SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 2104645
CASRN 2104-64-5
SynonymsEPN
Santox
Phosphorothioic acid, phenyl-, O-ethyl O-(p-nitrophenyl) ester
Analytical Method EPA Method 8141
Molecular FormulaC14H14NO4PS

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

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
Consumption Patterns ESSENTIALLY 100% AS AN INSECTICIDE FOR COTTON
Apparent Color LIGHT YELLOW CRYSTALLINE POWDER; White crystalline solid; Liquid; Light yellow oil
Odor AROMATIC ODOR
Boiling Point 215 deg C at 5 mm Hg
Melting Point 36 DEG C
Molecular Weight 323.31
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.
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.
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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