β-Hexachlorocyclohexane (β-HCH) is an organochloride which is one of the isomers of hexachlorocyclohexane (HCH).[1] It is a byproduct of the production of the insecticide lindane (γ-HCH). It is typically constitutes 5–14% of technical-grade lindane,[2] though it has not been produced or used in the United States since 1985.[1] As of 2009, the Stockholm Convention on Persistent Organic Pollutants classified α-hexachlorocyclohexane and β-HCH as persistent organic pollutants (POPs), due to the chemical's ability to persist in the environment, bioaccumulative, biomagnifying, and long-range transport capacity.
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| Names | |
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| Preferred IUPAC name
(1r,2r,3r,4r,5r,6r)-1,2,3,4,5,6-Hexachlorocyclohexane | |
| Other names
β-HCH
β-Benzenehexachloride β-BHC | |
| Identifiers | |
3D model (JSmol)
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| 1907338 | |
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| ECHA InfoCard | 100.005.703 |
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| KEGG | |
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CompTox Dashboard (EPA)
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| Properties | |
| C6H6Cl6 | |
| Molar mass | 290.83 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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This pesticide was widely used during the 1960s and 1970s, particularly on cotton plants. Although banned as a pesticide more than 30 years ago, traces of beta-HCH can still be found in water and soil. Animal studies show that organochlorine pesticides, including beta-HCH, are neurotoxic, cause oxidative stress, and damage the brain's dopaminergic system. Human studies show that exposure to beta-HCH is linked to Parkinson's and Alzheimer's disease.[3] β-HCH was present in elevated levels in some patients as recently as 2009. It was manufactured by exhausting chlorination of benzene and for this reason was called erroneously β-BHC. This synonym still persists.
In March 2005, the Italian National Monitoring System on Chemical Residuals in Food of Animal Origin detected levels of the pesticide β-HCH that were 20 times higher than the legal limit of 0.003 mg/kg in bulk milk from a dairy farm in the Sacco River valley. β-HCH, a lindane isomer and possible human carcinogen, was subsequently found in milk from several neighboring farms. A study was therefore undertaken to evaluate the extent and risk factors for contamination.[4][5]
See also
editReferences
edit- ^ a b Toxicological Profile for Alpha-, Beta-, Gamma-, and Delta-Hexachlorocyclohexane, U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry, August 2005
- ^ beta-hexachlorocyclohexane (Beta HCH) Archived July 20, 2008, at the Wayback Machine, Draft Risk Profile, May 2007
- ^ Medscape Medical News, Pesticide Exposure Linked to Parkinson's, Alzheimer's Disease, July 2009
- ^ Sala M, Caminiti A, Rombolà P, Volpe A, Roffi C, Caperna O, Miceli M, Ubaldi A, Battisti A, Scaramozzino P (2012). "[Beta-hexachlorocyclohexane contamination in dairy farms of the Sacco River Valley, Latium, Italy, 2005. A retrospective cohort study]". Epidemiol Prev (in Italian). 36 (5 Suppl 4): 34–43. PMID 23139187.
- ^ "Valle del Sacco: a poisoned land". 28 December 2012.