The Role of Chemistry in History

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Environmental Problems

April 23rd, 2008 · No Comments ·

Introduction / DDT molecule / Malaria / World War II

Environmental Problems / Insect Resistance / BeginUsing Again?  /  References

  • In Silent Spring, Rachel Carson claimed that DDT was responsible for:

    • the decline in the bird population because of thinning of eggshells

    • the decline of the fish population

  • However, a study conducted in 1998 in Great Britain suggests that eggshells were thinning about 47 years before DDT even became available

    • Rhys E. Green, of the Edinburgh office of the Royal Society for the Protection of Birds, speculated that the initial cause of the thinning was due to the beginning of industrialization because the polluntants that were released into the air may have contributed to a reduction in calcium which is needed for eggshells

  • Another study concurred with Carson and stated that DDT also accumulates in the tissues of animals which induce reproductive and neurological defects in birds and fish

  • And yet another study claimed that DDT also builds up in cows milk and can cause severe impairment in calves.

  • No matter what problems DDT may or may not cause the environment there has been evidence to suggest that it was only the massive agricultural use of DDT and not the malarial use that caused the environmental problems.

    • statistics gathered by Roberts, Laughlin, Hsheih, and Legters (see reference section):

      • more than 765 kilograms of DDT might be used to treat 100 acres during a growing season

      • that same amount is sufficient enough to treat more than 1,692 houses or approximately 8460 persons (assuming there are 4-5 persons per house)

  • It has also been discovered that the appearance of resistant mosquitoes coincides with locations where DDT was used for agricultural purposes.

Tags: DDT