Lec38_39_Pesticides_05D

Lec38_39_Pesticides_05D - Pesticides, Human Health, & the...

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the Environment V Students should. .. pesticides are used in human society Develop perspective on the complex issues surrounding pesticides Learn to weigh risks of pesticide use, both pro and con V Pesticides Through Time 1200 BC Armies salt and ash fields 900 AD Chinese use arsenic 1690 Tobacco extracts used as insecticide 1800s 1939 DDT discovered by Paul Muller 1946 DDT resistance in houseflies 1962 “Silent Spring” by Rachel Carson 1970 Environmental Protection Agency 1973 Endangered Species Act H
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Pesticides in the “Good Old Days” circa 1900-1920 BOTTOM LINE: Today’s pesticide are much safer and less harmful that those in the “Good Old Days” H Inorganics Stomach poisons Sulfur- fungicide used today arsenic boric acid- used today for cockroaches lead arsenate First insecticidal compounds Product for example only- does not constitute an endorsement by Virginia Tech V Organochlorines Nerve poison aldrin, dieldrin, toxaphene (soil insecticides) DDT Paul Muller won the Nobel Prize for discovering DDT Most beneficial use was in public health lice (typhus) fleas (plague) Used during WWII and adapted for agricultural use. Cheap! Persistent (DDT half life is 10 years) H
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Organophosphates By-product of nerve gas research in WWII in Germany Used to replace persistent organochlorines Examples: Malathion: human louse control, flea powder Non-persistent Many are systemic Product for example only- does not constitute an endorsement by Virginia Tech V Carbamates Nerve poisons: Inhibit cholinesterase Broad spectrum (low specificity) Short to medium persistence Relatively nontoxic to mammals Several systemic insecticides Examples: Dursban, for termite control Sevin, for home gardens Product for example only-
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This note was uploaded on 08/15/2011 for the course ENT 2004 taught by Professor Jrvoshell during the Spring '07 term at Virginia Tech.

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Lec38_39_Pesticides_05D - Pesticides, Human Health, & the...

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