| 環境中動態 | TERRESTRIAL FATE: Based on a classification scheme(1), a Koc value of 182(2), indicates that N,N-dimethylaniline is expected to have moderate mobility in soil(SRC). The pKa of N,N-dimethylaniline is 5.15(3), indicating that this compound will exist partially in the cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Volatilization of N,N-dimethylaniline from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.7X10-5 atm-cu m/mole(SRC), based upon its vapor pressure, 0.76 mm Hg(5), and water solubility, 1,450 mg/L(6). N,N-Dimethylaniline is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(5). Utilizing the Japanese MITI test, 1.9% of the Theoretical BOD was reached in 2 weeks(7) indicating that biodegradation is not an important environmental fate process in soil(SRC).AQUATIC FATE: Based on a classification scheme(1), a Koc value of 182(2), indicates that N,N-dimethylaniline is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 5.7X10-5 atm-cu m/mole(SRC), derived from its vapor pressure, 0.7 mm Hg(4), and water solubility, 1,450 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives of the neutral species for a model river and model lake are 20 hrs and 10 days, respectively(SRC). N,N-Dimethylaniline is degraded in aqueous environments by reaction with photochemically-produced hydroxyl radicals(SRC)the half-life for this reaction in water is estimated to be 34 days(SRC), calculated from its rate constant of 1.4X10+10 cu cm/molecule-sec(6). According to a classification scheme(7), a measured BCF of 5.4(8) suggests the potential for bioconcentration in aquatic organisms is low(SRC). Utilizing the Japanese MITI test, 1.9% of the Theoretical BOD was reached in 2 weeks(8) indicating that biodegradation is not an important environmental fate process in water(SRC).ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), N,N-dimethylaniline, which has a vapor pressure of 0.7 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase N,N-dimethylaniline 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 2 hrs(SRC), calculated from its rate constant of 1.48X10-10 cu cm/molecule-sec at 25 °C(3). Vapor-phase N,N-dimethylaniline is degraded in the atmosphere by reaction with photochemically-produced ozone radicals(SRC)the half-life for this reaction in air is estimated to be 29 hrs(SRC), calculated from the rate constant of 9.1X10-18 cu cm/molecule-sec at 25 °C(4). Night-time reaction with nitrate radicals may also contribute to the atmospheric transformation of N,N-dimethylaniline(4). A dilute aqueous solution of N,N-dimethylaniline exposed to fluorescent lamps having a continuous spectrum from 300-400 nm resulted in a 50% degradation in approximately 14 min(5)therefore, N,N-dimethylaniline may be susceptible to direct photolysis by sunlight(SRC). |
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