Part K : THE REGULATION OF RADIATION EXPOSURES K.1. What is an "acceptable" level of exposure to atomic radiation?
K.2. Who is responsible for regulating radiation exposure in Canada?
K.3. What is the basis for setting radiation standards?
K.4. What is "background radiation"?
K.5. Is background radiation increasing?
K.6. Is radon in homes a problem? how does it get there?
K.7. Are Australian exposure standards being made more stringent?
K.1. What is an "acceptable" level of exposure to atomic radiation?There is no convincing scientific evidence that there is a safe dose of atomic radiation. The evidence points strongly to the opposite conclusion -- that every dose of atomic radiation administered to a large population, no matter how small it may be, will cause a corresponding increase in the numbers of cancers, genetic defects in offspring and other diseases.
The increase in the incidence of cancers and genetic defects seems to be roughly proportional to the total radiation dose received by the entire population. If the radiation dose is cut in half, the increase in the number of people dying of cancer or having defective children will also be cut in half, but the degree of damage to each affected individual is undiminished. Lowering the dose reduces the frequency but not the severity of the medical consequences. Every regulatory body in the world uses this principle as the basis for regulating radiation exposures.
Since no dose is safe, there is no objective or scientific way to decide what dose is acceptable. It is a social or political choice, not a technical or scientific one. The situation is further complicated when the people who receive the benefits are not the only ones who are taking the risks.
Science can only help us to estimate the risks -- how many people are likely to get cancer, how many children are likely to be born defective, or what other types of illnesses might increase as a result of a given exposure to radiation. To judge whether or not these consequences are acceptable is beyond the scope of science.
K.2. Who is responsible for regulating radiation exposure in Canada? The Atomic Energy Control Board (AECB) is responsible for regulating radiation exposure in Canada in cooperation with the Radiological Protection Bureau of the federal Department of Health and Welfare. Since the AECB has little medical or epidemiological expertise, it also depends heavily on research done and recommendations made by bodies outside Canada.
In particular, it relies on the advice of the International Commission on Radiological Protection (ICRP), a self-appointed international advisory body consisting of prominent scientists who work in the field of atomic radiation. Critics have charged that ICRP members are in a conflict-of-interest situation, because their careers are based on jobs which inevitably expose people to man-made radiation.
The AECB sets maximum permissible levels of radiation exposure for atomic workers and for members of the general public. These levels are not regarded by the ICRP as acceptable levels for continuous exposure, but as upper limits beyond which radiation exposure becomes clearly unacceptable. Attempts are made to keep actual exposures to a small fraction of the maximum permissible limits, but there is no guarantee that this will always be the case.
The industry and the regulators claim to follow the ALARA principle, which means keeping radiation exposures "As Low As Reasonably Achievable, social and economic factors being taken into account." But who decides what is reasonable? Critics of the industry claim that current occupational and public exposures are already in many cases unreasonably high, particularly in the light of recent scientific studies published since 1988 which indicate that the risks from low-level radiation are from two to eight times as great as previously thought.
K.3. What is the basis for setting radiation standards? In a very real sense, radiation standards are arbitrary. While maximum permissible levels of radiation exposure have been defined for workers and for the general public, these exposures should not be regarded as safe, or even acceptable. The International Commission on Radiological Protection (ICRP) warns that it would be unacceptable for workers or for members of the general public to be exposed continuously to the maximum permissible dose levels.
Radiation standards are for people only, ignoring other species. The assumption that if humans are protected, so are non-humans, is now being seriously questioned.
Two approaches have been used to justify the existing radiation standards. The first involves estimating the risks of death and genetic damage from a given dose of radiation, and comparing these radiation risks with other risks (e.g. deaths from car accidents, hazardous work, fires, earthquakes, spontaneous birth defects, over-eating, etc.) in an effort to make these two kinds of risk more or less comparable. The second approach involves comparing the permissible levels of man-made radiation to the levels of naturally-occurring background radiation.
These approaches have been criticized. The first approach compares risks which people can take steps to avoid with risks of exposures to atomic radiation which are not within the individual's control or power to choose. This approach also assumes an accurate knowledge of the true risks of low-level radiation exposure; but there is growing scientific evidence that these risks have been seriously underestimated for decades. The second approach ignores differences between naturally-occurring radiation and man-made radiation; the latter sometimes involves radioactive substances or biological mechanisms which may not be characteristic of naturally occurring radiation.
Both approaches assume that it is acceptable to add the risks of "technologically enhanced" radiation exposure to all the other risks to which we are already exposed, or to multiply the risks from background radiation by some arbitrary factor.
K.4. What is "background radiation"? Some radiation exposure is unavoidable, even in the absence of uranium mining and nuclear technology. This "background radiation" is due to small quantities of radioactive materials in the natural environment -- food, water and air -- as well as penetrating rays from outer space to which we are all exposed.
In some places, background radiation is higher than in other places, depending on the altitude, the nature of the soil, and the type of building materials used. In recent years, it has become clear that the largest and most dangerous single source of exposure to background radiation is in the form of naturally occurring radon gas.
It is considered that many of the cancers and birth defects that spontaneously occur in human populations are caused by our unavoidable exposure to background radiation.
K.5. Is background radiation increasing? Because of man's activities, background radiation exposure is gradually increasing as greater quantities of naturally ocurring radioactive materials are being released into the biosphere (for example, through uranium mining).
We have added significantly to the unavoidable radiation exposure of all people on earth because of fallout from nuclear weapons testing and nuclear power plant discharges, particularly in the case of a large-scale accident like Chernobyl.
The medical profession has also added to our average radiation exposure through the use of x-rays. In addition, small quantities of medical and industrial radioisotopes (man-made radioactive substances used for "tracers" or therapeutic purposes) often end up in soil, water or air.
Although the term "background radiation" is not meant to include bomb fallout, reactor discharges, medical exposures or environmental contamination from radioisotopes, it is nevertheless a fact that people all over the world are being exposed to increasing doses of radiation because of these factors.
K.6. Is radon in homes a problem? how does it get there? In the U.S., the U.K. and Sweden (but not yet in Canada), the governments have recently urged all citizens to measure the radon in their homes for their own safety.
Radon in homes is produced from tiny amounts of radium found in the soil or in building materials. Radon can also enter homes dissolved in tap water. A certain amount of radon is natural and unavoidable, but nonetheless dangerous. The more radium there is, the greater the problem. Of course, in uranium mines and in uranium tailings the amount of radon is far greater than that in most homes.
In some places, such as Port Hope, Ontario, and Grand Junction, Colorado, elevated radon levels in homes and schools resulted from the use of abandoned uranium tailings or other uranium wastes in construction. In other places, such as Oka, Quebec, and St. Johns, Newfoundland, radium-contaminated materials have been sold to unsuspecting builders, leading to high radon levels in many homes.
A new British medical study (published in The Lancet in April 1990) has found a significant correlation between elevated radon levels in homes and serious illnesses like myeloid leukemia in children and kidney cancer in adults. This study uses published statistics from fifteen countries, including Canada.
K.7. Are Canadian exposure standards being made more stringent? In recent years, Canadian authorities have been relaxing exposure standards for atomic radiation rather than tightening them. Within the last decade, the maximum permissible concentration of radium in Canadian drinking water was increased by a factor of nine. The maximum permissible concentration of uranium in water is also being increased. New regulations proposed by the AECB, and not yet passed into law as of September 1990, will increase the maximum permissible intake of many radioactive subtances in the workplace.
Meanwhile, in other countries, the standards are being tightened because of new scientific evidence which indicates that the risks from low level exposure to atomic radiation are considerably higher than was thought just a few years ago. In the U.K., the suggested maximum permissible exposure for atomic workers has been lowered to 40 percent below Canada's current permissible level. In the U.S. and the U.K., the suggested maximum permissible exposures for members of the general public are much lower -- by more than a factor of ten -- than the corresponding figures in Canada.
Canadian regulatory authorities have never held public hearings to decide on radiation standards, despite numerous official recommendations that they do so. They have they never had any representation from the broad Canadian public on their decision-making bodies. It is ironic that radiation standards are now being passed into law in Canada, based on an antiquated report published by the ICRP in 1977, rather than on the best scientific evidence which is currently available.
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Back to the SEA-US Front Page Special thanks to Dr Gordon Edwards, CCNR (http://ccnr.org/)
for permission to adapt this discussion guide from his original version.