SilentSpring.pdf, Lecture notes of Public Health

Download SilentSpring.pdf and more Lecture notes Public Health in PDF only on Docsity! BY RACHEL CARSON Under the Sea-Wind The Sea Around Us The Edge of the Sea Silent Spring SUENT SPRING FORTIETH ANNIVERSARY EDITION RACHEL CARSON Introduction by Linda Lear Afterword by Edward 0. Wilson A MARINER BOOK HOUGHTON M1FFLIN COMPANY Boston New York Introduction by Linda Lear Headlines in the New York Times in July 1962 captured the national sentiment: "Silent Spring is now noisy summer." In the few months between the New Yorker's serialization of Silent Spring in June and its publication in book form that September, Rachel Carson's alarm touched off a national debate on the use of chemical pesticides, the responsibility of science, and the lim its of technological progress. When Carson died barely eighteen months later in the spring of 1964, at the age of fifty-six, she had set in motion a course of events that would result in a ban on the domestic production of DDT and the creation of a grass-roots movement demanding protection of the environment through state and federal regulation. Carson's writing initiated a trans formation in the relationship between humans and the natural world and stirred an awakening of public environmental con sciousness. It is hard to remember the cultural climate that greeted Silent Spring and to understand the fury that was launched against its quietly determined author. Carson's thesis that we were sub jecting ourselves to slow poisoning by the misuse of chemical pesticides that polluted the environment may seem like common currency now, but in 1962 Silent Spring contained the kernel of social revolution. Carson wrote at a time of new affluence and intense social conformity. The cold war, with its climate of suspi cion and intolerance, was at its zenith. The chemical industry, one of the chief beneficiaries of postwar technology, was also one of the chief authors of the nation's prosperity. DDT enabled the conquest of insect pests in agriculture and of ancient insect- borne disease just as surely as the atomic bomb destroyed Amer- INTRODUCTION XI ica's military enemies and dramatically altered the balance of power between humans and nature. The public endowed chemists, at work in their starched white coats in remote labora tories, with almost divine wisdom. The results of their labors were gilded with the presumption of beneficence. In postwar America, science was god, and science was male. Carson was an outsider who had never been part of the scien tific establishment, first because she was a woman but also be cause her chosen field, biology, was held in low esteem in the nuclear age. Her career path was nontraditional; she had no aca demic affiliation, no institutional voice. She deliberately wrote for the public rather than for a narrow scientific audience. For anyone else, such independence would have been an enor mous detriment. But by the time Silent Spring was published, Carson's outsider status had become a distinct advantage. As the science establishment would discover, it was impossible to dismiss her. Rachel Carson first discovered nature in the company of her mother, a devotee of the nature study movement. She wandered the banks of the Allegheny River in the pristine village of Springdale, Pennsylvania, just north of Pittsburgh, observing the wildlife and plants around her and particularly curious about the habits of birds. Her childhood, though isolated by poverty and family tur moil, was not lonely. She loved to read and displayed an obvious talent for writing, publishing her first story in a children's liter ary magazine at the age of ten. By the time she entered Pennsyl vania College for Women (now Chatham College), she had read widely in the English Romantic tradition and had articulated a personal sense of mission, her "vision splendid." A dynamic fe male zoology professor expanded her intellectual horizons by urging her to take the daring step of majoring in biology rather than English. In doing so, Carson discovered that science not only engaged her mind but gave her "something to write about." XVI INTRODUCTION gantly claimed dominion over nature was the philosophic root of the problem. Human beings, she insisted, were not in control of nature but simply one of its parts: the survival of one part de pended upon the health of all. She protested the "contamination of man's total environment" with substances that accumulate in the tissues of plants, animals, and humans and have the potential to alter the genetic structure of organisms. Carson argued that the human body was permeable and, as such, vulnerable to toxic substances in the environment. Levels of exposure could not be controlled, and scientists could not ac curately predict the long-term effects of bioaccumulation in the cells or the impact of such a mixture of chemicals on human health. She categorically rejected the notion proposed by indus try that there were human "thresholds" for such poisons, as well as its corollary, that the human body had "assimilative capacities" that rendered the poisons harmless. In one of the most contro versial parts of her book, Carson presented evidence that some human cancers were linked to pesticide exposure. That evidence and its subsequent elaboration by many other researchers con tinue to fuel one of the most challenging and acrimonious de bates within the scientific and environmental communities. Carson's concept of the ecology of the human body was a major departure in our thinking about the relationship between humans and the natural environment. It had enormous conse quences for our understanding of human health as well as our at titudes toward environmental risk. Silent Spring proved that our bodies are not boundaries. Chemical corruption of the globe af fects us from conception to death. Like the rest of nature, we are vulnerable to pesticides; we too are permeable. All forms of life are more alike than different. Carson believed that human health would ultimately reflect the environment's ills. Inevitably this idea has changed our re sponse to nature, to science, and to the technologies that devise and deliver contamination. Although the scientific community INTRODUCTION XV11 has been slow to acknowledge this aspect of Carson's work, her concept of the ecology of the human body may well prove to be one of her most lasting contributions. In 1962, however, the multimillion-dollar industrial chemical industry was not about to allow a former government editor, a female scientist without a Ph.D. or an institutional affiliation, known only for her lyrical books on the sea, to undermine public confidence in its products or to question its integrity. It was clear to the industry that Rachel Carson was a hysterical woman whose alarming view of the future could be ignored or, if neces sary, suppressed. She was a "bird and bunny lover," a woman who kept cats and was therefore clearly suspect. She was a ro mantic "spinster" who was simply overwrought about genetics. In short, Carson was a woman out of control. She had over stepped the bounds of her gender and her science. But just in case her claims did gain an audience, the industry spent a quarter of a million dollars to discredit her research and malign her char acter. In the end, the worst they could say was that she had told only one side of the story and had based her argument on unver- ifiable case studies. There is another, private side to the controversy over Silent Spring, Unbeknown to her detractors in government and indus try, Carson was fighting a far more powerful enemy than corpo rate outrage: a rapidly metastasizing breast cancer. The miracle is that she lived to complete the book at all, enduring a "cata logue of illnesses," as she called it. She was immune to the chem ical industry's efforts to malign her; rather, her energies were fo cused on the challenge of survival in order to bear witness to the truth as she saw it. She intended to disturb and disrupt, and she did so with dignity and deliberation. After Silent Spring caught the attention of President John F. Kennedy, federal and state investigations were launched into the validity of Carson's claims. Communities that had been sub jected to aerial spraying of pesticides against their wishes began XVU1 INTRODUCTION to organize on a grass-roots level against the continuation of toxic pollution. Legislation was readied at all governmental lev els to defend against a new kind of invisible fallout. The scien tists who had claimed a "holy grail" of knowledge were forced to admit a vast ignorance. While Carson knew that one book could not alter the dynamic of the capitalist system, an environmental movement grew from her challenge, led by a public that de manded that science and government be held accountable. Car son remains an example of what one committed individual can do to change the direction of society. She was a revolutionary spokesperson for the rights of all life. She dared to speak out and confront the issue of the destruction of nature and to frame it as a debate over the quality of all life. Rachel Carson knew before she died that her work had made a difference. She was honored by medals and awards, and posthu mously received the Presidential Medal of Freedom in 1981. But she also knew that the issues she had raised would not be solved quickly or easily and that affluent societies are slow to sacrifice for the good of the whole. It was not until six years after Carson's death that concerned Americans celebrated the first Earth Day and that Congress passed the National Environmental Policy Act establishing the Environmental Protection Agency as a buffer against our own handiwork. The domestic production of DDT was banned, but not its export, ensuring that the pollution of the earth's atmosphere, oceans, streams, and wildlife would continue unabated. DDT is found in the livers of birds and fish on every oceanic island on the planet and in the breast milk of every mother. In spite of decades of environmental protest and awareness, and in spite of Rachel Carson's apocalyptic call alert ing Americans to die problem of toxic chemicals, reduction of the use of pesticides has been one of the major policy failures of the environmental era. Global contamination is a fact of modern life. Silent Spring compels each generation to reevaluate its rela- INTRODUCTION XIX tionship to the natural world. We are a nation still debating the questions it raised, still unresolved as to how to act for the com mon good, how to achieve environmental justice. In arguing that public health and the environment, human and natural, are in separable, Rachel Carson insisted that the role of the expert had to be limited by democratic access and must include public de bate about the risks of hazardous technologies. She knew then, as we have learned since, that scientific evidence by its very na ture is incomplete and scientists will inevitably disagree on what constitutes certain proof of harm. It is difficult to make public policy in such cases when government's obligation to protect is mitigated by the nature of science itself. Rachel Carson left us a legacy that not only embraces the fu ture of life, in which she believed so fervently, but sustains the human spirit. She confronted us with the chemical corruption of the globe and called on us to regulate our appetites—a truly rev olutionary stance—for our self-preservation. "It seems reason able to believe," she wrote, "that the more clearly we can focus our attention on the wonders and realities of the universe about us, the less taste we shall have for the destruction of our race. Wonder and humility are wholesome emotions, and they do not exist side by side with a lust for destruction." Wonder and humility are just some of the gifts of Silent Spring. They remind us that we, like all other living creatures, are part of the vast ecosystems of the earth, part of the whole stream of life. This is a book to relish: not for the dark side of human nature, but for the promise of life's possibility. i. A Fable for Tomorrow There was once a town in the heart of America where all life seemed to live in harmony with its surroundings. The town lay in the midst of a checkerboard of prosperous farms, with fields of grain and hillsides of orchards where, in spring, white clouds of bloom drifted above the green fields. In autumn, oak and maple and birch set up a blaze of color that flamed and flickered across a backdrop of pines. Then foxes barked in the hills and deer silently crossed the fields, half hidden in the mists of the fall mornings. Along the roads, laurel, viburnum and alder, great ferns and wildflpwers delighted the traveler's eye through much of the SILENT SPRING in character. The most alarming of all man's assaults upon the environment is the contamination of air, earth, rivers, and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable; the chain of evil it initiates not only in the world that must support life but in living tissues is for the most part irreversible. In this now universal contam ination of the environment, chemicals are the sinister and little- recognized partners of radiation in changing the very nature of the world — the very nature of its life. Strontium 90, re leased through nuclear explosions into the air, comes to earth in rain or drifts down as fallout, lodges in soil, enters into the grass or corn or wheat grown there, and in time takes up its abode in the bones of a human being, there to remain until his death. Similarly, chemicals sprayed on croplands or forests or gardens lie long in soil, entering into living organisms, passing from one to another in a chain of poisoning and death. Or they pass mysteriously by underground streams until they emerge and, through the alchemy of air and sunlight, combine into new forms that kill vegetation, sicken cattle, and work unknown harm on those who drink from once pure wells. As Albert Schweitzer has said, "Man can hardly even recognize the devils of his own creation." It took hundreds of millions of years to produce the life that now inhabits the earth — eons of time in which that de veloping and evolving and diversifying life reached a state of adjustment and balance with its surroundings. The environ ment, rigorously shaping and directing the life it supported, contained elements that were hostile as well as supporting. Cer tain rocks gave out dangerous radiation; even within the light of the sun, from which all life draws its energy, there were short-wave radiations with power to injure. Given time — time not in years but in millennia — life adjusts, and a balance has been reached. For time is the essential ingredient; but in the modern world there is no time. THE OBLIGATION TO ENDURE 7 The rapidity of change and the speed with which new situa tions are created follow the impetuous and heedless pace of man rather than the deliberate pace of nature. Radiation is no longer merely the background radiation of rocks, the bombardment of cosmic raysrthe ultraviolet of the sun that have existed before there was any life on earth; radiation is now the unnatural crea tion of man's tampering with the atom. The chemicals to which life is asked to make its adjustment are no longer merely the calcium and silica and copper and all the rest of the minerals washed out of the rocks and carried in rivers to the sea; they are the synthetic creations of man's inventive mind, brewed in his laboratories, and having no counterparts in nature. To adjust to these chemicals would require time on the scale that is nature's; it would require not merely the years of a man's life but the life of generations. And even this, were it by some miracle possible, would be futile, for the new chemicals come from our laboratories in an endless stream; almost five hundred annually find their way into actual use in the United States alone. The figure is staggering and its implications are not easily grasped — 500 new chemicals to which the bodies of men and animals are required somehow to adapt each year, chemicals totally outside the limits of biologic experience. Among them are many that are used in man's war against nature. Since the mid-1940's over 200 basic chemicals have been created for use in killing insects, weeds, rodents, and other organisms described in the modern vernacular as "pests"; and they are sold under several thousand different brand names. These sprays, dusts, and aerosols are now applied almost uni versally to farms, gardens, forests, and homes — nonselective chemicals that have the power to kill every insect, the "good" and the "bad," to still the song of birds and the leaping of fish in the streams, to coat the leaves with a deadly film, and to linger on in soil — all this though the intended target may be only a few weeds or insects. Can anyone believe it is possible 8 SILENT SPRING to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life? They should not be called "insecticides," but "biocides." The whole process of spraying seems caught up in an endless spiral. Since DDT was released for civilian use, a process of escalation has been going on in which ever more toxic materials must be found. This has happened because insects, in a trium phant vindication of Darwin's principle of the survival of the fittest, have evolved super races immune to the particular in secticide used, hence a deadlier one has always to be developed — and then a deadlier one than that. It has happened also be cause, for reasons to be described later, destructive insects often undergo a "flareback," or resurgence, after spraying, in numbers greater than before. Thus the chemical war is never won, and all life is caught in its violent crossfire. Along with the possibility of the extinction of mankind by nuclear war, the central problem of our age has therefore be come the contamination of man's total environment with such substances of incredible potential for harm — substances that accumulate in the tissues of plants and animals and even pene trate the germ cells to shatter or alter the very material of heredity upon which the shape of the future depends. Some would-be architects of our future look toward a time when it will be possible to alter the human germ plasm by design. But we may easily be doing so now by inadvertence, for many chemicals, like radiation, bring about gene mutations. It is ironic to think that man might determine his own future by something so seemingly trivial as the choice of an insect spray. All this has been risked — for what? Future historians may well be amazed by our distorted sense of proportion. How could intelligent beings seek to control a few unwanted species by a method that contaminated the entire environment and brought the threat of disease and death even to their own kind? THE OBLIGATION TO ENDURE 9 Yet this is precisely what we have done. We have done it, moreover, for reasons that collapse the moment we examine them. We are told that the enormous and expanding use of pesticides is necessary to maintain farm production. Yet is our real problem not one of overproduction? Our farms, despite measures to remove acreages from production and to pay farmers not to produce, have yielded such a staggering excess of crops that the American taxpayer in 1962 is paying out more than one billion dollars a year as the total carrying cost of the surplus-food storage program. And is the situation helped when one branch of the Agriculture Department tries to reduce production while another states, as it did in 1958, "It is believed generally that reduction of crop acreages under provisions of the Soil Bank will stimulate interest in use of chemicals to obtain maximum production on the land retained in crops." All this is not to say there is no insect problem and no need of control. I am saying, rather, that control must be geared to realities, not to mythical situations, and that the methods em ployed must be such that they do not destroy us along with the insects. The problem whose attempted solution has brought such a train of disaster in its wake is an accompaniment of our modern way of life. Long before the age of man, insects inhabited the earth — a group of extraordinarily varied and adaptable beings. Over the course of time since man's advent, a small percentage of the more than half a million species of insects have come into conflict with human welfare in two principal ways: as competitors for the food supply and as carriers of human disease. Disease-carrying insects become important where human be ings are crowded together, especially under conditions where sanitation is poor, as in time of natural disaster or war or in situations of extreme poverty and deprivation. Then control of some sort becomes necessary. It is a sobering fact, however, jy2 SILENT SPRING Louisiana State University Agricultural Experiment Station, Dr. L. D. Newsom: "The imported fire ant 'eradication' pro gram which has been conducted by state and federal agencies is thus far a failure. There are more infested acres in Louisiana now than when the program began." A swing to more sane and conservative methods seems to have begun. Florida, reporting that "there are more fire ants in Florida now than there were when the program started," announced it was abandoning any idea of a broad eradication program and would instead concentrate on local control. Effective and inexpensive methods of local control have been known for years. The mound-building habit of the fire ant makes the chemical treatment of individual mounds a simple matter. Cost of such treatment is about one dollar per acre. For situations where mounds are numerous and mechanized methods are desirable, a cultivator which first levels and then applies chemical directly to the mounds has been developed by Mississippi's Agricultural Experiment Station. The method gives 90 to 95 per cent control of the ants. Its cost is only $.23 per acre. The Agriculture Department's mass control program, on the other hand, cost about $3.50 per acre — the most expensive, the most damaging, and the least effective program of all. il Beyond the Dreams of the Borgias The contamination of our world is not alone a matter of mass spraying. Indeed, for most of us this is of less importance than the innumerable small-scale exposures to which we are subjected day by day, year after year. Like the constant dripping of water that in turn wears away the hardest stone, this birth-to- death contact with dangerous chemicals may in the end prove disastrous. Each of these recurrent exposures, no matter how slight, contributes to the progressive buildup of chemicals in our bodies and so to cumulative poisoning. Probably no person is immune to contact with this spreading contamination unless 178 SILENT SPRING descriptive literature that may be picked up in any hardware- or garden-supply store seldom if ever reveals the true hazard involved in handling or applying the material. Instead, the typ ical illustration portrays a happy family scene, father and son smilingly preparing to apply the chemical to the lawn, small children tumbling over the grass with a dog. The question of chemical residues on the food we eat is a hotly debated issue. The existence of such residues is either played down by the industry as unimportant or is flatly de nied. Simultaneously, there is a strong tendency to brand as fanatics or cultists all who are so perverse as to demand that their food be free of insect poisons. In all this cloud of con troversy, what are the actual facts? It has been medically established that, as common sense would tell us, persons who lived and died before the dawn of the DDT era (about 1942) contained no trace of DDT or any similar material in their tissues. As mentioned in Chapter 3, samples of body fat collected from the general population between 1954 and 1956 averaged from 5.3 to 7.4 parts per million of DDT. There is some evidence that the average level has risen since then to a consistently higher figure, and individuals with oc cupational or other special exposures to insecticides of course store even more. Among the general population with no known gross expos ures to insecticides it may be assumed that much of the DDT stored in fat deposits has entered the body in food. To test this assumption, a scientific team from the United States Public Health Service sampled restaurant and institutional meals. Every meal sampled contained DDT. From this the investigators con cluded, reasonably enough, that "few if any foods can be relied upon to be entirely free of DDT." The quantities in such meals may be enormous. In a separate Public Health Service study, analysis of prison meals disclosed BEYOND THE DREAMS OF THE BORGIAS 179 such items as stewed dried fruit containing 69.6 parts per million and bread containing 100.9 V**** Per million of DDT! In the diet of the average home, meats and any products derived from animal fats contain the heaviest residues of chlo rinated hydrocarbons. This is because these chemicals are sol uble in fat. Residues on fruits and vegetables tend to be some what less. These are little affected by washing — the only remedy is to remove and discard all outside leaves of such vege tables as lettuce or cabbage, to peel fruit and to use no skins or outer covering whatever. Cooking does not destroy residues. Milk is one of the few foods in which no pesticide residues are permitted by Food and Drug Administration regulations. In actual fact, however, residues turn up whenever a check is made. They are heaviest in butter and other manufactured dairy products. A check of 461 samples of such products in i960 showed that a third contained residues, a situation which the Food and Drug Administration characterized as "far from encouraging." To find a diet free from DDT and related chemicals, it seems one must go to a remote and primitive land, still lacking the amenities of civilization. Such a land appears to exist, at least marginally, on the far Arctic shores of Alaska — although even there one may see the approaching shadow. When scientists investigated the native diet of the Eskimos in this region it was found to be free from insecticides. The fresh and dried fish; the fat, oil, or meat from beaver, beluga, caribou, moose, oogruk, polar bear, and walrus; cranberries, salmonberries and wild rhubarb all had so far escaped contamination. There was only one exception — two white owls from Point Hope carried small amounts of DDT, perhaps acquired in the course of some mi gratory journey. When some of the Eskimos themselves were checked by anal ysis of fat samples, small residues of DDT were found (o to 1.9 parts per million). The reason for this was clear. The fat i8o SILENT SPRING samples were taken from people who had left their native vil lages to enter the United States Public Health Service Hospital in Anchorage for surgery. There the ways of civilization pre vailed, and the meals in this hospital were found to contain as much DDT as those in the most populous city. For their brief stay in civilization the Eskimos were rewarded with a taint of poison. The fact that every meal we eat carries its load of chlorinated hydrocarbons is the inevitable consequence of the almost uni versal spraying or dusting of agricultural crops with these poi sons. If the farmer scrupulously follows the instructions on the labels, his use of agricultural chemicals will produce no residues larger than are permitted by the Food and Drug Administration. Leaving aside for the moment the question whether these legal residues are as "safe" as they are represented to be, there remains the well-known fact that farmers very frequently exceed the prescribed dosages, use the chemical too close to the time of har vest, use several insecticides where one would do, and in other ways display the common human failure to read the fine print. Even the chemical industry recognizes the frequent misuse of insecticides and the need for education of farmers. One of its leading trade journals recently declared that "many users do not seem to understand that they may exceed insecticide toler ances if they use higher dosages than recommended. And hap hazard use of insecticides on many crops may be based on farmers' whims." The files of the Food and Drug Administration contain records of a disturbing number of such violations. A few ex amples will serve to illustrate the disregard of directions: a let tuce farmer who applied not one but eight different insecticides to his crop within a short time of harvest, a shipper who had used the deadly parathion on celery in an amount five times the recommended maximum, growers using endrin — most toxic of all the chlorinated hydrocarbons — on lettuce although no resi- BEYOND THE DREAMS OF THE BORGIAS l8l due was allowable, spinach sprayed with DDT a week before harvest. There are also cases of chance or accidental contamination. Large lots of green coffee in burlap bags have become con taminated while being transported by vessels also carrying a cargo of insecticides. Packaged foods in warehouses are sub jected to repeated aerosol treatments with DDT, lindane, and other insecticides, which may penetrate the packaging materials and occur in measurable quantities on the contained foods. The longer the food remains in storage, the greater the danger of contamination. To the question "But doesn't the government protect us from such things?" the answer is, "Only to a limited extent." The activities of the Food and Drug Administration in the field of consumer protection against pesticides are severely limited by two facts. The first is that it has jurisdiction only over foods shipped in interstate commerce; foods grown and marketed within a state are entirely outside its sphere of authority, no matter what the violation. The second and critically limiting fact is the small number of inspectors on its staff — fewer than 600 men for all its varied work. According to a Food and Drug official, only an infinitesimal part of the crop products moving in interstate commerce — far less than 1 per cent— can be checked with existing facilities, and this is not enough to have statistical significance. As for food produced and sold within a state, the situation is even worse, for most states have woefully inadequate laws in this field. The system by which the Food and Drug Administration establishes maximum permissible limits of contamination, called "tolerances," has obvious defects. Under the conditions pre vailing it provides mere paper security and promotes a com pletely unjustified impression that safe limits have been estab lished and are being adhered to. As to the safety of allowing a sprinkling of poisons on our food — a little on this, a little on 182 SILENT SPRING that — many people contend, with highly persuasive reasons, that no poison is safe or desirable on food. In setting a tolerance level the Food and Drug Administration reviews tests of the poison on laboratory animals and then establishes a maximum level of contamination that is much less than required to produce symptoms in the test animal. This system, which is supposed to ensure safety, ignores a number of important facts. A labora tory animal, living under controlled and highly artificial condi tions, consuming a given amount of a specific chemical, is very different from a human being whose exposures to pesticides are not only multiple but for the most part unknown, unmeasur- able, and uncontrollable. Even if 7 parts per million of DDT on the lettuce in his luncheon salad were "safe," the meal includes other foods, each with allowable residues, and the pesticides on his food are, as we have seen, only a part, and possibly a small part, of his total exposure. This piling up of chemicals from many different sources creates a total exposure that cannot be measured. It is meaningless, therefore, to talk about the "safety" of any specific amount of residue. And there are other defects. Tolerances have sometimes been established against the better judgment of Food and Drug Ad ministration scientists, as in the case cited on page 224 ff., or they have been established on the basis of inadequate knowl edge of the chemical concerned. Better information has led to later reduction or withdrawal of the tolerance, but only after the public has been exposed to admittedly dangerous levels of the chemical for months or years. This happened when hepta- chlor was given a tolerance that later had to be revoked. For some chemicals no practical field method of analysis exists be fore a chemical is registered for use* Inspectors are therefore frustrated in their search for residues. This difficulty greatly hampered the work on the "cranberry chemical," aminotriazole. Analytical methods are lacking, too, for certain fungicides in common use for the treatment of seeds — seeds which if unused BEYOND THE DREAMS OF THE BORGIAS 183 at the end of the planting season, may very well find their way into human food. In effect, then, to establish tolerances is to authorize con tamination of public food supplies with poisonous chemicals in order that the farmer and the processor may enjoy the benefit of cheaper production — then to penalize the consumer by tax ing him to maintain a policing agency to make certain that he shall not get a lethal dose. But to do the policing job properly would cost money beyond any legislator's courage to appro priate, given the present volume and toxicity of agricultural chemicals. So in the end the luckless consumer pays his taxes but gets his poisons regardless. What is the solution? The first necessity is the elimination of tolerances on the chlorinated hydrocarbons, the organic phos phorus group, and other highly toxic chemicals. It will im mediately be objected that this will place an intolerable burden on the farmer. But if, as is now the presumable goal, it is pos sible to use chemicals in such a way that they leave a residue of only 7 parts per million (the tolerance for DDT), or of i part per million (the tolerance for parathion), or even of only o.i part per million as is required for dieldrin on a great variety of fruits and vegetables, then why is it not possible, with only a little more care, to prevent the occurrence of any residues at all? This, in fact, is what is required for some chemicals such as heptachlor, endrin, and dieldrin on certain crops. If it is con sidered practical in these instances, why not for all? But this is not a complete or final solution, for a zero tolerance on paper is of little value. At present, as we have seen, more than 99 per cent of the interstate food shipments slip by without inspection. A vigilant and aggressive Food and Drug Admin istration, with a greatly increased force of inspectors, is another urgent need. This system, however — deliberately poisoning our food, then policing the result — is too reminiscent of Lewis Carroll's White l88 SILENT SPRING The new environmental health problems are multiple — created by radiation in all its forms, born of the never-ending stream of chemicals of which pesticides are a part, chemicals now pervading the world in which we live, acting upon us directly and indirectly, separately and collectively. Their pres ence casts a shadow that is no less ominous because it is formless and obscure, no less frightening because it is simply impossible to predict the effects of lifetime exposure to chemical and phys ical agents that are not part of the biological experience of man. "We all live under the haunting fear that something may cor rupt the environment to the point where man joins the dinosaurs as an obsolete form of life," says Dr. David Price of the United States Public Health Service. "And what makes these thoughts all the more disturbing is the knowledge that our fate could perhaps be sealed twenty or more years before the development of symptoms." Where do pesticides fit into the picture of environmental dis ease? We have seen that they now contaminate soil, water, and food, that they have the power to make our streams fishless and our gardens and woodlands silent and birdless. Man, however much he may like to pretend the contrary, is part of nature. Can he escape a pollution that is now so thoroughly distributed throughout our world? We know that even single exposures to these chemicals, if the amount is large enough, can precipitate acute poisoning. But this is not the major problem. The sudden illness or death of farmers, spraymen, pilots, and others exposed to appreciable quantities of pesticides are tragic and should not occur. For the population as a whole, we must be more concerned with the delayed effects of absorbing small amounts of the pesticides that invisibly contaminate our world. Responsible public health officials have pointed out that the biological effects of chemicals are cumulative over long periods of time, and that the hazard to the individual may depend on the THE HUMAN PRICE 189 sum of the exposures received throughout his lifetime. For these very reasons the danger is easily ignored. It is human nature to shrug off what may seem to us a vague threat of future disaster. "Men are naturally most impressed by diseases which have obvious manifestations," says a wise physician, Dr. Rene Dubos, "yet some of their worst enemies creep on them unob trusively." For each of us, as for the robin in Michigan or the salmon in the Miramichi, this is a problem of ecology, of interrelation ships, of interdependence. We poison the caddis flies in a stream and the salmon runs dwindle and die. We poison the gnats in a lake and the poison travels from link to link of the food chain and soon the birds of the lake margins become its victims. We spray our elms and the following springs are silent of robin song, not because we sprayed the robins directly but because the poi son traveled, step by step, through the now familiar elm leaf- earthworm-robin cycle. These are matters of record, observ able, part of the visible world around us. They reflect the web of life — or death — that scientists know as ecology. But there is also an ecology of the world within our bodies. In this unseen world minute causes produce mighty effects; the effect, moreover, is often seemingly unrelated to the cause, ap pearing in a part of the body remote from the area where the original injury was sustained. "A change at one point, in one molecule even, may reverberate throughout the entire system to initiate changes in seemingly unrelated organs and tissues," says a recent summary of the present status of medical research. When one is concerned with the mysterious and wonderful functioning of the human body, cause and effect are seldom simple and easily demonstrated relationships. They may be widely separated both in space and time. To discover the agent of disease and death depends on a patient piecing together of many seemingly distinct and unrelated facts developed through a vast amount of research in widely separated fields. 190 SILENT SPRING We are accustomed to look for the gross and immediate effect and to ignore all else. Unless this appears promptly and in such obvious form that it cannot be ignored, we deny the existence of hazard. Even research men suffer from the handicap of in adequate methods of detecting the beginnings of injury. The lack of sufficiently delicate methods to detect injury before symptoms appear is one of the great unsolved problems in medicine. "But," someone will object, "I have used dieldrin sprays on the lawn many times but I have never had convulsions like the World Health Organization spraymen — so it hasn't harmed me." It is not that simple. Despite the absence of sudden and dramatic symptoms, one who handles such materials is unques tionably storing up toxic materials in his body. Storage of the chlorinated hydrocarbons, as we have seen, is cumulative, be ginning with the smallest intake. The toxic materials become lodged in all the fatty tissues of the body. When these reserves of fat are drawn upon the poison may then strike quickly. A New Zealand medical journal recently provided an example. A man under treatment for obesity suddenly developed symptoms of poisoning. On examination his fat was found to contain stored dieldrin, which had been metabolized as he lost weight. The same thing could happen with loss of weight in illness. The results of storage, on the other hand, could be even less obvious. Several years ago the Journal of the American Medical Association warned strongly of the hazards of insecticide storage in adipose tissue, pointing out that drugs or chemicals that are cumulative require greater caution than those having no tend ency to be stored in the tissues. The adipose tissue, we are warned, is not merely a place for the deposition of fat (which makes up about 18 per cent of the body weight), but has many important functions with which the stored poisons may inter fere. Furthermore, fats are very widely distributed in the organs and tissues of the whole body, even being constituents of cell THE HUMAN PRICE IOI membranes. It is important to remember, therefore, that the fat-soluble insecticides become stored in individual cells, where they are in position to interfere with the most vital and necessary functions of oxidation and energy production. This important aspect of the problem will be taken up in the next chapter. One of the most significant facts about the chlorinated hydro carbon insecticides is their effect on the liver. Of all organs in the body the liver is most extraordinary. In its versatility and in the indispensable nature of its functions it has no equal. It presides over so many vital activities that even the slightest damage to it is fraught with serious consequences. Not only does it provide bile for the digestion of fats, but because of its location and the special circulatory pathways that converge upon it the liver receives blood directly from the digestive tract and is deeply involved in the metabolism of all the principal foodstuffs. It stores sugar in the form of glycogen and releases it as glucose in carefully measured quantities to keep the blood sugar at a normal level. It builds body proteins, including some essential elements of blood plasma concerned with blood-clot ting. It maintains cholesterol at its proper level in the blood plasma, and inactivates the male and female hormones when they reach excessive levels. It is a storehouse of many vitamins, some of which in turn contribute to its own proper functioning. Without a normally functioning liver the body would be disarmed — defenseless against the great variety of poisons that continually invade it. Some of these are normal by-products of metabolism, which the liver swiftly and efficiently makes harm less by withdrawing their nitrogen. But poisons that have no normal place in the body may also be detoxified. The "harm less" insecticides malathion and methoxychlor are less poisonous than their relatives only because a liver enzyme deals with them, altering their molecules in such a way that their capacity for harm is lessened. In similar ways the liver deals with the major ity of the toxic materials to which we are exposed. I92 SILENT SPRING Our line of defense against invading poisons or poisons from within is now weakened and crumbling. A liver damaged by pesticides is not only incapable of protecting us from poisons, the whole wide range of its activities may be interfered with. Not only are the consequences far-reaching, but because of their variety and the fact that they may not immediately appear they may not be attributed to their true cause. In connection with the nearly universal use of insecticides that are liver poisons, it is interesting to note the sharp rise in hepatitis that began during the 1950's and is continuing a fluctuating climb. Cirrhosis also is said to be increasing. While it is admittedly difficult, in dealing with human beings rather than laboratory animals, to "prove" that cause A produces effect B, plain common sense suggests that the relation between a soaring rate of liver disease and the prevalence of liver poisons in the environment is no coincidence. Whether or not the chlorinated hydrocarbons are the primary cause, it seems hardly sensible under the circumstances to expose ourselves to poisons that have a proven ability to damage the liver and so presumably to make it less resistant to disease. Both major types of insecticides, the chlorinated hydrocar bons and the organic phosphates, directly affect the nervous system, although in somewhat different ways. This has been made clear by an infinite number of experiments on animals and by observations on human subjects as well. As for DDT, the first of the new organic insecticides to be widely used, its action is primarily on the central nervous system of man; the cerebellum and the higher motor cortex are thought to be the areas chiefly affected. Abnormal sensations as of prickling, burning, or itching, as well as tremors or even convulsions may follow exposure to appreciable amounts, according to a standard textbook of toxicology. Our first knowledge of the symptoms of acute poisoning by DDT was furnished by several British investigators, who delib- THE HUMAN PRICE 193 erately exposed themselves in order to learn the consequences. Two scientists at the British Royal Navy Physiological Labora tory invited absorption of DDT through the skin by direct con tact with walls covered with a water-soluble paint containing 2 per cent DDT, overlaid with a thin film of oil. The direct effect on the nervous system is apparent in their eloquent description of their symptoms: "The tiredness, heaviness, and aching of limbs were very real things, and the mental state was also most distressing . ♦ . [there was] extreme irritability . . . great distaste for work of any sort ... a feeling of mental incompetence in tackling the simplest mental task. The joint pains were quite violent at times." Another British experimenter who applied DDT in acetone solution to his skin reported heaviness and aching of limbs, mus cular weakness, and "spasms of extreme nervous tension." He took a holiday and improved, but on return to work his condi tion deteriorated. He then spent three weeks in bed, made mis erable by constant aching in limbs, insomnia, nervous tension, and feelings of acute anxiety. On occasion tremors shook his whole body — tremors of the sort now made all too familiar by the sight of birds poisoned by DDT, The experimenter lost 10 weeks from his work, and at the end of a year, when his case was reported in a British medical journal, recovery was not complete. (Despite this evidence, several American investigators con ducting an experiment with DDT on volunteer subjects dis missed the complaint of headache and "pain in every bone" as "obviously of psychoneurotic origin.") There are now many cases on record in which both the symp toms and the whole course of the illness point to insecticides as the cause. Typically, such a victim has had a known exposure to one of the insecticides, his symptoms have subsided under treatment which included the exclusion of all insecticides from his environment, and most significantly have returned with each 198 SILENT SPRING mental disease. That link has recently been supplied by investi gators at the University of Melbourne and Prince Henry's Hospital in Melbourne, who reported on 16 cases of mental disease. All had a history of prolonged exposure to organic phosphorus insecticides. Three were scientists checking the efficacy of sprays; 8 worked in greenhouses; 5 were farm workers. Their symptoms ranged from impairment of memory to schizophrenic and depressive reactions. All had normal medi cal histories before the chemicals they were using boomeranged and struck them down* Echoes of this sort of thing are to be found, as we have seen, widely scattered throughout medical literature, sometimes in volving the chlorinated hydrocarbons, sometimes the organic phosphates. Confusion, delusions, loss of memory, mania — a heavy price to pay for the temporary destruction of a few in sects, but a price that will continue to be exacted as long as we insist upon using chemicals that strike directly at the nervous system. f it 13. Through a Narrow Window The biologist George Wald once compared his work on an exceedingly specialized subject, the visual pigments of the eye, to "a very narrow window through which at a distance one can see only a crack of light. As one comes closer the view grows wider and wider, until finally through this same narrow window one is looking at the universe." So it is that only when we bring our focus to bear, first on the individual cells of the body, then on the minute structures within the cells, and finally on the ultimate reactions of mole cules within these structures — only when we do this can we comprehend the most serious and far-reaching effects of the I?. The Other Road We stand now where two roads diverge. But unlike the roads in Robert Frost's familiar poem, they are not equally fair. The road we have long been traveling is deceptively easy, a smooth superhighway on which we progress with great speed, but at its end lies disaster. The other fork of the road — the one "less traveled by" — offers our last, our only chance to reach a des tination that assures the preservation of our earth. The choice, after all, is ours to make. If, having endured ^&^^^,%;/;.V ';. - r :1 278 SILENT SPRING much, we have at last asserted our "right to know," and if, knowing, we have concluded that we are being asked to take senseless and frightening risks, then we should no longer accept the counsel of those who tell us that we must fill our world with poisonous chemicals; we should look about and see what other course is open to us. A truly extraordinary variety of alternatives to the chemical control of insects is available. Some are already in use and have achieved brilliant success. Others are in the stage of laboratory testing. Still others are little more than ideas in the minds of imaginative scientists, waiting for the opportunity to put them to the test. All have this in common: they are biological solu tions, based on understanding of the living organisms they seek to control, and of the whole fabric of life to which these organ isms belong. Specialists representing various areas of the vast field of biology are contributing — entomologists, pathologists, geneticists, physiologists, biochemists, ecologists — all pouring their knowledge and their creative inspirations into the forma tion of a new science of biotic controls. "Any science may be likened to a river," says a Johns Hopkins biologist, Professor Carl P. Swanson. "It has its obscure and unpretentious beginning; its quiet stretches as well as its rapids; its periods of drought as well as of fullness. It gathers momentum with the work of many investigators and as it is fed by other streams of thought; it is deepened and broadened by the concepts and generalizations that are gradually evolved." So it is with the science of biological control in its modern sense. In America it had its obscure beginnings a century ago with the first attempts to introduce natural enemies of insects that were proving troublesome to farmers, an effort that some times moved slowly or not at all, but now and again gathered speed and momentum under the impetus of an outstanding suc cess. It had its period of drought when workers in applied entomology, dazzled by the spectacular new insecticides of the THE OTHER ROAD 279 1940's, turned their backs on all biological methods and set foot on "the treadmill of chemical control." But the goal of an insect-free world continued to recede. Now at last, as it has become apparent that the heedless and unrestrained use of chemi cals is a greater menace to ourselves than to the targets, the river which is the science of biotic control flows again, fed by new streams of thought. Some of the most fascinating of the new methods are those that seek to turn the strength of a species against itself — to use the drive of an insect's life forces to destroy it. The most spec tacular of these approaches is the "male sterilization" technique developed by the chief of the United States Department of Agriculture's Entomology Research Branch, Dr. Edward Knip- ling, and his associates. About a quarter of a century ago Dr. Knipling startled his colleagues by proposing a unique method of insect control. If it were possible to sterilize and release large numbers of insects, he theorized, the sterilized males would, under certain condi tions, compete with the normal wild males so successfully that, after repeated releases, only infertile eggs would be produced and the population would die out. The proposal was met with bureaucratic inertia and with skepticism from scientists, but the idea persisted in Dr. Knipling's mind. One major problem remained to be solved before it could be put to the test — a practical method of insect sterilization had to be found. Academically, the fact that insects could be steril ized by exposure to X-ray had been known since 1916, when an entomologist by the name of G. A. Runner reported such sterilization of cigarette beetles. Hermann Muller's pioneering work on the production of mutations by X-ray opened up vast new areas of thought in the late 1920's, and by the mid dle of the century various workers had reported the steril ization by X-rays or gamma rays of at least a dozen species of insects.