| Chemical Abstract Number (CAS #) |
2104645
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| Synonyms | EPN |
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Santox | Phosphorothioic acid, phenyl-, O-ethyl O-(p-nitrophenyl) ester |
| Analytical Method |
EPA Method 8141A |
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| Molecular Formula | C14H14NO4PS |
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| Use | INSECTICIDE FOR COTTON FORMER USE
NON-SYSTEMIC INSECTICIDE & ACARICIDE FORMER USE
Excellent insecticide and acaricide for orchard pests, including apple flea weevil, plum curculio,
and coddling moth, and for some soil insects. Former use
EFFECTIVE AGAINST WIDE RANGE OF PESTS, INCL APHIDS, MITES, SCALE
INSECTS, EUROPEAN CORN BORER, MOSQUITO LARVAE, BOLL WEEVIL, PINK
BOLLWORM, CODLING MOTH, PLUM CURCULIO & OTHERS. FORMER USE
Effective at 0.5-1.0 kg ai/hectare against a wide range of lepidopterous larvae, especially
bollworms (Heliothis species and Pectinophora gossypiella) an Alabama argillacea on cotton, rice
stem borers and other leaf-eating larvae on fruit and vegetables. Former use
For tobacco budworm. Former use
Control of lepidopterous and other leaf-eating larvae on cotton, rice, vegetables, tobacco, fruit,
nuts, beans, tomatoes, sugar beet, and maize. Former use
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| Consumption Patterns | ESSENTIALLY 100% AS AN INSECTICIDE FOR COTTON
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| Apparent Color | LIGHT YELLOW CRYSTALLINE POWDER; White crystalline solid; Liquid;
Light yellow oil
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| Odor | AROMATIC ODOR
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| Boiling Point | 215 deg C at 5 mm Hg
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| Melting Point | 36 DEG C
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| Molecular Weight | 323.31
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| Environmental Impact | EPN is expected to be released to the environment primarily during aerial and ground
spraying of various agricultural crops. If released to soil or water, breakdown of EPN is expected
to proceed primarily through hydrolysis and oxidation to phenylphosphonic acid. Other
degradation products are EPN-oxon, desethyl EPN-oxon, O-ethyl
S-methylphenylphosphonothiolate, p-nitrophenol, O-ethyl O-methylphenylphosphonate, and
O-ethylphenylphosphonate. The half-life of EPN in soil under field conditions has been found to
range from about 2 weeks to 1 month. EPN is expected to be relatively immobile in soil. This
compound is not expected to volatilize significantly from dry soil surfaces. In water, adsorption to
suspended solids and sediments may be an important fate process. Significant bioaccumulation in
aquatic organisms is expected only when continuous exposure to this compound occurs.
Volatilization should not be a significant fate process. Based on a vapor pressure of 9.45X10-7
mm Hg at 25 deg C, EPN is expected to exist partly in the vapor phase and partly in the
particulate phase in the atmosphere. EPN vapor is expected to react rapidly with photochemically
generated hydroxyl radicals (half-life 5 hours). Particulate phase EPN may be removed from the
atmosphere by wet or dry deposition. In addition, EPN has the potential to undergo direct
photolysis. Workers involved in the manufacturer or use of the pesticide EPN are exposed to this
compound primarily by inhalation and dermal contact.
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| Environmental Fate | TERRESTRIAL FATE: The half-life of radiolabelled-EPN in soil was found to range
from about 2 wk under field conditions in Mississippi to 1 month under field conditions in
Delaware . 18 Mo after application, greater than 90% of the residual radiolabelled carbon was
found in the top 3 inches of soil, indicating no significant leaching of EPN or its degradation
products had occured. Under greenhouse conditions, EPN had a half-life of 5-6 wk .
Breakdown of EPN in soil proceeded primarily through hydrolysis and oxidation to
phenylphosphonic acid, followed by further degradation of the phenyl ring to CO2 . Under
laboratory conditions, the half-life of 1 ppm EPN in soil in upland conditions was 30-90 days and
in submerged conditions it was 3-15 days . In upland soils degradation products were
EPN-oxon, desethyl EPN-oxon, O-ethyl S-methylphenylphosphonothiolate, p-nitrophenol,
O-ethyl O-methylphenylphosphonate, O-ethylphenylphosphonate, and phenylphosphonic acid .
In a soil biometer study, 2 and 10 ppm EPN was added to sterile and nonsterile soils. After 36
weeks, radiolabelled-CO2 evolution was 8-25% in nonsterile soils and 1.1-6.1% in sterile soils
indicating that soil microorganisms were able to utilize EPN and/or its hydrolysis products as a
carbon source . EPN is not expected to volatilize significantly from dry soil surfaces.
AQUATIC FATE: Based on results of persistence studies done on EPN in soil, it appears that
EPN would degrade primarily through hydrolysis and oxidation to phenylphosphonic acid in
water. In addition, adsorption to suspended solids and sediments may be an important fate
process. Significant bioaccumulation in aquatic organisms has been experimentally demonstrated
but only when continuous exposure to this compound occurs because it is rapidly depurated.
Volatilization should not be a significant fate process.
ATMOSPHERIC FATE: Based on a vapor pressure of 9.45X10-7 mm Hg at 25 deg C , EPN
is expected to exist partly in the vapor phase and partly in the particulate phase in the
atmosphere(2,SRC). EPN vapor is expected to react rapidly with photochemically generated
hydroxyl radicals. Under typical conditions, the half-life for this reaction is estimated to be 5
hours(3,SRC). Particulate phase EPN may be removed from the atmosphere by wet or dry
deposition. EPN also has the potential to undergo direct photolysis.
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| Drinking Water Impact | DRINKING WATER: Not detected in tap water from Ottawa, Canada, detection limit
1 ng/l .
SURFACE WATER: 1973-74, tailwater pits (basins holding runoff from corn and sorghum
fields) in Haskell County, KS, 154 samples, 1.9% pos, mean concn detected 1.4 ppb .
GROUNDWATER: Not detected in groundwater samples collected in CA, detection limit 0.6
ppb .
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