Safe Levels of Radiation
In continuing this line of thought about whether or not any increase in radiation is safe I will quote from articles by Dr. Aaron Oakley, a popular writer on nuclear energy, who gives permission to reproduce his articles.
Exploding Nuclear Myths Part 1 – “No safe level of radiation”
By *Dr Aaron Oakley New Australian No. 136, 4 -10 October 1999
An important characteristic of activists is that they are prepared to use any argument – true, half-true or false – to support their ideological agenda. Hence truth plays second fiddle to expediency. This article examines a canard popular with anti-nuclear activists – that there is no level of radiation which is safe. This myth will be exposed along with certain activists who have repeated it. since 1959, the International Commission on Radiological Protection (ICRP) has dictated that regulations be based on the assumption that the effects of low doses of radiation may be derived by linear extrapolation from the effects of high doses (this is called the linear hypothesis). For example, 10,000 mSv of radiation (a very high dose!) would be expected to kill those exposed within hours, and by assuming a linear relationship, we would expect that a dose of 1 mSv would kill 1 in 10,000 people. The fact that we are not dropping like flies (background radiation averages about 2.4 mSv/year globally) immediately brings the hypothesis into question.
Since high doses of radiation have a deleterious effect on health, authorities have assumed that there is no safe dose, and regulations required the minimisation of all radiation exposure. This policy position does not reflect the scientific knowledge of the biological effects of low-dose radiation. As radiation science has advanced, it became apparent that the situation of health and radiation was not so clear-cut. Furthermore, the evidence that low dose radiation may be beneficial for health has been accumulating for over half a century. This effect is called hormesis. Even in the early days of the Manhattan project, there was evidence to suggest that certain doses of radiation could be beneficial to health: Experiments conducted in 1943 involved the exposure by inhalation of animals to uranium dust in the expectation that it would be deadly. Surprisingly, the exposed animals appeared healthier, lived longer, and produced more offspring than their non-exposed counterparts. These results were confirmed by subsequent research.
The graph on the right shows the effects expected from the two main models of the effect of radiation exposure. The linear hypothesis predicts negative effects of radiation at high and low doses, with toxic effects increasing with increased dose. With hormesis, beneficial effects are expected at low dose, but with toxic effects at higher dose. Since the Manhattan project, numerous research papers have produced convincing evidence for radiation hormesis. In 1994 the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) published a report on the stimulating and adaptive effects of low-dose radiation. It reported that in mammals, radiation hormesis manifests itself as enhanced defence reactions against infectious disease, increased longevity and improved fertility. Yet despite the growing evidence for hormesis, the ICRP continued to lower the limits for acceptable radiation exposure.
We should also consider the effects of living with radiation: Different regions of the world have different levels of background radiation. The global average background radiation level is 2.4 mSv/year, but can be as high as 240 mSv/year. Epidemiological studies involving large cohorts show that higher levels of background radiation provide further evidence for radiation hormesis. The graph shows the effects expected from the two main models of the effect of radiation exposure. The linear hypothesis predicts negative effects of radiation at high and low doses, with toxic effects increasing with increased dose. With hormesis, beneficial effects are expected at low dose, but with toxic effects at higher dose.
Between 1970 and 1986, people living in Yangjiang county in china (background radiation 5.5 mSv/year) were compared with people living in two adjacent low-background counties, Enping and Taishan (background radiation 2.1 mSv/year). (The cohorts were large: 74,000 people from Yangjiang and 77,000 from Enping and Taishan.) The data show that in an age group of 10 to 79 years, the general cancer mortality was 14.6 per cent less in Yangjiang compared with Enping and Taishan. Furthermore, the leukemia mortality was 16 per cent lower in men and 60 per cent lower in women from Yangjiang.
Results similar to the Yangjiang study have been obtained in France, Japan and elsewhere. Yet radiation regulatory authorities continue to assume that no level of radiation is safe…as have anti-nuclear activists. As we have seen, there is much evidence to show that low-does radiation is not only not harmful but may be beneficial. But still the myth that there is no safe dose of radiation is trotted out mindlessly. The myth has been repeated by the Australian Konservation Foundation, as previously documented. This non-fact has also been repeated by green politicians such as Western Australian MP Giz Watson. A further example is Gavin Mudd, who in the September issue of Australasian Science claimed that “New scientific evidence suggests that exposure to low levels of ionising nuclear radiation increases cancer risk”. It is a pity that no reference was given to support that claim, given the large body of contradictory evidence. Mudd also claimed that increases in background radiation have been linked to increases in cancer rates in areas such as Chernobyl in the Ukraine, Sellafield in the UK and Three Mile Island in the USA. Let us examine the facts.
In the case of Chernobyl, 31 people were killed in the immediate aftermath (29 were fire-fighters). Most of the deaths were due to burns, but a few were (not surprisingly) due to extreme radiation doses. Workers and others exposed to high radiation doses of radiation have also died since. A conference of experts sponsored by the World Health Organisation after the accident speculated that some 1,600 additional deaths by cancer induced by increases in background radiation might occur in Europe over the three decades following the accident (higher figures have also been bandied about). However, in making these estimates, the conference used the already suspect linear hypothesis. Even if we consider this estimate to be accurate, it is important to put it in perspective by noting that the expected cancer deaths (from other causes) in the population now alive in Europe is 120 million over that time-frame.
In what is probably the largest and most systematic study of the health effects of Chernobyl accident, the International Atomic Energy Agency, studying people living beyond the 18 mile “prohibition zone” around the accident site found “no health disorders that could be attributed directly to radiation exposure”. Earlier speculations of increased numbers of leukaemia and other cancers did not eventuate. They further concluded that “any increases over the natural rate incidence of cancer or hereditary effects would be difficult to discern, even with larger and well designed long-term epidemiological studies”. The agency did acknowledge the possibility of a statistically detectable increase in the number of thyroid cancers. (This is because the thyroid gland concentrates a radioisotope of iodine released in the accident). There have been about 800 cases of thyroid cancer in children, most of which were curable, though about ten have been fatal. It is note worth that the risk of thyroid cancer could have been avoided if simple prophylactic measures such as the distribution of potassium iodide tablets had been taken.
In the case of the British Nuclear Fuels plant in Sellafield UK, it is indeed mischievous to claim that increases in background radiation have lead to an increase in cancer rates. Studies of all 14,282 workers in the plant revealed that cancer rates were 4 per cent less than that of England and Wales, and was the same as that of the district of Cumbria where the plant is located. Many scare stories about Sellafield derive from epidemiological data suggesting that there was an increased risk of childhood leukaemia in the children of the Sellafield workforce. However, follow-up investigation revealed that this risk is inconsistent with other epidemiological data and experimental data. Thus, it is unlikely that the association observed in the children of the Sellafield workforce represents a causal relationship and that other factors may be to blame.
With regard to the Three Mile Island (TMI) accident, the death-toll currently stands at zero and is not expected to rise dramatically any time soon. There is no evidence of an increase in cancer rates in areas affected by the accident. To put things in perspective, health physicists have calculated that the number of premature deaths due to cancer within a 50-mile radius of the TMI plant to be about one. And this estimate is based on the questionable linear hypothesis! This is in comparison to the approximately 30,000 premature deaths to be expected in the same area over the same time-frame due to non-radiation induced cancer. Indeed, many of the journalists who flew to TMI after the accident would have received a higher dose of radiation – due to their flight – than the TMI residents received from the accident!
When we look at the facts about radiation, Chernobyl, Sellafield, and Three Mile Island it allows us to put the scaremongering of anti-nuclear propagandists in perspective. It is a great pity that journalists and those in the nuclear industry never bother to do this. Truth is usually the first casualty in an ideological war.
If any readers have observed other activists repeating the “no safe radiation” shibboleth, let me know and I will update this article to include them.
(c)1999 By Oakley Environmental Research. The right to reproduce this page is granted providing that attribution to the author is given and that this notice is reproduced.
Below is a second article where Dr. Oakley takes on SEA-US (Sustainable Energy & Anti-Uranium Service Inc.), an Australian Anti nuclear organization which uses many of the same arguments as the American ones.
Statements in quotation marks are from SEA-US which Dr. Oakley deftly counters. He accurately defends the point in discussion that increases in radiation are not harmful.
More Lies From SEA-US: Radiation Rancour
New Australian No. 141, 8-14 November 1999 By *Dr Aaron Oakley http://www.newaus.com.au/news141aaron.html
In order to advance their anti-nuclear jihad, the folks at SEA-US need to do everything they can to demonise nuclear energy and radiation. An important argument in their anti-nuclear arsenal is that there is “no safe level of radiation”. Like most articles of faith of the anti-nuclear mob, this argument disintegrates under scrutiny. This piece critically examines the SEA-US item “Ionising Radiation and Health Effects: THERE IS NO SAFE DOSE”. (I postulate that SEA-US thinks that the use of capital letters makes their argument more convincing)
To give the illusion that the writer of the article is an authority on the subject, there is a long-winded account of the types and properties of ionising radiation. We are told about alpha, beta and gamma rays, and their different abilities to penetrate matter. We are given a little history of radiation science, and a one-eyed view of scientists perception of the dangers posed by radiation over recent history:
“At least since the 1930s ionising radiation has been known to damage human health, even at extremely low exposures.”
For some strange reason, SEA-US did not care to inform readers about experiments conducted in the early days of the Manhattan project, showing that animals exposed to radioactive uranium dust lived longer, were healthier and produced more offspring. They even claim that non-ionising electromagnetic radiation can damage health, making me think that they have succumbed to the cell-phone paranoia we have been experiencing lately.
Another SEA-US web page claims:
“In the 1920s, women who painted watch dials with radium to make them luminous, suffered a high incidence of bone cancer.”
“In the first half of the twentieth century, radium was used to make a paint that glows in the dark. Radium is now considered too dangerous to use for such purposes. Many young women who used the paint in their work died from cancers of the bone or of the head. The bone cancers were caused by microscopic amounts of radium which were unintentionally swallowed. The head cancers resulted from radon gas generated inside the women’s bodies which collected in their sinus and mastoid cavities.”
Radium that is swallowed is absorbed into the bone (because it is chemically similar to calcium), and undergoes radioactive decay to radon, a radioactive gas that escapes bone. Some of the radon accumulates sinuses and about 30 per cent is exhaled. What SEA-US didn’t tell us that after decades of study of the radium dial painters there was no case of bone cancer and nasal sarcoma in the population of women exposed to relatively high doses up to 1000 cGy. In fact the radium dial painter data is often cited as evidence against the no-safe-level-of-radiation argument. Other adverse health effects, (including leukaemia) which was anticipated due to radiation doses to the bone marrow, are non-existent in this population, even in high-dose groups.
As is usually the case with the radiophobic green, the horrible consequences of the atomic bomb blasts above Hiroshima and Nagasaki are trotted out:
“The atomic bombings of Hiroshima and Nagasaki in August 1945 brought great human suffering from exposure to high levels of gamma rays. People suffered nausea, vomiting, loss of hair, haemorrhage and destruction of the digestive system leading to loss of body fluids.”
While these statements are true, they are only an indication of what can happen with extremely high radiation doses. They are about as relevant to the nuclear industry as third degree burns are to the coal electricity industry.
“Children born of mothers pregnant at the time of the bombing suffered a high rate of microencephaly – a reduction in the size of head and brain.”
SEA-US failed to mention that for those receiving single radiation doses between 400 and 600 mSv, their children had a 4 per cent lower mortality risk, 23 per cent less aneuploidy, 29 per cent fewer chromosomal aberrations and 30 per cent fewer mutations in blood proteins.
“People in the outer areas of the two cities received low radiation exposures. In the years since the bombings the survivors’ health has been closely followed. The number of deaths from cancer has been plotted against the radiation dose to individual survivors.”
Important data (deliberately?) omitted by SEA-US was that those exposed to between 100 and 200 mSv of radiation had a lower incidence of leukaemia than those exposed to less than 100 mSv. SEA-US also quotes the International Physicians for the Prevention of Nuclear War (a Soviet front organisation established in 1981 with the help of Georgi Arbatov, a KGB operative):
“A study of the health and environmental effects of radioactive fallout by the International Physicians for the Prevention of Nuclear War has found that: atmospheric testing will cause 430,000 cancer deaths by year 2000 and eventually over 2 million cancer deaths.”
The IPPNW is about as trustworthy as a kleptomaniac alcoholic in a liquor store with a blind attendant. Unsurprisingly, the 2 million deaths mooted above is absolute balderdash. These supposed deaths were calculated by assuming that the discredited no-safe-level-of-radiation hypothesis is in fact true. The reality is that we need not worry about the infinitesimal increase in background radiation resulting from past nuclear tests.
As usual, SEA-US wheeled out Chernobyl:
“According to Ukrainian physicist, Vladimir Chernousenko by 1990 the Black Book held 7000 names of people who had died from leukemia and birth defects. Depression of the immune system – called ‘Chernobyl AIDS’ – has reduced resistance to disease especially among children.”
Interestingly, I have been unable to find any references to these deaths in the peer-reviewed medical literature. What I was able to find was references to the lack of evidence for increased leukaemia rates. In what is probably the largest and most systematic study of the health effects of Chernobyl accident, the International Atomic Energy Agency, studying people living beyond the 18 mile “prohibition zone” around the accident site found “no health disorders that could be attributed directly to radiation exposure”. Speculations of increased numbers of leukaemia and other cancers did not eventuate. They further concluded that “any increases over the natural rate of incidence of cancer or hereditary effects would be difficult to discern, even with larger and well designed long-term epidemiological studies”.
“Seascale village lies three kilometres from Sellafield. The village children suffer an excess of leukemia and multiple myeloma six times the national rate. The villagers saw an obvious link with the plant but the management denied any link. Then in 1990 a research team, headed by Dr Martin Gardner, found that children of male workers at the plant had six times greater chance of developing cancer than other children.”
Once again, SEA-US (deliberately?) failed to tell the full story. Studies of all 14,282 workers in the plant revealed that cancer rates were 4 per cent less than that of England and Wales, and was the same as that of the district of Cumbria where the plant is located. Follow-up investigations to the Gardner study revealed that the apparent leukaemia risk was inconsistent with other epidemiological and experimental data. Thus, it is unlikely that the association observed in the children of the Sellafield workforce represents a causal relationship – and that other factors may be to blame. Medical researchers now favour something called “population mixing” as an explanation for the Gardner data. Don’t expect SEA-US to admit to this any time soon.
“On pastures strontium-90 and iodine-131 migrate from soil through the grass eaten by cows to milk. Cesium-137 accumulates in animals from farm fodder. Fungi and mosses concentrate radionuclides. Reindeer meat is the staple diet of Laplanders but since Chernobyl it has been highly contaminated with radionuclides from the fallout.”
The reality, again, is somewhat different. Cesium-137 mimics potassium and accumulated in reindeer muscle. Radiation specialists in Stockholm showed that many Swedes would have had to eat sixty 12-ounce ‘contaminated’ steaks a day for a year to expose themselves to the same level of radiation as they get from the radon in their homes. Another way of putting it is that eating 154 pounds of reindeer meat contaminated to 500 times the Swedish safety standard to presents a risk equivalent to smoking one cigarette a week! “So much for highly contaminated”!
“The ICRP 1956 dose limit, for workers, was 50 milliSieverts (milliSv) and 1 milliSv for members of the public. However, despite acknowledging radiation to be five times more dangerous the ICRP reduced its limit to only 20 milliSv for workers a little less than half the previous limit. Public exposure was not reduced at all and was kept at 1 milliSv. The dose limit should have been 10 milliSv for workers and 0.2 for members of the public. The new limit means that the annual risk of death (from cancer) for a uranium miner is 1 in 1250, which is nearly ten times the risk of fatal injury in Australian industry generally, which is 1 in 20,000.”
Once again SEA-US left out crucial information. The low levels of acceptable radiation exposure mentioned above reflects the increasing conservatism of radiation protection authorities, and certainly does not reflect the radiation health data accumulating in the peer-reviewed medical literature over the course of the century. Once again, the estimate of one death in 1250 for Australian uranium miners was made using the no-safe-level hypothesis. And as we would expect, the silliness of this estimate is demonstrated by the fact that uranium miners are not dropping dead at the predicted rate.
“Even so the uranium industry has protested that the ICRP’s new limits would be uneconomic for underground mining. In the Roxby mine underground miners have received up to 30 milliSv a year.”
The SEA-US agenda is clear: It wants to close down all Australian uranium mines. And the no-safe-level-of-radiation hypothesis is the club that SEA-US uses to make its case. Yet 30 mSv per year is less radiation than the average background radiation in many parts of the world including Norway with 365 mSv per year. The reality is that those miners have little to fear from the small doses they receive, except of course the loss of employment if SEA-US gets its way.
The rule at SEA-US appears to be “quote it if it supports your argument, ignore it if it doesn’t”. SEA-US’s article is extremely selective in the data it cites to support its ideological position that there is no safe level of radiation. And they have to be selective, given the more than 1,000 papers in the peer-reviewed literature that support the idea that small doses of radiation are actually beneficial. Perhaps the radio-phobes at SEA-US have can tell us why this vast body of research is wrong. I await their response with interest.
Editor: The situation in Australia has now reached the ridiculous stage where independent writers like Dr Aaron Oakley now feel morally impelled to step in, at their own expense, to defend the uranium industry, despite the fact that the industry is spending a fortune paying flaks to do this very job. That no heads have rolled as a consequence of the industry’s dismal PR failures is a grim reflection on its ability to successfully tackle green ideologues.
c)1999 By Oakley Environmental Research. The right to reproduce this page is granted providing that attribution to the author is given and that this notice is reproduced.
Nov 9, 2001
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