it, get his daddy's cap off his head, put it on his hornhead. So it makes
08:17us wonder.
08:21When the government's Black Report confirmed the existence of a cancer cluster at C-scale,
08:27local campaigners did their own research.
08:29We went to churchyards. We went through the church registers. We asked in the villages what
08:35had happened. And we found more cases than had been actually mentioned in the Black Report.
08:42We found about ten. Since then, there have been about four or five cases of cancer in under-25s
08:51in C-scale. And along this stretch of coast, the incidence of childhood leukemia seems to
08:59be high. When you actually plot the cases on a map and you see that the majority of them
09:06are situated along the Irish Sea coast, it makes you wonder and makes you think, particularly
09:13as the Irish Sea is the most radioactively contaminated sea in the world.
09:23Stellarfield routinely discharges liquid radioactive waste into the Irish Sea under government license.
09:30Inevitably, some finds its way ashore, adding to pollution.
09:36This year, the company's own monitors reported contaminated seaweed along a two-mile stretch
09:41of beach, washed ashore from the mouths of waste pipes.
09:50Scientists and the industry maintain levels of such contamination are too low to pose a threat
09:54to public health. But radioactive discharges remain the focus for campaigners' protests.
10:01Janine is convinced her own family problems were linked to the beach.
10:08When my son was 12 years old, he got leukemia. And the question about the discharges from
10:15Sellafield made me feel guilty and look back at the times when he was a baby. We used to take
10:22him all along the beach. We used to take him to Drigg. We used to take him to Seascale. We used to wash
10:30him clean at the end of a day with some of the streams that ran through the dump carrying radioactivity.
10:37And I am sure that the radioactive discharges from Sellafield, which at the time were about a hundred times
10:46of what they are now, will have something to do with his illness. And also talking to other parents,
10:52I think one of the things we have in common, that we all took our children to the beach one way
10:59or the other.
11:00A second cancer cluster was found at Doon Ray in Scotland. Childhood leukemia here is six
11:07times the national average. Like Sellafield, it's a plant where plutonium is handled. And from
11:15America, an independent report. Dr. Lowell Seaver investigated the Hanford plant, where plutonium
11:22is produced for the U.S. military. He found a raised incidence of congenital defects in babies
11:28of workers and of people living around the plant. A link with Hanford was thought unlikely. Such birth defects were not seen in Japan. At Sellafield, a similar study was found.
11:37But such observations only deepen the mystery. Scientists maintain that radiation levels around these plants would be too low to account for them. There is no obvious link.
12:00But two years ago, a new report set alarm bells ringing.
12:21Workers attended special meetings today called to discuss the possible link between the plant and child leukemia. As they took their places, British
12:28nuclear fuels revealed young family men were being moved away from high radiation areas at what it called a very rapid rate. At the same time, the company admitted that men very concerned about the report's findings should even consider not having children at all.
12:42Now, if somebody is that worried, then it may be that the proper advice is that if you are that worried that you don't have a family. But as I say, it's the individual thing we would want the individual doctor in the confidence of the consulting room to be able to discuss the worries of the individual.
13:00A clue had a clue. A clue had been found in the village of Seascale. Professor Martin Gardner had found four leukemia victims whose fathers all worked at the plant. He believed the father's sperm had been damaged by high doses of radiation before conception.
13:19Genetic mutations transferred to the embryo could have sown seeds for later illness, though the men themselves were not affected. But again, the idea didn't meet the benchmark. Children of fathers exposed to the bomb showed no evidence of this effect.
13:36From our present understanding of radiation risk, there shouldn't really be any groups of the population in Britain who are exposed to enough radiation from any source to produce marked increases in cancer of any sort.
13:50So if our present understanding remains correct, then reported clusters of leukemia or other diseases should not have been attributable to radiation, and indeed they may not be. But if they were to be due to radiation, that implies some gap in their understanding.
14:07There is a factor that's been overlooked. A type of radiation, alpha particles, to which bomb survivors were not exposed.
14:15They're given off by natural elements like uranium, or man-made material like plutonium.
14:24The range of an alpha particle is tiny. They're stopped by the skin. Other forms of radiation pass right through us.
14:32It takes thick lead or concrete to stop gamma rays, so they seem more dangerous.
14:38But radioactive materials can be swallowed or inhaled, and inside the body it's a different story.
14:46Gamma rays spread out, delivering a little knock to every cell of exposed tissue.
14:52At low doses, it will probably be repaired.
14:56Alpha particles are like high-energy bullets. They follow a single short track, damaging only two or three cells.
15:06But they punch out huge chunks of DNA. This damage cannot be repaired, and probably kills the cell.
15:15The lethal properties of alpha particles are well known to uranium miners. They breathe in radioactive dust and get lung cancer.
15:32In East Germany, deaths among uranium miners exceed deaths from the atom bomb.
15:42But miners are exposed to high doses.
15:46At low doses, alpha particles have never been seen as a hazard. They kill a few cells, which are soon replaced.
15:54It was thought for a very long time that if an alpha particle went through a cell, it would kill the cell.
16:01And if the cell is dead, it's of no great interest from the point of view of causing cancer or causing genetic disease.
16:08And a very few people have studied this area.
16:13But among those who have, they're beginning in the last few years to turn up results which show that our previous views were wrong.
16:21Among the first to challenge the dogma, Bristol scientist, Dr. Dennis Henshaw.
16:32He heard that a type of plastic, CR 39, used for making lenses, could detect alpha particles.
16:40He tried it out with an alpha source.
16:42Bombarding alphas hit the plastic, etching microscopic tracks.
16:48Through the microscope, these tracks show up as small black dots.
16:55To his surprise, he found that the lens was picking up alpha particles, not just from the source, but from the air around.
17:03When we processed the plastic, we found tracks of alpha particles all over the plastic, in places where we hadn't put the source.
17:18At first, it was a mystery as to where these particles came from.
17:23Until it dawned on us, what we were actually seeing was the natural background alpha radioactivity in the air from radon.
17:29Radon is everywhere, in rocks and soil.
17:34It's produced when uranium decays.
17:37Till then, it had scarcely been detectable at indoor levels.
17:41And it wasn't seen as a hazard in the home.
17:44Right, what we're going to do today is we're going to make a device which will measure the radon in your house.
17:50Because radon is a gas, a very natural gas, that appears inside the house.
17:54And we need to measure it because it has a possible link with cancers.
18:01We're not quite sure about that.
18:03And the device we're going to use today is a yogurt pot, a piece of blue tack, some elastic bands, and most important of all is a piece of plastic.
18:12This one has actually been made up.
18:14But this piece of plastic will detect the radon gas that's in your home.
18:19I'll give you a diagram of what it's like.
18:23Here you have the yogurt pot, a piece of blue tack at the bottom, the test track mounted on the top, some cling film...
18:30With a local teacher, Henshaw turned school children throughout Britain into radon detectives.
18:37The little plastic squares were simple to use.
18:40They measured radon levels all over Britain.
18:42Paul, you want to dig a nice round hole, OK?
18:50Yeah, you want to make sure it fits in perfectly, upside down.
18:54That's lovely.
18:56There were methods of measuring radon before, using other types of solid-state detectors.
19:00They were less reliable than CR-39 and using electronic methods.
19:04But of course electronic methods were very cumbersome, very expensive.
19:07What you have in CR-39 is a very simple method which can be used for mass surveys of radon in the home.
19:14Some of their results were surprisingly high, though the plastic picked up a range of levels.
19:22That looks quite a low one.
19:2530.
19:2730? So how much radon is that?
19:2930...
19:31Becquerels per cubic metre of radon. That's very low, isn't it?
19:33Yeah.
19:34Yeah, so whereabouts in your house would you put it?
19:35In my bedroom.
19:37In your bedroom.
19:38Oh, yes, OK.
19:40Paul, let's have a look at yours.
19:51Oh, that's really interesting.
19:54That's really very high, isn't it, Paul?
19:56Yeah.
19:57It takes quite a long time to count those, doesn't it?
19:59Yep.
20:00How many do you think there are, approximately?
20:03About 300.
20:04About 300.
20:05About 300.
20:06So how much radon would that be?
20:07300 becquerels per cubic metre.
20:09Oh, right.
20:10Well, whereabouts in your house did you leave that?
20:11In the cellar.
20:12Oh, in the cellar.
20:13Oh, just in the main living area, in the cellar.
20:15That's interesting.
20:17So, could radon be dangerous at the levels they were finding in the home?
20:22Henshaw began the grisly task of checking if the plastic detectors could pick up alpha
20:27tracks in the body using post-mortem samples.
20:30Links with lung cancer were suspected, but Henshaw believed, controversially, that other organs might be affected.
20:40When you inhale radon, it diffuses throughout the body and affects all of the organs.
20:45So just because the lung gets a very high dose from radon, it doesn't mean you shouldn't consider where else in the body that radon should go.
20:52So that's really what we set about doing, looking at organs other than the lung.
20:57Could radon get into bones and irradiate bone marrow?
21:02It was thought unlikely, because the range of an alpha particle is so short.
21:07But radon is a gas.
21:09It dissolves in marrow fat, which soaks it up like a sponge.
21:16Henshaw's plastic detected the improbable.
21:19Alpha tracks in sensitive bone marrow.
21:22Well, having realised that radon can actually reach the bone marrow, we then thought, well, what effect does this have?
21:31And, of course, the obvious question was, is radon exposure at all linked to leukaemia incidents?
21:36So what we did was to look for a link between radon exposure in the home and the incidence of leukaemia in the general population.
21:44And, to our surprise, we found just such a link.
21:48OK.
21:49Henshaw claims that raised levels of certain cancers are found in high radon areas, though cause and effect aren't proved.
21:58All we can say is that there are some very intriguing associations, correlations, between radon exposure in the home and incidence of these diseases,
22:07especially leukaemia, but also melanoma.
22:10Now, of course, we need far more detailed epidemiological studies to show whether those links are real.
22:22The idea is controversial, but Henshaw found further evidence in a Somerset beauty spot.
22:28His school children had found a radon hotspot in the little town of Street.
22:35It has all to do with a school, actually, a little school up the road, with little pots that about 100, I think, pupils took home.
22:47And then Dr Henshaw wrote to everyone round this area, you know, and the results, what we had, came out fairly high.
22:54It varies from house to house. It's not something that is in every house, I don't think, you know.
23:01I mean, it could be in yours, and next door it could be completely the opposite, you know.
23:07Was there any effect on high radon households? And if so, could it be detected?
23:13Blood samples from local people were sent for analysis.
23:16It seemed unlikely that even these doses would be high enough to cause mutations.
23:23More likely, the result would be a few dead cells, and they're easily replaced.
23:28But the Sussex team used a special test for detecting abnormalities.
23:34The mutations that we look for are, in themselves, unimportant.
23:39They're harmless, and we've all got some of them.
23:41But they indicate, if you have an excess of them, that you may have been exposed to something nasty.
23:50And much to our surprise, we did find, apparently, that there were more of this particular type of mutant in blood cells,
24:00of people living in houses with high radon levels, than in those who are living in houses with low radon levels.
24:06And this surprised us, because we didn't think that the radon levels would be high enough, by a long way, to produce any effect that we could detect.
24:18They're rechecking the experiment.
24:21But it could suggest that low-dose alphas might have harmful effects, which research, till now, has failed to spot.
24:28If our results are confirmed, then it would indicate that there is some substance to these ideas, that alpha particles at low doses may be doing things which we've been missing with other previous experiments, because of the way those experiments were done.
24:46An area of research has been opened up, which could have far-reaching implications.
24:53And this year, the dogma that low-level alphas are safe, has been shattered, in the Temple of Nuclear Science at Harwell.
25:01The mystery of the cancer clusters and the unexpected radon findings suggested a gap in our knowledge of low-level radiation.
25:19Harwell scientists were looking for some new and unexpected mechanism to explain these paradoxes.
25:25Dudley Goodhead and Eric Wright set up an unusual experiment to produce leukaemia in a test tube with the lowest possible dose of radiation.
25:36They bombarded mouse cells with alpha particles from a thin plutonium disc.
25:42They arranged the experiment so that each cell was hit by at most one or two alpha particles.
25:48Their chosen targets, stem cells, primitive cells in the bone marrow from which all types of blood cell are made.
26:01It's suspected that these are the vulnerable cells in leukaemia.
26:13Dr Eric Wright describes what happened.
26:15What we're talking about are just one or two tracks of radiation going through these cells.
26:24And only 10 or 20% of the cells were able to survive that.
26:28Now, those that did, when we took them out and put them into our specialised culture conditions, behaved perfectly normally.
26:36They divided, they grew normally, they looked normal.
26:40So a few cells did survive, and they seemed at first unharmed.
26:46They continued to divide.
26:48And chromosomes in the daughter cells at first looked normal.
26:56But after several divisions, something extraordinary began to happen.
27:00Cropping up randomly from time to time, they saw mutations.
27:04The parent cells were transmitting a kind of instability to daughter cells, not seen with other types of radiation.
27:14Bits of DNA were missing.
27:17Fragments swapped over.
27:19It seemed scarcely credible to the Harwell team.
27:21Our own data, staring us in the face, said just a single track of irradiation through one stem cell would allow that cell to transmit to its offspring abnormalities.
27:38You could think of our findings as being a sort of amplification process, that you put damage into one stem cell, it produces two, four stem cells.
27:51And now all those stem cells have that latent damage in them.
27:55So here was a mechanism whereby you could start thinking about how the very lowest doses of irradiation could actually transmit down into the blood-forming system.
28:05It was only found in low-dose alphas, overturning beliefs about radiation.
28:12It had been assumed that alpha particle radiations cause cell death.
28:18And that even the passage of just a few alpha particles through a cell nucleus would kill the cell.
28:24And even with one particle passing through a cell, there would be a certain number of those cells would be killed.
28:30The finding that it didn't, that the cell still had the capacity to reproduce but did not show any apparent abnormality until quite a large number of generations later.
28:45That was quite unexpected.
28:46And the fact that it was only observed with alpha particles and not observed with extra gamma radiation only deepened the mystery.
28:53It shows almost for the first time that there may be a real difference between different sorts of radiation, which in the past we had thought of as acting rather similarly.
29:03Although one being more efficient than the other in causing a biological effect.
29:08But now it seems it may not just be a matter of efficiency, it may be a real qualitative difference between what they do.
29:14A chasm of uncertainty opens up, for the survivors of the atom bomb were not exposed to alpha particles.
29:22The benchmark fails if the mouse result proves true for humans.
29:28These experiments are just beginning.
29:31Whilst it's clearly far too early to make any definitive statements, there is no doubt that abnormalities can be produced in human stem cell colonies.
29:44So the prediction would be that a similar phenomenon may be present in human marrow.
29:53He believes it would be a rare effect.
29:56But if there is a link between radon and leukemia, this could explain it.
30:01And stem cells are found in other parts of the body, which could also be vulnerable, whenever cells are constantly renewed.
30:07Your skin is continuously being sloughed off, it's produced from skin stem cells essentially.
30:17In your gastrointestinal tract, your gut, then the cells are continuously being eroded away and they're produced by essentially gut stem cells.
30:29In sperm production, the sperm are all derived from sperm stem cells.
30:34So that there are remarkable similarities in the biology of the different tissues of the body.
30:43Might this explain Martin Gardner's idea that a radiation dose to the father's sperm before conception could sow seeds for leukemia in a few unborn children?
30:57Wright cautiously suggests it might.
31:00You could argue that instability in the sperm stem cells could be transmitted eventually through to the embryo,
31:09which could then of course give rise to all sorts of problems.
31:13Are nuclear workers exposed to alpha particles?
31:19Only in plants like Sellafield and Dunray where plutonium is handled.
31:23There, there might be some risk.
31:26Two and a half thousand men routinely work where contamination is possible.
31:31The risk of such alpha effects would be low.
31:34But chronic exposure to low doses might raise the chances.
31:37How are they protected?
31:40Well, the first thing is have your plants properly designed so that the material doesn't get out into the working environment.
31:46But of course a lot of our plants are hands-on and therefore there is in various parts of the plant risks of small spreads of contamination.
31:54And in those places we have additional precautions.
31:55We make sure that the people who are working there are wearing clothing that we provide and we launder.
32:02And that the areas are properly monitored.
32:04That when those people go home they go through checks to make sure they don't carry any material outside of their working space.
32:11And we find it very effective.
32:12This is the kind of situation where exposure could occur.
32:18He's testing a sample of liquid from the waste plant.
32:24It's contaminated with plutonium.
32:29The container could break or his gloves might tear.
32:33At the end of the job an elaborate procedure checks there's no contamination on clothes or skin.
32:50But the real danger would be from inhalation once his mask is removed.
32:55Plutonium leaks do occur.
32:58Because of this risk the air in the plant is monitored throughout by state-of-the-art detectors, Harwell designed.
33:08A plastic filter picks up alpha particles.
33:11If levels rise too high an alarm is sounded.
33:17A leak would be spotted instantly and the area cleared.
33:21But there is always some low-level contamination in the air which workers could breathe in.
33:27Each wears his own portable detector.
33:30It's supposed to sample the air he breathes though it's worn on the shoulder.
33:34At the end of the shift these personal air samplers are handed in and checked for alpha particles.
33:41If they think he's above the limit he gives a sample of urine and faeces.
33:46From that they work out how much he's absorbed.
33:49How is this calculated?
33:50All this is based on a thing called a standard man.
33:54A rather odd shaped person really.
33:57With peculiar sized organs here and there.
33:59But it best represents a human being.
34:02And if this standard man breathes material then he will excrete at a certain rate.
34:07By knowing what is excreted by a person you can make an assumption as to what was in the man.
34:11Now clearly we're not all the same and we're not all like standard man thank goodness for some parts of his anatomy.
34:17And therefore we have to make some corrections for the individual concern.
34:21Is he a big person, is he a small person and so on.
34:24It's strictly within the letter of the law according to health and safety requirements.
34:29But how effective is this protection?
34:32How accurate are the estimates of internal dose?
34:34And how secure is the assumption that this procedure protects the worker?
34:40What is important really is whereabouts those alpha particles actually are.
34:46And what biological damage they're doing.
34:49And I think Eric Wright's work for example shows that there's still an awful lot we don't know about that.
34:54There's still quite a lot we don't know about where plutonium goes in the body.
34:59I don't think for example there is very much information on how much plutonium goes into the testicles.
35:07And that could be quite important from the point of view of causing damage to sperm cells.
35:18Behind the security fence of the government's hush-hush research laboratories at Harwell.
35:22Bizarre experiments are being carried out to try and answer the question.
35:27Where exactly does plutonium end up in the body?
35:35In charge of Harwell's alpha research is Dr. Nick Priest.
35:41He's injecting volunteer scientists with a safe form of plutonium.
35:45A post-Cold War gift from Russia.
35:47It doesn't emit alphas, only low-level gamma rays.
35:52Enough to track where it goes in the body.
35:58Wherever it lodges it will remain for years.
36:01Ticking away, giving off alphas which affect just a few surrounding cells.
36:06Till now most knowledge has been based on a dubious experiment with human guinea pigs.
36:11About 20 people in the United States who were terminally ill were injected with a microcurie of plutonium.
36:22I think without their knowledge.
36:24The value of the data, though it's been extensively used for a number of years,
36:29is actually questionable because many of these people didn't have livers
36:33and they didn't have proper guts and their kidneys weren't working properly or they had diseases.
36:41And so it's questionable about whether the results are useful
36:45and whether plutonium really behaves in normal people like this.
36:49But so far Priest's experiment does confirm what had been assumed.
36:53Most plutonium goes to liver and bone.
36:58But a small amount, less than 1%, does go to the testes.
37:02So it could target vulnerable stem cells which make sperm.
37:07At these very low doses, chromosome instability could result.
37:11But so little is known about alpha emitters.
37:20Where they end up in the body could be affected by whether or not you smoke.
37:28In this experiment, a volunteer has been asked to breathe a mixture of tobacco smoke
37:33and a natural radioactive gas.
37:34As the industry points out, plutonium is not the only alpha emitter to which workers are exposed.
37:45They receive much higher doses from natural radon.
37:52But radon is very different from plutonium.
37:57Radon is chemically inert so that when it goes into the body
38:01then it will tend to dissolve in tissue fluids.
38:05But it won't bind to them.
38:07Plutonium is far from being chemically inert.
38:11It's chemically very active so it binds very readily to components of tissues.
38:17Plutonium is very long-lived.
38:20It has a half-life of tens of thousands of years.
38:25Radon has a short half-life of only three to four days.
38:31So in many, many respects they're completely different.
38:35You couldn't have two substances which are more different.
38:38But in the important respect that they both give alpha radiation doses to tissues, they're very similar.
38:46So though the industry rightly maintains that the biggest dose of alpha radiation is from natural radon,
38:53plutonium adds a dangerous component.
38:56Are the public at risk from cellarfield discharges as campaigners insist?
39:03Anxieties have been raised along the northwest coast where radioactive hotspots have been found.
39:08In the 70s, BNFL dumped plutonium waste in the Irish Sea, believing it would stick to sediment.
39:17In fact, it's whipped up by currents and brought ashore.
39:21There's a swathe of alpha contamination from Lancashire to Scotland.
39:25Over the years, cellarfield has discharged about half a ton of plutonium into the sea.
39:33It's been shown, it's proved that it's coming back in land, and we actually find it in the estuary here.
39:39We've had the mud analysed by independent analysts, and the content of alpha radiation in the mud samples was something like 28,000 becquerels per kilogram.
39:58It's a level far beyond which would be allowed inside cellarfield.
40:04I think the equivalent is about 370 becquerels.
40:08The worrying thing is that once this mud dries out, the possibility of inhaling or ingesting plutonium is there.
40:18Plutonium is found in house dust, and I feel that a lot of research needs to be done into that,
40:25and the pathways and the dose that people will receive, in particular with children in mind who are so much more susceptible to radiation on adults.
40:38Raised incidence of leukaemia has been found round estuaries, but there's no proof it's linked with plutonium.
40:47And alpha particles have such a short range, it's hard to believe the public are at risk from breathing it in.
40:55So does cellarfield plutonium get into people?
40:59Harwell's Nick Priest has investigated.
41:02Now you might be surprised to think that there was plutonium in people, but it's there in everybody.
41:10Every time you breathe, you will breathe in a small, very small quantity, just a few atoms of plutonium.
41:15And that comes from two main sources.
41:25The first source, and the most important source, is from fallout.
41:30When the weapons were exploded, mostly in the 60s, in the atmosphere, then small quantities of plutonium were released into the atmosphere.
41:38These have gradually come down to earth over a long period of time.
41:43Some of these have been inhaled and resulted in really very tiny amounts ending up in people.
41:49The other source, obviously, in the United Kingdom is the operation of the nuclear cycle.
41:55The operations at British nuclear fuels have inevitably resulted in the release of some plutonium to the environment.
42:02And obviously, if it's in the environment, then it can get back into people.
42:07Again, the levels are incredibly low.
42:12But how much plutonium gets into C-scale residents?
42:19Post-mortem bone samples in Cumbria did show raised levels of plutonium.
42:23But no tests had been done on living people.
42:29Priest got help from radon expert Dennis Henshaw.
42:33He tested samples from Henshaw's deep freeze, collected for Bristol's own alpha research.
42:44One part of the skeleton is actually very accessible, and it's your teeth.
42:47And they're just like any other part of the skeleton.
42:52They get a blood supply.
42:53They've got surfaces.
42:55And when plutonium enters the body, then as it deposits in the skeleton, it deposits in the teeth as well.
43:02These are some of the results.
43:04We can see that there certainly is a higher level of plutonium in the teeth of children living in the coastal strip by the cellophil plant.
43:15However, surprisingly, we found that the highest levels weren't there at all.
43:20But we found very high levels in the Forth Valley, and we found very high levels elsewhere in the UK.
43:26So that's actually quite interesting, because it's indicating that despite these discharges into the environment,
43:32the consequences to individuals living in the area are perhaps much lower than people might have expected.
43:40The plutonium hotspots he found are in areas of high rainfall.
43:46It could be fallout from 60s bomb tests.
43:50But what gets into people from Sellafield may be more dangerous, even at low doses, because it isn't pure plutonium.
43:57All elements that are released into the environment are released in some chemical form, and then they undergo a whole lot of chemical reactions.
44:07They go into sea water, they are released together with other chemicals with which they may react.
44:11They are eaten by cows, they are eaten by fish, they are eaten by human beings.
44:16There are thousands of chemical reactions involved in all these processes.
44:20And as a consequence of that, we can't even begin to list all the chemical compounds which might be formed.
44:25And it may be just by bad luck you get some compounds formed in the environment which give you a tissue distribution different from what you think.
44:35Where these invisible compounds end up in our bodies isn't known.
44:40If they target vulnerable stem cells, even low doses could be doing us harm.
44:44Many uncertainties, many unknowns.
44:55The mystery of the cancer clusters has cast a blight on this beautiful coastline.
45:01The fear is that low level radiation may interact with other agents, chemical pollutants or viruses.
45:08These are complex new pathways for science to consider, and the contamination is out.
45:18The NFL claim they care about the environment, and now they're cleaning up their act.
45:24200 million pounds and 10 years work have been lavished on this new plant, codenamed ERP.
45:30It will remove almost every trace of alphas from liquid waste discharged into the Irish Sea.
45:36Under metres of gleaming metal and concrete, the alpha contaminants will be absorbed into a solid flock, packed into concrete and stored.
45:47The process within ERP is new, not only for BNFL, but for the whole of the nuclear industry.
45:53Although the filtration technology we use is actually used in the food industry.
45:58In champagne, cleaning plants, and in the cheese industry, for example.
46:02But just how pure will this effluent be?
46:06It won't be quite drinkable, but the analysts who have to deal with the ERP effluent have had to devise new techniques and new methods of counting,
46:15because the levels are so low that their current equipment can't manage the job.
46:19The plant is designed to be hands-off and maintenance-free, controlled by computer.
46:26It's part of the industry's drive to cut doses to workers.
46:30Learning the skills required to run a nuclear plant, a fitters mate and a laundry worker.
46:36But automation has its disadvantages.
46:41One of the dangers with computer control systems is, of course, that it becomes a bit like a computer game.
46:48And the operators have got to be continuously reminded that there is a real plant out there,
46:53and that they have to be responsible in what they do.
46:55So we have to have a balance between them sitting here working at the VDUs,
47:00and also going out onto the plant and undertaking, for example, sampling operations,
47:05where they get an appreciation of what they're dealing with.
47:08Would it be possible to design the plant so that workers would never be exposed to plutonium,
47:14or to alpha radiation from man-made sources?
47:16I doubt it, but it's just a matter of amounts.
47:21The amounts of people breathing here are extremely small already,
47:26and have quite no radiological significance.
47:29And therefore, to say, well, shouldn't it be 100 times less?
47:32Well, the answer, yes, you could design a plant like that,
47:35but it would simply cost you an awful lot more. And for what benefit?
47:38BNFL felt unable to comment on the Harwell work because of ongoing legal proceedings.
47:44But already, scientists have found that another form of radiation may have the same low-level risk.
47:52Neutrons, to which workers throughout the industry may be exposed.
47:57Ideas about nuclear protection could be turned upside down.
48:02The National Radiological Protection Board advises the government on nuclear safety.
48:08Their advice to public and industry is to keep annual doses as low as possible.
48:14But the concept of a single radiation dose could be put in question.
48:19It's worked out by adding up doses from all the sources to which we're exposed.
48:25Natural radon, X-rays, cosmic rays, and so on, with a small contribution from the industry.
48:32But if different types of radiation do different damage, as Eric Wright suggests,
48:37to combine them in a single dose could underestimate the risk.
48:41If it's for real, then I think it means we need to think about separately recording the doses which people receive,
48:51either in the environment or if they're working in industry, from alpha particles, neutrons, and gamma rays.
48:57And at present, that isn't routinely done in all cases.
49:01These doses may be added together, admittedly, in rather complicated ways to try and take allowance for the different biological effects.
49:08But I think that if you have different kinds of biological effects, qualitatively, coming from alpha particles, neutrons, and gamma rays,
49:17then you need to have at least three different sorts of recorded dose.
49:21And perhaps even that's not the end of the story.
49:23Maybe you have to regard radiation as not one carcinogen but many.
49:26And that these many carcinogens have their own properties which have to be independently researched and quantified.
49:32For 40 years, we've based our beliefs about nuclear risk on Japanese bomb survivors.
49:44Now, new research could threaten those beliefs.
49:49For the experiment at Harwell shows that alpha radiation may be linked to cancer at levels we believed were safe.
49:58It's still only in mice, but if it's confirmed in humans, the result would show how there could be a link between radon and leukemia,
50:08though numbers affected would be small.
50:11If there is a link, it would need chronic exposure, and we can prevent that by protecting our homes from radon.
50:19If the work is confirmed, it would also show how low doses of alpha radiation might lead to leukemia in the children of workers handling plutonium, in rare cases.
50:31The alpha link has still to be established, but Eric Wright has opened a Pandora's box.
50:38What nuclear science believed was safe now looks uncertain.
50:45What dark secrets of radiation are still to be revealed?
50:50What dark secrets of radiation can be found to be done in the world so that the media's found that it was safe.
50:59To be able to guti-pulling in the world, it was the most important thing in the world.
51:02The type of radiation can be struck by the Admiral and the Americanah's box.
Be the first to comment
Add your comment