How serious is the fallout threat?

Title

Creator

Buechl, Helen

Contributor

Helen Buechl

Language

English

Source

Panorama XII (10) October 1960

Year

1960

Rights

In Copyright - Educational Use Permitted

Fulltext

No kidding? How Serious Is the FALLOUT THREAT? by Helen Buechl Every time it rains, it rains fallout from nuclear blasts. The amount of fallout that comes down with each rainstorm varies, but the fact remains that radioactive particles accompany each show er. The fallout consists of such radioactive particles as iodine * 131, cesium-137—and strontium-90. Fallout is classified either as “local” or widely dis tributed. The larger particles produced by the nuclear explosion give the local fallout. This radioac tive debris falls to earth within a radius of a few hundred miles of the blast. Widely distributed fallout consists of smaller particles thrown very high into the at mosphere by the explosion. This debris tends to remain in the stratosphere for a few years, los ing some of its radioactivity during this period. Man receives radiation from the radioactive particles that drift down from these bomb blasts. He acquires this radio activity through the food he eats and drinks. The particles settle on vegetables and grains that man eats, and on the grains and feed that animals eat. When animal products are eaten by man, some of the animal’s radioactivity is added to the hu man diet. Such is the case with milk. 22 Panorama Local fallout can produce ra diation sickness, skin burns and death. These acute effects de pend mainly upon the dose of radiation. Chronic effects such as cancer, lowered resistance to stresses, premature aging and premature death also depend upon the size of the radiation dose from local fallout. ^^cientists are still wrestling with the concept of thres hold. That is, can man receive a certain dose of radiation with out harm, and if there is such a “safe” amount, what is it? An other unknown is the rate at which fallout is settling on the earth. In an attempt to answer these question, scientists have been studying the strontium-90 level in milk. This is a relatively re vealing indext of the amount of fallout reaching the United States daily. It is measured in strontium units. Strontium-90 levels in milk across the country reflect the increased amount of fallout that has cluttered the atmosphere since 1954. For instance, Atomic Energy Commission reports show that at that time the strontium-90 level in milk in New York City was 2.5 units or micro-microcuries of stronstium90 per gram of calcium. (A micromicrocurie is equal to one million-millionth of one curie; the curie is an amount of radia tion equal to that produced by one gram of radium.) Before January, 1959, the figures reveal, the level had ri sen to more than 11 micromicro curies of strontium-90 per gram of calcium. The National Committee on Radiological Protection has es tablished a maximum permissi ble level of 100 strontium units for the general population. Meanwhile, the International Committee on Radiological Pro tection (ICRP) has tentatively lowered the level to 67. This in cludes the entire radioactive count of strontium-90 in man’s complete diet, not just milk. The permissible level does not mean that any radiation le vel over the limit will automa tically cause death or injury, nor, on the other hand, does it imply that any dose below the level will automatically be safe. It is simply a recommended ceiling in the lifetime strontium concentration in the bones. Other data show that bread picked at random off the shelf of a supermarket in New York Ci ty in February, 1959, was four times as “hot” as the ICRP ma ximum permissible level. The clover grown on a Raleigh, N. C., farm in July of 1957 regis tered strontium-90 content of more than twice the 100 unite allowed. October 1960 23 ■Further alarming news was revealed in a summary re port by scientists on the 1959 Fallout Prediction Panel to the Congressional Joint Subcommit tee on Atomic Energy. The re port predicted that the dose of radiation to the reproductive or gans of Americans would dou ble within the next few years. This increase will occur when cesium-137, now stored in the stratosphere, begins to descend. This prediction applies to all persons living in the north tem perate zone, including Europe ans and Russians as well as Am ericans. Currently, the dose of radiation to the reproductive or gans of persons in this zone is already two and one half times the world average. This figure, however, is within the maximum permissible level, scientists reas sure. Despite this evidence, the General Adyisory Committee to the Atomic Energy Commission recently stated that total ex ternal radiation from fallout to date, together with any estimat ed fallout from future weapons tests, is less than 5 per cent as much as the average exposure to cosmic rays and other natu ral background radiation. The amount is also less than 5 per cent of the estimated average radiation dose Americans re ceive from X rays for medical purposes, the committee added. (Man-made radiation sources include X-ray machines, radio isotopes, fluoroscopes and radiaactive waste products. Another source is radium.) This, however, is only an average. The percentages fluc tuate from 15 percent to 30 per. cent, depending upon the sec tion of the U.S. that is sampled. T he committee also report * ■ ed that human beings have lived for many generations in parts of the world having five or more times the background radiation normally found in this country, or more than 100 times the average amount of radiation from fallout in the U.S. No one has yet proved these levels are safe, however. No studies have been made to de termine the biological effects of these higher levels. But it is now beyond question that humans exposed to fairly large doses of radiation have an increased chance of developing leukemia, Dr. Austin M. Brues, director of biological and medi cal research, Argonne National Laboratory, Lemont, Ill., stated before a Congressional Subcom mittee on Atomic Energy. Simi lar evidence makes it clear that radium in the human skeleton has been responsible for cancer of the bone in humans, he said. There is still no direct evi dence that small doses of radia tion, such as those from natural background and fallout, will de 24 Panorama finitely produce a proportional ly lower number of leukemias and cancers, nor that a low dose will necessarily shorten the average life span, the scientist said. On the other side of the coin, Dr. W. L. Russell of the Oak Ridge National Laboratory, Oak Ridge, Tenn., presented re\ealing evidence concerning the effects of radiation on pregnant mice. He showed that genetic dam age—sterility, for example—can occur in unborn female mice, depending upon the length of time a dose of radiation is di rected on a target. He suggested there may be a similar reaction to radiation in pregnant humans that could result in sterile baby girls. But this does not neces sarily lead to the conclusion that there is a threshold dose of radiation above which genetic damage will occur. I^cientists appear to agree that the most likely victim of radiation exposure will be the unborn child and the infant. This is due to radioactive iodine attracted to the thyroid gland, which, in the infant, receives some 15 to 20 times the dose re ceived by adults. In addition, bone growth is most rapid during this stage of human development. Since strontinum-90 is attracted to bone, and since both radioactive iodine and strontium are pre sent in milk, an important com ponent of the child’s diet, it seems logical that the young sters will be the more likely candidates for thyroid and bone cancers. Meanwhile, Atomic Energy Commission scientists are busy considering methods for testing weapons that will avoid creat ing fallout in the first place. Dr * . Willard F. Libby, a scientist on the Commission until last June 30, has reported several pro posed ideas. One method is un derground testing deep within rock formations. The rock con tains and seals off the radioacti vity produced. Five nuclear ex plosion have been detonated in this fashion to date. Weapons may someday be fired into outer space to avoid the dangers of fallout. A dis tance of halfway to the moon or beyond would be most desir able, the AEC scientist said. * * ¥ Philosopher: “What’s the difference between a stoic and a cynic?” Coed: “A stoic is what brings babies and a cynic is what we wash them in.” October 1960 25

pages

22-25

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