Tuesday, January 13, 2015

Frederick Rowe Davis's "Banned"

Frederick Rowe Davis is associate professor of history at Florida State University. A lifelong birder and naturalist, he is author of The Man Who Saved Sea Turtles. He lives with his son in Tallahassee, Florida.

He applied the “Page 99 Test” to his new book, Banned: A History of Pesticides and the Science of Toxicology, and reported the following:
Banned: A History of Pesticides and the Science of Toxicology traces the parallel development of chemical insecticides and the science of toxicology across the twentieth century. Page 99 falls in the middle of a Chapter 4: “The Toxicity of Organophosphate Chemicals.” The page reveals how officials at the Food and Drug Administration (FDA) analyzed novel synthetic insecticides in the years following World War II. As Chief of the Division of Pharmacology at FDA, Arnold J. Lehman presented an important review in 1948: “The Toxicology of the Newer Agricultural Chemicals.” Lehman compared the toxicities of two dozen insecticides including chlorinated hydrocarbons like DDT, organophosphates like TEPP and Parathion, and pesticides derived from plants like nicotine. By 1948, DDT was becoming the most popular insecticide in America.

Lehman used DDT as a reference standard. He constructed a hierarchy of insecticides based on their acute oral toxicities as well as the toxicity compared to DDT. Earlier in the book, I examine the development of the median lethal dose (LD50) as the standard measurement of acute toxicity at the University of Chicago Toxicity Laboratory under the direction of E.M.K. Geiling. Thus, Lehman could state that DDT had an LD50 of 250 mg/kg. In contrast, TEPP’s LD50 was 2 mg/kg (125 times more toxic than DDT) and Parathion’s was 3.5 mg/kg (35 times more toxic than DDT). By comparing the toxicity of DDT with organophosphate insecticides, Lehman demonstrated the relatively low acute toxicity of DDT (and the much higher toxicity of the organophosphates).

Thus, page 99 of Banned stands right at an important crossroads in this history of pesticides and the science of toxicology. Even as farmers began to use massive quantities of DDT, other chlorinated hydrocarbons, and even organophosphates, scientists at the FDA and the Chicago Tox Lab were revealing the toxicity of such agricultural chemicals. Subsequent chapters detail how Congress grappled with the toxicity of these chemicals, but it was Rachel Carson’s Silent Spring that revealed to the public the dangers of DDT and the organophosphates to wildlife, ecosystems, and humans. Banned reveals a tragic irony in use of pesticides following the DDT ban in 1972.
Learn more about Banned: A History of Pesticides and the Science of Toxicology at the Yale University Press website.

Cover story: Banned.

--Marshal Zeringue