For years, people have heard about the American Bald Eagle's declining population and the tremendous rebound that it made in the last few years. Even now the population is still endangered. Recently, bald eagle days have shown the massive support for one of our nation's emblems. This all could have been avoided by not using DDT, DDE, and DDD.
DDT was thefirst chlorinated organic insecticide. It was originally prepared in 1873, but it was not until 1939 that Paul Muller of Geigy Pharmaceutical in Switzerland discovered that DDT could be used as an effective insecticide. This was such an amazing discovery that in 1948 he was given the Nobel Prize in medicine and physiology. In the years that DDT was used as an insecticide, the World Health Organization estimated that approximately 25 million lives were saved as a result of insects that carry typhoid and malaria being killed.
For thefirst 2 decades that DDT was used, scientists thought that the toxicity of DDT and related insecticides were harmless to both plants and the animals that were not targeted by DDT. It was not until the late 1950's that the effects of DDT became widely researched. In 1962, Rachel Carson released her book Silent Spring. Shortly thereafter, scientists reported that DDT was threatening the survival of Predatory birds and was even shown in breast milk and in semen of humans.
Research showed that DDT could move up the food chain quickly. A common example would be there was an estimated .000003 parts per million of DDT in surface water during the heaviest use of DDT. Zooplankton, from living in the water and absorbing it, show about .04 parts per million of DDT. Small fish show about .5 parts per million. Large fish show about 2 to 5 parts per million. Finally, birds, such as Bald Eagles and Ospreys, have a concentration of 25 parts per million. This is a 1 billion percent increase from the surface water to the birds at the top.

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