Degradation of Selected Chlorinated Hydrocarbon Insecticides

The chemical and biological degradation of selected chlorinated hydrocarbon insecticides in aqueous solution was studied by means of electron-capture gas chromatography. Lindane, heptachlor, DDT, and endrin were subjected to the action of the oxidants chlorine, potassium permanganate, and potassium persulfate. None of the oxidants were effective in removing lindane or endrin. Less than 20-percent DDT removals were observed using potassium permanganate or potassium persulfate. Potasium permanganate removed more than 80 percent of the heptachlor in less than 5 hr. Alkaline decomposition of lindane and DDT was observed. Biological studies revealed that lindane is not subject to aerobic biodegradation. Heptachlor decomposes in aqueous solution to l-hydroxy chlordene and an undetermined compound. Heptachlor removals as large as 99.4 percent were observed to occur within 4 days.