Nuclear power is fine - radiation is good for you
by Dick Taverne
August 8, 2004
...why, with the notable exception of James Lovelock, the inventor of the Gaia hypothesis, do the world's environmentalists reject nuclear power, which emits almost no greenhouse gases? Because they are frightened of accidents and of radiation emanating from nuclear power stations and nuclear waste. Their fears of radiation are not only widely shared, but they are nourished by official sources and have even become official policy.
The present policies for radiation safety are based on the "linear no-threshold assumption", which is endorsed by the International Commission on Radiological Protection. This is the assumption that even the smallest amount of radiation is harmful and may cause cancer and genetic disorders, and that the risk of harm increases proportionately with the dose.
On this basis, we should aim to avoid any exposure at all. Accordingly, the standards for radiation protection set by the commission have become more exacting and the maximum exposure dose declared to be safe is continually lowered.
The standard measurement of radiation is set in terms of milliSieverts (mSv) per year. In the 1920s, the maximum dose regarded as safe was 700 mSv. By 1941, it was reduced to 70. By the 1990s, it became 20 for occupationally exposed people and 1 mSv for the general population. Some people believe that the maximum exposure dose should be lower still.
Unfortunately, far from safeguarding our health, current safety standards will almost certainly increase the incidence of cancer. The evidence shows that the effect of radiation on human health is not a linear one, but is a J-shaped curve. Exposure starts by being beneficial at low doses and only becomes harmful at higher doses. This effect is known as hormesis.
A low dose of ionising radiation seems to stimulate DNA repair and the immune system, so providing a measure of protection against cancer. The benefit of low doses of radiation in treating cancer have been known for some time and are confirmed by a mass of evidence, particularly from Japan where it has been studied in detail as a result of Hiroshima and Nagasaki.
Many other examples of the hormesis effect are well known. A bit of sunshine does you good; too much may cause skin cancer. Small doses of aspirin have many beneficial effects; too much will kill you. It also appears to apply to arsenic, cadmium, dioxins and residues of synthetic pesticides, but that is another story.
Epidemiological evidence confirms the hormesis effect of radiation. The prediction that there would be terrible after-effects from the atomic bombs dropped on Hiroshima and Nagasaki on the survivors and their children was proved wrong. Japanese studies of the life expectancy of survivors who suffered relatively low amounts of radiation show that their life expectancy turned out to be higher than those of the control group and no unusual genetic defects have been found in their children.
Again, a follow-up study of Japanese fishermen who were contaminated with plutonium after the nuclear tests at Bikini found 25 years later that none of them had died from cancer.
After the Chernobyl disaster it was also predicted that the incidence of cancer among those affected by fallout would greatly increase and there would be huge genetic damage to future generations. It was about as bad an accident to a nuclear power station (a badly constructed one) as is likely to happen. Its psychological effect was huge and changed people's perception of the risk of nuclear energy all over the world.
Indeed, it is constantly cited as an example of the unparalleled threat to health from nuclear disasters. Tragically, it led to 31 deaths, mainly among rescue workers who were exposed to very high doses of radiation. Yet in the areas around Chernobyl the extra radiation to which people were exposed in the nine years following the accident was slight - an increase of about 0.8- 1.4 mSv.
In May 2001, in the Ukrainian town of Pripyat, which is now a ghost town after its complete evacuation, the average amount of persistent radiation found was 0.9 mSv a year, five times lower than the level in New York's Grand Central Station. In parts of southwest France the levels of natural radiation are as high as 870 mSv a year.
There is strong evidence that people exposed to low doses of radiation - amounts 100 times more than the recommended range - actually benefit. The incidence of thyroid cancers among children under 15 exposed to fallout from Chernobyl was far lower than the normal incidence of thyroid cancer among Finnish children.
The death rate from leukemia of nuclear industry workers in Canada is 68 per cent lower than average. Workers in nuclear shipyards and other nuclear establishments in the US and many other countries have substantially lower death rates from all cancers and are much less likely to die from leukemia.
This might be explained by the fact that their health is regularly checked and that only healthy workers are employed. But it corresponds with a mass of other evidence that people who live in areas of unusually high natural radiation, in Japan, China, India and the US, are less likely to die from cancer than a control group.
These facts destroy what are perhaps the strongest objections to nuclear power. They show that the regulations seeking to enforce present, let alone proposed, minimum standards of safety not only cost billions of pounds and have undermined the prospects of our development of nuclear power, but do more harm than good.
It is time that we looked more closely at the phenomenon of hormesis and at the successful Japanese experience of using low-dose radiation to treat cancer. When the evidence is so clear, we should not allow it to be brushed aside by conventional wisdom and ignorance.
Adapted from an article in the August 2004 issue of Prospect magazine.
Dick Taverne is a British politician and independent social democrat. In 1974 he wrote The Future of the Left, Lincoln and After (Jonathan Cape), which predicted the split in the Labour party that happened seven years later. He is now a Liberal-Democrat peer. Becoming gradually more and more concerned about the increasing mood of hostility and suspicion towards science, in 2002 he founded the association 'Sense About Science' to promote an evidence-based approach to scientific issues.
Dick Taverne's book, The March of Unreason, will be published in April 2005 by OUP.
In The March of Unreason, Dick Taverne takes as his starting point his concern that irrationality is on the rise in Western society, and argues that public opinion is increasingly dominated by unreflecting prejudice and an unwillingness to engage with factual evidence. Experts no longer command respect, and polls show that the only scientists the public seem to trust are those who work for environmental pressure groups.
Full Version: Radiation Hormesis: low-level radiation
Common Ground Common Sense > Issues that Affect Our Lives > Energy Independence, Environment, Science and Technology > Energy, Environment, Science and Technology Issues Archive
great we can turn Chernobal into a spa with restorative mud baths 
QUOTE(underbear1 @ Mar 28 2005, 05:40 PM)
great we can turn Chernobal into a spa with restorative mud baths
You might not want to walk into the reactor structure, but the land around the Chernobyl reactor may be OK now. :nod:
"We reject nuclear energy with the same unreasoning arguments that our ancestors would have used to reject geothermal energy, the effort to harness the heat of the Earth. Compared with the imaginary dangers of nuclear power, the threat from the intensifying greenhouse effect seems all too real. I wholly support the Green wish to see all energy eventually come from renewable sources but I do not think that we have the time to wait until this happens. Nuclear power is unpopular but it is safer than power from fossil fuel. The worst that could happen, if Chernobyls become endemic, is that we live a little less long in a mildly radioactive world. To me this is preferable to the loss of our hard-won civilization in a greenhouse catastrophe. "
- James Lovelock, preeminent world leader in the development of environmental consciousness.
Natural Nuclear Reactors
A DOSE OF NUCLEAR RADIATION
- Excerpt from The Ages of Gaia
A nuclear fission reactor at the center of the Earth
—Earth is a gigantic natural nuclear power plant, Says geophysicist J. Marvin Herndon
Evidence of Possible Health Benefits from Low-Level Radiation:
Radiation thresholds
Why Radon Therapy
MISASA SPA
Radiation, Science, and Health
—Center for Nuclear Technology and Society, Worcester Polytechnic Institute (WPI)
Lessons of Chernobyl - with particular reference to thyroid cancer
by Zbigniew Jaworowski
April 30, 2004
Central Laboratory for Radiological Protection - CLOR, Warsaw, Poland
The Chernobyl catastrophe was a dramatic personal experience for me - a difficult exam, which I am not sure that I passed. For many people engaged in radiological protection, though not all, it was a watershed that changed their view on the paradigm on which the present safety regulations are based, the holy mantra of LNT - the linear no-threshold assumption, according to which even the lowest, near-zero doses of radiation may cause cancer and genetic harm. For everybody it might serve as a yardstick for comparison of radiation risks from natural and man-made sources. It also sheds light on how easily the global community may leave the realm of rationality when facing an imaginary emergency.
The LNT assumption is in direct contradiction to a vast sea of data on the beneficial effects of low doses of radiation. When in 1980, as a chairman of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), I tried to convince its members that we should not ignore but rather peruse and assess these data, published in the scientific literature since the end of 19th century, everybody in the Committee was against it. In each of the next seven years I repeated the proposal, to no avail. Finally, the accident at Chernobyl appeared to be an eye opener: two years after the accident, in 1988, the Committee saw the light and decided to study radiation hormesis, i.e. the adaptive and beneficial effects of low levels of radiation. Six years of the Committee's work and hot discussions later, Annex B "Adaptive responses to radiation in cells and organisms" appeared in the UNSCEAR 1994 Report, fourteen years after my original proposal. The Annex started a virtual revolution in research related to radiation protection but, because of many vested interests and conservatism to change the international and national regulations, there is still a long way to go.
The LNT/hormesis controversy is not limited to radiation. It poses questions for practically all noxious physical, chemical and biological agents which we meet in life [1]. Ionizing radiation was discovered rather lately - at the end of the 19th century - but, like these other agents, it has been with us since time immemorial.
The Chernobyl accident was a radiation event unique in human history, but not in the history of the biosphere. There is evidence of a number of episodes of greater radiation levels during the evolution of life on earth, e.g. due to supernovae. In terms of human losses it was a minor event as compared with many other man-made catastrophes but, in political, economic, social and psychological terms, its impact was enormous. Let's have a look at what happened.
About 9 a.m. on Monday 28 April 1986 at the entrance of CLOR in Warsaw I was greeted by my assistant with a statement: "Look, at 7:00 we received a telex from Mikolajki monitoring station saying that the radioactivity of air is there 550 000 times higher than a day before. A similar increase I found in the air filter from our station in the backyard, and the pavement in front of the institute is highly radioactive". Soon, to our relief, we found that the isotopic composition of radioactive dust was not from a nuclear explosion, but rather from a nuclear reactor. Reports inflowing successively from our 140 monitoring stations suggested that a radioactive cloud over Poland traveled westwards and that it arrived from the Soviet Union, but it was only about 6 p.m. that we learned from BBC radio that its source was in Chernobyl.
This was a terrible psychological shock. The air over the whole country was filled with the radioactive material, at levels hundreds of thousands times higher than anything we experienced in the past, even in 1963 - a record year for fallout from nuclear test explosions. It is curious that all my attention was concentrated on this enormous increase in air radioactivity, although I knew that on this first day of "Chernobyl in Poland", the dose rate of external radiation penetrating our bodies reached 30 µR per hour, or 2.6 mSv per year, i.e. only by a factor of 3 higher than a day before. This dose rate was four times lower than I would experience visiting places in Norway, where the natural external radiation (up to 11.3 mSv/year) from the rocks is higher than over the Central European plane. It was also some 100 times lower than in an Iranian resort Ramsar, where the annual dose reaches about 250 mSv per year, or more than 300 times lower than at the Brazilian beaches (790 mSv per year) or in South-West France (up to 870 mSv per year). No adverse health effects have ever been reported among the people living in these areas with high natural background radiation.
But, in 1986, the impact of a dramatic increase in atmospheric radioactivity dominated the thinking of myself and of everybody. This state of mind led to immediate serious consequences in Poland, in the Soviet Union, throughout the Europe, and later all over the globe. First, there were different hectic actions, such as ad hoc coining of different principles and emergency countermeasures, the sense and quality of which lagged far behind the excellent measuring techniques and monitoring systems. An example of this was the radionuclide concentration limits (derived intervention levels) implemented a few days after the accident by various countries and international organizations, which varied by a factor of up to 50,000. The base of some of these limits was not scientific, but reflected the emotional state of the decision makers, and also political and mercantile factors. For example, Sweden allowed for 30 times more activity in imported vegetables than in the domestic ones, and Israel imposed lower limits for radioactivity in food imported from Eastern than from Western Europe. The limit of cesium-137 concentration in meat of 6 Bq/kg was accepted in the Philippines and 6000 Bq/kg in Norway.
The monetary costs of such restrictions were estimated in Norway. At first, the cesium-137 limit for meat was accepted there as 600 Bq/kg, which from a health physics point of view is meaningless, as consumption of 1 kg of such a meat would correspond to a dose of 0.0078 mSv. If somebody would eat 0.25 kg of this meat each day for 1 year the internal radiation dose would reach 0.7 mSv. This limit was often surpassed in mutton, and the farmers received compensation for destroying the meat, and for special fodder they were forced to feed the sheep for months before slaughtering. Such a low limit could have destroyed the living of Lapps whose economy depends on reindeer, an animal having a special food chain based on lichens. Due to this chain the reindeer meat contained in 1986 high concentrations of cesium-137, reaching up to 40,000 Bq/kg. In November 1986, Norwegian authorities introduced a limit of 6000 Bq/kg of reindeer meat and game. Ordinary Norwegian diet includes only about 0.6 kg of reindeer meat per year, thus this limit was aimed to protect Norwegians against a radiation dose of 0.047 mSv/year. In 1994, the costs of this "protection" were evaluated: they reached over $51 million.
Sweden was not better. When the farmers near Stockholm discovered that the Chernobyl accident contaminated the milk of their cows with cesium-137 above the limit of 300 Bq per liter imposed by Swedish authorities, they wrote to them and asked if their milk could not be diluted with uncontaminated milk from other regions, until the limit were attained, for instance by mixing 1 liter of contaminated milk with 10 liters of clean milk. To the farmers' surprise the answer was "no", and the milk was to be discarded. This was strange, as it always was possible to do so for other pollutants in foodstuffs, and we also dilute the fumes from fireplaces or ovens with the atmospheric air. Authorities explained that even though one could reduce the individual risk by diluting the milk, at the same time, one would increase the number of consumers, and thus the risk would remain the same, although now spread over a larger population [3]. This was a dogmatic application of the LNT assumption, and of its offspring, the concept of "collective dose" (i.e. reaching terrifyingly great numbers of "man-sieverts", by multiplying tiny innocuous individual radiation doses by large number of exposed people). I believe that, in an earlier paper, I demonstrated clearly the lack of sense and negative consequences both of the LNT assumption and of the population dose concept [4]. Their dogmatic application may quite probably have caused the costs of the Chernobyl accident to exceed $100 billion in Western Europe [5].
The most nonsensical action, however, was the evacuation of 336 000 people from the regions of the former Soviet Union, where during the years 1986 - 1995 the Chernobyl fallout increased the average natural radiation dose (about 2.5 mSv per year) by 0.8 to 1.4 mSv per year, i.e. by about 30% to 50% [6]. The evacuation was based on radiation limits recommended by the International Commission for Radiological Protection (ICRP) for "the event of major radiation accidents" and on recommendations for protection of the general population, which were tens to hundreds of times lower than natural doses in many countries. In the asphalt paved streets of the "ghost town" of Pripyat, from which about 50 000 people were relocated, and where nobody can enter without special permission, the total external gamma dose rate measured by a Polish team in May 2001 was 0.9 mSv per year, i.e. the same as in Warsaw, and five times lower than at the Grand Central Station in New York. The evacuation led to development of mass psychosomatic disturbances, great economical losses, and traumatic social consequences. Obviously, ICRP will never accept responsibility for the disastrous effects of this dogmatic application of its armchair lucubrations which has caused the present system of "radiation protection [to] become a health hazard"[3].
In Poland, to save the population from effects of exposure to iodine-131, the government, upon my instigation, administered during three days a single dose of stable iodine to about 18.5 million people, the greatest prophylactic action in the history of medicine performed in so short a time. My medical colleagues and the Ministry of Health were rightly proud of the ingenious and innovative way they implemented this countermeasure. Recently several countries, including the USA, planned to follow in our flight. However, now I see this action as nonsensical. We endeavored to save Polish children from developing thyroid cancers by protecting them from a radiation dose of 50 mSv to the thyroid gland [7]. At this dose ICRP recommended implementation of stable iodine prophylaxis. But in studies of more than 34 000 Swedish patients whose thyroid glands received radiation doses reaching up to 40 000 mSv from iodine-131, there was no statistically significant increase in thyroid cancers in adults or children, who had not already been thought to have cancer before treatment with iodine-131. In fact, an opposite effect was observed: there was a 38% decrease in thyroid cancer incidence as compared with the non-irradiated population [8, 9]. In a much smaller British study of 7417 adult hyperthyroid patients whose thyroids received average radiation doses from iodine-131 reaching 300 000 mSv, a 17% deficit in incidence of all studied cancers was found [10]. Without the stable iodine prophylaxis and milk restrictions, the maximum thyroid dose would have reached about 1000 mSv in about 5% of Polish children [7]. All that I would now expect from this dose is a zero effect.
Fourteen years after the Chernobyl accident in the officially termed "highly contaminated" areas of the former Soviet Union, except for thyroid cancers, no increase in incidence in solid cancers and leukemia was reported. In its 2000 Report, UNSCEAR stated that the "population need not live in fear of serious health consequences", and "generally positive prospects for the future health of most individuals should prevail" [6]. No epidemics of cancers in the Northern Hemisphere, direly predicted from the LNT assumption to reach tens and hundreds of thousands, or even millions of cases, has ever occurred.
The number of 1800 new thyroid cancers registered among the children from Belarus, Russia and Ukraine should be viewed in respect to extremely high occurrence of the "occult" thyroid cancers in normal populations [11-14]. These cancers, not presenting adverse clinical effects, are detected at post mortem, or by ultrasonography examinations. Their incidence ranges from 5% in Colombia, to 9% in Poland, 13% in the USA, and 35% in Finland [12]. In Finland occult thyroid cancers appear in 2.4% of children 0 to 15 year old [11]. In Minsk, Belarus the normal incidence of occult thyroid cancers is 9.3% [15]. The greatest incidence of "Chernobyl" thyroid cancers in children under 15 years old, of 0.027%, was registered in 1994 in the Bryansk region of Russia, which was less by a factor of about 90 than the normal incidence of occult thyroid cancers among the Finnish children. The "Chernobyl" thyroid cancers are of the same type and similarly invasive as the occult cancers [13]. The first increase of these cancers was registered in 1987 in the Bryansk region, Russia, one year after the accident. Since 1995, the number of registered cancers tends to decline. This is not in agreement with what we know about radiation induced thyroid cancers, the latency time for which is about 5 years after irradiation, and the risk of which increases until 15 - 29 years after exposure [6]. In the United States the incidence rate of thyroid tumors detected between 1974 and 1979 during a screening program was 21 times higher than before the screening [16], an increase similar to that observed in three former Soviet countries. I believe that the increased registration of thyroid cancers in contaminated parts of these countries is a classical screening effect.
There were 28 fatalities caused by very high doses of radiation to rescue workers and employees of the power station, and 3 deaths in this group due to other reasons. Among 237 members of the reactor staff and emergency workers, initially examined for signs of acute radiation sickness, this diagnosis was confirmed in 134 patients. From among these patients, 11 died up to 1998. The causes of death were as follows: 3 cases of coronary heart disease, 2 cases of myelodysplastic syndrome, two cases of liver cirrhosis, and one death each of lung gangrene, lung tuberculosis and fat embolism. One patient, who was classified with Grade II acute radiation sickness (acute radiation dose of 2.2 - 4.1 Gy) died from acute myeloid leukemia. A substantial increase in the incidence of leukaemia amongst recovery operation workers was predicted, but the evidence for a measurable radiation effect on this incidence is somewhat mixed. The average standardized incidence ratio (SIR) for leukemia ranged among these workers for Belarus, Russia and Ukraine from 0.94 to 7.76, but the problem is that similar increase was found for chronic lymphatic leukemia, a subtype deemed not to be induced by radiation exposure. Contribution of a screening or diagnostic bias to these excesses cannot be excluded. The SIR for all cancers combined in the recovery operation workers ranged from 0.70 to 1.02 in Belarus, from 0.91 to 1.01 in Russia, and from 1.05 to 1.11 in Ukraine.
In the general population of the contaminated regions of Belarus, the SIR for leukemia was 0.46 to 0.62 (i.e. 46% to 62% of the normal incidence in Belarus), 0.93 to 0.99 in Russia and 1.05 to 1.43 in Ukraine. The SIR for all cancers combined ranged from 0.30 to 0.69 in Belarus, from 0.89 to 0.98 in Russia, and from 0.80 to 0.82 in Ukraine. Hence, the incidence of all cancers appears to have been lower than it would have been in a similar but unirradiated group. The only real adverse health consequence of the Chernobyl catastrophe among about five million people living in the contaminated regions is the epidemics of psychosomatic diseases [6]. These diseases were not due to irradiation with Chernobyl fallout, but were caused by radiophobia, induced by years of propaganda before and after the accident, and aggravated by improper administrative decisions. As a result of these decisions, several million people in three countries have "been labeled as, and perceive themselves as, actual or potential victims of Chernobyl"[17]. This was the main factor behind the economic losses caused by the Chernobyl catastrophe, estimated for Ukraine to reach $148 billion until 2000, and $235 billion until 2016 for Belarus [17].
In 1986 most of my professional colleagues and I, the authorities, and the public in Poland and elsewhere, were pre-conditioned for irrational reactions. Victims of the LNT dogma, we all wished to protect people even against the lowest, near zero doses of ionizing radiation. The dogma influenced behavior of everybody, leading to a mass psychosis, in fact to the greatest psychological catastrophe in history [2], into which the accident in Chernobyl, with the efficient help of media and national and international authorities, quickly evolved. It seems that professionals, international and national institutions, and the system of radiological protection did not meet the challenge of the Chernobyl catastrophe.
The following main lessons can be deduced from this accident:
(1) Ionizing radiation killed only a few occupationally exposed people. Due to rapid decay of short-lived radionuclides, the Chernobyl fallout did not expose the general population to harmful radiation doses. Near the burning reactor, the area covered by the dangerous radioactive fallout where, on April 26 1986, the radiation dose rate reached 1 Gy per hour (after one year it had decreased by a factor of about 3000), was limited to two patches totaling together about 0.5 km2 in an uninhabited location, and reaching a distance of 1.8 km from the burning nuclear reactor. Several hundred meters outside the 1 Gy isoline the dose rate dropped by two orders of magnitude, to a level of 0.01 to 0.001 Gy per hour. This is a completely different situation than after a surface explosion of a 10 Mt nuclear bomb, when the 1 Gy per hour isoline can reach a distance of 440 km, and the lethal fallout can cover tens of thousands km2, and endanger the life of millions of people.
(2) The reported excess of thyroid cancers in children and in adults exposed to Chernobyl fallout is not consistent with the knowledge on effects of medical use of iodine-131. The report of an "excess" appears to be an effect of screening, and is only a small fraction of the normal occult thyroid cancers incidence occurring in populations unexposed to iodine-131.
(3) Radionuclides were injected high into the stratosphere, at least up to 15 km altitude, which made possible its long distance migration in the whole Northern Hemisphere, and a penetration over the Equator down to the South Pole [18]. With unique, extremely sophisticated radiation monitoring systems, implemented in all developed countries, even the most tiny debris from the Chernobyl reactor was easily detected all over the world. No such system exists for any other potentially harmful environmental agent. Ironically, this excellence of radiological protection ignited the mass anxiety, with its disastrous consequences in the former Soviet Union, and strangulation of nuclear energy development elsewhere.
(4) Psychosomatic disorders and the screening effects were the only detectable health consequences among the general population. Fighting the panic and mass hysteria could be regarded as the most important countermeasure to protect the public against the effects of a similar accident should it occur again.
(5) This was the worst possible catastrophe of a badly constructed nuclear reactor, with a complete meltdown of the reactor core, followed by the ten-days long completely free emission of radionuclides into the atmosphere. Nothing worse could happen. It resulted in a comparatively small occupational death toll, amounting to about half of that of each weekend's traffic in Poland, and tens or hundreds of times lower than that of many other industrial catastrophes, and it is unlikely that any fatalities were caused by radiation among the public. In the centuries to come, the Chernobyl catastrophe will be seen as a proof that nuclear power is a safe means of energy production.
References
1. Calabrese, E.J. and L.A. Baldwin, Toxicology rethinks its central belief. Nature, 2003. 421(13 February): p. 691-692.
2. Jaworowski, Z., Chernobyl Proportions - Editorial. Chernobyl Accident: Regional and Global Impacts. Special Issue of Environment International. Guest Editor Zbigniew Jaworowski, 1988. 14(2): p. 69-73.
3. Walinder, G., Has radiation protection become a health hazard? 1995, Nykoping: The Swedish Nuclear Training & Safety Center. 126.
4. Jaworowski, Z., Radiation risk and ethics. Physics Today, 1999. 52(9): p. 24-29.
5. Becker, K. Ten years after Chernobyl. In ANS/ENS Conference 1996, Washington D.C. Nov. 10-14, 1996.
6. UNSCEAR, Sources and Effects of Ionizing Radiation. United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR 2000 Report to the General Assembly, with Scientific Annexes. 2000, United Nations: New York. p. 1220.
7. Jaworowski, Z. Chernobyl in Poland: The first few days, ten years after. in Zehn Jahre nach Tschernobyl, eine Bilanz. 1996. Munich, Germany: Gustav Fisher Verlag, Stuttgard.
8. Holm, L.E., et al., Thyroid cancer after diagnostic doses of iodine-131: A retrospective cohort study. Journal of the National Cancer Institute, 1988. 80(14): p. 1133-1138.
9. Hall, P., A. Mattsson, and J.D. Boice Jr., Thyroid cancer after diagnostic administration of iodine-131. Rad. res., 1996. 145: p. 86-92.
10. Franklyn, J.A., et al., Cancer incidence and mortality after radioiodine treatment for hyperthyroidism: a population-based cohort study. The Lancet, 1999. 353(June 19, 1999): p. 2111-2115.
11. Franssila, K.O. and H.R. Harach, Occult papillary carcinoma of the thyroid in children and young adults - A sytematic study in Finland. 1986. 58: p. 715-719.
12. Harach, H.R., K.O. Franssila, and V.M. Wasenius, Occult papillary carcinoma of the thyroid - A "normal" finding in Finland. A systematic study. 1985. 56: p. 531-538.
13. Moosa, M. and E.L. Mazzaferri, Occult thyroid carcinoma. The Cancer Journal, 1997. 10(4 (July-August)): p. 180-188.
14. Tan, G.H. and H. Gharib, Thyroid incidentalomas: Management approaches to nonpalpable nodules discovered incidentally on thyroid imaging. Annals of Internal Medicine, 1997. 126: p. 226-231.
15. Furmanchuk, A.W., N. Roussak, and C. Ruchti, Occult thyroid carcinomas in the region of Minsk, Belarus. An autopsy Study of 215 patients. Histopathology, 1993. 23: p. 319-325.
16. Ron, E., J. Lubin, and A.B. Schneider, Thyroid cancer incidence. Nature, 1992. 360: p. 113.
17. UNDP and UNICEF, The Human Consequences of the Chernobyl Nuclear Accident: A strategy for Recovery. 2002, United Nations Development Programme (UNDP) and the UN Children's Fund (UNICEF) with the support of the UN Office for Co-ordination of Humanitarian Affairs (OCHA) and WHO. p. 1-75.
18. Kownacka, L. and Z. Jaworowski, Nuclear weapon and Chernobyl debris in the troposphere and lower stratosphere. The Science of the Total Environment, 1994. 144: p. 201-215.
by Zbigniew Jaworowski
April 30, 2004
Central Laboratory for Radiological Protection - CLOR, Warsaw, Poland
The Chernobyl catastrophe was a dramatic personal experience for me - a difficult exam, which I am not sure that I passed. For many people engaged in radiological protection, though not all, it was a watershed that changed their view on the paradigm on which the present safety regulations are based, the holy mantra of LNT - the linear no-threshold assumption, according to which even the lowest, near-zero doses of radiation may cause cancer and genetic harm. For everybody it might serve as a yardstick for comparison of radiation risks from natural and man-made sources. It also sheds light on how easily the global community may leave the realm of rationality when facing an imaginary emergency.
The LNT assumption is in direct contradiction to a vast sea of data on the beneficial effects of low doses of radiation. When in 1980, as a chairman of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), I tried to convince its members that we should not ignore but rather peruse and assess these data, published in the scientific literature since the end of 19th century, everybody in the Committee was against it. In each of the next seven years I repeated the proposal, to no avail. Finally, the accident at Chernobyl appeared to be an eye opener: two years after the accident, in 1988, the Committee saw the light and decided to study radiation hormesis, i.e. the adaptive and beneficial effects of low levels of radiation. Six years of the Committee's work and hot discussions later, Annex B "Adaptive responses to radiation in cells and organisms" appeared in the UNSCEAR 1994 Report, fourteen years after my original proposal. The Annex started a virtual revolution in research related to radiation protection but, because of many vested interests and conservatism to change the international and national regulations, there is still a long way to go.
The LNT/hormesis controversy is not limited to radiation. It poses questions for practically all noxious physical, chemical and biological agents which we meet in life [1]. Ionizing radiation was discovered rather lately - at the end of the 19th century - but, like these other agents, it has been with us since time immemorial.
The Chernobyl accident was a radiation event unique in human history, but not in the history of the biosphere. There is evidence of a number of episodes of greater radiation levels during the evolution of life on earth, e.g. due to supernovae. In terms of human losses it was a minor event as compared with many other man-made catastrophes but, in political, economic, social and psychological terms, its impact was enormous. Let's have a look at what happened.
About 9 a.m. on Monday 28 April 1986 at the entrance of CLOR in Warsaw I was greeted by my assistant with a statement: "Look, at 7:00 we received a telex from Mikolajki monitoring station saying that the radioactivity of air is there 550 000 times higher than a day before. A similar increase I found in the air filter from our station in the backyard, and the pavement in front of the institute is highly radioactive". Soon, to our relief, we found that the isotopic composition of radioactive dust was not from a nuclear explosion, but rather from a nuclear reactor. Reports inflowing successively from our 140 monitoring stations suggested that a radioactive cloud over Poland traveled westwards and that it arrived from the Soviet Union, but it was only about 6 p.m. that we learned from BBC radio that its source was in Chernobyl.
This was a terrible psychological shock. The air over the whole country was filled with the radioactive material, at levels hundreds of thousands times higher than anything we experienced in the past, even in 1963 - a record year for fallout from nuclear test explosions. It is curious that all my attention was concentrated on this enormous increase in air radioactivity, although I knew that on this first day of "Chernobyl in Poland", the dose rate of external radiation penetrating our bodies reached 30 µR per hour, or 2.6 mSv per year, i.e. only by a factor of 3 higher than a day before. This dose rate was four times lower than I would experience visiting places in Norway, where the natural external radiation (up to 11.3 mSv/year) from the rocks is higher than over the Central European plane. It was also some 100 times lower than in an Iranian resort Ramsar, where the annual dose reaches about 250 mSv per year, or more than 300 times lower than at the Brazilian beaches (790 mSv per year) or in South-West France (up to 870 mSv per year). No adverse health effects have ever been reported among the people living in these areas with high natural background radiation.
But, in 1986, the impact of a dramatic increase in atmospheric radioactivity dominated the thinking of myself and of everybody. This state of mind led to immediate serious consequences in Poland, in the Soviet Union, throughout the Europe, and later all over the globe. First, there were different hectic actions, such as ad hoc coining of different principles and emergency countermeasures, the sense and quality of which lagged far behind the excellent measuring techniques and monitoring systems. An example of this was the radionuclide concentration limits (derived intervention levels) implemented a few days after the accident by various countries and international organizations, which varied by a factor of up to 50,000. The base of some of these limits was not scientific, but reflected the emotional state of the decision makers, and also political and mercantile factors. For example, Sweden allowed for 30 times more activity in imported vegetables than in the domestic ones, and Israel imposed lower limits for radioactivity in food imported from Eastern than from Western Europe. The limit of cesium-137 concentration in meat of 6 Bq/kg was accepted in the Philippines and 6000 Bq/kg in Norway.
The monetary costs of such restrictions were estimated in Norway. At first, the cesium-137 limit for meat was accepted there as 600 Bq/kg, which from a health physics point of view is meaningless, as consumption of 1 kg of such a meat would correspond to a dose of 0.0078 mSv. If somebody would eat 0.25 kg of this meat each day for 1 year the internal radiation dose would reach 0.7 mSv. This limit was often surpassed in mutton, and the farmers received compensation for destroying the meat, and for special fodder they were forced to feed the sheep for months before slaughtering. Such a low limit could have destroyed the living of Lapps whose economy depends on reindeer, an animal having a special food chain based on lichens. Due to this chain the reindeer meat contained in 1986 high concentrations of cesium-137, reaching up to 40,000 Bq/kg. In November 1986, Norwegian authorities introduced a limit of 6000 Bq/kg of reindeer meat and game. Ordinary Norwegian diet includes only about 0.6 kg of reindeer meat per year, thus this limit was aimed to protect Norwegians against a radiation dose of 0.047 mSv/year. In 1994, the costs of this "protection" were evaluated: they reached over $51 million.
Sweden was not better. When the farmers near Stockholm discovered that the Chernobyl accident contaminated the milk of their cows with cesium-137 above the limit of 300 Bq per liter imposed by Swedish authorities, they wrote to them and asked if their milk could not be diluted with uncontaminated milk from other regions, until the limit were attained, for instance by mixing 1 liter of contaminated milk with 10 liters of clean milk. To the farmers' surprise the answer was "no", and the milk was to be discarded. This was strange, as it always was possible to do so for other pollutants in foodstuffs, and we also dilute the fumes from fireplaces or ovens with the atmospheric air. Authorities explained that even though one could reduce the individual risk by diluting the milk, at the same time, one would increase the number of consumers, and thus the risk would remain the same, although now spread over a larger population [3]. This was a dogmatic application of the LNT assumption, and of its offspring, the concept of "collective dose" (i.e. reaching terrifyingly great numbers of "man-sieverts", by multiplying tiny innocuous individual radiation doses by large number of exposed people). I believe that, in an earlier paper, I demonstrated clearly the lack of sense and negative consequences both of the LNT assumption and of the population dose concept [4]. Their dogmatic application may quite probably have caused the costs of the Chernobyl accident to exceed $100 billion in Western Europe [5].
The most nonsensical action, however, was the evacuation of 336 000 people from the regions of the former Soviet Union, where during the years 1986 - 1995 the Chernobyl fallout increased the average natural radiation dose (about 2.5 mSv per year) by 0.8 to 1.4 mSv per year, i.e. by about 30% to 50% [6]. The evacuation was based on radiation limits recommended by the International Commission for Radiological Protection (ICRP) for "the event of major radiation accidents" and on recommendations for protection of the general population, which were tens to hundreds of times lower than natural doses in many countries. In the asphalt paved streets of the "ghost town" of Pripyat, from which about 50 000 people were relocated, and where nobody can enter without special permission, the total external gamma dose rate measured by a Polish team in May 2001 was 0.9 mSv per year, i.e. the same as in Warsaw, and five times lower than at the Grand Central Station in New York. The evacuation led to development of mass psychosomatic disturbances, great economical losses, and traumatic social consequences. Obviously, ICRP will never accept responsibility for the disastrous effects of this dogmatic application of its armchair lucubrations which has caused the present system of "radiation protection [to] become a health hazard"[3].
In Poland, to save the population from effects of exposure to iodine-131, the government, upon my instigation, administered during three days a single dose of stable iodine to about 18.5 million people, the greatest prophylactic action in the history of medicine performed in so short a time. My medical colleagues and the Ministry of Health were rightly proud of the ingenious and innovative way they implemented this countermeasure. Recently several countries, including the USA, planned to follow in our flight. However, now I see this action as nonsensical. We endeavored to save Polish children from developing thyroid cancers by protecting them from a radiation dose of 50 mSv to the thyroid gland [7]. At this dose ICRP recommended implementation of stable iodine prophylaxis. But in studies of more than 34 000 Swedish patients whose thyroid glands received radiation doses reaching up to 40 000 mSv from iodine-131, there was no statistically significant increase in thyroid cancers in adults or children, who had not already been thought to have cancer before treatment with iodine-131. In fact, an opposite effect was observed: there was a 38% decrease in thyroid cancer incidence as compared with the non-irradiated population [8, 9]. In a much smaller British study of 7417 adult hyperthyroid patients whose thyroids received average radiation doses from iodine-131 reaching 300 000 mSv, a 17% deficit in incidence of all studied cancers was found [10]. Without the stable iodine prophylaxis and milk restrictions, the maximum thyroid dose would have reached about 1000 mSv in about 5% of Polish children [7]. All that I would now expect from this dose is a zero effect.
Fourteen years after the Chernobyl accident in the officially termed "highly contaminated" areas of the former Soviet Union, except for thyroid cancers, no increase in incidence in solid cancers and leukemia was reported. In its 2000 Report, UNSCEAR stated that the "population need not live in fear of serious health consequences", and "generally positive prospects for the future health of most individuals should prevail" [6]. No epidemics of cancers in the Northern Hemisphere, direly predicted from the LNT assumption to reach tens and hundreds of thousands, or even millions of cases, has ever occurred.
The number of 1800 new thyroid cancers registered among the children from Belarus, Russia and Ukraine should be viewed in respect to extremely high occurrence of the "occult" thyroid cancers in normal populations [11-14]. These cancers, not presenting adverse clinical effects, are detected at post mortem, or by ultrasonography examinations. Their incidence ranges from 5% in Colombia, to 9% in Poland, 13% in the USA, and 35% in Finland [12]. In Finland occult thyroid cancers appear in 2.4% of children 0 to 15 year old [11]. In Minsk, Belarus the normal incidence of occult thyroid cancers is 9.3% [15]. The greatest incidence of "Chernobyl" thyroid cancers in children under 15 years old, of 0.027%, was registered in 1994 in the Bryansk region of Russia, which was less by a factor of about 90 than the normal incidence of occult thyroid cancers among the Finnish children. The "Chernobyl" thyroid cancers are of the same type and similarly invasive as the occult cancers [13]. The first increase of these cancers was registered in 1987 in the Bryansk region, Russia, one year after the accident. Since 1995, the number of registered cancers tends to decline. This is not in agreement with what we know about radiation induced thyroid cancers, the latency time for which is about 5 years after irradiation, and the risk of which increases until 15 - 29 years after exposure [6]. In the United States the incidence rate of thyroid tumors detected between 1974 and 1979 during a screening program was 21 times higher than before the screening [16], an increase similar to that observed in three former Soviet countries. I believe that the increased registration of thyroid cancers in contaminated parts of these countries is a classical screening effect.
There were 28 fatalities caused by very high doses of radiation to rescue workers and employees of the power station, and 3 deaths in this group due to other reasons. Among 237 members of the reactor staff and emergency workers, initially examined for signs of acute radiation sickness, this diagnosis was confirmed in 134 patients. From among these patients, 11 died up to 1998. The causes of death were as follows: 3 cases of coronary heart disease, 2 cases of myelodysplastic syndrome, two cases of liver cirrhosis, and one death each of lung gangrene, lung tuberculosis and fat embolism. One patient, who was classified with Grade II acute radiation sickness (acute radiation dose of 2.2 - 4.1 Gy) died from acute myeloid leukemia. A substantial increase in the incidence of leukaemia amongst recovery operation workers was predicted, but the evidence for a measurable radiation effect on this incidence is somewhat mixed. The average standardized incidence ratio (SIR) for leukemia ranged among these workers for Belarus, Russia and Ukraine from 0.94 to 7.76, but the problem is that similar increase was found for chronic lymphatic leukemia, a subtype deemed not to be induced by radiation exposure. Contribution of a screening or diagnostic bias to these excesses cannot be excluded. The SIR for all cancers combined in the recovery operation workers ranged from 0.70 to 1.02 in Belarus, from 0.91 to 1.01 in Russia, and from 1.05 to 1.11 in Ukraine.
In the general population of the contaminated regions of Belarus, the SIR for leukemia was 0.46 to 0.62 (i.e. 46% to 62% of the normal incidence in Belarus), 0.93 to 0.99 in Russia and 1.05 to 1.43 in Ukraine. The SIR for all cancers combined ranged from 0.30 to 0.69 in Belarus, from 0.89 to 0.98 in Russia, and from 0.80 to 0.82 in Ukraine. Hence, the incidence of all cancers appears to have been lower than it would have been in a similar but unirradiated group. The only real adverse health consequence of the Chernobyl catastrophe among about five million people living in the contaminated regions is the epidemics of psychosomatic diseases [6]. These diseases were not due to irradiation with Chernobyl fallout, but were caused by radiophobia, induced by years of propaganda before and after the accident, and aggravated by improper administrative decisions. As a result of these decisions, several million people in three countries have "been labeled as, and perceive themselves as, actual or potential victims of Chernobyl"[17]. This was the main factor behind the economic losses caused by the Chernobyl catastrophe, estimated for Ukraine to reach $148 billion until 2000, and $235 billion until 2016 for Belarus [17].
In 1986 most of my professional colleagues and I, the authorities, and the public in Poland and elsewhere, were pre-conditioned for irrational reactions. Victims of the LNT dogma, we all wished to protect people even against the lowest, near zero doses of ionizing radiation. The dogma influenced behavior of everybody, leading to a mass psychosis, in fact to the greatest psychological catastrophe in history [2], into which the accident in Chernobyl, with the efficient help of media and national and international authorities, quickly evolved. It seems that professionals, international and national institutions, and the system of radiological protection did not meet the challenge of the Chernobyl catastrophe.
The following main lessons can be deduced from this accident:
(1) Ionizing radiation killed only a few occupationally exposed people. Due to rapid decay of short-lived radionuclides, the Chernobyl fallout did not expose the general population to harmful radiation doses. Near the burning reactor, the area covered by the dangerous radioactive fallout where, on April 26 1986, the radiation dose rate reached 1 Gy per hour (after one year it had decreased by a factor of about 3000), was limited to two patches totaling together about 0.5 km2 in an uninhabited location, and reaching a distance of 1.8 km from the burning nuclear reactor. Several hundred meters outside the 1 Gy isoline the dose rate dropped by two orders of magnitude, to a level of 0.01 to 0.001 Gy per hour. This is a completely different situation than after a surface explosion of a 10 Mt nuclear bomb, when the 1 Gy per hour isoline can reach a distance of 440 km, and the lethal fallout can cover tens of thousands km2, and endanger the life of millions of people.
(2) The reported excess of thyroid cancers in children and in adults exposed to Chernobyl fallout is not consistent with the knowledge on effects of medical use of iodine-131. The report of an "excess" appears to be an effect of screening, and is only a small fraction of the normal occult thyroid cancers incidence occurring in populations unexposed to iodine-131.
(3) Radionuclides were injected high into the stratosphere, at least up to 15 km altitude, which made possible its long distance migration in the whole Northern Hemisphere, and a penetration over the Equator down to the South Pole [18]. With unique, extremely sophisticated radiation monitoring systems, implemented in all developed countries, even the most tiny debris from the Chernobyl reactor was easily detected all over the world. No such system exists for any other potentially harmful environmental agent. Ironically, this excellence of radiological protection ignited the mass anxiety, with its disastrous consequences in the former Soviet Union, and strangulation of nuclear energy development elsewhere.
(4) Psychosomatic disorders and the screening effects were the only detectable health consequences among the general population. Fighting the panic and mass hysteria could be regarded as the most important countermeasure to protect the public against the effects of a similar accident should it occur again.
(5) This was the worst possible catastrophe of a badly constructed nuclear reactor, with a complete meltdown of the reactor core, followed by the ten-days long completely free emission of radionuclides into the atmosphere. Nothing worse could happen. It resulted in a comparatively small occupational death toll, amounting to about half of that of each weekend's traffic in Poland, and tens or hundreds of times lower than that of many other industrial catastrophes, and it is unlikely that any fatalities were caused by radiation among the public. In the centuries to come, the Chernobyl catastrophe will be seen as a proof that nuclear power is a safe means of energy production.
References
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