Lindane, also known as gamma-hexachlorocyclohexane (γ-HCH), gammaxene, Gammallin and benzene hexachloride (BHC),[3] is an organochlorine chemical and an isomer of hexachlorocyclohexane that has been used both as an agricultural insecticide and as a pharmaceutical treatment for lice and scabies.
[4][5] Lindane is a neurotoxin that interferes with GABA neurotransmitter function by interacting with the GABAA receptor-chloride channel complex at the picrotoxin binding site.
[8][9][10] The World Health Organization classifies lindane as "moderately hazardous", and its international trade is restricted and regulated under the Rotterdam Convention on Prior Informed Consent.
[14] Work in the 1930s at the Jealott's Hill laboratories of Imperial Chemical Industries Ltd (ICI) led in 1942 to the realization that the γ isomer was the key active component in the mixture which had hitherto been tested.
Development work in the UK was accelerated because at that time in World War II imports of derris containing the insecticide rotenone were restricted owing to the Japanese occupation of Malaya and alternatives were urgently needed.
In trials in 1943 it was found that a five-fold increase in the yield of oats and wheat was achieved using a dust formulation of the available material, owing to its efficacy against wireworm pests.
"[31] California banned the pharmaceutical lindane, effective 2002, and the Michigan House of Representatives passed a bill in 2009 to restrict its use to doctors' offices.
The authors concluded, "The California experience suggests elimination of pharmaceutical lindane produced environmental benefits, was associated with a reduction in reported unintentional exposures and did not adversely affect head lice and scabies treatment.
[35] Rudd & Genelly 1954 noticed that bird pests seemed uninterested in treated seeds, specifically pheasants and blackbirds around Davis, CA, US.
Most of the adverse human health effects reported for lindane have been related to agricultural uses and chronic, occupational exposure of seed-treatment workers.
[34] Exposure to large amounts of lindane can harm the nervous system, producing a range of symptoms from headache and dizziness to seizures, convulsions, and more rarely, death.
[6] Prenatal exposure to β-HCH, an isomer of lindane and production byproduct, has been associated with altered thyroid hormone levels and could affect brain development.
[46] A variety of adverse reactions to lindane pharmaceuticals have been reported, ranging from skin irritation to seizures, and, in rare instances, death.
[48] Lindane is a persistent organic pollutant: it is relatively long-lived in the environment, it is transported long distances by natural processes like global distillation, and it can bioaccumulate in food chains, though it is rapidly eliminated when exposure is discontinued.
"[53] Modern manufacturing standards for lindane involve the treatment and conversion of waste isomers to less toxic molecules, a process known as "cracking".
[18][24] Over time, lindane is broken down in soil, sediment, and water into less harmful substances by algae, fungi, and bacteria; however, the process is relatively slow and dependent on ambient environmental conditions.
[6] Lindane residues in honey and beeswax are reported to be the highest of any historical or current pesticide and to continue to pose a threat to honeybee health.
[20] Note that the EPA has set the maximum contaminant level or "MCL" for lindane allowed in public water supplies and considered safe for drinking at 200 parts per trillion (ppt).
[8][59][60][61] The EPA stated that the change resulted from "significant scientific advances made in the last two decades particularly in the areas of cancer and noncancer risk assessments.
[54][62] Modern manufacturing standards for lindane involve the treatment and conversion of waste isomers to less toxic industrial chemicals, a process known as "cracking".