Other Organochlorine Insecticides Cyclodienes –Aldrin and dieldrin, endrin and isodrin –Chlordane and heptachlor –Mirex and chlordecone Lindane Endosulfan Hexachlorobenzene and pentachlorophenol Toxaphene

Cyclodiene Insecticides Common synthetic pathway –Diels-Alder reaction Very heavily used –Aerial applications for gypsy moth control –Soil incorporation Corn rootworms Termites –House and garden insecticides Roaches, flies, ants

Dieldrin

Aldrin and Dieldrin Dieldrin –Metabolized to aldrin by P450 enzymes –epoxide of aldrin Extremely persistent Bioaccumulative Toxicology –Acute toxicity: ca 45 mg/kg – too toxic for WHO malaria program –Neurotoxic –Carcinogen

Heptachlor

Heptachlor and its epoxide Use pattern similar to dieldrin Toxicity –Acute toxicity: 100 mg/kg Uses banned –Agriculture, 1970s –Termiticide, 1988 – Hawaiian pineapple contamination

Chlordane

Mirex Chlordecone = Kepone®

Mirex and Chlordecone Mirex –Acute toxicity: 235 mg/kg –Primarily produced On shores of Lake Erie As fire retardant for plastics –90% of production –Insecticidal use against imported fire ant (Solenopsis invicta) Chlordecone [Kepone TM ] –Acute toxicity: 95 mg/kg –Single manufacturing site Hopewell, VA Massively bioaccumulative Extremely persistent

Toxaphene Mixture of over 177 congeners –Acute toxicity of technical toxaphene: 40 mg/kg –Toxicant A: ca 3 mg/kg in mice? Produced by chlorinating camphene from pines Used on cotton –formulated together with methyl parathion –1976, 26,000,000 lbs used on cotton (41% of all insectides used on cotton that year) Not bioaccumulative Some fractions are very toxic to fish Present in air from Asia

Toxaphene

Toxaphene Toxicant A (Saleh and Casida 1978) accounts for < 3% of total mixture

Summary: Cyclodienes Most are produced by the Diels-Alder reaction Extremely persistent Acute toxicity varies –Between compounds –Between phyla Insecticidal action is neurotoxic Mammalian toxicities include –Neurotoxicity –Carcinogenicity

Ecological toxicity Persistence Bioaccumulation