| Chemical Abstract Number (CAS #) |
63252
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| Synonyms | Sevin |
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Carbamic acid, methyl-, 1-naphthyl ester | Carbaryl | 1-Naphthyl methylcarbamate |
| Analytical Methods |
EPA Method 531.1 |
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EPA Method 553 |
EPA Method 632 |
| Molecular Formula | C12H11NO2 |
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| Use | INSECTICIDE FOR CORN, ALFALFA, LIVESTOCK, POULTRY, OTHER
NON-AGRICULTURAL USES (EG, HOME USE), GARDENS, LAWNS, & FOR
COMMERCIAL/INDUSTRIAL USE; ACARICIDE & MOLLUSCICIDE
TO CONTROL LEPIDOPTERA, COLEOPTERA, & OTHER CHEWING & SUCKING
INSECTS ON MORE THAN 120 CROPS, INCLUDING VEGETABLES, TREE FRUIT (INCL
CITRUS), MANGOES, BANANAS, STRAWBERRIES, NUTS, VINES, OLIVES, OKRA,
CURCURBITS, GROUNDNUTS, SOYBEANS, COTTON, RICE, TOBACCO, CEREALS,
BEET, MAIZE, SORGHUM, LUCERNE, POTATOES, ORNAMENTALS, FORESTRY ETC;
CONTROL OF EARTHWORMS IN TURF; USED AS A GROWTH REGULATOR FOR
FRUIT THINNING OF APPLES; ALSO USED AS AN ANIMAL ECTOPARASITICIDE
TO CONTROL FLEAS, LICE, TICKS, & MITES ON ANIMALS, POULTRY, & PREMISES,
INCL SARCOPTIC MANGE ON BUFFALOES; LICE, TICKS, & MANGE MITES ON
CATTLE; FLEAS & RESISTANT FLEAS ON DOGS; & FOWL MITES, LICE, & FLEAS ON
POULTRY.
Medication (Vet): Parasiticide (external use)
Use in medical facilities, & in sewage treatment plants
Carbaryl has been used to treat oyster grounds and has become a controversial issue in the
Pacific northwest. Oyster growers maintain carbaryl is needed to kill two types of burrowing
shrimp which render Pacific oyster beds soft and silty, preventing oyster culture.
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| Consumption Patterns | INSECTICIDE FOR CORN, 14%; VEGETABLES, 13%; SOYBEANS, 11%;
COTTON, 4%; DECIDUOUS FRUITS & NUTS, 4%; TOBACCO, 4%; SORGHUM, 2%;
ALFALFA, 1%; CITRUS, 1%; OTHER FIELD CROPS, 17%; FORESTS, 2%; LIVESTOCK &
POULTRY, 1%; OTHER NON-AGRICULTURAL USES, 28% (1982)
1.5 million lbs on soybeans, 0.2 million lbs on corn, 0.2 million lbs on peanuts, 0.1 million lbs on
tobacco, & 0.1 million lbs on other small grains (1982)
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| Apparent Color | WHITE OR GRAY SOLID ; Colorless solid
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| Odor | Essentially odorless.
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| Melting Point | 145 DEG C
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| Molecular Weight | 201.22
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| Density | 1.232 @ 20 DEG C/20 DEG C
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| Sensitivity Data | Irritating to skin & eyes.
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| Environmental Impact | Carbaryl release to the environment results from its uses as a molluscicide and an
insecticide and acaricide on a variety of crops. Release to soil will result in photolysis at the soil
surface at a rate dependent upon the soil water content (half-life = 97 hr (dry)-688 hr (wet)).
Carbaryl will hydrolyze relatively rapidly in moist alkaline soil, but only slowly in acidic soil.
Carbaryl may leach to groundwater based on its moderate soil sorption coefficient. Release to
water will result in rapid hydrolysis at pH values of 7 and above (half-life = 10.5 days, 1.8 days
and 2.5 hours at pH's 7, 8 and 9, respectively, 20 deg C). In acidic water, hydrolysis will be slow
(half-life = 1500 days at pH 5, 27 deg C). Photolysis will be significant (half-life = 52-264 hr). At
lower pH values, biodegradation may be signficant. Adsorption to high organic content sediments
has been demonstrated to be important. Bioconcentration is not expected to be significant.
Release to the atmosphere may result in direct photolysis as carbaryl absorbs light wavelengths
above 290 nm. The estimated half-life for the reaction of vapor phase carbaryl with
photochemically generated, atmospheric hydroxyl radicals is 12.6 hours. Monitoring data indicate
that carbaryl is a contaminant in food and a minor contaminant in drinking and surface water.
Human exposure to carbaryl is expected to result mainly from ingestion of contaminated food and
occupational exposure in farm workers is expected.
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| Environmental Fate | CARBARYL PERSISTED LONGER IN SOIL WATER THAN IN LAKE WATER.
FOUR DAYS AFTER TREATMENT OF SOIL WATER, 1-NAPHTHOL AS WELL AS
CARBARYL WAS RECOVERED.
TERRESTRIAL FATE: Carbaryl is expected to slowly photolyze on surface soil at a rate
dependent on the water content (half-life = 97-251 hr in dry soil, 458-688 hr in wet or saturated
soil) . In neutral and alkaline soils, carbaryl is expected to hydrolyze rapidly. Hydrolysis will be
slower in acidic soils. Carbaryl is also expected to biodegrade slowly in the soil. Based on its log
soil-sorption coefficient in the range 1.9-2.5, carbaryl is expected to be moderately mobile in soil
and may leach to groundwater.
AQUATIC FATE: One ppm of carbaryl was incubated in autoclaved and unautoclaved creek
water at 9 deg C . After 50 days, an average of 39.3% and 56.9% carbaryl was recovered from
the unautoclaved and the autoclaved creek water samples, respectively . Average recoveries
from creek water and bottom sediments following addition of 1 ppm carbaryl were 11.8% and
16.2%, respectively, in non-autoclaved samples, after 50 weeks at 9 deg C . Average recoveries
from creek water and bottom sediments were 12.8% and 45.1% respectively in autoclaved
samples after 50 weeks at 9 deg C . Recovery from pond water and bottom sediments following
addition of 1 ppm carbaryl averaged 13.75% and 13.9%, respectively, after 42 days at 9 deg C .
Within 4 days of carbaryl addition to Fall Creek water, >60% of the carbaryl added at 30 ug/ml
and 300 ng/ml was converted to carbon dioxide compared with <10% conversion of carbaryl
added at 3.0 ug/ml and 30 ng/ml . Due to the rapid hydrolysis of carbaryl under the conditions
of the experiment, it is not possible to determine how much carbon dioxide resulted from carbaryl
biodegradation and how much from biodegradation of the hydrolysis product, 1-naphthol .
Carbaryl was completely degraded after 4 weeks incubation in the dark at 21 deg C in water from
the Holland Marsh drainage canal . Carbaryl in streams, rivers and brooks as a result of forest
spraying decayed with half-lives of 25, 28 and 23 hr, respectively . Carbaryl was incubated in
estuarine water in the presence and absence of estuarine mud . In the absence of mud, 50% of
the initial carbaryl had disappeared after 38 days at 8 deg C and nearly all had disappeared after
17 days at 20 deg C with 43% being converted to 1-naphthol . In the presence of mud, after 10
days at 8 deg C, 90% of the initial carbaryl had been removed from the water. This was attributed
to the adsorption of the carbaryl on the mud, in which degradation proceeded more slowly than in
the sea water . Carbaryl was detectable in the mud for up to 3 weeks . Carbaryl persisted in
mud treated with 10 pounds active ingredient per acre for up to 42 days . At neutral and basic
pH values, carbaryl is expected to hydrolyze rapidly (half-life = 10.5 days at pH 7 and 20 degC;
half-life = 1.8 days at pH 8 at 20 deg C). The lifetime of carbaryl in water at pH 7 is about 70
days (99% hydrolyzed). In acidic water, hydrolysis is not expected to be significant (half-life =
1500 days at pH 5 and 27 deg C; half-life = 406 days at pH 6 and 25 deg C). The photolysis
half-life of carbaryl calculated from experimentally determined parameters ranged from 52-264 hr
for a summer day at latitude 40 degrees north. Biodegradation may be significant, but at pH
values of 7 and above, hydrolysis is expected to predominate. Bioconcentration is not
expected to be important.
ATMOSPHERIC FATE: Based on a vapor pressure of 1.5X10-6 mm Hg at 25 deg C , carbaryl
could exist in both the vapor-phase and particulate-phase in ambient atmosphere(2,SRC). The
half-life of carbaryl in the vapor phase with photochemically generated hydroxyl radicals in the
atmosphere was estimated to be 12.60 hours . Since carbaryl exhibits an absorption maximum
at 312.5 nm (extinction coefficient= 378 l/mol cm) , carbaryl may directly photolyze in the
atmosphere, but the rate cannot be estimated from the available data.
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| Drinking Water Impact | SURFACE WATER: Carbaryl was detected but not quantified in organic extracts from
British or West German river water samples . Carbaryl at a concentration 0.003 ppm was
detected in a stream water adjacent to a land spraying area in Canada 5 days following an
application rate of 280 g A.I./ha .
DRINKING WATER: Detected but not quantified in USA drinking water .
GROUNDWATER: Not detected at a detection limit of 1 ug/L in 10 farm wells where the land
was treated with the pesticide . Detected in three groundwaters in California .
The persistence of carbaryl in water has been found to be dependent on pH and temperature.
Creek and pond water samples containing 1 ppm of carbaryl were incubated at 9 deg C with and
without sediment. Autoclaved and non-autoclaved samples were also analyzed. Persistence of
carbaryl in the creek water having a pH of 7.0 to 7.1 was greater than in the slightly alkaline pond
water, pH 7.5 to 7.8. After 21 days incubation about 66 to 62% of added carbaryl remained in
creek water whereas 46 to 39% was found in pond water. Autoclaving and the presence of
sediment also increased persistence. In the pond water incubated with sediment there was a steady
decrease in the carbaryl concentration of the water but the sediment concentration remained about
the same from 2 days after inoculation through day 21 of the experiment.
EFFL: Air emisions from carbaryl manufacture have been reported to consist of 1.5 kg of
hydrocarbons & 0.5 kg of carbaryl per metric ton of pesticide produced.
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