However, the effects in humans exposed to TCDD have been more difficult to ascertain. Although dioxins do occur naturally, they are not intentionally manufactured by industry. Various formulations of 2,4,5-T have been used extensively for weed control on roads, crops, rangelands, and roadways throughout the world. Dioxins have been released to the environment during the manufacturing, use, and disposal of these chemicals, and are also formed during the chlorine bleaching processes used by pulp and paper mills. Dioxin and related compounds enter the atmosphere directly through air emissions or indirectly, for example, through volatilization from land or water or from resuspension of particles.
Deposition can occur directly on to soil or on to plant surfaces.
Certain segments of the population may be exposed to additional increments of exposure by being in proximity to point sources or because of dietary practices. However, they seem consistent with levels measured in studies in Western Europe and Canada. Dioxins in Food - UK Dietary Intakes US EPA, Office of Prevention, Pesticides and Toxic Substances Endocrine Disruptors References 1. Congressional Testimony, Public Health Implications of Dioxins, Testimony by Barry L. Johnson, Ph.D. June 10, 1992.