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The Deadly Dust: The Unhappy History Of DDT
February 1971 | Volume 22, Issue 2
Small wonder that the discoverer of DDT was honored throughout the world during the postwar years. Though he held no medical degree and had never engaged in medical research, Dr. Paul Herman Müller was awarded a Nobel Prize in Medicine for DDT in 1948. And then—at the very height of his glory—Müller dropped from public view.
Three years later, Rachel Carson became famous. In 1951 her lyric yet scientifically accurate book about the sea, The Sea Around Us , was published to a chorus of praise; it sold so well that, abruptly, its author became financially independent. She resigned her government job the next year to devote herself to research and writing. Her third book, The Edge of the Sea , appeared in 1955, adding even more luster to her reputation and marking a transition point in her career. The concern she had first felt during the war, as she read about the wartime uses of DDT and about the field and forest tests of the “miracle” insecticide, had become a deeply felt anxiety by the time The Edge of the Sea was published.
She had been quick to grasp the significance of an announcement in early 1946 that U.S.D.A. entomologists had succeeded in producing, through selective breeding in a laboratory, a strain of housefly much more resistant to DI)I than the common stock. “In view of the increasing use of DDT for housefly and mosquito control,” said Science , cautiously, on March 12, 1946, “it seems possible that, in time, a similar increase in resistance may occur under natural conditions.” It had happened before, with other insecticides. And, sure enough, DDT-resistant strains of houseflies, mosquitoes, and crop-destroying insects soon began to appear naturally and in such numbers in some areas that ever more massive doses of insecticide were required to control them.
Miss Carson recognized the implications of this genetic evolution. What if DDT’s effectiveness were so reduced, in the not-distant future, as to require extensive use of the even more toxic chlorinated hydrocarbons (dicldrin, aldrin, chlordane, endrin) which DDT’s success had inspired? Would not these in turn lose effectiveness? No doubt chemicals still more toxic would by then be available; but what consequences would follow from their use if, indeed, they were not so lethal to men as to be unusable?
Rachel Carson, like other biologists, saw nightmare answers to these questions. The end of the process might be an environment far more hostile to man than to his insect “enemies.” After all, insect generations succeed themselves hundreds of times more rapidly than human generations. If man insisted on running a genetic adaptability race with insects, he was bound to lose.
The evidence that DDT was poisoning the environment multiplied throughout the iggo’s. There were increasingly frequent reports of direct poisonings of birds, of fish, of small game, sometimes after applications in excess of prescribed amounts but often, too, when the prescriptions were precisely followed.
One day in January, 1958, Olga Huckins wrote a long, eloquently angry letter to her friend Rachel Carson, describing the deadly effect of DDT spraying for mosquito control over the Huckinses’ private two-acre bird sanctuary at Powder Point, in Duxbury, Massachusetts. Not long afterward Miss Carson was a house guest at Powder Point when, late in the afternoon, the spraying plane came over. The next morning she went through the estuary with the Huckinses in their boat. She was sickened by what she saw—dead and dying fish everywhere, crayfish and crabs dead or staggering as their nervous systems were destroyed. “You ought to write about this,” the Huckinses kept saying. “You’ve got to.…”
And Rachel Carson, publicity shy, no controversialist by temperament, acutely aware of the abuse in store for anyone who dared challenge the million-dollar pesticide industry, was forced to agree —especially as she came to realize that the direct kills were by no means the worst effect of the chemical pesticides. More widespread and disastrous by far were the delayed kills, coupled with the inhibition of reproductive processes. Entire species of birds were threatened with extinction. And how could a substance so toxic to other warm-blooded animals fail to have toxic effects, in the long run, on humans?
For as the stubbornly persistent DDT enters a food chain that begins with herbivores and runs through small to large and then larger carnivores, including man, the process known as “biological magnification” occurs. An early instance was recorded on the East Lansing campus of Michigan State University. Annual spraying of elms with DDT began there in 1954 to control the beetle that spreads Dutch elm disease. For the first year or so there were no apparent side effects. But then people noticed that there were no more robins on the campus. Earthworms feeding on elm leaves with tiny amounts of DDT on them accumulated the stuff in their body fat until a level toxic to robins was reached. Robins that ate those worms died—and robins unfortunate enough to visit the campus even two years after spraying had been discontinued also died.