by N. J. BERRILL
EVERY time an atomic bomb explodes, every time in the atomic age to come an industrial atomic plant erupts, every time we become careless in the disposal of atomic wastes that will accumulate in embarrassing quantities, the world we live in will become a little more radioactive. Some of the radioactivity will be short-lived; some of the products on each occasion will remain radioactive for generations.
If we make a persistent preparation for atomic war or if we develop atomic energy with the same carefree abandon characteristic of the industrial age so far, we can look forward to living in an environment increasingly contaminated with radioactive particles of kinds that can actually enter our system and lodge there with disconcerting consequences.
Radiation, even radioactivity, is not new. The life of the planet has been subjected to and in part called forth by solar radiation, both visible and invisible, from infrared to ultraviolet, and at all times has been bombarded by cosmic rays and the discharge of radioactive rocks. And inasmuch as living matter, whether of a pine tree or a man, embodies the earthly elements it feeds upon, we should not be surprised that we are to a slight degree naturally radioactive ourselves.
We take unto ourselves and incorporate into our very protoplasm whatever elements come our way, for better or for worse. The lighter elements come and go quickly, taking their place in the protoplasmic architecture within an hour or two of ingestion, remaining for a few days or weeks or even longer but sooner or later moving on as newcomers move in and displace them. Water itself behaves in this manner and so with carbon, nitrogen, oxygen, sodium, potassium, and a host of others. The heavier and rarer elements tend to occupy key positions, like jewels in the chemical clocks, and remain in them for longer periods, perhaps indefinitely so long as they are not jostled out of place.
Insofar as there is a certain natural radioactivity in the earth and air around us, the radioactive elements responsible stream through our substance together with the rest. There is, for instance, the same proportion of radioactive carbon in our bones and tissues as there is in the atmosphere, which comes to us by way of the food we eat. There is even a trace of radium. The total radioactivity is measurable but it does us no harm, for it has been a condition of life for so long a time, probably even from the beginning, that all living processes are adjusted or reconciled to its presence. Trouble arises only when the external intensity of radiation or cosmic bombardment increases or when larger quantities of radioactive elements enter the living system and become built into the cells and tissues.
The effects of radiation are cumulative, and a dose is usually estimated as a product of intensity and duration. Radioactive agents may be of various kinds according to their source, and range from almost insignificant electrons of X rays to the massive alpha particles emitted by radium or the relatively enormous nuclear particles resulting from atomic fission. They all act in essentially the same way when they enter a living cell, although with varying effectiveness, and either act directly as disturbers of the peace or indirectly by jarring the native chemical inhabitants so that they in turn are stirred to unwonted action.
Sooner or later, depending on the size of the active agents, how many of them enter within a given time, and how long the attack continues, some vital component of the delicate living mechanism will receive a direct hit or the whole will become so electrically charged by the invading energy that the cell either disintegrates or is so changed as to be a dangerous outlaw unable to conform to the rules of good tissue behavior. No matter how small the missiles thrown into the machinery or how gentle the trickle of electrolyzing energy entering the cell, if the activity is kept up long enough something vital will be damaged. For this reason there is no threshold below which man-made radiation can be considered safe. All radioactivity above the natural level is dangerous to life if continued indefinitely, and in the age to come public ignorance in this matter and official secrecy may readily become the unforgivable biological sin. Nature accepts no excuse for stupidity.
AT THE most innocuous level, radioactive substances are used for investigative purposes both in plants and animals, including humans. The radioactive isotopes of such elements as phosphorus and potassium are commonly employed to trace these elements through the tissues. Their radioactivity, however, is usually weak and the time spent in the body is short, so that radiation damage is negligible, as is the case when radioactive iodine is employed in localizing and estimating thyroid gland activity. The thyroid normally extracts iodine which has entered the blood from the digestive tract and builds it into its own active agent which regulates the basal rate of the metabolism of the body, but it does not discriminate between ordinary iodine and radioactive iodine, and when this is made available, the isotope rapidly accumulates in the gland with the rest anti yields information in somewhat the same manner as tracer bullets indicate the flight of an otherwise invisible stream.
Radioactive iodine can he used as a biological weapon as well as a detector. In the case of Graves’ disease, which arises from overactivity of the thyroid gland, radioactive iodine is allowed to accumulate in the gland to an extent that delivers a dose of radioactivity five hundred times as large as the tracer dose, which is strong enough to kill many of the thyroid cells, thereby reducing the overall activity of the gland and bringing it within the normal range.
The most spectacular use of the iodine isotope, however, is in the treatment of cancer of the thyroid. Sufficient is introduced into the patient to deliver radiation ten times as great again as that employed to control overactivity, so that cells accumulating the radioactive element are killed by its action. Advantage is taken of the avid appetite for iodine, whether radioactive or not, which thyroid tumor cells possess in common with normal thyroid cells, and the malignant tissue in this instance is destroyed by its own lack of discrimination.
Yet already we are faced with a radiation hazard. The patient of course may himself suffer somewhat from the general radiation of the iodine isotope, but these effects will he mild compared with the penalties of harboring an actively growing thyroid cancer. He will also irradiate the region immediately around him, although, like light radiating from a source, the radiation disperses or weakens as distance increases. Such a patient must wash his own neck, for the hands of a nurse would receive as much as a day’s allowable radiation if she permitted them to remain for one minute within three inches of the neck with its contained radioactive substance; and the patient’s urine must be stored in lead containers for seven weeks before it can safely be discarded.
What can happen to a cell or a tissue can happen to the whole organism. Cells are killed if the radiation is intense or of long duration, or the cells may continue to live out their individual lives but he unable to divide and so serve as a growing tissue. The distinction is important if you prefer one kind of death to another. One can die from direct injury to tissues, whether from radioactivity or simply heat radiation; or one can die because fresh replacement cells are no longer produced to take the place of those that are constantly dropping out of existence, particularly in the case of blood cells. These, both red and white, have but limited individual lives of a few weeks at the most, and millions are born and die each day. Your continued existence depends upon this steady renewal, and anything that restricts the source of supplies jeopardizes your whole being.
The same situation holds in the case of the skin, where new cells are forever being produced at the basal layer and dead tissue continually sloughs off from the surface. And so with many other tissues. Irradiation can put a stop to all this. You might be unaware of being hurt but, according to the degree to which the general capacity for cell divisions is reduced, you might suffer or even die from anemia or from some other equally insidious interruption of the peculiar activity which is you.
Of all the tissues of the body, the marrow of the bones appears to be more secluded and out of harm’s reach than any other. This is the tissue which manufactures both red and white blood cells and also the minute blood platelets which enable the blood to clot. Yet powerful radiation can penetrate the marrow as though nothing were in the way but water. When this occurs, as it did in the case of most of the victims of the Japanese bombings who escaped being killed by the heat blast, the effects are devastating. The body defenses against bacterial disease are broken down when the white blood cells fail to enter the blood stream in adequate numbers. The linings of the throat, lungs, and intestine ulcerate and become diseased as the ever-present bacteria invade the tissues; the majority of the more belated A-bomb deaths arose from this deficiency. Another major cause of death was the tendency of the body linings of skin, lungs, and intestine to suffer widespread pinpoint bleeding, a sort of diffuse and seeping hemorrhage resulting from the lack of blood platelets which normally plug every microscopic break in the living dikes the moment one appears. Other victims, whose marrow tissue was not quite so severely affected, suffered from various degrees of red cell anemia, leading at the very least to oxygen lack throughout the body and to impaired vitality.
The fishermen of the Fortunate Dragon who came under the fall-out of pulverized radioactive coral dust three hours after the explosion at Bikini in March, 1954, were found by Japanese physicians to be extremely deficient in both while cells and platelets, and to have both radium and radioiodine in their systems. Only some exceptional medical treatment based upon experience gained after the Hiroshima holocaust has limited the fatality so far to the single death of last September. Even now it is too soon to say that the surviving men are safely through their ordeal; for quite apart from the probable retention of radium in the body, there is a possible delayed effect which has been demonstrated in animals subjected experimentally to radiation exposure. Dr. John C. Bugher, head of the Atomic Energy Commission’s biological and medical committee, has informed the armed services subcommittee of the Senate that there is a statistical shortening of life expectancy, not from any specific cause of death but from a general acceleration of the aging process. Cell replacement rates are lowered, and the waning struggle to replace worn-out units sets in sooner and reaches its mortal climax at an earlier date.
The massive experiment on human beings is still too recent for any significant results to be available. In a few more decades, if statistical records of the Hiroshima population are kept, we may know whether we are as susceptible as our laboratory animals. As a countercheck we have the three hundred individuals of the Marshall Islands and task force personnel who also received injurious radiation in the March, 1954, Bikini test, according to Dr. Bugher. The probability, however, is that the life expectancy of irradiated humans has been as definitely shortened as it has been in laboratory rats and mice.
An ominous sign would be the occurrence of incipient cataract at an unusually early age, such as was seen shortly after the end of the war in a number of American scientists all of whom had worked with the atomic cyclotrons, and in over 40 per cent of those irradiated persons who survived the Hiroshima blast. Even X rays of a certain dosage produce lens opacity or cataract in rabbits after a latent period of about six months. The damage appears to be within the slowly dividing cells of the lens epithelium, which subsequently give rise to degenerate lens fibers. Yet this is but a visible sign of radiation impact. The tissues of the body as a whole are just as vulnerable, although some are more sensitive than others; white blood cells lead the way, bone and nerve are the least susceptible, while the basal cells of the reproductive glands are somewhere between.
THE general pervasive effect of external radiation, however, is — so far as the individual is concerned —overshadowed by the heavy radioactive elements or particles which readily enter the living system and there take up a more or less permanent abode. Radium itself has long been notorious in this connection, for it localizes in the skeleton, and workers in industries using luminous paint were the first victims of ignorance of this danger. The hard substance of bone is made up mostly of crystals of calcium phosphate; but while there is a steady turnover of material as in other kinds of tissues, the process here is relatively very slow and years may elapse before displacement occurs. Elements of the same group as calcium, however, have the same predisposition to enter and become part of the bony tissue; or perhaps it is better to say that bone cells do not distinguish between calcium and its richer and heavier relatives such as strontium and radium. Strontium is usually harmless since it is not normally radioactive, but radium as such is naturally unstable and is in the process of changing to lead with the emission of alpha particles and electrons of tremendous energy, which leads to a somewhat paradoxical biological situation.
Radium encased in platinum to regulate the radiation has been extensively employed during the first half of this century as needles implanted in cancerous tissue to kill off the malignant cells within a certain short range, in the same manner that radioiodine kills thyroid cells. The far more powerfully radioactive isotope of cobalt now being produced in atomic plants by long-continued bombardment of ordinary cobalt with high-energy neutrons, however, seems about to take its place in the treatment of cancer. On the other hand these therapeutic radioactive agents are themselves only too well able to cause cancer; they can produce it and they can cure it, though under very different circumstances.
A living cell is vulnerable in several ways. The whole can be smashed to smithereens if the radiation is excessive. At a lower radiative level the cell may be left intact but be unable to divide to form two daughter cells, with whatever consequences to the organism as a whole that such restriction implies. If, however, the radiation, particularly the kind emitted by radium, is not too disruptive and does not interfere with the cell’s capacity to undergo division, it may still produce a change in the chromosomes of the cell so that it behaves as a stranger among its neighbors.
A dislocation of the cell’s internal governing agents may be brought about by a lucky or unlucky shot so that, while the cell remains as vigorous as ever, it no longer is held in bounds by the normal restraints and now proliferates with a wild abandon, invading the tissues of its host and onetime parent as a malignant cancerous growth. Radium incorporated into bone and discharging its radiation unceasingly into adjacent cells is likely to bring about such a change as this after firing away at random for about fifteen years, and about 10 per cent of its victims suffer consequent cancer of the bone since bone cells are those that are within closest range.
In the past the likelihood of developing bone cancer as the result of absorption of radium was slight, once the danger was recognized. The hazards now facing us are much more formidable. Uranium miners, for instance, appear to have assumed the role of the earlier radium workers, although in the case of miners generally the occupational hazard is primarily the dust which lodges as particles in the lining of the lungs. When the dust is radioactive, the lining cells are subject to the same sort of unremitting bombardment as are bone cells in the case of radium. And according to Dr. Wilhelm Hueper of the National Cancer Institute at Bethesda, lung cancer by 1953 had killed 40 to 50 per cent of uranium miners in Joachimsthal and from 75 to 80 per cent of the miners in other radioactive mines in Schneeberg in Central Europe.
Aside from the unthinkable catastrophe of atomic war, the greatest threats we probably have to contend with — greater perhaps even than a continuation of test explosions — are the common failings of industry intensified to a fantastic degree by radioactivity: namely, the faulty disposal of atomic waste and the possibility of accidents either to workers within an atomic plant or to the plant itself and the community around it.
Accidents can happen, as in the case of the Chalk River Atomic Pile in Canada in 1952 when a crack in the reactor allowed a stream of neutrons to escape and contaminate the plant with radioactivity, causing a three-month shutdown while the plant was decontaminated. So far as is known, no harm was done to the personnel, the radioactivity has been brought under control, and virtually all of the radioactive water which escaped was recovered. Chalk River, moreover, is a well-isolated community comparable in its own way to Los Alamos, When atomic power plants become numerous and the problem of disposing of the large quantities of waste fission products becomes acute, the penalties for carelessness or stupidity may become too great to be tolerated.
Unwanted and deadly fission products somehow must be disposed of. Dr. L. P. Hatch of the Atomic Energy Commission laboratory at Brookhaven predicts that by the year 2000 the annual wastes will be equivalent to more than 400,000 tons of radium. What shall we do with them? The suggestion made in England that they be buried in deep abandoned coal mines raised a protest among miners, and the containers were quietly sunk in the Atlantic Ocean beyond the edge of the continental shelf. By the time the containers have eroded, the radioactivity within supposedly will have subsided; thus the deep sea may in fact be a safe place for such disposal. The products can, of course, be put to some use, such as destroying or sterilizing insect pests in grain or preventing the sprouting of tubers in storage, as proposed by the director of the American Machine and Foundry Company’s Atomic Energy Department in New York City. Human ingenuity will undoubtedly find many uses for them — which is the trouble, for fission products are not like fire, which burns but can be seen. They are as deadly as their rays are invisible, and it is only human to make mistakes,
ONE of the fission products most likely to be produced as a by-product of atomic energy and probably from test bomb explosions is radioactive strontium, which acts like a lighter and more lively radium. If exposure to radiostrontium is acute, dogs and goats, for instance, remain in good health until about a week before death; then fever, lethargy, loss of weight, cutaneous bleeding, and ulceration of the skin and mouth all appear as the animals’ tissues come rather suddenly to the end of their resources for renewal — and death occurs. In its chronic effects, however, radiostrontium is a producer of bone tumors outranking radium itself. Within two hours of inhalation or ingestion the maximum amount is already incorporated in the bones and will stay there for as long as twentyfive years, occupying the same chemical positions as calcium. Accordingly, much more gets built into the skeleton of young growing animals or of any individuals who have been on a low calcium diet and are, chemically speaking, reaching out for as much calcium, or what appears to be calcium, as they can get. Young people would be exposed to greater risk than older persons, whose bones are hard and fully formed. Specific substances of this sort together with the subtle effects of general irradiation typify the dangers of the atomic age.
Accidents, however, can happen on a scale comparable to small atomic bomb explosions, for the nuclear power plants that will inevitably be built may have a wildness of their own far surpassing any of her industrial projects. Nuclear power reactors are more hazardous machines than any other kind, because they will at all times contain radioactive materials, fission products, and certain kinds of reactor fuel, and because a plant will at times contain much more fissionable material than the safe amount.
The fission products are produced by the reactor fuel during the process of fuel consumption, and consequently are bound to accumulate as the power is generated. They include a large variety of radioactive chemicals which if inhaled or swallowed would be from three million to one thousand million times as poisonous as chlorine, itself the most deadly of the more common industrial poisons until now. Dr. Edward Teller, of hydrogen-bomb fame, says that “there is still no foolproof system that couldn’t be made to work wrongly by a big enough fool. The real danger occurs when a false sense of security causes a letdown of caution.”For a nuclear power plant has a built-in capacity for self-destruction within a fraction of a second, resulting from the fact that the reactor core under certain circumstances will accumulate enough fissionable material to start a runaway chain reaction and blast. If this should happen, the plant of course would be wrecked, but the main hazard would be the release of the radioactive fission products in the form of a cloud which would be lethal for most of the plant personnel. If such a cloud should escape from the building, it would have much the same effect as the fall-out from an atomic bomb, although on a more restricted scale.
In discussing this topic at a meeting of the Atomic Industrial Forum in Now York, Dr. George Weil, who in a sense initiated the atomic age himself by pulling out the last control rod of the first atomic pile, predicted that if such a cloud drifted away at three or four miles an hour from a plant which had been producing 100,000 kilowatts, people in the path of the cloud for a distance of several miles would inhale lethal quantities of the fission substances; and if the cloud should touch the ground, the lethal distance would extend further, with varying degrees of non-lethal or delayed injury affecting a much wider area. Dr. Weil suggested that since it is impractical for a power industry to be located in remote unpopulated regions, and since it is too expensive to build elsewhere on sites large enough to contain the damage, buildings must be built gas-tight and fission-tight, with warning systems to enable a community to run from the path of any fission cloud that might escape.
INSOFAR as we develop atomic energy, exploit radioactive isotopes, and prepare for atomic war without protecting ourselves from radiation, we will injure ourselves in peculiarly nasty ways. We can blame only ourselves if we permit this venture to get out of hand, knowing beforehand the penalties we invoke for stupid or careless action. The menace of the atomic age now forces mankind as a whole to look forward, seeing with troubled concern the biological sins of the parents descending upon the children generation after generation.
The problem is this: that the progressive evolution of any species, man included, occurs to a great extent by little spontaneous changes or mutations in the hereditary chromosomes of the reproductive cells. These changes appear to be at random, and the only reason why they result in a progressive change in a particular direction is the natural selection of those variations which make their owners more likely to leave progeny. Which changes are valuable and which are not depend greatly upon external circumstances, but the random nature of the changes themselves seems to be for the most part due to an inherent chemical instability in the hereditary substances.
A small percentage of the changes, however, appears to be the result of bombardment by cosmic rays from outer space and of radioactivity from the crust of the earth, and any increase in this high-energy radiation increases the frequency of the changes without in any way altering their random character. The more frequent the changes, therefore, the greater the need to select the good from the bad; and unless there is such an intensification of selection when the rate of change or mutation is raised, the long-term consequences may be disastrous to the health and prospects of the species.
The present concern of scientists everywhere — except in Russia, where the generally accepted theory of genetics has been repudiated — comes from recognition of the particular radiosensitivity of both male and female reproductive cells, and of the fact that there is no level below which radiation can be considered to have no effect. Not even the natural radioactivity level of the environment itself is safe if we should counteract the process of natural selection altogether, which in some ways we are tending to do. Generally speaking, unless circumstances are forcing a species to change its character to some extent in order to survive, almost all hereditary mutations must be considered to be disadvantageous. The great majority of mutations so far observed involve a loss of vigor and a lowered reproduction rate. In the case of mammals, one quarter of such naturally occurring mutations are thought to be caused by the normal environmental radiation, although all the relevant information is not yet available. In our own case, considering our exceptionally long exposure to such radiation before we reach our usual reproductive age, the percentage may be even higher.
Persistent radiation of a human population at only a slightly higher level than that already existing may accordingly, in the course of many generations, result in a progressive inferiority and lower vitality and breeding potential. Dr. Curt Stern of the University of California, has shown experimentally that even in short-lived insects like the fruit fly an increase in total radiation level to merely twice that of the normal environment produces a marked increase in the frequency of mutations. We would be no less susceptible under similar conditions, and it is exactly those conditions which are now in sight.
The present rate of setting off test bomb explosions in the United States and elsewhere, if maintained, is calculated to double the total radiation level of the environment within a few decades. If the practice or its equivalent is continued indefinitely, the results can be disastrous, particularly to mankind. We are in any case inclined to let all breed who can, irrespective of quality; and if by chance the changed individuals should be more rather than less fertile, which is a possibility, the process of deterioration would be speeded up and could well become catastrophic. Of one thing we can be certain, which is that persistent radiation, however weak, is bound to produce change, however subtle, and that such change will affect, the whole organism and nearly always in a detrimental sense.
In a report released in March, 1955, Dr. Robert H. Holmes, director of the United States Atomic Bonb Casually Commission in Japan, stated that the 70,000 babies born to A-bomb irradiated parents seemed healthy and happy, but said that whether their descendants will be affected remains to be seen. It is, as he implies, much too soon to estimate what the consequences may be. The immediate damage to the parental reproductive glands has already passed. Infertility existed among the adult survivors for a while but it disappeared eventually as the damaged cells died and were replaced by others, which may have suffered small mutational changes in their chromosomes but were otherwise healthy. Early miscarriages took care of most of the abnormal embryos conceived during the transitional period. Yet the fact remains that mutations almost certainly did occur in response to the radiation and that sooner or later they will make themselves felt.
We must expect all the distressing hereditary conditions known to man, such as hemophilia, color blindness, congenital deafness, and so forth, to be increased in frequency by irradiation which reaches the reproductive organs; and since the effects are cumulative, even the smallest doses of lowest intensity will add their quota to suffering and distress. They may be long delayed, possibly for hundreds of years, yet eventually genetic murder will out. If such effects are considered by policy makers to be too insignificant to justify measures to avoid them and mutations are invoked every generation, the effects would pile up layer on layer and the general decline would accelerate. Only a corresponding rise in the overall birth rate, accompanied by a stringent selection, could counteract it. This, as a matter of fact, is where the problem becomes aggravated.
Mankind can be divided into three sections according to its practice or philosophy with regard to reproduction. The Western world, insofar as it promotes the welfare of the individual and raises the average life expectancy close to the Biblical span, reduces the birth rate and tends to bring the population more into balance with its resources. At the same time it very definitely curtails the selective force of circumstance, for the more we take care of the less vigorous and less well endowed members of our society and allow them to be more rather than less propagative than the rest, the more vulnerable as a whole do we become to radiative reproduction rot.
In southeast Asia, including China and India, the situation is very different. Average life expectancy is less than thirty years instead of more than sixty, and both the death rate and the birth rate are approximately at the biological maximum for a human population. In such communities as these the untoward effects of atomic radiation, while still serious, would be progressively eliminated at a much faster rate than in our own society. In fact if the human race as a whole subjects itself to excess of atomic radiation beyond a certain but undetermined amount, a general return to the short-lived but rapidly reproducing populations characteristic of humanity everywhere until a few centuries ago may well be a condition of survival.
The third section of mankind is Russia, which fits neither the Western nor the Eastern category. It is intent upon raising the average life expectancy to a level comparable with that of the West and at the same time raising the total population as rapidly as possible— a high birth rate and a low death rate, which is essentially a transitional stage between the old and the new. The peculiar state of mind lies less in the reproductive trend than in the officially propagated belief concerning the nature of inheritance. This might be unimportant if the consequence were merely Russian misunderstanding concerning the breeding of crops and domestic animals, but it places Russia in the role of a man playing with a shotgun he believes is not loaded. If it goes off, we are all likely to be in the line of fire.