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.
Chemical Properties
yellow waxy solid
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).
Uses
Formerly used as an insecticide
Uses
Pesticide used primarily on cotton, lettuce, tomatoes, corn, peanuts, wheat and
soybean.
Uses
Toxaphene is an insecticide that contains over 200–700
chemicals and can exist as an yellow to amber solid or gas.
Heavily used in the United States until 1982, its use was
completely banned in 1990. Toxaphene was used primarily to
control insects on cotton crops in the southern United States; it
has also been used to control pests on livestock and to control
unwanted fish in aquatic environments. Reports have indicated
that fish are low metabolizers of toxaphene, whereas other
aquatic life such as snails can be extensive metabolizers, thus
reducing the toxicity of toxaphene to aquatic life other than fish
(Isensee et al., 1979).
Uses
Insecticide. Not recommended for use in dairy barns or on milking animals (Penumarthy).
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.
Production Methods
Camphechlor is produced through the photochlorination of camphene using elemental chlorine gas under ultraviolet irradiation. This process yields a complex mixture of chlorinated bornanes and camphenes, typically containing 67–69% chlorine by weight. In laboratory settings, alternative chlorinating agents like sulfuryl chloride have been used to replicate the composition of both low- and high-chlorinated camphechlor mixtures.
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.
Health Hazard
Highly toxic by ingestion; moderately toxicby skin contact and inhalation; may causeskin irritation and allergic dermatitis; causedadverse reproductive effects in experimentalanimals; ingestion of about 1.5–3 g may befatal to adult human; toxic effects in animals include central nervous system stimulation, tremors, convulsions, and liver injury;oral LD50 value (rats): ～100 mg/kg: sufficient evidence of carcinogenicity in animals,causing liver cancer; RCRA Waste Number P123.
LD50 oral (rat): 50 mg/kg
LD50 skin (rat): 600 mg/kg
Studies on the cancer risk assessment oftoxaphene in rodents have shown that itincreased incidence of neoplasms of endocrine organs, thyroid, pituitary, adrenal andmammary glands and reproductive systems(Buranatrevedth 2004).
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.
Mechanism of action
A non-systemic contact and stomach insecticide. It acts on the neurons, causing an imbalance in sodium and potassium ions, similar to that of the cyclodiene insecticides.
Safety Profile
Confirmed carcinogen
with experimental carcinogenic and
tumorigenic data. Human poison by
ingestion and possibly other routes.
Experimental poison by ingestion,
intraperitoneal, and possibly other routes.
Moderately toxic experimentally by
inhalation and skin contact. Human systemic
effects by ingestion and skin contact:
somnolence, convulsions or effect on
seizure threshold, coma, and allergic skin
dermatitis. A skin irritant; absorbed through
the skin. Experimental teratogenic and
reproductive effects. Human mutation data
reported. Liver injury has been reported.
Lethal amounts of toxaphene can enter the
body through the mouth, lungs, and skin.
Systemic absorption of the insecticide is
increased by the presence of lgestible oils,
and liquid preparations of the insecticide,
which penetrate the skin more readily than
do dusts and wettable powders.A toxic mixture of organochlorine
pesticides stored to some extent in body fat.
It resembles chlordane and, to some extent,
camphor in its physiological action. It causes
diffuse stimulation of the brain and spinal
cord resulting in generahzed convulsions of
a tonic or clonic character. Death usually
results from respiratory failure.
Detoxification appears to occur in the liver.
The lethal ingestion dose for humans is
estimated to be 2-7 g, a toxicity of about
four times that of DDT. At least seven
human deaths have been reported due to
toxaphene, all in chddren. Two families have
been made ill by eating vegetables
containing a large residue of toxaphene.
When heated to decomposition it emits
toxic fumes of Cl-.
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.
Toxics Screening Level
The initial risk screening level (IRSL) for toxaphene is 0.003 μg/m3 (annual averaging time).
Pesticide Type
Insecticide; Acaricide; Veterinary substance
