DDT (Dichlorodiphenyl-Trichloroacetic Acid)

Chlorinated hydrocarbons are a diverse group of synthetic compounds of carbon, hydrogen, and chlorine, used as pesticides and for other purposes. DDT is a particular chlorinated hydrocarbon with the formula 2,2-bis-(p-chlorophenyl)-1,1,1-trichloroethane.

The insecticidal relatives of DDT include DDD, aldrin, dieldrin, heptachlor, and methoxychlor. DDE is a related non-insecticidal chemical, and an important, persistent, metabolic-breakdown product of DDT and DDD that accumulates in organisms. Residues of DDT and its relatives are persistent in the environment, for example, having a typical half-life of 5-10 years in soil.

A global contamination with DDT and related chlorinated hydrocarbons has resulted from the combination of their persistence and a tendency to become widely dispersed with wind-blown dusts. In addition, their selective partitioning into fats and lipids causes these chemicals to bioaccumulate. Persistence, coupled with bioaccumulation, results in the largest concentrations of these chemicals occurring in predators near or at the top of ecological food webs.