Chemical Properties
yellow waxy solid
Uses
Insecticide. Not recommended for use in dairy barns or on milking animals (Penumarthy).
General Description
Yellow, waxy solid with a pleasant piney odor. Used as an insecticide, primarily for cotton and early growth stages of vegetables. Also peas, soybeans, peanut, corn, and wheat. Not produced commercially in the U.S. since 1982. Only registered for scabies control on cattle in the U.S.
Air & Water Reactions
Insoluble in water.
Reactivity Profile
TOXAPHENE is decomposed by sunlight and heat. TOXAPHENE is decomposed in the presence of alkali. TOXAPHENE is corrosive to iron. TOXAPHENE is incompatible with strong oxidizers. TOXAPHENE is non corrosive in the absence of moisture.
Health Hazard
Camphechlor is extremely toxic: the probable oral lethal dose (human) is 5-50 mg/kg or between 7 drops and 1 teaspoonful for 70 kg (150 lb.) person.
Fire Hazard
Container may explode in heat of fire. Toxic vapors are generated when heated. Releases hydrochloric acid in the presence of alkali, on prolonged exposure to sunlight, and at temperatures above 311F. Avoid strong oxidizers, corrosive to iron.
Description
Toxaphene is an organochlorine insecticide that is similar to
other compounds such as endrin, dieldrin, aldrin, dichlorodiphenyltrichloroethane
(DDT), lindane, and chlordecone.
Manufacturing of toxaphene was started in the 1940s and
was highly effective on cotton and certain food crops. In
addition to its use as an insecticide, toxaphene was also used
to eliminate certain species of fish in aquatic environments.
Toxaphene itself consists of a mixture of hundreds of
different chemicals with a major identified toxic component
being heptachlorobornane. The use of toxaphene peaked in
1974 after DDT was banned in 1972 with nearly
400 000 metric tons being distributed into the environment
(both land and aquatic uses). This use began to subside, yet
nearly 100 000 metric tons was still used in 1980 shortly
before the complete ban on toxaphene usage. Large quantities
of toxaphene were released into the environment. The
overall chlorine content of toxaphene is nearly 70% by
weight with most of the organic compounds comprising
toxaphene being chlorinated. The molecular weight of the
various components of toxaphene can range from 308 to
551 g mol-1. The mean formula weight is approximately
414 g mol-1. Toxaphene can be found as an yellowish-waxy
substance that is relatively volatile and can be transported in
the atmosphere. If inhaled, especially in larger quantities,
toxaphene has been shown to cause significant damage to
the lungs/respiratory tract, central nervous system, and
kidneys. The use of toxaphene as an insecticide was banned in the early 1980s and completely banned in the United
States in 1990. In addition to its ban in North America,
toxaphene has been also banned in Europe, yet its use in
developing countries still persists. Toxaphene is not readily
soluble in water and tends to deposit in the soil and sediment,
as well as the atmosphere. Microorganisms in the soil
tend to degrade toxaphene very slowly. Toxaphene does not
degrade as slowly as DDT but has been demonstrated to
persist in the environment for extended and significant
periods of time.
Physical properties
Yellow, waxy, nonflammable solid with a chlorine or terpene-like odor. Odor threshold
concentration from water is 140 μg/L (quoted, Keith and Walters, 1992).
Definition
Following release of technical toxaphene into the environment, the congeners are expected to undergo differential transformation, and degradation via abiotic and biotic processes, resulting in different mixtures of persistent toxaphene congeners, commonly termed weathered. Transformation and degradation processes are expected to include dechlorination and dehydrochlorination.
Carcinogenicity
Toxaphene is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
Environmental Fate
Soil. Under reduced soil conditions, about 50% of the C-Cl bonds were cleaved
(dechlorinated) by Fe2+ porphyrins forming two major toxicants having molecular formulas
C10H10Cl8 (Toxicant A) and C10H11Cl7 (Toxicant B). Toxicant A reacted with reduced
hematin yielding two reductive dechlorination products (C10H11Cl7), two dehydrodechlo-
rination products (C10H9Cl7) and two other products (C10H10Cl6). Similarly, products
formed from the reaction of Toxicant B with reduced hematin included two reductive
dechlorination products (C10H12Cl6), one dehydrochlorination product (C10H10Cl6) and two
products having the molecular formula C10H11Cl5 (Khalifa et al., 1976). The reported
dissipation rate of toxaphene from soil is 0.010/day (Seiber et al., 1979).
Photolytic. Dehydrochlorination will occur after prolonged exposure to sunlight releas-
ing hydrochloric acid (U.S. Department of Health and Human Services, 1989). Two
compounds isolated from toxaphene, 2-exo,3-exo,5,5,6-endo,8,9,10,10-nonachlor
Chemical/Physical. Saleh and Casida (1978) demonstrated that Toxicant B (2,2,5-
endo,6-exo,8,9,10-heptachlorobornane), the most active component of toxaphene, under-
went reductive dechlorination at the geminal dichloro position yielding 2-endo,
Toxaphene will slowly undergo hydrolysis resulting in the loss of chlorine atoms and
the formation of hydrochloric acid (Kollig, 1993). The hydrolysis rate constant for tox-
aphene at pH 7 and 25°C was determined to be 8 × 10–6/hour, resulting in a half-life of
9.9 years (Ellington et al., 1987).
Emits toxic chloride fumes when heated to decomposition (Lewis, 1990).
Toxicity evaluation
The neuroexcitatory properties of toxaphene are due to its
ability to reduce chloride uptake into neurons, leading to
depolarization of the cells and hyperactivity. It is believed that
toxaphene acts on the picrotoxin-binding site on the gammaaminobutyric
acid (GABA)A receptor. Toxaphene may also
impair calcium transport which will interfere with numerous
neuronal pathways and function.
