JR> Last year I called the Ortho company and asked questions about
 JR> their 'Sevin' product.  I didn't get the full answer, or perhaps the
 JR> answer I wanted.  Does anyone know if Sevin will harm wildlife, birds
                      E  X  T  O  X  N  E  T
                   EXTENSION TOXICOLOGY NETWORK
A Pesticide Information Project of Cooperative Extension Offices
of Cornell University, Michigan State University, Oregon State
University, and University of California at Davis.  Major support
and funding was provided by the USDA/Extension Service/National
Agricultural Pesticide Impact Assessment Program.
Revised 9/93.
EXTOXNET primary files maintained and archived at Oregon State
University.
                         Carbaryl
TRADE OR OTHER NAMES
     Product names include Carbamine, Denapon, Dicarbam, Hexavin,
Karbaspray, Nac, Ravyon, Septene, Sevin, Tercyl, Tricarnam, and
Union Carbide 7744.
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.  The chemical name for carbaryl is 1-naphthol
N-methylcarbamate.
     Carbaryl is formulated as a solid which varies from
colorless to white to gray, depending on the purity of the
compound.  The crystals are odorless. This chemical is stable to
heat, light and acids under storage conditions.  It is
non-corrosive to metals, packaging materials, or application
equipment.  It is found in all types of formulations including
baits, dusts, wettable powder, granules, oil, molassas, aqueous
dispersions and suspensions (13).
     Carbaryl is a general use pesticide.
TOXICOLOGICAL EFFECTS
ACUTE TOXICITY
     Carbaryl is moderately to very toxic, and is labeled with a
WARNING signal word.  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. About fifty cases of
occupational or accidental illnesses due to exposure to carbaryl
have been reported, but no fatalities have been documented.  The
only documented fatality from carbaryl was through intentional
ingestion. 
     The oral LD50 of carbaryl ranges from 250 mg/kg to 850 mg/kg
for rats, and from 100 mg/kg to 650 mg/kg for mice (12, 13).  The
inhalation LC50 for rats is 0,005 to 0.023 mg/kg (13). Low doses
can cause minor skin and eye irritation in rabbits, whose dermal
LD50 has been measured at greater than 2,000 mg/kg (12). 
Technical carbaryl has little potential for skin or eye
irritation.
     Occupational workers have the greatest potential for
exposure through inhalation or through the skin.  The general
public's highest risk of exposure is through ingestion of
contaminated food (14).
CHRONIC TOXICITY
     Athough it may cause minor skin and eye irritation, carbaryl
does not appear to be a significant chronic health risk at or
below occupational levels.  Male volunteers who consumed low
doses of carbaryl for six weeks did not show symptoms, but tests
indicated slight changes in their body chemistry (12).
Reproductive and Teratogenic Effects
     No reproductive or fetal effects were observed during a
long-term study of rats which were fed high doses of carbaryl
(12).  The evidence for teratogenic effects due to chronic
exposure are minimal in test amimals.  Birth defects in rabbit
and guinea pig offspring occurred only at dosage levels which
were highly toxic to the mother.  A 1980 New Jersey
epidemiological study found no evidence of excess birth defects
in a town sprayed with carbaryl for gypsy moth control. There is
only limited evidence that carbaryl causes birth defects in
humans.  The EPA has concluded that carbaryl does not pose a
teratogenic risk to humans if used properly (16).
Mutagenic Effects
     Numerous studies indicate that carbaryl poses only a slight
mutagenic risk (8, 12).  However, carbaryl can react with nitrite
under certain conditions to give rise to N-nitrosocarbaryl.
Nitrosocarbaryl has been shown to be highly mutagenic at low
levels in laboratory test systems.  This may be a concern to
humans because there is a possibility that carbaryl, a pesticide,
and nitrite, a substance found in food additives and in human
saliva, may react in the human stomach to form nitrosocarbaryl
(2, 8).  Carbaryl has been shown to affect cell mitosis (cell
division) and chromosomes in rats (13).
Carcinogenic Effects
     Carbaryl has not caused tumors in ten longterm and lifetime
studies of mice and rats. Rats were administered high daily doses
of the pesticide for two years, and mice for eighteen months,
with no signs of carcinogenicity (3).  However,
N-nitrosocarbaryl, formed by the reaction of carbaryl and
nitrite, has been shown to be carcinogenic in rats at high doses
(7).  Also, mice exposed to carbaryl in the product, tricaprylin,
for four weeks each, developed lung tumors (12).
Organ Toxicity
     Ingestion of carbaryl affects the lungs, kidneys and liver. 
Inhalation will also affect the lungs (14, 17). Nerve damage can
occur after administration of high doses for 50 days in rats and
pigs (12).  Several studies indicate that carbaryl can affect the
immune system in animals and insects.  These effects however have
not been documented in humans.
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 (13).  This is consistent with information on other
species which excreted nearly three quarters of a dose in their
urine within 24 hours of administration (14).  The metabolism of
up to 85% of carbaryl occurs within 24 hours after administration
(13).
ECOLOGICAL EFFECTS 
     Carbaryl is lethal to many nontarget insects. The pesticide
is more active in insects than in mammals.  The destruction of
honeybee populations in sprayed areas is sometimes a problem. 
Carbaryl is moderately toxic to aquatic organisms, such as
rainbow and lake trout, bluegill, and cutthroat. It is also
moderately toxic to wild bird species, with low toxicity to
Canada geese (12).
     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 (14).
ENVIRONMENTAL FATE
     Carbaryl has a short residual life on treated crops. The
insecticide remains at the application site, where it is slowly
taken into the plant and metabolized.  Insecticidal properties
are retained for 3-10 days. Loss of carbaryl is due to
evaporation and uptake into plants.  Breakdown by sunlight does
not appear to be significant.
     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
days in aerobic soil and 28 days in anaerobic soil (9). 
Degradation of carbaryl in crops occurs by hydrolysis inside the
plants. It has a short residual life of less than two weeks. The
metabolites of carbaryl have lower toxicity to humans than
carbaryl itself. The breakdown of this substance is strongly
dependant on acidity and temperature.
     In pond water, carbaryl is broken down by bacteria through
chemical processes.  Evaporation does not occur. Carbaryl has a
half-life of from 1 to 32 days in pond water.   In a stream,
carbaryl that had washed in from forest spraying, decayed to 50%
within a 24 hour period.  It has been shown to degrade more
slowly in the presence of mud in aquatic habitats.  Carbaryl has
been detected in groundwater in three separate cases in
California.
     Carbaryl has a half-life in the air of one to four months. 
Crops, shade trees, shrubs and other vegetation in bloom should
not be sprayed with carbaryl as bee kills are possible. 
PHYSICAL PROPERTIES AND GUIDELINES
     Carbaryl is a solid which 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 non-corrosive to
metals, packaging materials or application equipment.
Exposure Guidelines:
NOEL:  0.06 mg/kg/day
ADI:  0.1 mg/kg/day 
STEL:  10 mg/m3
TLV:  air TWA 5 mg/m3
CL:  625 mg/m3
Drinking Water Health Advisory:  Drinking Water Equivalent Level: 
(DWEL):  3.5 mg/L (13)
Physical Properties
CAS #:  63-25-2
Chemical Name:  1-naphthyl N-methylcarbamine
Solubility in water:  0.005 g/100 g (20 degrees C), 0.004 g/100 g
(30 degrees C)
Solubility in solvents:  Carbaryl is soluble in ethanol,
petroleum ether, diethyl ether,and chloroform; moderately soluble
in polar solvents such as acetone, dimethyl sulfoxide, mixed
cresols, and cyclohexanone. 
Melting point:  145 degrees C
Vapor pressure:  <0.0001 torr (20-25 degrees C) 
Log P:  <-3.00
Kow:  64.6-229.1 (1, 5, 6, 10) 
Koc:  205.0-457.1 (1, 4, 5) 
K(d):  nonionic
BCF:  28.2-28.8 (1, 5) 
H:  <9.9 x 10 to the minus 5 power torr/M
BASIC MANUFACTURER
Rhone-Poulenc Ag. Co.
P.O. Box 12014
TW Alexander Dr.
Research Triangle Park, NC 27709
Telephone:  919-549-2000
Emergency:  800-334-7577
Review by Basic Manufacturer:
Comments solicited:  October, 1992
Comments received:  
REFERENCES
(1)  Bracha, P. and O'Brian, R.  1966.  J. Econ. Entomol.
59:1255.
(2)  Elespuru, R., Lijinski, W., and Setlow, J.K.  1974.  Nature
(London). 247:386-387.
(3)  "Evaluation of Carcinogenic, Teratogenic, and Mutagenic 
Activities of Selected Pesticides and Industrial Chemicals,"
Volume 1:  "Carcinogenic Study."  1968.   National Technical
Information Service, Washington, D.C.
(4)  Farmer, W.J.  1976.  "Leaching, Diffusion, and Sorption." 
From A Literature  Survey of Benchmark Pesticides. Science
Communication Division of George Washington University Medical
Center, pp. 185-245.
(5)  Fujita, T., et al.  1974.  Agric. Biol. Chem. 38:1521.
(6)  Mount, M.E. and Oehme, F.W.  1981.  Residue Rev. 80:1-64.
(7)  Regan, J.D., Setlow, R.B., Francis, A.A., and Lijinsky, W. 
1976.  Mutat. Res. 38:293
(8)  Siebert, D. and Eisenbrand, G.  1974.  Mutat. Res. 22:121.
(9)  Wauchope, R.D.  1978.  J. Environ. Qual. 7:459-472.
(10)  Windholz, M., et al., eds.  1976.  The Merck Index, 9th ed.
Merck and Co., Inc.: Rathway, NJ. 
(11)  Vettorazzi, Gaston. 1979. International Regulatory Aspects
(12)  National Library of Medicine. Hazardous Substances
Databank.   Carbaryl.  February 4, 1992.
(13)  U.S. Environmental Protection Agency, Office of Drinking
Water.  Carbaryl Health Advisory.  Draft Report.  August 1987.
(14)  Baron, Ronald L.  (1991).  Carbamate Insecticides.  in
Handbook of Pesticide Toxocology, Volume 3, Classes of
Pesticides.  Wayland J. Hayyes, Jr. and Edward R. Lawes, Jr.
editors.  Academic Press, Inc.  NY.
(15)  Howard, Philip H.  (1991).  Handbook of Environmental Fate
and  Exposure data for Organic Chenicals, Volume III.  Lewis
Publishers,  Chelsea, MI.
(16)  ACGIH.  1991. Documentation of rgw Threshold Limit Values
and Biological Indices.  American Conference of Governmental and
Industrial Hygienists, Inc., Cincinnati, OH.
(17)  Carpenter, C.P., et.al.  1961.  Mammalian toxicity of
1-Napthyl-N-Methylcarbamte (Sevin Insecticide).  Agricultural and
Food Chemistry 9 (1): 30-39.
     This PIP is part of the EXTOXNET Pesticide Information
Notebook.  For more information, contact the Pesticide Management
Education Program, Cornell University, 5123 Comstock Hall,
Ithaca, N.Y.  14853-0901.
DISCLAIMER:  The information in this profile does not in any way
replace or supersede the information on the pesticide product
label/ing or other regulatory requirements.  Please refer to the
pesticide product label/ing.
... #16. A deal is a deal
---
---------------