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The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised 9/95.

BIFENTHRIN

REGULATORY STATUS: Bifenthrin is a Restricted Use Pesticide (RUP). It is for retail sale to and use only by certified applicators or persons under their direct supervision. It is only for the uses covered by the applicators certification (11). In the U.S., bifenthrin is registered for use on greenhouse ornamentals and cotton (12).

INTRODUCTION: Bifenthrin is a member of the pyrethroid chemical class. It is an insecticide and acaricide which affects the nervous system and causes paralysis in insects (61, 11). It is very highly toxic to fish and aquatic organisms (11, 62). The U.S. EPA has classified bifenthrin as Toxicity Class II-moderately toxic. Products containing bifenthrin must bear the SIGNAL WORD: WARNING. It is available as an emulsifiable concentrate or a wettable powder (12).

TOXICOLOGICAL EFFECTS

• Acute Toxicity: Bifenthrin is moderately toxic to mammals when ingested. Large doses may cause incoordination, tremor, salivation, vomiting, diarrhea, and irritability to sound and touch (68). The dose at which half of the test animal die, the LD50, for bifenthrin is about 54 mg/kg in female rats and 70 mg/kg in male rats (63). The LD50 for rabbits whose skin is exposed to bifenthrin is greater than 2,000 mg/kg (11). Bifenthrin does not sensitize the skin of guinea pigs (62). Although it does not cause inflammation or irritation on human skin, it can cause a tingling sensation which lasts about 12 hours. It is virtually non-irritating to rabbit eyes (68).
• Chronic Toxicity: No information Available.
• Reproductive Effects: The dose at which no toxic effect of bifenthrin is observed on the mother (maternal toxicity NOEL) is 1 mg/kg/day for rats and 2.67 mg/kg/day for rabbits. At higher doses, test animals had tremors (67). The dose at which no toxic effect is observed on development (developmental toxicity NOEL) is 1 mg/kg/day for rats and is greater than 8 mg/kg/day for rabbits (11).
• Teratogenic Effects: Bifenthrin does not demonstrate any teratogenic effects at the highest levels tested (100 ppm, approximately 5.5 mg/kg/day) in a two-generational study in rats (63).
• Mutagenic Effects: Evidence of mutagenic effects from exposure to bifenthrin are inconclusive. Studies of mouse white blood cells were positive for gene mutation. However, other tests of bifenthrinÕs mutagenic effects, including the Ames test and studies in live rat bone marrow cells, were negative (11).
• Carcinogenic Effects: There was no evidence of cancer in a 2-year study of rats who ate as much as 10 mg/kg/day of bifenthrin. However, an 87 week feeding study of mice with doses of 7, 29, 71, and 86 mg/kg showed a significantly higher, dose related trend of increased tumor incidence in the male urinary bladder (63, 67). The incidence was significantly increased at 86 mg/kg/day. Also, females had higher incidences of lung cancer than the controls at doses of 7 mg/kg and higher (67). The EPA has classified bifenthrin as a class C carcinogen, a possible human carcinogen (11, 63).
• Organ Toxicity: Pyrethroids are poisons that affect the electrical impulses in nerves, over-stimulating nerve cells causing tremors and eventually causing paralysis (11).
• Fate in Humans and Animals: Bifenthrin is absorbed through intact skin when applied topically (68). It undergoes similar modes of breakdown within animal systems as other pyrethroid insecticides. In mammals, bifenthrin is rapidly broken down and promptly excreted. Rats treated with 4 to 5 mg/kg, excreted 70 % in the urine and 20% in the feces within 7 days. After 7 days, the remaining bifenthrin was found accumulated in tissues with high fat content such as the skin and fat in males and females and the ovaries of females (67). Bifenthrin is less toxic to warm-blooded animals, such as mammals, than to cold-blooded animals (68).

ECOLOGICAL EFFECTS

• Effects on Birds: Bifenthrin is moderately toxic to many species of birds (61). The dietary concentration (8 day) at which half of the test animals die, the LC50, is 1,280 ppm for mallard ducks and 4,450 ppm for bobwhite quail (65). The acute oral LD50 is 1,800 mg/kg for bobwhite quail and 2,150 mg/kg for mallard ducks. There is concern about possible bioaccumulation in birds (63).
• Effects on Aquatic Organisms: Bifenthrin is very highly toxic to fish, crustaceans and aquatic animals (61, 11). The LC50 after a 96-hour exposure is 0.00015 mg/l for rainbow trout, 0.00035 mg/l for bluegill, and 0.0016 mg/l for Daphnia (12, 63). Because of its low water soilubility and high affinity for soil, bifenthrin is not likely to be found in aquatic systems.
• Effects on Other Animals (Nontarget species): Bifenthrin is toxic to bees (62).

ENVIRONMENTAL FATE

• Breakdown of Chemical in Soil & Groundwater: Bifenthrin does not move in soils with large amounts of organic matter, clay and silt. It also has a low mobility in sandy soils that are low in organic matter. Bifenthrin is relatively insoluble in water, so there are no concerns about groundwater contamination through leaching. ItÕs half-life in soil, the amount of time it takes to degrade to half of its original concentration, is 7 days to 8 months depending on the soil type and the amount of air in the soil (11, 62).
• Breakdown of Chemical in Vegetation: Bifenthrin is not absorbed by plant foliage, nor does it translocate in the plant (63).

PHYSICAL PROPERTIES AND GUIDELINES: . It is photostable, stable to hydrolysis, has minimal volatility, and is stable in storage. It has a negative temperature coefficient, so it works better at lower temperatures (66).

Physical Properties:

• Appearance: Bifenthrin is an off-white to pale tan waxy solid with a faint, slightly sweet smell (63)
• Chemical Name: (2-methyl-1,1-biphenyl-3-y1)-methyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylate
• CAS Number: 82657-04-3
• Molecular Weight: 422.9
• Water Solubility: 0.1 mg/l (12)
• Solubility in Other Solvents: Bifenthrin is soluble in methylene chloride, acetone, chloroform, ether and toluene. It is slightly soluble in heptane and methanol (12).
• Melting Point: 68-70.6 degrees C (63)
• Vapor Pressure: Not Available
• Partition Coefficient: >6
• Adsorption Coefficient: octonal/water) Kow = 1,000,000 (12)

Exposure Guidelines:

• ADI: 0.015 mg/kg (12)
• MCL: Not Available
• RfD:0.015 mg/kg/day (64)
• PEL: Not Available
• HA: Not Available
• TLV: Not Available
• NOEL: 2.5 mg/kg/day (rat); 1.5 mg/kg/day (dog) (11, 64)

BASIC MANUFACTURER:

FMC Corporation
Agricultural Chemicals Group
2000 Market Street
Philadelphia, PA 19103

• Telephone: 215-299-6000
• Emergency: 800-331-3148
  

REFERENCESReferences for the information in this PIP can be found in Reference List Number 2