chlorinated hydrocarbon (CHC)

Definition

Hydrocarbon whose some or most hydrogen atoms have been replaced by chlorine atoms. Chemically and thermally stable, chlorinated hydrocarbons are used mainly in the manufacture of synthetic solvents and insecticides. Their danger to the environment comes from their toxicity, great stability (persistence in the environment), and propensity to evaporate with water into the atmosphere. CHCs become concentrated in animal fat and attack heart and liver; some have anesthetic or narcotic effect. Action of sunlight on chlorinated hydrocarbons forms chlorine monoxide which contributes to breaking-down of the ozone-layer, causing wide 'holes' through which cancer-causing ultraviolet (UV) rays can reach the earth's surface. See also chlorofluorocarbon and chlorofluoromethane.