Dioxins

Dioxin (Chemical Abstracts Service Registry Number 1746-01-6) refers to chlorinated dibenzodioxins (CDDs) of which there are 75 congeners based on number and position of chlorine atoms. Dioxins are contaminants of some herbicides, and are formed during combustion of industrial waste and during fires. They are persistent environmental contaminants in the air, water, and soil. Due to their high lipophilicity, bioaccumulation potential is high, resulting in the occurrence of dioxins throughout the biota. All dioxins are toxic, especially 2,3,7,8-tetrachlorodibenzo-p-dioxin, the form for which most data are available. A severe form of acne known as chloracne is a prominent effect in humans following acute exposure to dioxin. Other targets of toxicity include the liver, kidney, gastrointestinal tract, and immune system, especially thymic effects. Some dioxins may cause cancer. The mode of toxicity is complex and not fully understood. There is no known use for dioxins and they have no commercial value.