Hexachlorocyclohexane

HCH; 1,2,3,4,5,6-Hexachlorocyclohexane; benzene hexachloride; formula: C6H6Cl6; CAS Registry Number: 608-73-1
General Structure of Hexachlorocyclohexane
Source: PubChem
Identifier: CID 727
URL: https://pubchem.ncbi.nlm.nih.gov/compound/727#section=2D-Structure

Several isomeric compounds among the group of chlorinated hydrocarbons

Commercial production of Hexachlorocyclohexane (HCH) started after the 2nd world war. During the process of synthesis which requires benzene and chlorine, a mixture of different isomers evolves. This so called technical HCH consists of 65-70% α-HCH, 7-20% β-HCH, 14-15% γ-HCH, 6-10% δ-HCH , and 1-2% ε-HCH. Of all isomers, only γ-HCH has insecticidal properties. A product consisting of at least 99% γ-HCH is called Lindane.

Technical HCH has been banned in the Federal Republic of Germany in 1977 and the uses of the insecticide Lindane are restricted to date. In the former German Democratic Republic (GDR) lindane was, next to DDT, the most widely used insecticide since the 1970s. Considerable amounts of lindane were produced in the GDR itself but it was also imported from other Eastern Bloc States.

HCH contamination of the environment is a result of former uses of products containing HCH or lindane, e.g. in agriculture and forestry, in veterinary medicine and in households. Furthermore, residues from lindane production are still present in the environment. The production of one metric ton of lindane generates about nine tons of non-insecticidal isomers which were often improvidently disposed on dumping grounds.

The three main HCH-isomers alpha, beta and gamma were included in the Stockholm POP-Convention in 2009.

Substances

  • alpha-HCH
    The main constituent of technical HCH
  • Lindane (gamma-HCH)
    Highly effective insecticide that was banned from agricultural use in 2002 and restricted in pharmaceutical use in 2007
  • beta-HCH
    Most persistent HCH-isomer with the highest potential for biomagnification

Specimen

Sampling area

Sampling period

1985 - 2019