Phosacetim

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

0.34 [mg/m3]

3.7 [mg/m3]

9.5 [mg/m3]

For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)

LD50 Gopher oral 1.0 mg/kg

LD50 Peromyscus maniculatus (Deer mouse) oral 18 mg/kg

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 5.6X10+4(SRC), determined from a structure estimation method(2), indicates that phosacetim is expected to be immobile in soil(SRC). Volatilization of phosacetim from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 4.8X10-9 atm-cu m/mole(3)(SRC), using a fragment constant estimation method(3). Phosacetim is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 7.4X10-8 mm Hg(SRC), determined from a fragment constant method(4). Biodegradation data were not available(SRC, 2005).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 5.6X10+4(SRC), determined from a structure estimation method(2), indicates that phosacetim is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 4.8X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 140(SRC), from an estimated log Kow of 3.69(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is high(SRC). Biodegradation data were not available(SRC, 2005).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), phosacetim, which has an estimated vapor pressure of 7.4X10-8 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase phosacetim may be removed from the air by wet and dry deposition(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for phosacetim can be estimated to be 5.6X10+4(SRC). According to a classification scheme(2), this estimated Koc value suggests that phosacetim is expected to be immobile in soil.

/SIGNS AND SYMPTOMS/ Exposure to the vapor or to particulate material may cause miosis, sometimes unequal, hyperanemia of the conjunctiva, dimness of vision, rhinorrhoea, frontal headache, bronchoconstriction, incr bronchial secretion, cough, nausea, vomiting, and fasciculation and sweating at the site of contact. Toxic effects may incl anorexia, abdominal cramps, nausea, vomiting, diarrhea, incontinence, eye changes, weakness, dyspnoea, bronchospasm, lachrymation, incr salivation and sweating, bradycardia, hypotension or hypertension due to asphyxia, cyanosis, and muscular twitching of the eyelids, tongue, face, and neck, possibly progressing to convulsions. CNS symptoms incl restlessness, anxiety, dizziness, drowsiness, tremor, ataxia, depression, confusion, and coma. Death may occur from depression of the resp or cardiovascular system. /Organophosphorus insecticides/

An estimated BCF of 140 was calculated for phosacetim(SRC), using an estimated log Kow of 3.69(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC).

The Henry's Law constant for phosacetim is estimated as 4.8X10-9 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that phosacetim is expected to be essentially nonvolatile from water surfaces(2). Phosacetim is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 7.4X10-8 mm Hg(SRC), determined from a fragment constant method(3).

The rate constant for the vapor-phase reaction of phosacetim with photochemically-produced hydroxyl radicals has been estimated as 2.3X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 1.7 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Phosacetim may undergo hydrolysis under basic conditions in the environment(2), however this is not expected to be an important fate process. Phosacetim is not expected to directly photolyze due to the lack of absorption in the environmental UV spectrum (>290 nm).

Occupational exposure and general population exposure should be low or non-existent since phosacetim is no longer produced or used. In the past, phosacetim was released directly to the environment as a pesticide and exposure to this compound was primarily in the workplace where phosacetim was produced or used. (SRC)

Phosacetim's former production and use as a rodenticide may have resulted in its direct release to the environment. If released to air, an estimated vapor pressure of 7.4X10-8 mm Hg at 25 °C indicates phosacetim will exist solely in the particulate phase in the ambient atmosphere. Particulate-phase phosacetim will be removed from the atmosphere by wet and dry deposition. If released to soil, phosacetim is expected to have no mobility based upon an estimated Koc of 5.6X10+4. Biodegradation data were not available. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 4.8X10-9 atm-cu m/mole. If released into water, phosacetim is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 140 suggests the potential for bioconcentration in aquatic organisms is high. Phosacetim may undergo hydrolysis under basic conditions in the environment, however this is not expected to be an important fate process. Occupational exposure and general population exposure should be low or non-existent since phosacetim is no longer produced or used. In the past, phosacetim was released directly to the environment as a pesticide and exposure to this compound was primarily in the workplace where phosacetim was produced or used. (SRC)

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA '88 were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern and List D pesticides of less concern. Phosacetim is found on List B. Case No: 2520; Pesticide type: rodenticide; Case Status: No products containing the pesticide are actively registered. Therefore, we are characterizing the case as "cancelled." Under FIFRA, pesticide producers may voluntarily cancel their registered products. EPA also may cancel pesticide registrations if registrants fail to pay required fees or make/meet certain reregistration commitments, or if EPA reaches findings of unreasonable adverse effects.; Active ingredient (AI): O,O-Bis(p-chlorophenyl) acetimidoylphosphoramidothioate; AI Status: The active ingredient is no longer contained in any registered products ... "cancelled.".

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Phosacetim is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 100 or 10,000 lbs. Extremely hazardous substances that are solids are subject to either of two threshold planning quantities ... The lower quantity applies only if the solid exists in powdered form and has a particle size less than 100 microns; or is handled in solution or in molten form; or meets the criteria for a National Fire Protection Association (NFPA) rating of 2, 3 or 4 for reactivity. If the solid does not meet any of these criteria, it is subject to the upper ... threshold planning quantity ... .