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ESE= 112.5 degrees = ?

Posted By: Bloodrain <bloodrain@clanplaid.net>
Date: 10 June 2001, 20:51

I did a little mental flip on this and ran a Google search on "boiling point 112.5" and "melting point 112.5" -- who says "degrees" always has to mean the same thing? -- and the most prevalent thing I found was an insecticide called Lindane, formula C6H6Cl6, which has a melting point of 112.5 degrees C.

Here's some data:


Production and Use
Lindane, the gamma-isomer of hexachlorocyclohexane (HCH), is a colorless, crystalline solid, which is soluble in water. Commercial lindane is 99% gamma HCH. Technical- grade HCH is a mixture of isomers containing 64% alpha-, 10% beta-, 13% gamma-, 9% delta-, and 1% epsilon-HCH. It is produced by the chlorination of benzene under ultraviolet light. Commercial production of lindane began in the United States in 1945 and peaked in the 1950s, when 8 million kg of the compound were manufactured. Lindane has not been produced in the United States since 1977. However, it is still imported to and formulated in the United States. Its use is restricted by the U.S. EPA and can be applied only by certified applicator (Smith, 1991).

Lindane is used primarily as an insecticidal treatment for hardwood logs and lumber, seed grains, and livestock. Other major uses are as an insecticide for several dozen fruit and vegetable crops, and for personal hygiene as a scabicide and pediculicide in the form of a lotion, cream, or shampoo. Agricultural uses accounted for about 95% of the lindane and other HCH isomers used in 1974; the remaining uses were industrial.

Physical/Chemical Properties
Molecular weight: 290.85
Vapor Pressure: 3x10-5 torr @ 25 C
Henry's Law Coefficient: 3x10-6 atm-m3/mol
Water Solubility: 7.3 mg/L of water at 25 C; Slightly soluble in water
Octanol/Water Partition (Kow): 5012
Soil sorption coefficient: average Koc = 1081; low soil mobility
Melting Point (oC): 112.5
Boiling Point (oC): 323.4
Density/Spec. Grav.: 1.85 gr/cm3 @20 oC

Entry and Fate in the Environment
Like other organochlorine insecticides, lindane can enter the environment through numerous pathways. Its half-life is 1.2 years in soil and can last up to 6.5 years, depending on soil type. Roughly 20% of the amount of lindane applied to soil is volatilized within 40 days (Brown, 1978; International Organization of Consumers Unions, 1986).

In air, Lindane is thought to travel as small crystals in the atmosphere adhered to dust particles or water droplets. These crystals spend about 30 days in the atmosphere before they are washed out by rainfall. Lindane vapors on the other hand stay in the atmosphere for 2 to 4 months (Brown, 1978).

When an air mass containing lindane comes in contact with a water body, air-water surface interactions occur. Once lindane enters the thin water surface layer it can either be evaporated or volatilized back out into the atmosphere or it can go into bulk concentration with the water. Once in the water, lindane can be taken up by aquatic life or be deposited into the sediment layer. In the sediment layer microorganisms can degrade lindane both aerobically and anaerobically. Microorganisms within the lake sediments convert lindane (Y-HCH) to mostly a-HCH and some d-HCH. The alpha isomer is about one quarter less toxic than lindane (Brown, 1978).

Environmental Risk and Toxicity
Because lindane is internationally used, concentrations have been measured in the air and water around the world. Therefore, exposure occurs on a daily basis to humans and organisms on land or in aquatic environments. Since lindane is used extensively for agricultural purposes, residues are often found in fruits, vegetables, milk, and meat. It has been reported that the average daily lindane intake an adult receives from food is 0.14 g. Drinking water contaminated with lindane is another common exposure pathway (U.S. Army, 1997). Although lindane concentrations in drinking water are generally low (0.05-0.1 ug/L), high concentrations may be a problem in localized areas. Breathing contaminated air near treated agricultural lands, industrial plants that manufacture lindane, and workplace air are other common ways humans are exposed to lindane. Because humans and animals can be exposed to lindane through various pathways, studies have been conducted to determine its toxicity (Smith, 1991).

Short-term exposure of humans to lindane may interfere with transmission of nerve impulses, disrupting the function of the central nervous system. Acute effects of lindane exposure include nausea, vomiting, gastroenteritis, weakness, numbness, respiratory problems, behavioral disturbances, chloracne, hepatic damage, and renal injury. Excessive dermal or oral intake causes functional alterations in the nervous system in the form of seizures and uncontrollable eye movements. Lindane also appears to have a definite inhibitory effect on white blood cells in vitro. Chronic exposure may result in liver and kidney damage, hormonal disturbances, mental changes, weight loss joint pain, visual disturbances (Smith, 1991).

Lindane is very toxic to fish, aquatic invertebrates, and amphibians. The 96-hour LC50 ranges from 1.7 to 32 ug/L for trout and salmon to 44 to 131 ug/L for catfish, perch and goldfish. Lindane is believed to cause birth defects in amphibians (Johnson and Finley, 1980).

I doubt this is helpful, but maybe there are other "112.5 degrees" out there that are meaningful.

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