How does DDT accumulate in the food chain? Use the following terms: soil, ocean, pesticide, fish, birds, runoff. (People is given.)

D.D.T. is a highly persistent chemical called an organophosphate. It is readily absorbed by the soil and is hydrophobic. It was used extensively during W.W.II against malaria and to control the insect vectors of Typhus. In 1962, Rachel Carson wrote the book, Silent Spring, detailing the dangers to the environment of pesticide use. By 1972, the use of this pesticide was banned in the United States as well as many other countries for agricultural reasons and new insecticides were developed to control insect pests. D.D.T. is problematic because it stays in the ecosystem for many, many years. It enters food chains and bioaccumulation occurs. At each trophic level of the food chain, the amount of D.D.T. accumulating in the organisms' tissues magnifies. Unfortunately for birds, many of their eggshells became weakened due to this pesticide and reproductive failure of the embryos occurred. The bald eagle almost went extinct but their population began to rebound once the ban on the use of D.D.T. went into effect. When runoff occurs on areas that were sprayed with D.D.T., the pesticide can be transported to lakes, streams, rivers, etc. This again caused problems to various fish species whose eggs develop in the water and many did not develop properly. D.D.T. is an agent known to be carcinogenic. It is also an endocrine disrupter and can cause reproductive and developmental problems in humans and other species.

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