Tuesday was the 54th anniversary of the publication of Silent Spring, the seminal work that many credit with sparking the modern environmental role. The importance of Michigan in the book, and the citizen effort to ban “hard pesticides,” is often overlooked. The following is an excerpt from Chapter 9 of my environmental history of Michigan, Ruin and Recovery.
Man, for the first time in his history, has chemicals at his disposal that can completely alter his own food chain. By wiping out certain insects or minute sea-creatures he removes link after link in the very delicately balanced chain of life on which he depends…[T]here is enough evidence for us to be greatly concerned and to start bringing the unnecessary and widespread use of these persistent chemicals to a halt.”
— Ralph A. MacMullan, Director, Michigan Department of Natural Resources, Michigan Natural Resources Magazine, March-April 1969
Although reports of bird mortality were made as early as 1947, they first came to the attention of an important Michigan bird lover in the spring of 1955, the year after the City of East Lansing began its Dutch elm disease control program. A graduate student in zoology at Michigan State University, John Mehner, was performing a study comparing robin populations in unsprayed areas in Pittsburgh with two sprayed areas in East Lansing, including a five-acre plot that had once housed the university’s horticultural gardens. Mehner brought the results of his study to Dr. George J. Wallace, a professor of zoology. Wallace would later describe them as “dramatic and disturbing.”
By 1958 no study was needed to suggest something was wrong. Wallace and others observed dead robins in growing numbers. Robins had been virtually eliminated from the main campus and some areas in East Lansing. At first believing the deaths were caused by an affliction of the nervous system, Wallace soon began to suspect DDT, despite assurances from the applicators that the sprays were safe. The robins “invariably exhibited,” Wallace said, “the well-known symptoms of loss of balance, followed by tremors, convulsions, and death.” He soon traced the birds’ exposure to earthworms, which accumulated the chemical in their bodies after feeding from contaminated leaf litter. Consuming the downed leaves in the fall, the earthworms were themselves consumed by robins on their return to the north in the spring, thus causing the increasing seasonal die-offs each year.
In addition to the properties that made it effective in combatting insects, DDT had a characteristic not found in natural substances: it failed to break down, and in fact accumulated in living tissue in greater and greater concentrations as it passed up the food chain. Concentrations of DDT and others of the so-called persistent, bioaccumulative chemicals increased a hundred-, a thousand-fold or more as they passed from the lowest level of the food chain to the next level of predators. Hence the MSU robins built up dangerously high levels of the pesticide.
“If this and other pest-eradication programs are carried out as now projected.” Wallace said, ‘we shall have been witnesses, within a single decade, to a greater extermination of animal life than in all the previous years of man’s history on earth, if not since glaciation profoundly altered the life of the northern hemisphere.” Such a blunt statement was not typical for the quiet Wallace.
Ironically, DDT had begun to plague the grounds of a university whose faculty and agriculture extension agents had enthusiastically promoted the use of it and other chemical pesticides. Convinced of the righteousness of their cause, they deplored Wallace’s repeated denunciations of DDT.
Wallace’s message would soon be bigger news. A well-known science writer by the name of Rachel Carson was preparing a book that would bring the issue of pesticides to the attention of millions of Americans. When Silent Spring was published in 1962, it aroused an immediate storm of controversy, and further publicized Wallace’s studies. Carson emphasized Wallace’s discovery that DDT appeared to inhibit or prevent the robins’ reproduction. Calling the problem “sinister,” Carson quoted Wallace’s Congressional testimony that he had found high concentrations of DDT in the testes and ovaries of breeding birds. In addition to immediate lethality, then, DDT could neuter birds, and thus raise the specter of an eventual “silent spring.”
The book had a revolutionary effect, although its greatest consequences came years after Carson’s death from cancer in 1964. It prompted immediate political scurrying, including a request by President John F. Kennedy that his science advisory committee review the issue of pesticide safety. “In developing the case against DDT,” Thomas Dunlap wrote,” Carson also made what was the clearest case to that time of the central tenet of the environmental movement: that human action has become the dominant environmental influence on the rest of the planet…”