Toxicity cyclodienes

Some data on cyclodiene toxicity is presented in Table 5.9. Aldrin and dieldrin have similar levels of acute toxicity indeed, the toxicity of aldrin has been largely attributed to its stable metabolite, dieldrin. Dieldrin is highly toxic to fish, mammals. 

The cyclodiene insecticides aldrin, dieldrin, endrin, heptachlor, endosulfan, and others were introduced in the early 1950s. They were used to control a variety of pests, parasites, and, in developing countries, certain vectors of disease such as the tsetse fly. However, some of them (e.g., dieldrin) combined high toxicity to vertebrates with marked persistence and were soon found to have serious side effects in the field, notably in Western European countries where they were extensively used. During the 1960s, severe restrictions were placed on cyclodienes so that few uses remained by the 1980s. 

Apart from the oxidations just mentioned, cyclodienes are rather stable chemically. It should, however, be noted that dieldrin can undergo photochemical rearrangement under the influence of sunlight to the persistent and toxic molecule photo dieldrin, which occurs as a residue following the application of this insecticide in the field. 

Cyclodienes A group of organochlorine (OC) insecticides, some of which are highly toxic and persistent (e.g., aldrin, dieldrin, and heptachlor). 

The most serious toxicological effect of endrin is central neurotoxicity (Klaasen et al. 1986). Organo-chlorines interfere with the normal flux of cations across the axon, disrupting central nervous system homeostasis (Finkel 1983 Klaasen et al. 1986). Endrin is one of the most toxic cyclodienes, and seizure activity may develop rapidly after exposure (Proctor et al. 1988). In most cases, recovery is rapid. However, headaches, dizziness, weakness, and anorexia may persist for 2-4 weeks. 

Stanker LH, Watkins B, Vanderlaan M, et al. 1989. Analysis of heptachlor and related cyclodiene insecticides in food products. In Vanderlaan M, ed. ACS (American Chemical Society) Symposium Series, 451. Immunoassays for trace chemical analysis Monitoring toxic chemicals in humans, food and the environment Meeting, Honolulu, Hawaii, December 17-22. Washington, DC American Chemical Society, 108-123. 

Georgacakis, E. and Khan, M.A.Q. Toxicity of the photoisomers of cyclodiene insecticides to freshwater animals. Nature... 

Poisonings resulting in convulsions have occurred in manufacturing workers. Recovery after occupational exposures is usually complete within 24 hours. Unlike dieldrin, which persists in the body, endrin is rapidly eliminated from the body and apparently does not accumulate, even in fatty tissue. However, endrin is the most acutely toxic of the cyclodiene compounds, which also include chlordane, heptachlor, dieldrin, and aldrin. ... 

Other chemicals are agonists such as those that directly affect the y-butyric acid receptor (GABAa) receptor in neurons. Drugs such as barbiturates and benzodiazepines are agonists (activators) for this receptor and cause neuronal inhibition and sedation at therapeutic doses but coma and depression at higher doses. Conversely, antagonists (inhibitors) for this receptor such as the insecticides lindane and cyclodienes and picrotoxin inhibit neurons and may cause tremor and convulsions at toxic doses. 

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