Part J : THE HEALTH EFFECTS OF ATOMIC RADIATION J.1. Can the human body protect itself from radioactive materials?
J.2. How does atomic radiation cause cancer?
J.3. How does atomic radiation cause genetic defects in children?
J.3a. How do we know that atomic radiation causes genetic damage?
J.4. How else can atomic radiation damage unborn children?
J.5. Is there a cure for radiation victims?
J.6. Can radioactivity be detected by human senses?
J.7. Are medical and dental x-rays free of risk?
J.1. Can the human body protect itself from radioactive materials?The body has no way of protecting itself from radioactive substances in food or air. It takes them in and stores them in the lungs, muscles, bones and other organs, just as if they were natural foods.
Inside the body, when the radioactive material decays, it explodes (microscopically), causing damage to the tiny living cells. When many of these cells are damaged, the body is less able to fight off a variety of infectious diseases.
J.2. How does atomic radiation cause cancer? Chronic illnesses -- including leukemia or cancer -- can be caused by atomic radiation. When cells are damaged in such a way that they begin to reproduce in an abnormal and uncontrolled fashion, they have become cancer cells. As the cancer spreads, it destroys healthy tissue, and unless arrested, it eventually kills the host organism. Leukemia is a cancer of the bone marrow, which results in the uncontrolled overproduction of white blood cells to the detriment of other blood cells.
It takes time for a cancer to grow, so the effect is not apparent immediately. It often takes many years before cancer caused by breathing radioactive air or eating contaminated food can be spotted by a doctor. Even then, it is usually impossible for the doctor to tell whether that specific cancer was caused by atomic radiation.
J.3. How does atomic radiation cause genetic defects in children?
Radiation damage to the father's sperm or the mother's eggs can result in a damaged child. Atomic radiation workers, such as uranium miners, take the greatest risk of having a damaged child because they are in closest contact with radioactive materials. A child suffering from genetic damage can pass that damage on to future generations.
Since the father's sperm is replaced every three or four months, he could theoretically wait for some time after working in the mine before fathering a child. However, if his body is contaminated with long-lived radioactive materials, his sperm could continue to be damaged by internal exposure to radiation even after quitting his mining job.
Women carry in their bodies from birth, all the eggs they will ever have. Damage to a woman's eggs at any one time can result in a damaged baby many years later.
J.3a. How do we know that atomic radiation causes genetic damage? Genetic damage has been observed and documented in every laboratory species that has been so far studied, including mammals, insects, micro-organisms and plants.
Genetic damage sometimes results in an unviable organism, leading to spontaneous abortion or premature death. Some kinds of genetic damage result in gross abnormalities or deformities, whereas other types involve subtle differences which are difficult to detect. In fact, some forms of genetic damage are not seen in the first or second generations, but only later, after several generations have passed.
Among human populations, there is little direct evidence of radiation-induced genetic damage. Several scientific studies have found a significant increase in the incidence of a genetic disease known as Down's syndrome (also called mongolism) following irradiation of the mother, but other studies have not shown a comparable increase. An unusually high incidence of Down's syndrome has also been reported from some geographical regions where the background radiation levels are likewise unusually high. Thus, while there is evidence that radiation causes Down's syndrome, the evidence is not conclusive.
Despite the lack of conclusive studies showing genetic effects in humans, scientists consider it virtually certain that such effects are indeed caused in humans by exposure to atomic radiation, since these effects have been demonstrated in many other species.
J.4. How else can atomic radiation damage unborn children?
A recent British study (the Gardner Report, published in the Journal of the British Medical Association in February, 1990) shows that the children of men who work in the Sellafield nuclear plant in northern England experience a much higher rate of leukemia than other children. The radiation exposure of the father appears to play an important role. It may be that damage to the sperm before conception causes leukemia in the children born later on -- but no one knows exactly how or why.
Even if the father and the mother conceive a healthy baby, that baby is vulnerable to radiation while it is growing in the mother's womb. Whatever the mother eats can travel through the umbilical chord to the baby and damage it so that it is born with a disease or a deformity. The unborn child can also be affected by penetrating radiation from outside the mother's body. Sometimes when a baby is seriously damaged before birth it is spontaneously aborted or it dies at the time of birth.
Mental retardation due to brain damage is the most likely form of developmental abnormality resulting from exposure to atomic radiation, if the fÏtus is exposed during the critical period when the child's brain is being formed. Radiation-induced mental retardation has been observed and documented in animals as well as humans.
J.5. Is there a cure for radiation victims? Some of the damage caused by radiation is healed by the body's own power to heal itself. Rarely is the healing perfect. Medical treatment can relieve some of the side effects of radiation damage and can prolong life through cancer surgery or treatment.
J.6. Can radioactivity be detected by human senses? In concentrated form, radium or thorium or polonium can give a person a severe burn. Also, when uranium is exploded in an atomic bomb or "burnt" in a nuclear reactor, many radioactive substances are produced, that give off atomic radiation intense enough to kill a person very quickly with burning pain.
However, at much lower doses, such as those experienced in uranium mining, atomic radiation cannot be detected by any of our human senses. Special instruments are needed. Alpha radiation, the kind associated with radon gas and most of the other uranium decay products, is difficult to detect even with instruments.
J.7. Are medical and dental x-rays free of risk? Although x-rays are often useful and sometimes necessary, they do cause damage to living cells, slightly increasing the risk of both cancer in the individual exposed and genetic damage to his or her subsequent offspring. That's why lead aprons or shields are now used to protect the patient's gonads.
As with all forms of atomic radiation, the risk from x-rays is cumulative; it increases with each extra little dose. That's why doctors, nurses and technicians often leave the room or duck behind a wall while a patient is being x-rayed.
Although the risk from one x-ray is small, the public health consequences of routine exposures can be serious because of the large numbers of people exposed to that small extra risk. That's why x-ray machines in shoe stores (letting kids see their toes wriggle) have been disallowed, and mass programs of chest x-rays have also been discontinued.
Twenty-five years ago, Dr. Alice Stewart (a British M.D.) showed that a single diagnostic x-ray to the abdomen of a pregnant woman increased by fifty percent the chance that her child would later develop leukemia. It is no longer acceptable to x-ray unborn babies unless there is a compelling medical reason to do so.
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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.