The total value of DDT to mankind is inestimable. Most of the peoples of the globe have received benefit from it either directly by protection from infectious diseases and pestiferous insects, or indirectly by better nutrition, cleaner food, and increased disease resistance. The discovery of DDT will always remain an historic event in the fields of public health and agriculture. 188
Such being the perversity of human nature, it could only be a matter of time before people started finding reasons why something as good as that couldn't be allowed to continue.
Opening Assault: Silent Spring
Throughout history there have been those who opposed, or who were simply left not especially impressed by, the furthering of technology and its application to ends traditionally considered indicative of human progress toward better things. Their motives vary from sincere conviction as to the folly of playing God and the likely outcomes of meddling with nature, through simple disenchantment with the results, political opportunism, publicity and status seeking, to resentment at society's building itself around values that they feel exclude them. In some ages they have been lonely minorities, largely ignored and at odds with the fashion of the times; at others, particularly when change has been rapid or heightened social conflict results in yearnings for stability or a return to the imagined tranquility of an earlier age, their influence has been significant in shaping the flow of events.
The 1960s was a time when all these currents converged. A new generation separated from roots in the past by the disruptions of World War II was manifesting an awakening social conscience through such channels as the civil rights movement and challenges to all forms of traditional authority. The destructiveness of the war, particularly its climaxing in the atomic devastation of two Japanese cities, followed by the specter of general nuclear annihilation promulgated through the Cold War with the Soviet Union, made for a climate of distrust in "Big Science" wedded to "Big Politics," with widespread questioning of whether all the effort and upheaval had brought any worthwhile benefits at all. And waves of radical technological change coming in such forms as mass automobile and jet travel, computing and electronics, nuclear energy, the space program, coupled with social revolutions sweeping away the old political and economic order across three quarters of the world had left people everywhere reeling in bewilderment and the social organism in need of respite to collect itself back together and regain cohesion.
In 1962, naturalist and writer Rachel Carson published a book called Silent Spring that touched a sympathetic note in just about every one of the simmering discontents and nagging apprehensions waiting to be released. But for once, the dangers were straightforward and comprehensible, the villains of the piece identifiable, and rising frustrations saw the prospect of relief through a chance to take action that could make a difference. Carson's work was an eloquent and passionate indictment of what many had come to regard as man's reckless chemical assault in the name of misplaced humanitarianism and the pursuit of profits on the natural environment. Its major target was DDT. The general tenor can perhaps be assessed from the following, taken from the first chapter, "Fable for Tomorrow," which in execution and effect must be described as brilliant.
"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." The idyllic picture is developed at some length and concludes, "So it had been from the days many years ago when the first settlers raised their houses, sank their wells, and built their barns."
There continues (pp. 13–14):
Then a strange blight crept over the area and everything began to change. Some evil spell had settled on the community: mysterious maladies swept the flocks of chickens; the cattle and sheep sickened and died. Everywhere was a shadow of death. The farmers spoke of much illness among their families. In the town the doctors had become more and more puzzled by new kinds of sicknesses appearing among their patients. . . .
There was a strange stillness. The birds, for example—where had they gone? . . . The few birds seen anywhere were moribund; they trembled violently and could not fly. It was a spring without voices. On the morning that had once throbbed with the dawn chorus . . . only silence lay over the fields and woods and marsh. . . .
The roadsides, once so attractive, were now lined with browned and withered vegetation as though swept by fire. These, too, were silent, deserted by all living things. Even the streams were now lifeless. Anglers no longer visited them, for all the fish had died.
In the gutters under the eaves and between the shingles of the roofs, a white granular powder still showed a few patches; some weeks before it had fallen like snow upon the roofs and the lawns, the fields and streams.
No witchcraft, no enemy action had silenced the rebirth of new life in this stricken world. The people had done it themselves.
J. Gordon Edwards is a professor emeritus of entomology at San Jose State University in California, having taught biology and entomology there for over forty years, and a lifetime fellow of the California Academy of Sciences. He is also a long-term member of both the Audubon Society and the Sierra Club, the latter of which published his book Climbers' Guide to Glacier National Park. Such a person should certainly qualify as a sincere lover of nature and knowledgeable scientist with concerns for protecting living things. In 1992 he wrote of Silent Spring:
" . . . I was delighted. I belonged to several environmental-type organizations, had no feelings of respect for industry or big business, had one of my own books published by the Sierra Club, and I had written articles for The Indiana Waltonian, Audubon Magazine, and other environmental magazines. . . . I eagerly read the condensed version of Silent Spring in the New Yorker magazine and bought a copy of the book as soon as I could find it in the stores." 189 The enthusiasm carried him onward for a while. "As I read the first several chapters, I noticed many statements that I realized were false; however, one can overlook such things when they are produced by one's cohorts, and I did just that."
But by the middle of the book, his feeling had grown that "Rachel Carson was really playing loose with the facts and deliberately wording many sentences in such a way as to make them imply certain things without actually saying them." Upon checking the references that were cited, Edwards found that they did not support the book's contentions about harm being caused by pesticides. He concluded, "When leading scientists began to publish harsh criticisms of her methods and her allegations, it slowly dawned on me that Rachel Carson was not interested in the truth about these topics, and that I really was being duped, along with millions of other Americans."
Millions of other Americans, however, did not possess the background knowledge of somebody like Edwards or read the journals in which leading scientists published their criticisms. What they did see was a media and journalistic frenzy of sensationalism, nascent action groups discovering a moral crusade of fund-raising potential that was without precedent, and politicians vying for public visibility as champions of the cause. Leading environmentalist organizations found they had become big business and campaigned to expand the operation. In July 1969 the National Audubon Society distributed seventeen thousand leaflets to its members urging them to support the position that DDT should be banned throughout the United States and its export prohibited. In February 1971 the director of the Sierra Club declared , "The Sierra Club wants a ban, not a curb, on pesticides, even in the tropical countries where DDT has kept malaria under control." 190
The Offensive Develops
The attack against DDT was based, essentially, on three broad allegations: (1) that it interfered with bird reproduction, causing mass die-offs among the population; (2) that it persisted in the environment and its concentration was magnified at higher levels of the food chain, and (3) that it caused cancer. While all of these claims continued to draw vigorous opposition within
the scientific community, the popular imagery depicted a heroic grass-roots battle affecting everyone.
The imagery and attendant political pressures had their effects overseas, too. Many of the countries that had joined energetically in the war on malaria cut back or abandoned their programs. In 1967 the World Health Organization (WHO) changed its official goal from worldwide "eradication" to "control of the disease, where possible." In India, where health officials at one point had believed malaria on the point of being eradicated, the number of cases returned to a million in 1972, to quadruple by 1974. Ceylon, which in 1963 had brought its incidence down to just 17 cases with no deaths, halted its program on the strength of the claims and public opposition in the West. The number of cases went back up to 308 in 1965; 3,466 in 1967; 17,000 in January 1968; 42,000 in February, and thereafter, millions. 191
A new phenomenon in the midst of all the stirred-up passions was the emergence of groups of scientists taking openly partisan positions on controversial issues. Hence, in addition to receiving a one-sided treatment from large sections of the press, the public was also exposed to statements from positions accepted as carrying scientific authority, but which represented advocacy rather than the impartial exposition that was expected. The situation was exacerbated by the tendency for professional disapproval of such practices to be expressed in limited-circulation, specialized journals rather than the popular media where the original slanted material appeared.
In 1967 the Environmental Defense Fund (EDF) was founded by Victor Yannacone, a New York attorney; Charles Wurster, then assistant professor of biology at the State University of New York, Stony Brook; George Woodwell, a plant physiologist at the Brookhaven National Laboratories on Long Island, and several other scientists with environmental concerns. The stated aim was "to create, through litigation, a body of legal interpretations for natural resource conservation and abatement of ecologically perilous situations." The law courts, then, would be made the forum for the environmental debate. This meant that procedures followed in legal hearings, where each side presents only those points that best support its case, would be applied to deciding what were essentially scientific issues—even if the consequences had significant social implications. But a scientific debate can only be properly decided after consideration of all the pertinent data and all of the available evidence. The truth value of a scientific statement is not affected by debating skill or the persuasive powers of a trained advocate.
In the late sixties the EDF initiated a number of legal actions challenging local practices in various areas, an example being 1967, where it filed suit in western Michigan to restrain nine municipalities from using DDT to spray trees against Dutch elm disease. While in the main these cases lost in court, they were successful nevertheless in gaining publicity and attracting broadbased support through a process of education-by-headlines. Scientists heady with the new feeling of celebrity status took to the laboratories and produced results backing their claims, for example two studies published in 1969 purporting to show that DDT caused cancer in mice. 192 When public interest waned, they called journalists to organize press conferences.
In 1971 a group of environmentalist organizations led by the EDF brought suit against the recently formed (1970) Environmental Protection Agency, which had taken over from the Department of Agriculture the regulation of pesticide registration and use, for the sale and use of DDT to be banned. In response to an appeal by the Montrose Chemical Company, the sole remaining manufacturer of DDT in the United States, and the Department of Agriculture in conjunction with about thirty suppliers of products containing DDT, the EPA appointed a scientific advisory committee to investigate and report on the situation. The hearings began in August 1971.
The 1971 EPA Hearings
Well-Designed, Well-Executed Experiments:
DDT as a Carcinogen
One of the major causes of public concern was the claim that even small amounts of DDT residues could accumulate in the body tissues over time and cause cancers. Samuel Epstein, a principal witness for the EDF, testified that DDT had been shown to be carcinogenic in well-designed experiments, and that in his opinion there was no safe exposure level. 193 This was immediately picked up and echoed widely by the popular press, and also cited in the "Point of View" column in Science (175: 610). None of the press, however, gave space to the testimonies of several other experts, among them Jesse Steinfield, the U.S. Surgeon General, and John Higginson, director of the International Agency for Research on Cancer, that DDT is not a human carcinogen. Neither did Science condescend to publish a letter from W. H. Butler of the British Medical Research Council, who also testified at the hearing, opposing the view expressed by Epstein. So, regardless of the hyped phrases and the font sizes in which the headlines were set, what can be made of the facts?
Repeated incessantly by the media, and still heard today, was the mantra that a single molecule of a carcinogen is capable of initiating a tumor, and hence no level of exposure is safe. All one can say here is that this goes against the long-established principle of toxicology that recognizes a threshold of dose below which adverse effects become undetectable—and hence to assert their reality becomes a matter of faith, not science. This was acknowledged as far back as the sixteenth century by Paracelsus, who noted that "The dose makes the poison." Were it not so, it is doubtful whether any individual could ever survive to maturity and perpetuate the species, for in sufficient doses and under suitable conditions just about anything can be made to induce cancers, examples being honey, egg yolk, plain table salt, and even water. Of course, anyone is free to disagree. But when such a view is presented in such a way that it is likely to be taken as representative of expert opinion, the result is clearly misleading. In the words of Claus and Bolander (p. 324):
[F]or although [Epstein's] right to hold his own opinions and make dissenting evaluations cannot be questioned, his views cease to be mere private judgments when he either claims or implies the agreement of his scientific colleagues and speaks for them in a public forum. It then becomes a matter for public argument whether he represents properly what is in the literature and whether he describes accurately the consensus among scientists.
Now let's return to the well-designed experiments that showed DDT to be a carcinogen.
Extensive human and animal studies to assess the toxicity of DDT had been conducted ever since its introduction. In 1956, a group of human volunteers ingesting DDT for periods of from twelve to eighteen months at 1,750 times the average amount for the United States population showed no adverse effects either at the conclusion of the trial or in follow-up studies five years later. A 1964 study of the incidence of different forms of cancer from all areas of the U.S. from 1927 to the early 1960s showed no correlation with the use patterns of DDT, nor with its presence in food or human body tissues. Similar results were reported from studies of industrial workers exposed for years to 600 to 900 times the intake of the general population, inhabitants of tropical countries who had been liberally dusted with DDT, and the work crews employed in applying it as spray and powder. The FDA had conducted prolonged investigations of fifteen groups of heavily exposed persons, each group consisting of one hundred individuals matched with controls, that looked especially for gradual or delayed effects but found none. One paper of a different kind described an experiment in the therapeutic use of DDT, where administration of a daily dose 7,500 times greater than the average produced no ill effects but was highly effective as a treatment for congenital jaundice. 194
Epstein's response was to dismiss all of these studies as "irrelevant" or "a travesty of the scientific data." 195 The irrelevance seemed to follow from his emphatic statement that there were no data to be found anywhere in the literature on chronic inhalation studies, which was a significant mode of human exposure. Claus and Bolander offer a list of references to precisely such studies covering the period 1945 to 1969 that were right there, in the literature. A direct contradiction. What more can be said? The latter comm
ent is apparently to be taken as meaning that it's a travesty of the data to find a substance safe simply because no carcinogenic effects can be found among heavily exposed humans after many years.
This attrition left just seven papers presumably judged to be relevant, separated into two categories: (1) three that were considered "highly suggestive" but flawed in method or statistical analysis, and (2) the remaining four, "conclusive." One of the first group dealt with rainbow trout (exceptionally sensitive to DDT) reported as developing liver cancers. However, the doses involved, over a period of twenty months, were up to 27,000 times what other researchers had found to be lethal, which makes it difficult to see how any of the fish could have lived at all, let alone develop tumors of any kind, and so results can only be suspect. The second group included two WHO studies that were in progress at the time, one being conducted in France, the other in Italy. Since they were as yet incomplete, the appellation "conclusive" is hardly justified. What, then, of the four papers that this leaves?
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