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The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised June 1996

Lindane

Trade and Other Names: Trade or other names for lindane include Agrocide, Ambrocide, Aparasin, Aphitiria, Benesan, Benexane, benhexachlor, benzene hexachloride, BHC, BoreKil, Borer-Tox, Exagama, Gallogama, Gamaphex, gamma-BHC, Gamma-Col, gamma-HCH, Gammex, Gammexane, Gamasan, Gexane, hexachlorocyclohexane, HCH, Isotox, Jacutin, Kwell, Lindafor, Lindagronox, Lindaterra, Lindatox, Lintox, Lorexane, New Kotol, Noviagam, Quellada, Steward, Streunex, and Tri-6.

NOTE: Lindane (or hexachlorocyclohexane, HCH) has historically and widely been inappropriately referred to as "benzene hexachloride" or "BHC". This compound should not be confused with hexachlorobenzene, or HCB.

Regulatory Status: Lindane is a moderately toxic compound in EPA toxicity class II. Labels for products containing it must bear the Signal Word WARNING. Some formulations of lindane are classified as Restricted Use Pesticides (RUP), and as such may only be purchased and used by certified pesticide applicators. Lindane is no longer manufactured in the U.S., and most agricultural and dairy uses have been cancelled by the EPA because of concerns about the compound's potential to cause cancer.

Chemical Class: organochlorine

Introduction: Lindane is an organochlorine insecticide and fumigant which has been used on a wide range of soil-dwelling and plant-eating (phytophagous) insects. It is commonly used on a wide variety of crops, in warehouses, in public health to control insect-borne diseases, and (with fungicides) as a seed treatment. Lindane is also presently used in lotions, creams, and shampoos for the control of lice and mites (scabies) in humans.

Technical lindane is comprised of the gamma-isomer of hexachlorocyclohexane, HCH. Five other isomers (molecules with a unique structural arrangement, but identical chemical formulas) of HCH are commonly found in technical lindane, but the gamma-isomer is the predominant one, comprising at least 99% of the mixture of isomers. Data presented in this profile are for the technical product unless otherwise stated; lindane, HCH, or BHC refer to technical lindane, i.e., Gamma-hexachlorocyclohexane. Gamma-HCH has been shown to be the insecticidally effective isomer.

Lindane may also be found in formulations with a host of fungicides and insecticides. It is available as a suspension, emulsifiable concentrate, fumigant, seed treatment, wettable and dustable powder, and ultra low volume (ULV) liquid.

Formulation: Lindane may also be found in formulations with a host of fungicides and insecticides. It is available as a suspension, emulsifiable concentrate, fumigant, seed treatment, wettable and dustable powder, and ultra-low volume (ULV) liquid.

Toxicological Effects:

• Acute toxicity: Lindane is a moderately toxic compound via oral exposure, with a reported oral LD50 of 88 to 190 mg/kg in rats [2]. Other reported oral LD50 values are 59 to 562 mg/kg in mice, 100 to 127 mg/kg in guinea pigs, and 200 mg/kg in rabbits [2,9]. Gamma-HCH is generally considered to be the most acutely toxic of the isomers following single administration [2]. It is moderately toxic via the dermal route as well, with reported dermal LD50 values of 500 to 1000 mg/kg in rats, 300 mg/kg in mice, 400 mg/kg in guinea pigs, and 300 mg/kg in rabbits [2,9]. Notably, a 1% solution of linadane in vanishing creme resulted in a six-fold increase in acute toxicity via the dermal route in rabbits, with a reported dermal LD50 of 50 mg/kg [2]. It is reported to be a skin and eye irritant [9]. Younger animals may be more susceptible to linadane's toxic effects [2]. Calves are especially susceptible to dermal application [2]. Effects of high acute exposure to lindane may include central nervous system stimulation (usually developing within 1 hour), mental/motor impairment, excitation, clonic (intermittent) and tonic (continuous) convulsions, increased respiratory rate and/or failure, pulmonary edema, and dermatitis [2]. Other symptoms in humans are more behavioral in nature such as loss of balance, grinding of the teeth, and hyper-irritability [2]. Most acute effects in humans have been due to accidental or intentional ingestion, although inhalation toxicity occurred (especially among children) when it was used in vaporizers. Workers may be exposed to the product through skin absorption and through inhalation if handled incorrectly. Lotions (10%) applied for scabies have resulted in severe intoxication in some children and infants [17]. It is reported that single administrations of 120 mg/kg inhibited the ability of white blood cells to attack and kill foreign bacteria in the blood of rats, and 60 mg/kg inhibited antibody formation to human serum albumin [3]. It is not clear whether these effects were temporary, or for how long they may have lasted [2].
• Chronic toxicity: Doses of 1.25 mg/kg/day in mice, rats, and dogs produced no observable effects over periods of up to 2 years [2,3]. Doses of 40 to 80 mg/kg/day were rapidly fatal to dogs in a study over 2 years, and doses of 2.6 to 5.0 mg/kg/day resulted in convulsions in some test animals [2]. This same dose level caused liver lesions in rats [2]. In one study, 6 to 10 mg/kg/day was reported to have no observable effects on mice, but in another study, that dose caused apparent metabolic changes in the liver [2]. Other studies in mice have demonstrated liver damage at higher doses [2]. In a 2-year rat study, significant liver changes were attributed to the dietary intake of approximately 5 mg/kg/day [2]. Sufficiently high repeated administration of lindane has caused kidney, pancreas, testes, and nasal mucous membrane damage in test animals [2]. There have been reported links of lindane to immune system effects; however, these have not been amply demonstrated in test animals or in humans in a long-term study [2]. Long-term toxicity of the gamma-isomer may be less than that of the alpha- and beta-isomers due to its more rapid transformation and elimination and lesser storage in the body [2]. Sixty male workers in a lindane producing factory had no signs of neurological impairment or perturbation after 1 to 30 years exposure [17]. Another study of chronically exposed workers showed subtle differences between their electrocardiographs (graphs of the heart beat impulses) and those of unexposed workers [17].
• Reproductive effects: In rats, doses of 10 mg/kg/day for 138 days resulted in marked reductions in fecundity and litter size [2], and half that dose (5 mg/kg/day) reportedly had no effect [2]. In another study in rats, doses as low as 0.5 mg/kg/day over 4 months caused observable disturbances in the rat estrus cycle, lengthened gestation time, decreased fecundity, and increased fetal mortality [2]. Lindane was found to be slightly estrogenic to female rats and mice, and also caused the testes of male rats to become atrophied. Semeniferous tubules and and Leydig cells (important for production of sperm) were completely degenerated at doses of 8 mg/kg/day over a 10-day period [2]. Reversible decreases in sperm cell production were noted in male mice fed approximately 60 mg/kg/day for 8 months [2]. It is unlikely that lindane will cause effects at the low levels of exposure expected in human populations.
• Teratogenic effects: In rats, doses as low as 0.5 mg/kg/day over 4 months caused decreased growth in offspring [2]. Beagles given 7.5 or 15 mg/kg/day from day 5 throughout gestation did not produce pups with any noticeable birth defects. Pregnant rats given small amounts of lindane in their food had offspring unaffected by the pesticide [17]. It appears that lindane is unlikely to cause developmental effects at levels of exposure expected in human populations.
• Mutagenic effects: Most tests on mice and on microorganisms have shown no mutagenicity due to lindane exposure [2]. However, lindane has been shown to induce some changes in the chromosomes of cultured human lymphocytes at 5 and 10 ppm in the culture medium. Some chromosomal damage was also noted at a concentration of 1 ppm in this study as well. An in vivo (in live animals) study of the effects of lindane on rat leukocytes (white blood cells) did not find chromosomal abnormalities after a single administration of 75 mg/kg [2]. It is unlikely that lindane would pose a mutagenic risk in humans at normal exposure levels.
• Carcinogenic effects: No tumors were found in groups of 20 mice fed the beta-, gamma-, and delta-isomers of HCH at about 64 mg/kg/day, but tumors occurred in 100% of the mice fed the alpha-isomer only [2]. In rats similar findings were noted at doses of about 49 mg/kg/day [2]. Other work suggests that rodents may suffer from liver tumors from high doses of the gamma-isomer (lindane) [2]. HCH was not found to promote tumors initiated by benz[a]anthracene [2]. The available evidence is contradictory, and does not allow assessment of the potential for carcinogenic effects in humans from lindane exposure.
• Organ toxicity: Data from animal tests indicate that lindane may affect the central nervous system, liver, kidney, pancreas, testes, and nasal mucous membrane.

• Fate in humans and animals: Animal studies show that lindane is readily absorbed through the gastrointestinal tract, skin, and lungs [2]. Studies show that systemic distribution may be similarly rapid [2]. The metabolism of the different isomers of HCH is complex and occurs via many different pathways. The metabolism of lindane, while complex, is nonetheless fairly rapid [2,9]. The main pathways include stepwise elimination of chlorines to form tri- and tetrachlorophenols and conjugation with sulfates or glucuronides and subsequent elimination [2]. Other pathways involve the ultimate formation of mercapturates [2]. These water soluble end-products are elimated via the urine [2]. Less is known of the metabolism of the other isomers [2]. While all isomers of HCH are stored in fat, the gamma-isomer is stored at very much larger rates than the other isomers, which are more readily metabolized and eliminated [2]. Storage equilibrium, at low levels of lindane in rats, is reached after 2 to 7 days, while that for beta-HCH or other isomers may take longer [2]. Of a single dose of 40 mg/kg to rats, 80% was excreted in urine and 20% in feces [2]. Half of the administered lindane is excreted in 3 or 4 days [2].

Ecological Effects:

• Effects on birds: Lindane is moderately to practically nontoxic to bird species, with a reported LD50 of more than 2000 mg/kg in the mallard duck. The 5-day dietary LC50 of lindane in Japanese quail is 490 ppm [54]. The LC50 values of lindane in pheasant and bobwhite quail are 561 ppm and 882 ppm, respectively [64]. Egg-shell thinning and reduced egg production has occurred in birds exposed to lindane [64]. Lindane can be stored in the fat of birds; birds of prey in the Netherlands contained up to 89 ppm in their fat [64]. Residues can also find their way into egg yolks at measurable concentrations for 32 days after dosing [64].
• Effects on aquatic organisms: Lindane is highly to very highly toxic to fish and aquatic invertebrate species. Reported 96-hour LC50 values range from 1.7 to 90 ug/L in trout (rainbow, brown, and lake), coho salmon, carp, fathead minnow, bluegill, largemouth bass, and yellow perch [55]. Water hardness did not seem to alter the toxicity to fish, but increased temperature caused increased toxicity for some species and decreased toxicity for others. Reported 96-hour LC50 values in aquatic invertebrates were: in Daphnia, 460 ug/L; in scuds, 10-88 ug/L; and in Pteronarcys (stone flies), 4.5 ug/L [55]. The bioconcentration factor for the compound is 1400 times ambient water concentrations, indicating significant bioaccumulation [64].
• Effects on other organisms: Lindane is highly toxic to bees [9].

Environmental Fate:

• Breakdown in soil and groundwater: Lindane is highly persistent in most soils, with a field half-life of approximately 15 months [14]. When sprayed on the surface, the half-life was typically much shorter than when incorporated into the soil [64]. It shows a low affinity for soil binding [14], and may be mobile in soils with especially low organic matter content or subject to high rainfall. It may pose a risk of groundwater contamination. The pesticide has been found in a significant number of groundwater samples in New Jersey, California, Mississippi, South Carolina, and in Italy at concentrations of less than 1 ug/L (ppb) [12]. Lindane is a contaminant in water in the Great Lakes at very low concentrations as well [17].
• Breakdown in water: Lindane is very stable in both fresh and salt water environments, and is resistant to photodegradation [9]. It will disappear from the water by secondary mechanisms such as adsorption on sediment, biological breakdown by microflora and fauna, and adsorption by fish through gills, skin, and food [64].
• Breakdown in vegetation: Plants may pick up residues from not only direct application, but through water and vapor phases. Persistence is seen when plants are rich in lipid content, and crops like cauliflower and spinach will build up less residue than crops like carrots [64]. The metabolism in plants is not well understood, but carrots are estimated to metabolize lindane with a half-life of just over 10 weeks (based on plant uptake) whereas it may have a half-life in lettuce of only 3 to 4 days [64].

Physical Properties:

• Appearance: Lindane is a colorless crystal compound.
• Chemical Name: gamma-1,2,3,4,5,6-hexachlorocyclohexane [9]
• CAS Number: 58-89-9
• Molecular Weight: 290.85
• Water Solubility: 7.3 mg/L @ 25 C [9]
• Solubility in Other Solvents: v.s. in acetone, benzene, and ethanol [9]
• Melting Point: Approximately 113 C [9]
• Vapor Pressure: 5.6 mPa @ 20 C [9]
• Partition Coefficient: Not Available
• Adsorption Coefficient: 1100 [14]

Exposure Guidelines:

• ADI: 0.008 mg/kg/day [27]
• MCL: 0.0002 mg/L [8]
• RfD: 0.0003 mg/kg/day [18]
• PEL: 0.5 mg/m3 (8-hour) [28]
• HA: Not Available
• TLV: Not Available

Basic Manufacturer:

Drexel Chemical Company
1700 Channel Avenue
Memphis, TN 38113

• Phone: 901-774-4370
• Emergency: Not Available
  

References:

References for the information in this PIP can be found in Reference List Number 6

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.