Carbaryl - Chemical Fact Sheet 3/84
CHEMICAL FACT SHEET FOR:
CARBARYL
FACT SHEET NUMBER: 21
DATE ISSUED: MARCH 30, 1984
1. DESCRIPTION OF CHEMICAL
- Generic Name: 1-napthyl N-methylcarbamate
- Common Name: carbaryl
- Trade Name: Sevin
- EPA Shaughnessy Code: 056801
- Chemical Abstracts Service (CAS) Number: 63-25-2
- Year of Initial Registration: 1958
- Pesticide Type: Insecticide
- Chemical Family: Carbamates
- U.S. and Foreign Producers: Union Carbide, Makteshim Chemical Works,
Inc.
2. USE PATTERNS AND FORMULATIONS
- Application sites: citrus, pome, stone and berry fruits, forage,
field and vegetable crops, nuts, lawns, forests, ornamental plants,
rangeland, shade trees, poultry and pets, indoor use
- Types of formulations: baits, dusts, granules, wettable powders,
flowables, and aqueous dispersions
- Types and methods of application: ground and aerial
- Application rates: range from 0.53 lbs. a.i./A to 6.4 lbs. a.i./A
- Usual carriers: synthetic clays, talc, various solvents
3. SCIENCE FINDINGS
Chemical Characteristics
- Physical state: crystalline solid
- Color: white
- Odor: essentially odorless
- Melting point: 142 degrees C
- Vapor pressure: < 0.005 mm H9 at 26 C
- Flash point: 380 degrees F
Toxicological Characteristics
- Acute Oral LD50: 225 mg/kg, Toxicity Category II
- Acute Dermal LD50: > 2 g/kg, Toxicity Category III
- Primary Dermal Irritation: no irritation, Toxicity Category IV
- Primary Eye Irritation: Conjunctival irritation at 24 hours. Cleared
at 48 hours. Toxicity Category III
- Acute Inhalation LC50: data gap
Oncogenicity:
Ten studies. Each study classified as supplemental. Collectively
these studies provide sufficient evidence that carbaryl is not oncogenic
in experimental animals. Eighteen-month mouse study was negative at 400
ppm. A 2-year rat feeding and oncogenicity study was negative at 200
ppm.
Teratogenicity:
Twenty-four studies have been evaluated to determine the
teratogenic potential of carbaryl. In evaluating these studies, some
were found to be flawed. Other studies demonstrated no teratogenicity or
maternal toxicity. There are studies which demonstrate teratogenic
effects, although the doses also caused maternal toxicity. Two studies
produced teratogenic effects in the beagle dog. These two studies are
the primary reason carbaryl was made a candidate for RPAR in 1976.
The Agency has concluded (45 FR 81869) that carbaryl does not
constitute a potential human teratogen or reproductive hazard under
proper environmental usage. However, the Agency is requesting that the
teratology study in the beagle dog be repeated, because the results of
the dog studies continue to be a concern that has never been fully
resolved. A repeat dog study will provide the basis for any appropriate
regulatory action. In the interim, the Agency has determined that a
label precaution stating not to use carbaryl on pregnant dogs is
warranted until a new dog teratology study is submitted and reviewed.
There have been proposals that there are differences in the
metabolism of carbaryl between the dog and man. These differences,
however, have never been demonstrated. Therefore, a metabolism study in
the beagle dog versus the rat is being required. This metabolism study
should allow us to determine if there are meaningful differences between
the dog and other mammalian species.
Reproduction: A rat 3-generation study was negative at 200 mg/kg.
Mutagenicity: Carbaryl is characterized as a weak mutagen. The Agency
has determined that carbaryl does not pose a mutagenic risk. No
additional data are being requested.
- 1-year dog feeding study:
- 2-year rat feeding study: Demonstrated an apparent effect on renal
function. A kidney effect was also noted in a short-term human study.
A 1-year dog feeding study using carbaryl is being requested in order
to determine the effects of carbaryl on kidney dysfunction. The
results of these may necessitate a re-evaluation of the ADI for
carbaryl.
Physiological and Biochemical Behavioral Characteristics
- Mechanism of pesticidal action: A contact insecticide which causes
reversible carbamylation of the acetylcholinesterase enzyme of
tissues, allowing accumulation of acetylcholine at cholinergic
neuroeffector junctions (muscarinic effects), and at skeletal muscle
myoneural junctions and autonomic ganglia. Poisoning also impairs the
central nervous system function.
- Metabolism and persistence in plants and animals: Carbaryl is rapidly
excreted in animals, mainly in the urine. Residues in animals are
carbaryl, 1-naphthol, and hydroxycarbaryl. The hydroxy metabolites are
found mainly as glucuronide and sulfate conjugates. Carbaryl is slowly
taken up into plants, after which it is metabolized. The disappearance
of carbaryl residue from plant surfaces is attributed to mechanical
attribution, volatilization and uptake into plant. Photochemical
degradation does not appear to be a factor. 1-naphthol is the major
metabolite.
Environmental Characteristics
- Available data are insufficient to fully assess the environmental fate
of carbaryl.
- Adsorption and leaching in basic soil types: The Agency is requesting
data to determine if carbaryl will contaminate groundwater.
- Microbial breakdown: Carbaryl is degraded by fungi. The soil fungi
attack carbaryl by hydroxylation of the side chain and ring structure.
- Loss from photodecomposition: Data gaps. Data are required.
- Bioaccumulation: Preliminary data indicate that there may be a
potential for carbaryl and its residue(s) to accumulate in catfish,
crayfish, snail. duckweed, and algae. Additional data are requested.
- Resultant average persistence: Carbaryl is metabolized by pure and
mixed cultures of bacteria, fungi, and to some extent by other soil
and water organisms. The half-life appears to range from 7 to 28 days
in aerobic and anaerobic soils, respectively.
Ecological Characteristics
- Avian oral LD50: Mallard duck, > 2179 mg/kg; Ring-necked pheasant,
> 2000 mg/kg
- Avian dietary LC50: Mallard duck, > 5000 ppm, Ring-necked pheasant,
> 5000 ppm, Bobwhite quail, > 5000 ppm
- Freshwater fish LC50: coldwater fish, rainbow trout, 1.95 ppm;
warmwater fish, bluegill sunfish, 6.76 ppm
- Acute LC50 freshwater invertebrates - Daphnia pulex - 6.4 ppb
- Acute LC50 estuarine and marine organisms: Data gap. Data being
requested.
- Freshwater fish early life-stage: Fathead minnow, Maximum Acceptable
Theoretical Concentration (MATC) - >0.21 < 0.68 ppb
- No precautionary language is required for birds or fish. However
carbaryl is highly toxic to aquatic invertebrates. There is
insufficient information to characterize the chronic toxicity of
carbaryl to aquatic invertebrates.
Tolerance Assessments
- The Agency is unable to complete a full tolerance reassessment because
of certain residue chemistry and toxicology data gaps, namely a 1-year
dog feeding study and the need for residue data on various processed
food commodities.
Tolerances:
___________
Commodity Parts Per Million
Alfalfa 100
Almonds 1
Almonds, hulls 40
Apples 10
Apricots 10
Asparagus 10
Bananas 10
Barley, grain 0
Barley, green fodder 100
Barley, straw 100
Beans 10
Beans, forage 100
Beans, hay 100
Beets, garden (roots) 5
Beets, garden (tops) 12
Birdsfoot trefoil, forage 100
Birdsfoot trefoil, hay 100
Blackberries 12
Blueberries 10
Boysenberries 12
Broccoli 10
Brussels sprouts 10
Cabbage 10
Carrots 10
Cauliflower 10
Celery 10
Cherries 10
Chestnuts 1
Chinese cabbage 10
Citrus fruits 10
Clover 100
Clover, hay 100
Collards 12
Corn, fresh (including sweet) Kernel (K) 5
+ Corn with husk removed (CWHR)
Corn, fodder 100
Corn, forage 100
Cotton, forage 100
Cottonseed 0
Cowpeas 5
Cowpeas, forage 100
Cowpeas, hay 100
Cranberries 10
Cucumbers 10
Dandelions 12
Dewberries 12
Eggplants 10
Endive (escarole) 10
Filberts (hazelnuts) 1
Flax, seed 5
Flax, straw 100
Grapes 10
Grass 100
Grass, hay 100
Horseradish 5
Kale 12
Kohlrabi 10
Lentils 10
Lettuce 10
Loganberries 12
Maple sap 0.5
Melons 10
Millet, proso, grain 3
Millet, proso, straw 100
Mustard greens 12
Nectarines 10
oats, fodder, green 100
Oats, grain 0
Oats, straw 100
Okra 0
Olives 10
Oysters 0.25
Parsley 12
Parsnips 5
Peaches 10
Peanuts 5
Peanuts, hay 100
Pears 10
Peas (with pods) 10
Peavines 100
Pecans 1
Peppers 10
Pistachio nuts 1
Plums (fresh prunes) 10
Poultry, fat 5
Poultry, meat 5
Potatoes 0.2(N)
Prickly pear cactus, fruit 12 0
Prickly pear cactus, pads 12.0
Pumpkins 10
Radishes 5
Raspberries 12
Rice 5
Rice, straw 100
Rutabagas 5
Rye, fodder, green 100
Rye, grain 0
Rye, straw 100
Salsify (roots) 5
Salsify (tops) 10
Sorghum, forage 100
Sorghum, grain 10
Soybeans 5
Soybeans. forage 100
Soybeans, hay 100
Spinach 12
Squash, summer 10
Squash, winter 10
Strawberries 10
Sugar beets, tops 100
Sunflower seeds 1
Sweet potatoes 0.2
Swiss chard 12
Tomatoes 10
Turnips, roots 5
Turnips, tops 12
Walnuts 1
Wheat, fodder, green 100
Wheat (grain) 3
Wheat, straw 100
Cattle, fat 0.1
Cattle, kidney 1
Cattle, liver 1
Cattle, meat 0.1
Cattle, (mbyp) 0.1
Goats, fat 0.1
Goats, kidney 1
Goats, liver 1
Goats, meat 0.1
Goats, (mbyp) 0.1
Horses, fat 0.1
Horses, kidney 1
Horses, liver 1
Horses, meat 0.1
Horses, (mbyp) 0.1
Sheep, fat 0.1
Sheep, kidney 1
Sheep, liver 1
Sheep, meat 0.1
Sheep (mbyp) 0.1
Swine, fat 0.1
Swine, kidney 1
Swine, liver 1
Swine, meat 0.1
- Based on established tolerances, the theoretical maximum residue
contribution (TMRC) for carbaryl residues in the human diet is
calculated to be 5.48 mg/day. The acceptable daily intake (ADI) of
carbaryl is 0.1 mg/kg/day. The maximum permissible intake (MPI) is 6
mg/day. To provide for conformity between U.S. tolerances for carbaryl
and tolerances established by the Codex Alimentarius, Canada and
Mexico, the expression of the U.S. tolerances for carbaryl will be
changed to omit reference to 1-naphthol.
- A 1-year dog feeding study is being requested in order to determine
the effects of carbaryl on kidney dysfunction. The results of these
data may require that the ADI for carbaryl be recalculated.
- U.S. tolerances for most raw agricultural commodities are supported by
current residue chemistry data. In some cases, however, more data are
required.
Summary Science Statement
Carbaryl has moderate to low mammalian toxicity. It is not
considered to be an oncogen. It is a weak mutagen. Available data
indicates that carbaryl has only low teratogenic potential. Long-term
dietary studies in rats and dogs and a short-term study in humans
(highest dose only) demonstrate an apparent effect on renal function.
No reentry interval is necessary for carbaryl. Carbaryl is not
expected to contaminate groundwater. Data are insufficient to assess the
environmental fate of carbaryl.
Carbaryl is extremely toxic to aquatic invertebrates and certain
estuarine organisms. It is extremely toxic to honeybees. It is
moderately toxic to both warmwater and coldwater fishes and has only low
toxicity to birds.
A full tolerance reassessment cannot be completed. A 1-year dog
feeding study is required, as well as residue data on numerous processed
commodities.
4. SUMMARY OF REGULATORY POSITION AND RATIONALE
The Agency has determined that it should continue to allow the
registration of carbaryl. Adequate studies are available to assess the
acute toxicological effects of carbaryl to humans. None of the criteria
listed in section 162.11(a) of Title 40 of the U.S. Code of Federal
Regulations have been met or exceeded. However, because of gaps in the
data base, a full risk assessment of carbaryl cannot be completed.
A full tolerance reassessment cannot be completed because of
certain residue chemistry and toxicology data gaps, namely a 1-year dog
feeding study and the need for residue data on various processed
commodities.
No federal or state reentry intervals have been established for
carbaryl or will be established.
Available data are insufficient to fully assess the environmental
fate of carbaryl. The Agency is requesting data to determine if carbaryl
will contaminate groundwater.
5. SUMMARY OF MAJOR DATA GAPS
- Residue data on various processed commodities
- 1-year dog feeding study
- Teratology study in beagle dog
- Hydrolysis study
- Photodegradation studies
- Soil metabolism studies
- Mobility studies
- Dissipation studies
- Accumulation studies
- Acute LC50 freshwater invertebrates study
- Metabolism study in dog versus rat
6. CONTACT PERSON AT EPA
Jay S. Ellenberger
Product Manager (12)
Insecticide-Rodenticide Branch
Registration Division (TS-767C)
Office of Pesticide Programs
Environmental Protection Agency
401 M Street, S.W.
Washington, DC 20460
Office location and telephone number:
Room 202, Crystal Mall #2
1921 Jefferson Davis Highway
Arlington, VA 22202
(703) 557-2386
DISCLAIMER: THE INFORMATION PRESENTED IN THIS CHEMICAL INFORMATION FACT
SHEET IS FOR INFORMATIONAL PURPOSES ONLY AND NOT TO BE USED TO FULFILL
DATA REQUIREMENTS FOR PESTICIDE REGISTRATION AND REREGISTRATION.
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criticism of unnamed products implied. Most of this information is historical
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