910628-36

910628-36
Caption: DDT (insecticide) crystals. DDT (Dichloro-diphenyl-trichloroethane), an organochlorine, is a colorless crystalline substance that is practically insoluble in water but highly soluble in fats and most organic solvents. It is the best known of a number of chlorine-containing pesticides used in the 1940s and 1950s. DDT was developed as the first of the modern insecticides early in World War II. It was initially used with great effect to combat mosquitoes spreading malaria, typhus, and other insect-borne human diseases among both military and civilian populations. DDT was responsible for eradicating malaria from Europe and North America. Because of DDT's singular effectiveness in the control of the mosquito (which vectors malaria) it is still used in many countries throughout the world where malaria has proven difficult to control. Use of DDT to control mosquitoes is primarily done inside buildings and through inclusion in household products and selective spraying; this greatly reduces the risk of strong environmental impact. In the 1960s DDT was claimed to cause cancer and DDT caused cancer and harmed bird reproduction by thinning eggshells. This eventually led to the pesticide being banned for agricultural use in most developed nations, and was one of the signature events in the birth of the environmental movement. The resulting ban is widely regarded as a major factor in the recovery of bald eagle populations in the United States. In the 1950s, doses of DDT and other insecticides had to be doubled or tripled as some resistant insect strains developed, and evidence began to grow that the chemical was concentrated in the food chain. DDT is not particularly toxic to humans, compared to other widely used pesticides. In particular, no link to cancer has yet been established.
Magnification*: x30
Type: LM
Copyright 1985 Dennis Kunkel Microscopy, Inc.
Keywords: 910628-36,12.01.04,crystal,crystals,DDT,dichloro-diphenyl-trichloroethane,insecticide,insect control,insect eradication,malaria,mosquito control,organochlorine,pesticide,typhus,dichlorodiphenyltrichloroethane,LM