| Chemical Abstract Number (CAS #) |
52645531
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| Synonyms | Ambush |
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Cyclopropanecarboxylic acid, 3-(2,2-dichlorethenyl)-2,2-dimethyl-,
(3-phenoxyphenyl)methyl ester | Permethrin | Ectiban | Pertox | Persect | Indothrin |
| Analytical Methods |
EPA Method 508 |
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EPA Method 508 |
EPA Method 608.2 |
| Molecular Formula | C21H20Cl2O3 |
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| Use | Medication (vet): ectoparasiticide
It has a potential application for forest protection and vector control for the control of noxious
insects in the household and on cattle, for the control of body lice, and in mosquito nets.
Nematocide, acaricide
Control of larvae (and also adults and eggs) of chewing lepidopterous and coleopterous insect
pests on pome fruit, stone fruit, berry fruit, citrus fruit,vines, olives, vegetables, cereals, maize,
oilseed rape, cotton, tobacco, soya beans, and in conifer nurseries; whiteflies and other glasshouse
pests on glasshouse cucumbers, tomatoes, and ornamentals; and sciarid flies and phorid flies on
mushrooms. Also used for control of crawling and flying insects (e.g flies, ants, fleas,
cockroaches, silverfish, etc.) in public health, and in agricultural premises including animals
houses; and as an ectoparasiticide on animals.
Insecticide Pyrethrins
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| Consumption Patterns | Tick repellent
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| Apparent Color | Pale brown liquid
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| Boiling Point | ca 200 deg C at 0.01 mm Hg
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| Melting Point | 34-35 deg C
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| Molecular Weight | 391.29
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| Density | 1.19 - 1.27 at 20 deg C
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| Sensitivity Data | Mild irritant to skin and eyes. Technical permethrin
Immediately irritating to the eye. Pyrethrins
The chief effect from exposure is skin rash particularly on moist areas of the skin. May
irritate the eyes. Pyrethroids
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| Environmental Impact | Permethrin will be released to the environment primarily during agricultural spraying
operations. In the ambient atmosphere, permethrin is expected to exist almost entirely in the
particulate-phase because of its low vapor pressure. Degradation of vapor phase permethrin by
reaction with photochemically produced hydroxyl radicals (estimated half-life of 9.9 hrs) may take
place. Particulate phase permethrin will be removed from air via dry deposition. In soil, a
degradation half-life of 30 days was estimated for permethrin and its strong adsorption to soil
suggests that leaching is not important. Biodegradation will be important. Photolysis may occur
on soil surfaces exposed to sunlight and hydrolysis in alkaline moist soils may contribute to the
removal of permethrin from soil. In water, permethrin may hydrolyze producing
3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid and 3-phenoxybenzyl alcohol
(estimated half-life of 20 days at pH 9). Biodegradation, bioconcentration in fish, and photolysis
in near-surface waters exposed to sunlight may be important processes in water. Furthermore,
adsorption from the water column to sediments and suspended material will be important (Koc of
63,100). Volatilization will not be important because of its low Henry'a Law constant. Exposure
of the general population to permethrin may occur through ingestion of contaminated foods as
well as inhalation of dust and dermal contact resulting from its use. Workers may be exposed via
dermal contact and inhalation of dust.
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| Environmental Fate | TERRESTRIAL FATE: According to all available data in the U.S. Department of
Agriculture's Pesticide Properties Database, a degradation half-life of 30 days was estimated for
permethrin in soil . The half-life of permethrin in aerobically incubated soil is less than 4 weeks
and is 32 to greater than 64 days in anaerobic flooded soils . In moist alkaline soils, hydrolysis
probably takes place in conjunction with biodegradation; estimated aqueous hydrolysis
half-life of 20 days at pH 9 . An experimental Koc value of 63,100 indicates no soil mobility
and strong soil adsorption. Photodegradation half-lives of 5-17 days were determined for
permethrin on thin films suggesting that permethrin may be removed from soil surfaces via
direct photolysis.
AQUATIC FATE: An experimental Koc value of 63,096 indicates that adsorption from the
water column to sediment and suspended solids will occur. A BCF of about 480 for
Sheepshead minnow (Cyprinodon variegatus) indicates that bioconcentration in fish may be an
important aquatic fate process. The major metabolic pathway of permethrin involves the
hydrolysis of the ester bond producing 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic
acid and 3-phenoxybenzyl alcohol ; estimated half-life of 20 days at pH 9 . Permethrin in
near-surface waters will be susceptible to photolysis; photolysis half-lives of 27.1 and 19.6
hrs were determined for respective cis- and trans-isomers in 800 mL pond water exposed to
sunlight . Volatilization from water will not be an important removal process based on an
estimated Henry's Law constant of 2.51X10-8 atm-cu m/mole at 20 deg C.
ATMOSPHERIC FATE: Based on an experimental vapor pressure of 9.75.X10-9 mm Hg at 20
deg C , permethrin is expected to exist almost entirely in the particulate phase in the ambient
atmosphere . Vapor phase permethrin will degrade in the ambient atmosphere by reaction with
photochemically formed hydroxyl radicals; the half-life for this reaction in air can be estimated to
be about 9.9 hrs(3,SRC). Photodegradation half-lives of 5-17 days were determined for
permethrin on thin films suggesting that permethrin may be removed from the atmosphere via
direct photolysis. Particulate phase permethrin is removed via dry deposition.
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| Drinking Water Impact | Permethrin was detected 6 hrs post-application at concns of 17 and 18 ng/L in 2 of 6
samples from a creek approximately 60-100 m from a potato field where permethrin was applied
via aerial spraying .
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