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Attitudes towards Radiation Protection
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VII. | Natural background radiation is no measure of harmlessness. |
When criticised for the official dose levels or for topical events such as the recent scandal of the long-concealed contamination of transport containers for spent nuclear fuel, when persons were continuously exposed, the responsible ministries and radiation protection commissions as well as the government agency for radiation protection always claim that this exposure is comparable to natural background radiation level which can be taken as a measure of relative harmlessness. There is, however, no reason to believe that this inevitable natural radiation has no detrimental consequences. It is one of many causes of cancer and genetic disorders and adds to the aging of tissues and to life limitation, as demonstrated by the following examples. British scientists (Stewart et al.) were able to correlate child cancer cases with terrestrial gamma radiation [14]. Exposure to radon is the most important source of natural radiation exposure for the population at large. The vast majority of lung cancer cases in non-smokers is probably due to this source. Large-scale epidemiological studies have produced evidence of a correlation between leukaemias and other malignant tumours in childhood and radon levels (Henshaw et al.) [15]. Two American studies have shown a correlation of leukaemias and other cancer cases with radium levels in drinking water (Bean et al., Lyman et al.) [16].
The reason is the well known radiobiological mechanism of genetically induced changes in the cell which lead to mutations and cancer. For such effects no minimal dose (threshold dose) is necessary because every radiation quant (X-rays or gamma-rays) or an alpha or beta particle deposits enough energy during a primary interaction with matter to induce the required biochemical changes. Every additional dose in a population thus leads to a additional biological damage. The class of effects induced by cell mutations is stochastic because the occurrence of these effects in individuals is not predictable and can only be evaluated by probability. The number of stochastic lesions in an irradiated collective is proportional to the dose. The ICRP assumes that in the low-dose range at half the dose, half the amount of damage may be expected (linear correlation between dose and effect). This was recently confirmed again by Doll and Wakeford [17].
Irrespective of whether or not radiation-induced effects are statistically detectable in a population, the effects of natural environmental radiation may be estimated by combining collective dose with probability for detriment. The much-cited concept of the German radiation protection commission that radiation exposure may be negligible as long as it is within the range of natural background radiation (as is the case in Bavaria and Lower Saxony, for example, due to different altitude and terrestrial radiation) thus means only that the additional lesions occurring do not become apparent in a collective even if the affected individuals fall ill or die prematurely.
Applying the risk factors adopted by the ICRP it may be deduced that natural environmental radiation is responsible for 5 to 15% of the occurring cancer cases. While this number is most probably an underestimate, preventing additional cancer cases of this magnitude in the population by preventing increases in unavoidable exposures, is thus advisable.
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VIII. | Limitation of the collective equivalent dose is a matter of extreme urgency. |
According to the principle of stochastic injury, the collective equivalent dose (the sum of all single doses) determines the number of injuries induced in a population. It does not matter whether this collective dose is induced by many smaller or a few bigger exposures. Operators of nuclear power plants emitting radioactive material may be within the limits of the law if they dilute the radionuclides by installing very high chimneys, thus spreading the radioactivity over a greater area. For the law requires only a dose limit of 0.3 mSv in air and water per person per year, corresponding to an individual dose. The damage caused by those emissions world-wide is totally ignored.
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IX. | Implementation of radiation protection against economic interests is possible. |
As in the case of the most recent scandal involving contaminated transportation containers, government radiation protection experts have always aimed at playing down accidents and malfunctions in order to preserve the good image of nuclear technology and to guarantee further acceptance of this form of energy production. How can the government of radiation protection commission know that there was no health hazard from the surface contamination as claimed? Billions of radioactive particles might have been washed off these containers in the past and may have been incorporated by humans. In fact, no scientist can honestly deny that, especially as the exact circumstances of the contamination cannot be reconstructed.
The Chernobyl reactor accident resulted in large fractions of society turning away from nuclear energy and in a number of scientists revising their assessment of safe operation and consequences of this technique. Nevertheless, many scientists from the expert community have accepted the declarations of the nuclear industry and their supporting government agencies.. One typical example of this is the official estimate of the health consequences of the Chernobyl accident. The International Atomic Energy Organisation (IAEO) announced in 1991 that it had asked 200 western experts to analyze the consequences of the radiation and its effects on the health of the population in the affected area. The IAEO commission, the IAEA, propagated worldwide the finding that there was no statistically verifiable damage to health from the radioactivity. At that time there was already a more than 30-fold increase in thyroid cancer incidences among children in Belarus. This was, however, admitted only years later under the pressure of overwhelming evidence.
Nevertheless, similar accommodation expertises, recognizable as such even to the layman, continued to be published, for example in 1996 at a major congress of the IAEO and the World Health Organisation (WHO) in Vienna on the occasion of the 10th anniversary of the Chernobyl disaster. The German environmental minister, Angela Merkel, declared in public that there had been 31 immediate deaths but no further casualties according to the scientific community. The dramatically increased thyroid cancer cases were declared, as it were, to be curable.
This IAEO report and further efforts to play down the health consequences of Chernobyl were the subject of worldwide protests. Scientists from the CIS states who had been given no opportunity to speak at the Vienna Congress caught the attention of the western specialist media. Environmental protection groups and independent scientists combined their activities. This is an ongoing development and one which suggests that hard facts and efforts by independent scientists outside the nuclear "lobby system” together with an internationally growing protest movement involving environmental protection organizations and civic action groups will lead to better radiation protection standards.
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6th August 1998
Prof. Dr. Wolfgang Köhnlein,
Münster, FRG
President of the German Society for Radiation Protection
(Gesellschaft für Strahlenschutz e.V.)
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| http://www.gfstrahlenschutz.de/en/detmen4.htm Last Update: 15.02.1999 Responsible: Prof. Kuni, horst@kuni.org | Homepage Prof. Kuni |