Aldrin is an organochlorine insecticide that was widely used until the 1990s, when it was banned in most countries. It is a colourless solid. Before the ban, it was heavily used as a pesticide to treat seed and soil. Aldrin and related "cyclodiene" pesticides (a term for pesticides derived from Hexachlorocyclopentadiene) became notorious as persistent organic pollutants.
Aldrin is produced by combining hexachlorocyclopentadiene with norbornadiene in a Diels-Alder reaction to give the adduct.
Similarly, an isomer of aldrin, known as isodrin, is produced by reaction of hexachloronobornadiene with cyclopentadiene.
Aldrin is named after the German chemist Kurt Alder, one of the coinventors of this kind of reaction. An estimated 270 million kilograms of aldrin and related cyclodiene pesticides were produced between 1946 and 1976.
In soil, on plant surfaces, or in the digestive tracts of insects, aldrin oxidizes to the epoxide dieldrin, which is more strongly insecticidal.
Like related polychlorinated pesticides, aldrin is highly lipophilic. Its solubility in water is only 0.027 mg/L, which exacerbates its persistence in the environment. It was banned by the Stockholm Convention on Persistent Organic Pollutants. In the U.S., aldrin was cancelled in 1974. The substance is banned from use for plant protection by the EU.
Aldrin has rat of 39 to 60 mg/kg (oral in rats). For fish however, it is extremely toxic, with an LC50 of 0.006 – 0.01 for trout and bluegill.
In the US, aldrin is considered a potential occupational carcinogen by the Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health; these agencies have set an occupational exposure limit for dermal exposures at 0.25 mg/m3 over an eight-hour time-weighted average. Further, an IDLH limit has been set at 25 mg/m3, based on acute toxicity data in humans to which subjects reacted with convulsions within 20 minutes of exposure.
It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.
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10.1039/JR9610004809. 946. Cyclisations and rearrangements in the isodrin?aldrin series. 1961. Bird. C. W.. Cookson. R. C.. Crundwell. E.. Journal of the Chemical Society (Resumed). 4809.
Web site: Chemicals Regulation Directorate. Banned and Non-Authorised Pesticides in the United Kingdom. 1 December 2009.
Web site: Centers for Disease Control and Prevention. Aldrin. NIOSH Pocket Guide to Chemical Hazards. 4 April 2011. 13 November 2013.
Web site: Centers for Disease Control and Prevention. Aldrin. Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs). May 1994. 13 November 2013.
Government Printing Office. 40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities. July 1, 2008. October 29, 2011. ..
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