DDT is an insecticide, or insect killer, used on plants. The main ingredient in DDT is known as DDE (Dichlordiphenylethylene). DDT was used when crops were beginning to be destroyed by insects. The farmer saved his crops in this way. DDT was sprayed (sometimes from a plane) on to the plants to kill the insects. It was easy to get and could just be bought at a store back in the 50s and 60s. DDT was the first, and only insecticide back then.

DDT comes in many forms such as; aerosols, dusting powders and wet powders. These are all equal in their results of killing bugs and birds.

DDT was first concocted in 1873. No one knew of the effects of DDT until 1939 when Paul Muller of a pharmaceutical company in Switzerland, found what it did to birds, and other creatures. Muller won a Noble Prize in medicine and physiology in 1948 for his discovery. The huge problem with DDT wasn't that it killed the birds directly. Birds ate the insects that had been sprayed. Then the birds began laying eggs with very thin eggshells. During incubation the eggs broke so the species was not reproducing. This lead to near extinction for many birds. Additionally, once an animal has consumed DDT they live a “half-life” for about 8 years until death. Their death is slow and very painful. The animal will stop normal activity and start to shake, constantly, until dead.

How did peregrine falcons figure in to all of this? Peregrines are at the top of the food chain in the bird world. They ate other birds - birds that had consumed DDT. They too began laying eggs that had very thin shells and suffering the same painful effects as other birds. The results were the peregrine became endangered.

Scientist knew for about 30 years what it could do, but nothing was done to ban its use. Thankfully in the early 1970s DDT was band from use in the U.S., but it is still used widely in South America today. You might not think this is a problem, but birds – the peregrine falcon included – migrate to South America in the winter months. In doing this falcons are still on the borderline of endangered lists in some states, even though they have been removed from the federal endangered list.

Bibliography

http://www.chem.ox.ac.uk/mom/ddt/ddt.html ; "Molecules of the Month"; University of Bristol; Karl Harrison; 1996.

http://micro.magnet.fsu.edu/pesticides/pages/endosulfan.html ; "Molecular Expressions"; Florida State University; 1995-2003.

http://ace.ace.orst.edu/info/extoxnet/pips/ddt.htm ; "DDT"; Extoxnet - Oregon State University; 1996.

http://www.epa.gov/history/topics/ddt/01.htm ; "DDT Ban Takes Effect"; press release 1972; U.S. Environmental Protection Agency.