DDT was selected as the compound for this study due to paucity of data regarding environmental effects of other classes of pesticides. Human exposure to pesticides was examined from two major pathways; the direct pathway which deals with direct uptake from primary sources of pesticide release, and the indirect pathway which involves human exposure by translocation through air, water, or food. Reductions in accidential poisonings could be made by limiting the total toxicant contents of home packages of pesticides, and means to reduce deaths from aerial applications warrant further study of this method of application. The control of human burden of pesticides by control of food residues is only partially effective since evidence on pesticide distribution in the environment suggests that about half of the intake is from inhalation of insecticide aerosols or dust laden with insecticides. There is presently no evidence that pesticide exposure directly shortens human life. Fish and birds are more sensitive to pesticides in the environment. Fish lack the basic microsomal oxidase enzyme systems which detoxify pesticides and birds appear to be very sensitive to the sterodal hormone mimicking effects of the chlorinated hydrocarbons. (Author)