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CAS No. 58-59-9

Photo: Wikimedia Commons^[1]

IARC Monograph Vol. 20, Suppl. 7, 1987 (Group 2B)

General Information

Lindane is the common name for the gamma (γ) isomer of hexachlorocyclohexane (HCH).^[2] HCH is a synthetic chemical with eight chemical forms (isomers).^[2] Lindane is a white to brown solid that dissolves in water.^[3] Technical grade-HCH is a mixture of several isomers (including 10-15% lindane).^[2]

Lindane may also be referred to as gamma-HCH (γ-HCH) or cyclohexane.^[4] There are numerous other synonyms and product names; see HSDB for more information.^[4]

Lindane was classified by IARC as Group 2B, possibly carcinogenic to humans, based on adequate evidence in animals.^[5] Dietary exposures in mice led to increased incidence of liver tumours and lymphatic system neoplasms in mice.^[3] The few epidemiological studies on lindane were limited by small sample sizes, having only observational data, or lack of control for other chemical exposures.

Additionally, inhalation of lindane can cause blood disorders, dizziness, headaches and changes in hormone levels in the blood. These effects have been observed in occupational settings via vapour inhalation during pesticide manufacturing.^[2]

How did CAREX choose this agent for review?

Regulations and Guidelines

Occupational Exposure Limits (OEL)

Canadian Jurisdictions	OEL (mg/m³)
Canada Labour Code	0.5 [sk]
BC, AB, MB, ON, QC, NL, PE, NB, NS	0.5 [sk]
SK, YT, NT, NU	0.5 [sk] 1.5 [stel]
Other Jurisdiction	OEL (mg/m³)
ACGIH 2011 TLV	0.5 [sk]

mg/m³

stel = short term exposure limit (15 min. maximum)

sk = easily absorbed through the skin

Canadian Environmental Guidelines

Jurisdiction	Limit	Year
Canadian Drinking Water Guidelines	Archived	2010^[6]
US Environmental Protection Agency	Drinking water limit: 0.0002 mg/L	1991^[8]
Cosmetic Ingredients Hotlist	Not Permitted	2011^[23]

Lindane was not included in other Canadian government environmental guidelines reviewed.^[7]

Canadian Maximum Residue Limits (Food)

Food Item(s)	MRL (ppm)	Year
Fruits and vegetables	3.0	2004^[9]
Meat and by-products	2.0	2004^[9]
Poultry and by-products	0.7	2004^[9]
Dairy products	0.2	2004^[9]

MRL = Maximum residue limit

Canadian Agencies/Organizations

Lindane was not included in the Canadian government chemical listings reviewed.^[10,16,17]

Main Uses

In the past, lindane was used primarily as an insecticide on fruit, vegetables, forest crops, livestock and animal premises,^[2] hard wood logs and lumber, and seed grains.^[3] It is no longer used in Canada for agricultural purposes.^[11]

Lindane is still used in prescription medicines such as lotions, creams or shampoos for scabies and head lice treatment.^[2] It may also be used for rodent control in baits.^[3]

Canadian Production and Trade

Lindane is no longer produced or manufactured in Canada.^[12]

Global production of lindane was estimated to be 720,000 tonnes and consumption to be 55,000 tonnes in 2000. During that time Canada was the sixth largest global user of lindane.^[12]

According to provincial pesticide use surveys, 239 kilograms of lindane were sold in BC in 1999 and 249 kg were sold in 2003.^[18] There were no Ontario sales reported, but the Ontario report only includes agricultural uses.^[19]

Production and Trade

Activity	Quantity	Year
Canadian Production	Voluntarily discontinued by manufacturer	1972^[12]
Export: N/A	None	2010^[20]
Import: N/A	None	2010^[20]

Occupational Exposures

Inhalation, dermal and ingestion are all potential routes of occupational exposure.^[3]

Workers involved in production, formulation or application of lindane products may be exposed.^[2] Production exposure is unlikely in Canada as it is no longer manufactured in the country.^[12] In Canada, use of lindane in the forestry industry may expose tree planters and other workers involved in wood processing and handing.^[14]

Environmental Exposures

Lindane is not a naturally occurring substance, and is persistent once introduced to the environment by human activities.^[2] Although it does biodegrade, the process is slow.^[2]

Lindane may be been found in air, soil, sediments and water.^[2] A major source of lindane in the air is fugitive dust particles from wind erosion of contaminated soil, as well as volatilization from treated agricultural soil and plant foliage.^[12] As a vapour in the air it attaches to dust particles where it can persist and travel long distances according to season and weather conditions.^[2,12] Particles are gradually broken down and removed by rain or other compounds found in the atmosphere.^[2]

Lindane bioaccumulates in the fat tissues of organisms.^[12]

The general public may be exposed to lindane through medicinal use and ingestion of contaminated foods, breathing contaminated air, or being in contact with contaminated soil or water (although drinking water is not thought to be an important source of exposure).^[2] Lindane is metabolized into many other substances (including chlorophenols), some of which have toxic properties.^[2]

Direct exposure to lindane can occur via absorption through the skin from prescription medication that contains the compound.^[2] This is the most likely route of exposure for children.^[2]

Foods with the greatest potential for containing lindane include foods with high fat content,^[3] such as milk, eggs, other dairy products, and some seafood. Pickles and raw mushrooms were also found to have high concentrations of lindane.^[3] Exposure can occur via lindane residues on food products or accumulation in animal tissue. Lindane has also been found in breast milk.^[2]

In Canada, lindane is found throughout the arctic environment from atmospheric deposition and ocean currents. It is not known whether the source of lindane found in the arctic is from lindane or technical HCH, which may still be in use in other countries.^[12] Persistent organic pollutants (POPs) including lindane were found in the 1980s at high concentrations in the arctic with no local source association. Fortunately levels have shown a decline since 1979 as a result of decreased use of alpha-HCH in developing countries.^[12]

Potential health implications for northern aboriginal peoples are of primary concern, as they tend to be more susceptible to accumulation of contaminants as a result of their traditional diet. The majority of Aboriginal households (90%) in the Northwest Territories report consuming traditional foods such as harvested wildlife and or marine mammals.^[12]

The most recent Health Canada Total Diet Study (TDS) that included pesticides was conducted in Whitehorse in 1998. The results for lindane were:^[21]

Food Type	Concentration (ppm)	% of MRL
Ice cream	0.61	0.3%
Cheese	0.25	0.1%
All cheese (processed)	0.60	0.3%
Butter	1.12	0.6%
Cookies	1.45	N/A
Muffins	0.48	N/A
Candy & chocolate	3.71	N/A

MRL = Maximum residue limit

ppm=parts per million

The average daily dietary intake of lindane for Canadians was also calculated in the TDS in 1998. The average daily intake for lindane was 1.28 nanograms per kilogram of body weight per day, 0.13% of the acceptable daily intake as set by the World Health Organization.^[22]

Lindane releases are not reportable to the National Pollutant Release Inventory (NPRI).^[24] No consumer products containing lindane were found in the US Household Products Database.^[25]

Sources

Other Resources

Published March 2012

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Lindane