Metabolism of Heptachlor and Its Degradation Products by Soil Microorganisms1

Chemical and soil microbial degradation of heptachlor proceeded by at least 3 pathways: epoxidation, hydrolysis, and reduction. Soil microorganisms converting heptachlor to its epoxide were identified. Thirty-five of 47 fungi, and 26 of 45 bacteria and actinomycetes isolated from soil produced the epoxide. In aqueous media, heptachlor hydrolyzed chemically to 1-hydroxychlordene, which the soil microorganisms were able to epoxidize to I-hydroxy. 2,3-epoxychlordenc. Heptachlor was dechlorinated by bacteria to chlordene which was then epoxidized to chlor dene epoxide. The insecticide and its byproducts were concentrated in the fungal mycelium. The presence of cyclodiene insecticides in the media appeared to influence some microbial metabolic processes.