From Great Lakes Wiki

Wikipedia page on DDT

Dichloro-Diphenyl-Trichloroethane, better known as DDT, is a synthetic pesticide. It was widely used after 1939 to combat mosquitos and other insects, primarily to aid in combating the spread of malaria.

In Michigan it was manufactured by Michigan Chemical/Velsicol in St Louis, Michigan. That location on the Pine River is now closed, and is maintained as the Pine River Superfund Site.

The harm its use had on birds was discovered by George J. Wallace, an ornithologist at Michigan State University in the 1950s. The notion of biomagnification is credited in part to Wallace who discovered that worms ingested the chemical from leaf litter. Birds died after eating enough worms to deliver a lethal dose of DDT.

Much of Wallace's data was used in Rachel Carson's book, Silent Spring.

Controversy

The Argument for Banning DDT

There are many who feel that DDTs harmful effects are so great that it should be banned from use entirely.

The negative effects of DDT have been observed most famously in birds by George J. Wallace. It is known to cause thin shells in bird eggs, as well as cause deformities in the birds that do manage to hatch and survive.

Its effects on mammals is less well understood, but there are known effects. At levels around 6-10mg/kg DDT causes a variety of symptoms in human beings such as headache, nausea, vomiting, confusion, and tremors. Levels above 236 mg/kg are lethal in humans. It can be transmitted through breast milk, and is currently the subject of some debate as to its link to breast cancer.

For these reasons - its negative effects on nature and its human health risks - many think that DDT should be banned from use completely.

Sources: Chemistry Department at Duke University

The Argument for Using DDT in Some Situations

There are many who feel that DDT, when used properly, has more benefits than harm. Its use in preventing the spread of malaria, in particular, is pointed to as a greater benefit than any of the other health and environmental problems is causes.

On 11 April, 2004 the New York Times published an article called What the World Needs Now Is DDT (link). It argued "what really merits outrage about DDT today is not that South Africa still uses it, as do about five other countries for routine malaria control and about 10 more for emergencies. It is that dozens more do not. ...and global health institutions like W.H.O. and its malaria program, Roll Back Malaria, actively discourage countries from using [DDT]."

Other resources:

African American Environmentalist Association site advocating the use of DDT to stop deaths from malaria in Africa.

Another pro-DDT site also containing a fair amount of information about DDT in general.

Africa Fighting Malaria, a Pro-DDT site.