Polychlorinated aromatic compounds as environmental poisons

Abstract

Chlorinated fungicides, insecticides and herbicides often contain highly toxic byproducts or can be converted into toxic compounds. Polychlorinated naphthalenes are potential byproducts of chloronaphthalene, a widely used wood preservative; they can cause "perna disease" in man and "x disease" in cattle. Tetrachlorodibenzodioxin, a breakdown product of the herbicide 2.4.5-trichlorophenoxyacetic acid and probably of pentachlorophenol, is extremely poisonous and also causes perna disease, and has teratogenic and probably carcinogenic effects. Polychlorinated diphenyls are rather stable pollutants, frequently found in birds, fishes and human food. They, too, are extremely poisonous and cause perna disease and probably cancer. Their wide distribution may be due to the use of wood preservatives containing such compounds, and to conversion of the insecticide dichloro-diphenyl-trichloroethane (DDT). There is some suspicion that the wood pulp bleaching effluents may be a source of pollution, by reason of their content of chlorinated phenols, derived from lignin.