Schenker, M.B., S. Louie, L. Mehler and T. Albertson
IN: Environmental and Occupational Medicine, 3rd Edition. Rom, William N. ED. 1157-1172. Lippincott-Raven. Philadelphia/New York. 1998.
Pesticides are biocidal agents used to control a wide variety of organisms that pose a threat to health or compete for food or other materials (Table 1). Selective toxicity is the principle of pesticide use, but because organisms are similar at the cellular or subcellular level, adverse human health effects may occur. The earliest pesticides included metals such as arsenic, mercury, and lead. Other pesticides are inorganic chemicals, such as sulfur, and organic chemicals, such as nicotine derived from plants. After the discovery of dichlorodiphenyltrichloroethane (DDT) in 1939, the world has witnessed an unprecedented increase in the search for and production of synthetic organic pesticides. Production of inorganic pesticides such as arsenicals has steadily declined since the 1940s. The prolonged ecologic half-life and lack of species selectivity of DDT and other organochlorine pesticides was recognized in the 1960s. These pesticide characteristics and concern about the effects of accumulation of organochlorines in human adipose tissue caused the banning or severe restriction of most of these agents in the United States. In their place, newer synthetic pesticides, predominantly organophosphorus compounds, have been developed and are now widely used. These agents cause less environmental damage through accumulation but are more acutely toxic to humans and other animal species. The manufacture, distribution, and handling of pesticides in the United States is regulated under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).. The act, administered by the Environmental Protection Agency (EPA), was passed in 1947 and has been amended several times. There are approximately 600 active pesticides ingredients, configured in more than 45,000 formulations in use today. United States production is just over 1 billion pounds of active ingredients, and worldwide approximately 4 billion pounds of pesticides are used in agriculture as well as in most household gardens today. More ominously, toxic organophosphates such as the nerve gas sarin have been used by terrorists to attack large numbers of people in cities in Japan.