The Conversion of Heptachlor to Its Epoxide on Plants1

Abstract

The conversion of heptachlor to heptachlor epoxide in substantial quantities occurs on certain plants and may be common on all plants. A 1-pound per acre treatment of heptachlor on alfalfa yielded residues of heptachlor which persisted above 0.1 p.p.m. for 13 days while the epoxide produced did not reach this level until 25 days after treatment. This is of importance not only because the epoxide is the more persistent of the two but also because it has a higher insect and mammalian toxicity than the parent material, heptachlor. The Conversion has been proved by specific colorimetric, total organic chloride, bioassay, paper chromatographic, and infrared spectroscopic methods.