Β-Hexachlorocyclohexane

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.

β-Hexachlorocyclohexane

Names
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
CAS Number	319-85-7 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1907338
ChEBI	CHEBI:28428 Y
ChEMBL	ChEMBL389022 Y
ChemSpider	10468512 Y
ECHA InfoCard	100.005.703
EC Number	206-271-3
KEGG	C06988
UNII	YM80ODM9PD Y
CompTox Dashboard (EPA)	DTXSID7020685
InChI InChI=1S/C6H6Cl6/c7-1-2(8)4(10)6(12)5(11)3(1)9/h1-6H/t1-,2-,3+,4+,5-,6- Y Key: JLYXXMFPNIAWKQ-CDRYSYESSA-N Y InChI=1/C6H6Cl6/c7-1-2(8)4(10)6(12)5(11)3(1)9/h1-6H/t1-,2-,3+,4+,5-,6- Key: JLYXXMFPNIAWKQ-CDRYSYESBR
SMILES Cl[C@H]1[C@H](Cl)[C@@H](Cl)[C@H](Cl)[C@@H](Cl)[C@@H]1Cl
Properties
Chemical formula	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). Y verify (what is YN ?) Infobox references

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

• α-Hexachlorocyclohexane

References

1. 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
2. beta-hexachlorocyclohexane (Beta HCH) Archived July 20, 2008, at the Wayback Machine, Draft Risk Profile, May 2007
3. Medscape Medical News, Pesticide Exposure Linked to Parkinson's, Alzheimer's Disease, July 2009
4. 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.
5. "Valle del Sacco: a poisoned land". 28 December 2012.

External links

• beta-Hexachlorocyclohexane (beta-HCH) - Integrated Risk Information System – US EPA
• Cyclohexane, 1,2,3,4,5,6-hexachloro-, (1α,2β,3α,4β,5α,6β)- – NIST