Soil pollution is caused by the presence of xenobiotic (man-made) chemicals or other alteration in the natural soil environment, that has some detrimental effect on the soil. Some common causes of soil pollution are sewage leakage, and toxic chemicals. The most common toxic chemical that causes soil pollution is pesticides. One pesticide that infamous for its harmful effects on both people and animals is DDT (Dichlorodiphenyltrichloroethane.) DDT was first used to kill insects during World War II, we realized how well it worked killing insects that we started using it on crops to kill several different kinds of bugs, and some tropical countries used it to control mosquitos mainly carrying malaria. Some of the different species of birds that nearly went extinct due to the use of DDT were; Osprey, Eagles, Pelicans, Falcons, and Hawks. Once DDT enters the environment it takes a very long time for it to break down. It lingers in soil, water and animal tissues for a long time. Once a bird or any animal ingests DDT it then becomes stored in their body fat and slowly attacks the animal's nervous system. Birds often would eat smaller bugs that had been treated with DDT and then the bird would become affected. This would most likely move up the food chain. A bird eats a bug and then another predator eats the bird and so on. Since DDT is sometimes stored in the fat, a bird going through a period of time where it is low on food its body will use its stored fat to feed itself releasing the DDT that has built up in the fat, creating a fatal dose of the pesticide. DDT also causes problems with with calcium metabolism in birds, resulting in abnormal eggshells. Eggs become thin-shelled and won't allow the exchange of air for the developing embryo. Which can cause eggs break and embryos to die during the incubation period. DDT use was banned in America in 1972, but it is still being used in many tropical countries to kill insects that carry malaria and yellow fever. Although the U.S. has abandon the everyday use , DDT can still be used in times of emergency, and is still being produced to export to other countries.
http://www.chem.duke.edu/~jds/cruise_chem/pest/pest1.html
http://www.chem.duke.edu/~jds/cruise_chem/pest/effects.html#birds
http://www.suite101.com/content/birds-and-pesticides-a25855
http://www.pat-med.k12.ny.us/schools/hs/departments/science/coveney/5Animals.htm
http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/ddt-ext.html
