From Wikipedia, the free encyclopedia
Jump to: navigation, search
IUPAC name
Mendrin, Compound 269 (1aR,2S,2aS,3S,6R,6aR,7R,7aS)-3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-dimethanonaphtho[2,3-b]oxirene
72-20-8 YesY
ChemSpider 21782117 YesY
Jmol-3D images Image
KEGG C18124 YesY
Molar mass 380.91 g·mol−1
Melting point 200 °C (392 °F; 473 K) (decomposes)
US health exposure limits (NIOSH):
TWA 0.1 mg/m3 [skin][1]
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY verify (what isYesY/N?)
Infobox references

Endrin is an organochloride that was primarily used as an insecticide, as well as a rodenticide. It is a colourless odorless solid, although commercial samples are often off-white. Endrin was also sold as an emulsifiable solution known commercially as Shell Endrix. The compound endrin became infamous as a persistent organic pollutant and for this reason it is banned in many countries.[2][full citation needed][3][page needed]


Endrin is produced via a multistep route from hexachlorocyclopentadiene.[3][page needed] Diels-Alder addition of acetylene results in an isomer of hexachloronorbornadiene. This compound undergoes a second Diels-Alder addition, this time with cyclopentadiene. The resulting polycyclic derivative is epoxidized to give endrin. Endrin is a stereoisomer of dieldrin.[citation needed]


The majority of endrin (about 80%) was consumed[when?] as a spray to control insect pests of cotton.[citation needed] The remaining 20% was also used on rice, to some extent on sugar cane, in a limited way on grain crops and sugar beets, and in Australia on tobacco and cole crops. It was occasionally used in orchards as a control of rodents, where it is sprayed on the ground under the trees in autumn or spring, often as a solution in mineral oil. As a seed treatment, it was used for cotton seed in the United States, and for beans seeds in Australia. In Malaysia an emulsifiable solution of endrin was used to rid mine pools and fish ponds of unwanted predatory fish.[4]

Environmental problems[edit]

Currently[when?], the use of endrin is banned in countries that ratified the Stockholm Convention. Like related organochlorine pesticides, it is lipophilic and thusly it tends to accumulate in fatty tissues of organisms, mainly those dwelling in water. While some[which?] estimates indicate its half-life in soil is over 10 years, the EPA has recently[when?] released data indicating the half-life to be that of 14 years.[5] In comparison with dieldrin, endrin is less persistent in the environment.[citation needed]


Endrin is toxic with an LD50 of 3 mg/kg (oral, rat).[6] Acute endrin poisoning in humans affects primarily the nervous system. Food contaminated with endrin caused several clusters of poisonings worldwide, especially affecting children.[2] Orally ingested endrin is eliminated mostly in feces.[7][full citation needed] It is very toxic to aquatic organisms, namely fish, aquatic invertebrates, and phytoplankton. The U.S. EPA has set a freshwater acute criterion of 0.086 ug/L and a chronic criterion of 0.036 ug/L. In saltwater, the numbers are acute 0.037 and chronic 0.0023 ug/L.[8][full citation needed] Human health contaminate criterion for water plus organism is 0.059 ug/L.[9][full citation needed] Drinking water limits (maximum contaminant level (mcl)) is set to 2 ppb.[10][full citation needed]

For occupational exposures to endrin, the Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health, have set dermal exposure limits at 0.1 mg/m3 over an eight hour time-weighted average.[11][full citation needed]


  1. ^ "NIOSH Pocket Guide to Chemical Hazards". National Institute for Occupational Safety and Health (NIOSH). id=0252. 
  2. ^ a b "Poison Control: Dangers of 'persistent organic pollutants' in the environment."
  3. ^ a b Robert L. Metcalf "Insect Control" in Ullmann’s Encyclopedia of Industrial Chemistry" Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a14_263
  4. ^ Soong Min Kong. "Shell 'Endrix' Used as a Fish Toxicant." The Progressive Fish-Culturist, vol. 22 (1960), issue 2, page 93.
  5. ^ "Technical Factsheet on: Endrin". EPA. n.d. Retrieved 4 March 2013. 
  6. ^ Endrin in the ChemIDplus database
  7. ^ WHO report: 1970 Evaluations of some pesticide residues in food. 1970
  8. ^ US EPA Criteria for Aquatic Life (pdf)
  9. ^ US EPA human health criteria document
  10. ^ US EPA Drinking water document
  11. ^ CDC - NIOSH Pocket Guide to Chemical Hazards

See also[edit]