The Environmental Repercussions of Pesticides on Food

Bioaccumulation of pesticides on food can lead to a much higher concentration of toxins in the environment than is originally intended, with disastrous consequences.

American robin

Birds like this robin and other predators often pay the price for relatively low-concentration application of pesticides on food crops, as the toxins bioaccumulate in prey animals and ultimately reach the upper levels of the food chain.

Photo by Fotolia/Andrea Izzotti

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The result of a rigorous two-year investigation that took award-winning journalist and filmmaker Marie-Monique Robin across North America, Europe and Asia, Our Daily Poison is a shocking account of the dangerous chemical compounds that have infiltrated our food chain. Robin documents the many ways in which we encounter chemicals in our everyday lives—from the pesticides that blanket our crops to the additives and plastics that contaminate our food—and their effects over time. The following excerpt is from chapter 3, “Elixirs of Death.”

The Silence of the Birds

An expert ornithologist ever since her long walks on the banks of the river of her childhood, Rachel Carson had thought of titling her book The Silence of the Birds, because the fate of those innocent creatures seemed to her emblematic of the process of destruction at work. In her research she had consulted hundreds of letters to government agencies and universities, such as a letter from a housewife of Hinsdale, Illinois, found in the archives of Robert Cushman Murphy, a renowned ornithologist at the American Museum of Natural History: “When we moved here six years ago, there was a wealth of bird life,” she wrote. “After several years of DDT spray, the town is almost devoid of robins and starlings; chickadees have not been on my shelf for two years, and this year the cardinals are gone too; the nesting population in the neighborhood seems to consist of one dove pair and perhaps one catbird family. It is hard to explain to the children that the birds have been killed off, when they have learned in school that a Federal law protects the birds from killing or capture.”

These individual observations—chemical industry skeptics called them “anecdotal”—were confirmed all through the 1950s in reports from such official organizations as the U.S. Fish and Wildlife Service (which employed Carson). It noted the striking phenomenon of “blank spots weirdly empty of virtually all bird life.” The same thing occurred in Europe, as shown by “the deluge of reports of dead birds [that] reached…the Royal Society for the Protection of Birds”; the cause was the treatment of seeds with fungicides and insecticides before planting, which indirectly led to the death of 1,300 foxes between November 1959 and April 1960. The foxes died because they ate the poisoned birds, who had filled up on earthworms, themselves stuffed with the poison covering the seeds.

To fully understand the twofold phenomenon of bioaccumulation and bioconcentration—I repeat this because it is of the greatest importance—it is necessary to refer to the long study conducted by Professor George Wallace, an ornithologist at the University of Michigan, following DDT spraying of the campus and the surrounding area in 1954. The purpose of the “program” was to exterminate the bark beetles thought to be the carriers of Dutch elm disease. The following spring everything seemed normal: robins returned to the leafy campus to build their nests. Then suddenly, the campus turned into a “graveyard.” According to Wallace, “ ‘in spite of the assurances of the insecticide people that their sprays were “harmless to birds,” the robins were really dying of insecticidal poisoning; they exhibited the well-known symptoms of loss of balance, followed by tremors, convulsions, and death.’ ”

Perplexed, the ornithologist contacted Dr. Roy Barker, a member of an Illinois research center, whose work had “traced the intricate cycle of events by which the robins’ fate is linked to the elm trees by way of the earthworms.” DDT forms a “tenacious film” over leaves and bark, killing, along with the targeted bark beetles, beneficial insects, predators invaluable for ecological balance and plant protection. In the autumn the worms swallow the insecticide deposited on the dead leaves and in the earth through poisoned insects, and accumulate it in their fatty tissue without being directly affected. Pesticides are like Russian roulette: their effects vary from species to species and in this case earthworms are not sensitive to DDT (by contrast, however, Monsanto’s Roundup is fatal to them). The following spring, the heedless robins sign their death warrant by eating the earthworms. According to Barker, a fatal dose takes only eleven worms.

But that was not the end of the story. In the years after the campus spraying, Wallace observed that the robins that had survived had lost the ability to produce offspring. The numbers are eloquent: in 1953 the adult bird population was 370; five years later it had fallen to “two or three dozen.” This drastic population reduction was coupled with a disturbing phenomenon: Wallace had “ ‘records of robins and other birds building nests but laying no eggs, and others laying eggs and incubating them but not hatching them. We have one record of a robin that sat on its eggs faithfully for 21 days and they did not hatch.’ ”

Although not all robins have been exterminated, the survivors live under what Carson called the “shadow of sterility.” At the time, no one was yet able to explain the process at the origin of this dysfunction threatening the survival of the species. It is now known that DDT acts as an endocrine disrupter, which affects the development of exposed organisms in the fetal phase. In a 1960 congressional hearing Wallace reported finding extremely high levels of DDT in bird ovaries and testicles. In her chapter on the collapse of bird populations, Carson cites “important studies” showing that “insecticidal poison affects a generation once removed from initial contact with it. Storage of poison in the egg, in the yolk material that nourishes the developing embryo…explains why so many…birds died in the egg or a few days after hatching.”

American Industry’s Arrogance and Denial

“The major claims of Miss Rachel Carson’s book, Silent Spring, are gross distortions of the actual facts, completely unsupported by scientific, experimental evidence, and general practical experience in the field. Her suggestion that pesticides are in fact biocides destroying all life is obviously absurd in the light of the fact that without selective biologicals these compounds would be completely useless.” In transcribing these words from Robert White-Stevens, a biochemist working for American Cyanamid (one of the major pesticide manufacturers at the time), I wondered if the CBS correspondent interviewing him on April 3, 1963, had pointed out how counterproductive and even ridiculous his argument was. The designated spokesman for the chemical industry, a man with a low voice and a mechanical delivery, was one of Carson’s most vitriolic critics; he described her as an obscurantist opposed to sacrosanct “progress”: “If man were to follow the teachings of Miss Carson, we would return to the Dark Ages, and the insects and diseases and vermin would once again inherit the earth.”

This apocalyptic vision of a world without pesticides was the theme of a parody published by Monsanto only a month after Silent Spring, titled “The Desolate Year.” It’s hard to find a copy today; the insipid work seems to have fallen through history’s trapdoor. The firm uses science fiction to describe the horrors that would afflict the United States if DDT were banned. Here is a typical example of the painful prose: “Without pesticides, the pest control firms had automatically gone out of business. Of a sudden, some of the starkness of the time dawned on other people. No more protection against moths in clothing, furniture, carpets; no weapon but a flyswatter against rampant bedbugs, silverfish, fleas, slithering cockroaches, and spreading ants. More people shuddered, then, and still the desolate year was young.”

Taken by surprise—this was the first time the usefulness of their “miracle products” had been called into question—the pesticide manufacturers reacted violently and with the full force of their arrogance. This was nothing like the subtle disinformation campaigns of the 2000s carefully orchestrated by public relations agencies working in the shadows; in the early 1960s, chemical manufacturers were untouchable gods, arousing respect and gratitude because they were considered guarantors of the progress and abundance that were supposed to characterize civilized society. Certain of his position, in his letter sent along with “The Desolate Year” to the country’s decision makers, the CEO of Monsanto was not afraid to resort to sexist insults, calling “Miss Rachel Carson” a “hysterical woman,” “a bird and bunny lover,” and a “member of the cult of the balance of nature.”

The critics of Silent Spring also received support from the press which had adopted the reigning orthodoxy, such as Time, which in September 1962, denounced the “emotional and inaccurate outburst” of a book “full of oversimplifications and downright errors.” This did not prevent the same magazine thirty-seven years later from classifying Rachel Carson as one of the hundred most influential people of the twentieth century, correctly recalling the “huge counterattack organized and led by Monsanto, Velsicol, American Cyanamid—indeed, the whole chemical industry—duly supported by the Agriculture Department as well as the more cautious in the media.” In a letter to former president Dwight D. Eisenhower, the former secretary of agriculture, Ezra Taft Benson, who actively encouraged the development of chemical agriculture in the 1950s, wondered “why a spinster with no children was so worried about genetics.” His explanation was that she was “probably a Communist.”

But outrageous denials by supporters of pesticides did not succeed in stifling the incredible response to Silent Spring, even in the White House. In a press conference on August 29, 1962, a reporter questioned President John F. Kennedy “as to the possibility of dangerous long-range side effects from the widespread use of DDT and other pesticides. Have you considered asking the Department of Agriculture or the Public Health Service to take a closer look at this?” The president replied: “Yes, and I know that they already are. I think particularly, of course, since Miss Carson’s book, but they are examining the matter.”

Indeed, in the days following its serial publication in the New Yorker, Kennedy asked his science adviser Jerome Wiesner to set up a committee to study the “use of pesticides.” The committee presented its report on May 15, 1963.

Its conclusions “add[ed] up to a fairly thorough-going vindication of Rachel Carson’s Silent Spring thesis,” according to an article in Science, because it recommended as a goal the “elimination of persistent toxic pesticides.” In their introduction, the authors acknowledge that “until the publication of Silent Spring, people were generally unaware of the toxicity of pesticides.”

Following the publication of the report the Senate held a series of hearings on environmental risks, including testimony from Rachel Carson. Her work contributed to the establishment of the EPA on December 3, 1970, the first such agency in the world. Two years later, despite industry delaying tactics, the new agency banned the agricultural use of DDT, because it “posed unacceptable risks to the environment and potential harm to human health.”

This was a notable posthumous victory for Rachel Carson, dead prematurely from cancer on April 14, 1964, at the age of fifty-six. When they voted to ratify the establishment of the EPA, no doubt some American congressmen recalled her words: “The question is whether any civilization can wage relentless war on life without destroying itself, and without losing the right to be called civilized.”


Copyright © 2014 by Editions La Découverte, ARTE Editions. English translation copyright © 2014 by The New Press. This excerpt originally appeared in Our Daily Poison: From Pesticides to Packaging, How Chemicals Have Contaminated the Food Chain and Are Making Us Sick, published by The New Press, and is used here with permission.