Hexachlorocyclohexane (HCH)

The substance
The most important of the eight isomers of HCH are the alpha, beta, gamma and delta forms, of which gamma-HCH ('lindane') has been used as an insecticide. Lindane is a slightly volatile white solid at room temperature with a slightly musty odour.

Use
Lindane was used as a timber insecticide. The use of lindane as an agricultural and domestic insecticide is strictly limited in the EU.

Major emissions
Lindane releases to air were caused mainly by timber treatment. In the air, lindane (and other HCH isomers) can be present as vapour or attached to tiny dust particles. It can remain in the air for several months and travel long distances. In soils, sediments and water, HCH is broken down to less harmful substances by microorganisms-usually within 30 days in the case of water. The length of time HCH isomers can persist in soils is less known.

Impacts on human health and environment
Excessive exposure to hexachlorocyclohexane may affect the blood, brain, breastfed babies, eye, liver, reproductive system and skin, and may cause cancer. Lindane is harmful to insects and fish and releases to water are therefore expected to harm wildlife. Lindane can accumulate in the fatty tissue of fish. Lindane is regarded as a 'persistent organic pollutant' (POP). It is listed as a priority hazardous substance in the Water Framework Directive.

Emission to air reporting threshold: 10 kg/year

Emission to water reporting threshold: 1 kg/year

Data source: European Pollutant Emission Register