Rachel Louise Carson (May 27, 1907 ‐ April 14, 1964)

Abstract

Fifty years ago, we lost an influential scientist whose work fueled a social movement. Rachel Louise Carson was a reproductive biologist, a zoologist, an ecologist, a developmental biologist, a marine biologist, an environmental scientist… but moreover, she was a careful worker. Carson stimulated a foundational change in the United States, and perhaps in the world. Her most influential work, Silent Spring(1962), was a powerful and insightful analysis of human influence on the environment. The work was considered depressing for many - not because of the tenor or the language used, but because of its clarity and stark view of habitat destruction. Publication of Silent Spring coincided with the rapid post-war growth in the United States, a time of exorbitant use of resources and disregard of the environment at a staggering rate. Carson predicted the trajectory this behavior would have on ecosystems. She particularly pointed out that, contrary to what society believed, the world was not an endless resource; rather, ignorance of downstream, ecosystems-level consequences to human actions would only accelerate the decline of our habitats. A focal point of Silent Spring is the insecticide compound dichlorodiphenyltrichloroethane (DDT). The discovery and application of DTT was awarded the Nobel Prize in 1948 (to Paul Muller), and its use was pivotal in early anti-mosquito / malaria campaigns. It was often sprayed indiscriminately, intensively, and without regard to the consequences - except for decreases in mosquito populations. Yet, it is toxic to a wide range of living organisms, including marine arthropods, many species of fish, and predatory birds, and thus Carson argued to refer to it as a “biocide” since its effects are rarely limited to the intended target. Further, DDT is a bioaccumulation chemical that becomes enriched in lipid deposits of organisms exposed to the chemical, and it persists generation after generation. DDT also causes eggshell thinning, leading to severe population declines in multiple North American and European avian species. The biological-thinning mechanism is not understood, but strong evidence suggests that its metabolite dichlorodiphenyldichloroethylene (DDE) inhibits calcium ATPase in the shell gland, reducing the transport of calcium carbonate from the blood into the eggshell gland and resulting in a dose-dependent reduction of its thickness. DDT metabolites also appear to disrupt female-reproductive-tract development, impairing later eggshell quality. Social acceptance of Carson's thesis may have been enhanced by the strange temporal congruence of another disastrous chemical, thalidomide, in the same year that Silent Spring was published. France Oldham Kelsey, a new reviewer at the Food and Drug Administration, denied use of thalidomide in the United States market until further tests could be accomplished regarding its relationship to birth defects. She, like Carson, was ostracized by many, especially the industry attempting to heavily market the compound in the United States but she resisted. What Dr. Kelsey did for the children born in the early 1960's in the United States by protecting them from debilitating birth defects, Carson did for environmental health. While Carson and the book's thesis were very controversial - she was labeled as anti-American, a communist (in part because she was categorized by a group of men as attractive, yet she was not married; really, quite curious logic), and a hater of industrial growth - her science, her methodology, and now the accuracy of her insight, was not. Carson was a loner of a student who excelled at the Pennsylvania College for Women (today known as Chatham University), and later at a summer course at the Marine Biological Laboratory (Woods Hole, MA USA) and as an assistant in Raymond Pearl's laboratory at John's Hopkins University, where she worked with rats, Drosophila, snakes, and squirrels. She finally settled on fish, completing a Master's dissertation in 1932 on the development of their pronephros system. Although she intended to complete a doctorate degree, the death of her father caused severe financial hardship on the family, forcing Carson instead to find work. She accepted a temporary position with the United States. Bureau of Fisheries, writing radio stories for a weekly series entitled “Romance Under the Waters”. Her writings were so effective that Carson's supervisor helped her secure a full-time position, only the second woman to be hired full-time by the Bureau of Fisheries. This position poised her effectively to analyze eco-systems and the rapid changes resulting from human practices. Lytle, Mark Hamilton (2007). The Gentle Subversive: Rachel Carson, Silent Spring, and the Rise of the Environmental Movement. New York: Oxford University Press. Quaratiello, Arlene (2010). Rachel Carson: A Biography. Amherst, New York: Prometheus. en.wikipedia.org/wiki/Rachel_Carson rachelcarson.org Gary M. Wessel