Chemical Fact Sheet

Chemical Abstract Number (CAS #) 299843
CASRN 299-84-3
Phosphorothioic acid, O,O-dimethyl O-(2,4,5-trichlorophenyl) ester
Analytical Method EPA Method 8141
Molecular FormulaC8H8Cl3O3PS

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

Use Medication: (Human and Vet). Former use ANTHELMINTIC. INSECTICIDE USED ON BEEF CATTLE, DAIRY CATTLE, GOATS, HOGS; FOR USE IN AGRICULTURAL PREMISES HOUSING LIVESTOCK. FORMER USE USED FOR CONTROL OF FLIES AND OTHER HOUSEHOLD PESTS. FORMER USE USED AS A SHAMPOO FOR THE CONTROL OF ECTOPARASITES ON DOGS. /Ronnel is known to be effective on contact against cockroaches and flies. Ronnel is effective against cattle grub, and occasional reports indicate utility against sheep keds, sheep nasal botfly, chicken lice and mites, dog fleas, and ticks. Former use SYSTEMIC INSECTICIDE & ACARICIDE OF CONTACT & STOMACH ACTION. USEFUL IN CONTROLLING FLIES, ROACHES, CATTLE ECTOPARASITES. USED MAINLY ON LIVESTOCK. NON-PHYTOTOXIC TO CROPS EXCEPT CUCUMBERS, APPLES & ROSES. FORMER USE EFFECTIVE AS DUST FOR HOG LICE, LICE & MITES ON POULTRY & PREMISES (1% RESIDUAL SPRAY). ONE OF SAFER INSECTICIDES AROUND DUCK PREMISES. 5% DUSTS APPEAR TO BE SAFE FOR MINK & MICE MAY BE USEFUL IN CONTROLLING MYIASIS. TOPICALLY EFFECTIVE AGAINST FLEAS, LICE, TICKS, & EAR MITES ON DOGS. WARNING: ALTHOUGH OFTEN RECOMMENDED FOR CATS, IT IS OFTEN TOO TOXIC FOR THEM. FORMER USE As residual insecticidal treatment for control of cockroaches & flies in animal houses, dairies, food storage areas, food containers & packaging, food processing equipment, certain stored foodstuffs, & refuse tips. Used as string impregnation in poultry houses. Control insects in fodder beet, sugar beet, & mangolds. Former use
Odor Mercaptan odor
Boiling Point 97 Deg C @ 0.013 mbar
Melting Point 41 DEG C
Molecular Weight 321.57
Density 1.485 @ 25 DEG C/4 DEG C
Sensitivity Data irritations of the throat and facial skin were occasionally reported by veterinarians treating grub infestations in cattle with pour-on applications of ronnel in poorly ventilated areas.
Environmental Impact Ronnel was be released in the environment during its production and use as an insecticide primarily for livestock applications. Ronnel has not been manufactured in the U.S. since 1979. EPA cancelled the registration of all products containing ronnel as the active ingredient on Jan 22, 1991. If released to soil, the loss of ronnel will occur by biodegradation. Loss of ronnel from soil due to volatilization, photolysis, and hydrolysis will be relatively slow. Ronnel is expected to have low mobility in most soils. The major pathway for the loss of ronnel from water appears to be adsorption to suspended solids and sediment. Other losses in water may occur as a result of biodegradation, hydrolysis, and photolysis. The bioconcentration of ronnel in aquatic organisms may be important. Reaction with photochemically produced hydroxyl radicals will be an important loss process for vapor phase ronnel in the atmosphere. The half-life of ronnel due to this reaction has been estimated to be 2.1 hrs. Partial removal of ronnel will also occur as a result of dry deposition. Those who apply may be exposed to trace amounts of ronnel from contaminated food consumption. Ronnel is not registered for use in the U.S. and therefore exposure of applicators, other workers will be limited.
Environmental Fate TERRESTRIAL FATE: Based on photolysis in aqueous solution (estimated half-life at water surface - 9 days ), the loss of ronnel from soil due to photolysis by sunlight is probably not important due to the light attentuation by soil. Hydrolysis of ronnel was not accelerated by sediment-sorption which suggests that soil catalyzed hydrolysis should not be important(2,SRC). The Koc values estimated from water solubility and Kow(3-4), and regression equations indicate that the leaching potential of ronnel from soil is low. Based on its low vapor pressure , moderate Henry's Law constant and high Koc value, volatilization should not be important for the dissipation of ronnel from soil. In soil the biodegradation of ronnel may be fast since the mean half-life in surface waters is 8.4 days(6). AQUATIC FATE: The hydrolysis half-life of ronnel in distilled water at 35 deg C was estimated to be 24 days(1-2). The hydrolysis is faster at alkaline pH(1,7) and the hydrolysis half-life is reduced to 6 hrs in the presence of 0.1 mmole copper (II) catalyst . Although ronnel readily photolyses with light of wavelength less than 290, the rate of photolysis is slow in water with natural sunlight(4-5) and the half-life due to sunlight photolysis at near surface of a water body is 17.5 days based on 12 hr daylight . Biodegradation of ronnel in surface waters has a mean half-life of 8.4 days and the rate can be accelerated by adding inorganic nutrients to water(6). AQUATIC FATE: In a sediment sample from the Mississippi River that contained 1.4% organic carbon, 96% of ronnel was found in the sediment-sorbed phase . This and the Koc values of 3.64-4.09 estimated from regression equations indicate that ronnel would remain strongly adsorbed to suspended solids and sediment in water. Based on the Henry's Law constant value of 3.2X10-5 atm-cu m/mole estimated from the ratio of the vapor pressure and water solubility , volatilization half-life from a model river is estimated to be 1.4 days and from a model pond to be 24.8 days considering the effect of adsorption(2,5,SRC). However, the importance of volatilization from water will substantially decrease due to strong adsorption of ronnel to suspended solid and sediment. A lipid weight basis bioconcentration factor of 43650 in the guppy (Poecilia reticulata) indicates that bioconcentration of ronnel in aquatic organisms will be important. ATMOSPHERIC FATE: A vapor pressure of 7.5X10-5 mm Hg at 20 deg C indicates that ronnel may be present partly in the vapor phase and partly in the particulate form in air(2,SRC). Based on an estimation method , vapor phase ronnel may be removed from the atmosphere with a half-life of 2.1 hrs due to reaction with photochemically produced hydroxyl radicals. Partial removal of particulate ronnel from the air may occur by dry deposition. Particulate ronnel has been found to undergo long distance transport .
Drinking Water Impact SURFACE WATER: During 1964-1966, 82 surface water samples were collected from farms in New York state known to use pesticides. At a detection limit of 0.04 ppb, none of the samples contained ronnel . At a detection limit of 0.005 ppb, ronnel was not detected in water samples collected from the upper Great Lakes during the summer of 1974 . DRINKING WATER: Ronnel was not detected in tap water from Ottawa, Canada at a detection limit of 1 ng/l .

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