Chemical Fact Sheet

Chemical Abstract Number (CAS #) 58899
CASRN 58-89-9
Hexachlorocyclohexane (gamma)
Cyclohexane, 1,2,3,4,5,6-hexachloro-, (1-alpha, 2-alpha,3-beta, 4-alpha, 5-alpha, 6-beta)
Analytical Methods EPA Method 505
EPA Method 508
EPA Method 525.2
EPA Method 608
EPA Method 617
EPA Method 625
EPA Method 8081
EPA Method 8270
Molecular FormulaC6H6Cl6

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use INSECTICIDE FOR FIELD CROPS CORN, WHEAT INSECTICIDE FOR ORNAMENTALS, PASTURE, & FORAGE CROPS INSECTICIDE FOR FORESTRY, TIMBER PROTECTION, & LIVESTOCK INSECTICIDE FOR SOIL & SEED TREATMENT & VITICULTURE Medication (Human: pediculicide, scabicide; Vet: ectoparasiticide) Used in baits & seed treatments for rodent control. Application rates: Range from 0.25 to 2.25 ounces/100 lb of seed for seed treatment; 0.1 to 2.06 lb/acre for foliar and soil treatment; 0.8 to 1.5 oz/50,000 cubic feet of greenhouse; 0.006 to 0.11 lb/gallon for bark; 0.023 to 3% sprays, dips, and dusts for indoor and animal treatment; <0.01 lb/1000 square feet for animal premises; <4 lb/1000 square feet (14.64% solutions) for wood, and wooden structures; and 1% dust for human skin/clothing treatment (military use only). Medication: pediculicide, scabicide Medication (vet): ectoparasiticide
Odor SLIGHT MUSTY ODOR ; SLIGHT AROMATIC ODOR ; Pure lindane is odorless.
Boiling Point 323.4 DEG C AT 760 MM HG
Melting Point 112.5 DEG C
Molecular Weight 290.85
Density 1.85
Environmental Impact Lindane is used as an insecticide on hardwood logs and lumber, seeds, vegetables and fruits, woody ornamentals, hardwood forests, livestock and pets, and existing structures. When released to water, lindane is not expected to volatilize significantly. Lindane released to acidic or neutral water is not expected to hydrolyze significantly, but in basic water, significant hydrolysis may occur (t1/2=95 hr at pH 9.3). Transport to the sediment should be slow and result predominantly from diffusion rather than settling. Release of lindane to soil will most likely result in volatilization and slow leaching of lindane to groundwater. Lindane in the atmosphere is likely to be subject to rain-out and dry deposition. The estimated half-life for the reaction of vapor phase lindane with atmospheric hydroxyl radicals is 1.63 days. Lindane may slowly biodegrade in aerobic media and will rapidly degrade under anaerobic conditions. Lindane has been reported to photodegrade in water in spite of the lack of a photoreactive center, but photolysis is not considered to be a major environmental fate process. Lindane will bioconcentrate slightly in fish. Monitoring data indicate that lindane is a contaminant in air, water, sediment, soil, fish and other aquatic organisms, wildlife, food, and humans. Human exposure results primarily from food.
Environmental Fate TERRESTRIAL FATE: As the sole carbon source, lindane was found to support the growth of 71 of 147 microorganisms isolated from loamy sand. Chloride ion formation was noted in these cultures. The extent of lindane biodegradation by these pure cultures was not given . From moist, aerated soil, 62% of the lindane applied was recovered, and 3% of the applied (14)C was released as (14)CO2 after 105 days. After 140 days, 17.8% of the applied (14)C was released from submerged soil. As measured by gas-liquid chromatography, the loss of lindane from submerged anaerobic soil was nearly quantitative, with only 4% of the applied lindane recoverable . Six weeks following treatment of soil with lindane and submergence of the soil, 1,2,4-trichlorobenzene, 1,2,3,5- and/or 1,2,4,5-tetrachlorobenzene, 1,2,3,4-tetrachlorobenzene, gamma-2,3,4,5,6-pentachlorocyclohex-1-ene and gamma-3,4,5,6-tetrachlorocyclohexene were detected in the soil by GC. The absence of these products from sterilized soil treated with lindane was cited as evidence that the lindane metabolites resulted from biodegradation . Incubation of aerobic and anaerobic soil suspensions of lindane for three weeks resulted in the disappearance of 0 and 63.8% of the applied lindane, respectively . This result was said to indicate that anaerobic degradation of lindane is more extensive than aerobic degradation . Agricultural loam plots treated with 10 or 100 lb of lindane retained only 0.2% of the added lindane on the plots after 15 years regardless of the dosage applied . After 50 hr, 26% and 100% of the surface applied lindane remained on Hatboro silt loam and Norfolk sandy loam, respectively(6). The resistance of lindane on the sandy loam to volatilization was concluded to be due to the dryness of the soil. From a moist soil surface, the lindane content decreased to 50% and 10% of the amount applied after 6 hr and 6 days, respectively, while 50 hr after lindane application to dry soil, 88% of the applied lindane remained(6). A mean Koc of 1080.9 was obtained from Koc determinations on three soils(7). The average organic carbon content of the soils used was 13%(7). Based on this moderate Koc value and a water solubility of 17 ppm(8), lindane is expected to leach slowly to groundwater. The leaching of lindane from Gezira soil (38.8% sand, 34.7% silt, 26.2% clay and 4.6% organic carbon) from the Sudan was slow(9). After 45 days, <50% of the applied lindane had leached from the soil(9). Freundlich constants for lindane sorption and desorption were determined for four systems as follows. Montmorillonite clay-distilled water: 1258.9 or both sorption and desorption, Roselawn Cemetery water-sediment: 354.8 and 4.26, Cross Lake water- sediment: 2238.7 and 4.26 for sorption and desorption, respectively. The high desorption constant for the Cross Lake system was said to suggest a strong interaction between lindane and the organic material in the samples, although the organic contents, 1.34% and 1.33% for the Roselawn Cemetery and Cross Lake, respectively, of the two sediment samples were similar(10). AQUATIC FATE: Hydrolysis rate constants of 7.5X10-3, 8.99X10-4, and 1.07X10-3 1/hr were determined in surface water samples from a eutrophic pond in Texas, a dystrophic reservoir in Louisiana and an oligotrophic rock quarry in Indiana, respectively . The corresponding hydrolysis half-lives are 92, 771, and 648 hr for the TX, LA, and IN samples, respectively. The hydrolysis reactions follow first-order kinetics. A temperature of 25 deg C was used and pH's were 7.3 (LA), 7.8 (IN), and 9.3 (TX). First order aqueous photolysis of lindane was observed in direct sunlight photolysis experiments. The rate constants were 4.1X10-3 (TX), 3.9X10-4 (LA), and 4.5X10-4 1/hr (IN). The half-life values were 169 (TX), 1,791 (LA), and 1.540 hr (IN). The relative rapidity of reaction in the TX water samples was attributed to its higher pH. The reaction products of lindane hydrolysis were said to be more susceptible to photolysis than lindane . After 16 weeks, <30% of the applied lindane remained in unsterilized natural waters in capped bottles . Biodegradation was concluded to be responsible for this result, although it was unclear to what extent hydrolysis may have contributed to the result . River, lake and groundwater half-lives for lindane were estimated from degradation data in these bodies to be 3-30, 30-300, and >300 days, respectively . The fate of lindane has been studied in a field experiment . The role of particle transport in the transport of lindane to the sediment was found to be small compared to diffusion . After 100 days, 75% of the lindane added was found in the water column and sediment layer of the quarry. The water column contained more than 75% of this amount . The volatilization half-life of lindane from water has been estimated to be 115 days . Assuming a depth of 1 m, the volatilization half-life of lindane from water was estimated to be 191 days(6). A half-life of 3.2 days for the volatilization of lindane from 4.5 cm deep, still, pure water at 24 deg C while with stirring, the half-life was 1.5 days(7). Using an equation relating water depth to volatilization half-life(7), the experimental half-life of 3.2 days from 4.5 cm was used to project a half-life of 692 days from a depth of 1 m. This figure is of the same order of magnitude as the estimated half-lives of 115 and 191 days for volatilization from 1 m, so these figures can be considered to be valid estimates of the tendency of lindane to volatilize. ATMOSPHERIC FATE: The half-life of the reaction of lindane with hydroxyl radicals in the atmosphere was estimated to be 1.63 days . Lindane removal rates in percent/week by rainfall and dry deposition are 2.5 and 3.3, respectively, and the estimated residence time of lindane in the atmosphere is 17 weeks . Aquatic Fate : The fate of lindane in a very oligotrophic, lentic lake aquatic system was studied/. Equal concentrations of lindane and DDE were added in late May to a flooded limestone quarry and the pesticide concentrations in the water, sediment, and biota were monitored for a year's time. The lake was thermally stratified during the summer, was intermittently covered with ice in the winter, and received a large influx of sediment because of a rainstorm that occured one day after the pesticides were introduced into the system Conclusions drawn indicate the following/:

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