3-Bromo-1-propyne

CAS RN: 106-96-7

Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 1.1 and 5.3(2) indicate that 3-bromo-1-propyne is expected to have very high mobility in soil(SRC). Volatilization of 3-bromo-1-propyne from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 1.13X10-3 atm-cu m/mole(2). 3-Bromo-1-propyne is expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 108 mm Hg(SRC), calculated using a water solubility of 1.49X10+4 mg/L(2) and the Henry's Law constant(2). Biodegradation in soil is not expected to compete with chemical degradation processes based on similar half-lives in sterile soil (0.37-11 days) and nonsterile soil (0.046-12 days)(2,3,4). It has been proposed that the alkylation of soil organic matter is the primary degradation process for 3-bromo-1-propyne in soil(2-4).
TERRESTRIAL FATE: The measured first-order degradation rate constants for 310 mg/kg 3-bromo-1-propyne in autoclaved Arlington sand loam, nonautoclaved Arlington sand loam, autoclaved Linne clay loam, and nonautoclaved Linne clay loam were 0.065, 0.056, 0.20, and 0.20 per day, respectively, which correspond to half-lives of 11, 12, 3.5, and 3.5 days, respectively(1). The measured first-order degradation rate constants for 20 mg/kg 3-bromo-1-propyne in sterile Arlington sandy loam, Carsitas loamy sand, and Linne clay loam were 0.18, 0.57, and 0.39 per day, respectively, which correspond to half-lives of 3.9, 1.2, and 1.8 days, respectively(2). Measured rate constants for this substance (20 mg/kg) in nonsterile Arlington sandy loam, Carsitas loamy sand, and Linne clay loam were 0.14, 0.46, and 0.48 per day, respectively, which correspond to half-lives of 5.0, 1.5, and 1.4 days, respectively(2). Half-lives determined from first-order degradation rate constants for 0.7 mg/kg 3-bromo-1-propyne in sterile Coachella fine sand, Arlington sandy loam, Chualar loam, and Florida muck were 2.4, 2.4, 1.0, and 0.37 days, respectively at an inital concentration of 0.7 mg/kg; 3.2, 4.6, 3.0, and 0.71 days, respectively at an initial concentration of 7 mg/kg; and 6.3, 6.9, 3.5, and 1.2 days, respectively at an initial concentration of 70 mg/kg(3). Half-lives determined from first-order degradation rate constants for 0.7 mg/kg propargyl bromide in non-sterile Coachella fine sand, Arlington sandy loam, Chualar loam, and Florida muck were 3.5, 0.39, 0.36, and 0.046 days, respectively at an inital concentration of 0.7 mg/kg; 4.1, 3.6, 2.8, and 0.43 days, respectively at an initial concentration of 7 mg/kg; and 8.7, 7.7, 4.6, and 1.1 days, respectively at an initial concentration of 70 mg/kg(3).
AQUATIC FATE: Based on a classification scheme(1), Koc values of 1.1 and 5.3(2), indicate that 3-bromo-1-propyne is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 1.13X10-3 atm-cu m/mole(2). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 2 hours and 5 days, respectively(SRC). According to a classification scheme(4), an estimated BCF of 3(SRC), from a water solubility of 1.49X10+4 mg/L(2) and a regression-derived equation(5), suggests the potential for bioconcentration in aquatic organisms is low(SRC). 3-Bromo-1-propyne is expected to undergo hydrolysis based on measured half-lives of 64 and 47 days at 22 and 25 deg C, respectively(2,6). Biodegradation in water is not expected to compete with chemical degradation processes based on similar half-lives in sterile soil (0.37-11 days) and nonsterile soil (0.046-12 days)(2,6,7).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 3-bromo-1-propyne, which has an estimated vapor pressure of 108 mm Hg at 25 deg C(SRC), calculated from a water solubility of 1.49X10+4 mg/L(2) and a Henry's Law constant of 1.13X10-3 atm-cu m/mol(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 3-bromo-1-propyne is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 3 days(SRC), calculated from its rate constant of 5.6X10-12 cu cm/molecule-sec at 25 deg C(SRC) that was derived using a structure estimation method(3). Propargyl bromide does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).
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