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The information in this profile may be out-of-date.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 June 1996

Carbaryl

Trade and Other Names: Product names include Adios, Bugmaster, Carbamec, Carbamine, Crunch, Denapon, Dicarbam, Hexavin, Karbaspray, Nac, Rayvon, Septene, Sevin, Tercyl, Torndao, Thinsec, Tricarnam, and Union Carbide 7744.

Regulatory Status: Carbaryl is a General Use Pesticide (GUP). However, various formulations vary widely in toxicity. For example, it is categorized as toxicity class I - highly toxic for Tercyl; toxicity class II - moderately toxic for Sevin 803; and toxicity class III - slightly toxic for some other products. Products containing carbaryl may bear the Signal Word DANGER - POISON, WARNING, or CAUTION depending on the product formulation.

Chemical Class: carbamate

Introduction: Carbaryl is a wide-spectrum carbamate insecticide which controls over 100 species of insects on citrus, fruit, cotton, forests, lawns, nuts, ornamentals, shade trees, and other crops, as well as on poultry, livestock, and pets. It is also used as a molluscicide and an acaricide. Carbaryl works whether it is ingested into the stomach of the pest or absorbed through direct contact. It is available as bait, dusts, wettable powders, granules, dispersions and suspensions.

Formulation: It is available as bait, dusts, wettable powders, granules, dispersions, and suspensions.

Toxicological Effects:

• Acute toxicity: Carbaryl is moderately to very toxic. It can produce adverse effects in humans by skin contact, inhalation, or ingestion. The symptoms of acute toxicity are typical of the other carbamates. Direct contact of the skin or eyes with moderate levels of this pesticide can cause burns. Inhalation or ingestion of very large amounts can be toxic to the nervous and respiratory systems resulting in nausea, stomach cramps, diarrhea, and excessive salivation. Other symptoms at high doses include sweating, blurring of vision, incoordination, and convulsions. The only documented fatality from carbaryl was through intentional ingestion. The oral LD50 of carbaryl ranges from 250 mg/kg to 850 mg/kg in rats, and from 100 mg/kg to 650 mg/kg in mice [8,24]. The inhalation LC50 in rats is greater than 200 mg/L [24]. Low doses can cause minor skin and eye irritation in rabbits, a species in which carbaryl's dermal LD50 has been measured at greater than 2000 mg/kg [8].
• Chronic toxicity: Not Available
• Reproductive effects: No reproductive or fetal effects were observed during a long-term study of rats fed high doses of carbaryl [8].
• Teratogenic effects: The evidence for teratogenic effects due to chronic exposure is minimal in test animals. Birth defects in rabbit and guinea pig offspring occurred only at dosage levels that were highly toxic to the mother [25].
• Mutagenic effects: Carbaryl has been shown to affect cell division and chromosomes in rats [24]. However, numerous studies indicate that carbaryl poses only a slight mutagenic risk [8,26]. There is a possibility that carbaryl may react in the human stomach to form a more mutagenic compound, but this has not been demonstrated. In sum, the evidence suggests that carbaryl is unlikely to be mutagenic to humans [26,27].
• Carcinogenic effects: Technical-grade carbaryl has not caused tumors in long-term and lifetime studies of mice and rats. Rats were administered high daily doses of the pesticide for 2 years, and mice for 18 months, with no signs of carcinogenicity [28]. While N-nitrosocarbaryl, a possible by-product, has been shown to be carcinogenic in rats at high doses, this product has not been detected. Thus, the evidence indicates that carbaryl is unlikely to be carcinogenic to humans [29].
• Organ toxicity: Ingestion of carbaryl affects the lungs, kidneys, and liver. Inhalation will also affect the lungs [5,30]. Nerve damage can occur after administration of high doses for 50 days in rats and pigs [18]. Several studies indicate that carbaryl can affect the immune system in animals and insects. Male volunteers who consumed low doses of carbaryl for 6 weeks did not show symptoms, but tests indicate slight changes in their body chemistry [8]. A 2-year study with rats revealed no effects at or below a dose of 10 mg/kg/day [25].

• Fate in humans and animals: Most animals, including humans, readily break down carbaryl and rapidly excrete it in the urine and feces. Workers occupationally exposed by inhalation to carbaryl dust excreted 74% of the inhaled dose in the urine in the form of a breakdown product [24]. The metabolism of up to 85% of carbaryl occurs within 24 hours after administration [24].

Ecological Effects:

• Effects on birds: Carbaryl is practically nontoxic to wild bird species. The LD50 values are greater than 2000 mg/kg in mallards and pheasants, 2230 mg/kg in quail, and 1000 to 3000 mg/kg in pigeons [10].
• Effects on aquatic organisms: Carbaryl is moderately toxic to aquatic organisms, such as rainbow trout (LC50 of 1.3 mg/L), and bluegill (LC50 of 10 mg/L) [10]. Some accumulation of carbaryl can occur in catfish, crawfish, and snails, as well as in algae and duckweed. Residue levels in fish were 140-fold greater than the concentration of carbaryl in water. In general, due to its rapid metabolism and rapid degradation, carbaryl should not pose a significant bioaccumulation risk in alkaline waters. However, under conditions below neutrality, it may be significant [10].
• Effects on other organisms: Carbaryl is lethal to many non-target insects, including bees and beneficial insects [10].

Environmental Fate:

• Breakdown in soil and groundwater: Carbaryl has a low persistence in soil. Degradation of carbaryl in the soil is mostly due to sunlight and bacterial action. It is bound by organic matter and can be transported in soil runoff. Carbaryl has a half-life of 7 to 14 days in sandy loam soil and 14 to 28 days in clay loam soil. Carbaryl has been detected in groundwater in three separate cases in California [14].
• Breakdown in water: In surface water, carbaryl is broken down by bacteria and through hydrolysis. Evaporation is very slow. Carbaryl has a half-life of about 10 days at neutral pH. The half-life varies greatly with water acidity [14].
• Breakdown in vegetation: Degradation of carbaryl in crops occurs by hydrolysis inside the plants. It has a short residual life of less than 2 weeks. The metabolites of carbaryl have lower toxicity to humans than carbaryl itself. The breakdown of this substance is strongly dependent on acidity and temperature [8].

Physical Properties:

• Appearance: Carbaryl is a solid that varies from colorless to white or gray, depending on the purity of the compound. The crystals are odorless. Carbaryl is stable to heat, light, and acids. It is not stable under alkaline conditions. It is noncorrosive to metals, packaging materials, and application equipment.
• Chemical Name: 1-napthyl methylcarbamate [10]
• CAS Number: 63-25-2
• Molecular Weight: 201.23
• Water Solubility: 40 mg/L @ 30 C [10]
• Solubility in Other Solvents: dimethylformaldehyde v.s; acetone s.; dimethyl sulfoxide v.s.; cyclohexanone s. [10]
• Melting Point: 142 C [10]
• Vapor Pressure: <5.3 mPa @ 25 C [10]
• Partition Coefficient: Not Available
• Adsorption Coefficient: 300 [10]

Exposure Guidelines:

• ADI: 0.01 mg/kg/day [10]
• MCL: Not Available
• RfD: 0.1 mg/kg/day [20]
• PEL: 5 mg/m3 (8-hour) [31]
• HA: 0.7 mg/L (lifetime) [24]
• TLV: Not Available

Basic Manufacturer:

Rhone-Poulec Ag. Co.
P.O. Box 12014
2 T.W. Alexander Dr.
Research Triangle Park, NC 27709

• Phone: 919-549-2000
• Emergency: 800-334-7577
  

References:

References for the information in this PIP can be found in Reference List Number 3

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.