SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 114261
CASRN 114-26-1
SynonymsPropoxur
Phenol, 2-(1-methylethoxy)-, methylcarbamate
Baygon
Analytical Methods EPA Method 531.1
EPA Method 632
EPA Method 8318
Molecular FormulaC11H15NO3

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

Use Insecticide; Molluscicide BAYGON: EFFECTIVE AGAINST COCKROACHES, FLIES, MOSQUITOES . ALSO FOR CONTROL OF WOOLY APHIDS, BUGS, & LEAF HOPPERS. VET: EFFECTIVE AGAINST FLEAS & TICKS ON CATTLE, HORSE, CATS, & DOGS & SARCOPTIC MANGE OF CATTLE PROTECTION AGAINST TICKS APPEARS TO WANE AFTER 1 WK.
Consumption Patterns OVER 50% AS AN INSECTICIDE FOR MOSQUITOES IN OUTDOOR AREAS; UNDER 50% IN ALL OTHER APPLICATIONS AS AN INSECTICIDE (FOR FLIES ON AGRICULTURAL PREMISES, FOR FLEAS & TICKS ON PETS, ON LAWNS & TURF, FOR ANTS ON FLOWERING PLANTS, & IN DWELLINGS & PUBLIC FACILITIES) (1974)
Apparent Color MINUTE CRYSTALS ; WHITE TO TAN CRYSTALLINE SOLID
Melting Point 91.5 DEG C
Molecular Weight 209.24
Environmental Impact Propoxur, known chemically by o-isopropoxyphenyl N-methylcarbamate or 2-(1-methylethoxy)phenol methylcarbamate, is an insecticide and molluscide characterized by a fast knockdown and long residual effect. It will be released to the environment when it is applied as a spray or dust or used in bait to control household pests as well as lawn and garden insects. If released on soil it would not adsorb strongly to the soil. In one field study, 75% of propoxur disappeared from sandy soil in 100 days but levels were virtually unchanged in muck and silt loam soils. However, the rate of biodegradation is markedly increased when the soil has been previously exposed to methylcarbamate pesticides. Additionally, abiotic hydrolysis should be important in alkaline soils. Propoxur is readily degradable in water (half-life from 1 day to 1 week). In surface layers of water it will photolyze relatively rapidly, especially when humic material is present (half-life 13 - 88 hr). Degradability increases with temperature, high microbial populations, the presence of mud and biota, and increasing pH. Volatilization, adsorption to sediment and bioconcentration in fish should not be important fate processes. Propoxur would be released into the atmosphere primarily as a dust or aerosol and be subject to gravitational settling. The vapor phase chemical should react with photochemically produced hydroxyl radicals and have a half-life of about 4 hr. People will primarily be exposed to propoxur where it is used to control insects, both indoors and outdoors.
Environmental Fate TERRESTRIAL FATE: 25% OF APPLIED BAYGON WAS LOST FROM SAND IN 100 DAYS, BUT PRACTICALLY NO DECLINE IN SILT-LOAM SOIL DURING 6 MO PERIOD TERRESTRIAL FATE: Propoxur is not strongly adsorbed to soil and is highly persistent in neutral and acid soils. While 75% of the insecticide degraded in 100 days in a sandy soil, in a muck and silt loam soil, virtually no loss occurred during the same period and the propoxur persisted in these soils beyond six months . Other studies show that when the resident microorganisms are acclimated to methylcarbamate pesticides, biodegradation is markedly enhanced and in one study propoxur had largely disappeared in one day. Since propoxur hydrolyzes in basic media (half-life 16 days at pH 8), this process would be expected to contribute to propoxur loss in alkaline soil. AQUATIC FATE: Propoxur was found to be readily degradable in water. It was degraded in a model aquatic ecosystem containing the standard food chain members, algae, daphnia, mosquito larvae, snails, and fish , and highly biodegradable in components of a model terrestrial-aquatic ecosystem containing the same food chain members in the aqueous compartment . After 1 month, observed concentrations of propoxur were: 0.2 ppb in water, 15 ppb in snails, 50 ppb in fish, and traces in mosquito larvae . It was the second most labile of 9 pesticides dosed in lighted, agitated river water. The half-lives of the 9 pesticides ranged from 0.42 for carbaryl to 11.91 for lindane; the specific half-life of propoxur was not reported . The degradation rates were temperature dependent and altered by the presence of mud, aquatic plants and invertebrates . Propoxur has also been shown to photolyze in waters (half-life 88 hr), and this photolysis is enhanced by the presence of humic material (half-life 13 - 41 hr) . Therefore photolysis may be a major factor affecting propoxur disappearance in surface water as exemplified by a 1 week half-life in water from the Little Miami River . ATMOSPHERIC FATE: Propoxur would be primarily released to the atmosphere in the form of a dust or aerosol during its use as an insecticide and would be subject to gravitational settling. However propoxur also has been shown to volatilize from baits. Vapor phase propoxur resulting from this volatilization is estimated to have a half-life of 4.3 hr with an average ambient hydroxyl radical concentration of 5X10 5 radicals/cc . However indoors, the half-life should be much longer because the concentration of hydroxyl radicals is lower.
Drinking Water Impact SURFACE WATER: After propoxur was aerially applied around Winnipeg, Manitoba for mosquito control, half of the samples collected from surface water in and around the city was positive for the insecticide . The highest level was 36.4 ppb, in a creek 12 hr after spraying. Four other samples were in excess of 17.5 ppb.

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