DDT

Toxic pesticides as BHC, PCB, DDT etc., are not easily degraded and are long-lasting in the environment. Their concentration therefore goes on increasing in water and soil with successive applications.

DDT was sprayed for many years on marshes to control mosquitoes.

The DDT has bio-magnified from water to fish eating birds and humans. DDT is known to depress the activity of estrogen, the female sex hormone and testosterone, male sex hormone. Fish die due to eating of DDT-killed insects; turtles die because of eating DDT-killed fish and so on. DDT deposited in butter fat of milk is a potential danger to infants.

The end result of DDT use is that whole population of predatory birds such as the fist hawk (osprey) and of detritus feeders as fiddler crab are wiped out. Birds are more vulnerable as DDT interferes with egg shell formation by causing a breakdown in steroid hormones which results in fragile eggs that break before the young can hatch.