| 環境中動態 | TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1600(SRC), determined from a structure estimation method(2), indicates that 1,2-diethylbenzene is expected to have low mobility in soil(SRC). Volatilization of 1,2-diethylbenzene from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 0.00261 atm-cu m/mole(3) estimated from its vapor pressure, 1.05 mm Hg(5), and water solubility, 71.1 mg/l(6). The potential for volatilization of 1,2-diethylbenzene from dry soil surfaces may exist based upon a vapor pressure of 1.05 mm Hg(5). 1,2-Diethylbenzene at a concn of 22.7 ug/l was completely removed within 5 days from a gas oil mixture at a concn of about 2 mg/l added to acclimated fresh-wellwater grab samples from Tuffenwies and Zurich, Switzerland, with a pH of 8.0, at 10 and 25 °C and microbial populations of 300-400 cells/ml(7). A gas oil mixture with a concn of 0.5 ppm contained 1,2-diethylbenzene, which degraded in North Sea coastal water maintained at 20 °C for 14 days(8).AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1600(SRC), determined from an estimation method(2), indicates that 1,2-diethylbenzene 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 0.00261 atm-cu m/mole(4) estimated from its vapor pressure, 1.05 mm Hg(8), and water solubility, 71.1 mg/l(9). Using this estimated Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 1.4 hr and 5 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 150(SRC), from its log Kow of 3.72(6), and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is high. Groundwater(10) and marine water grab sample tests(11), in which 1,2-diethylbenzene was a constituent of gas oil mixtures, suggests that 1,2-diethylbenzene may biodegrade in the aquatic environment.ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,2-diethylbenzene, which has a vapor pressure of 1.05 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,2-diethylbenzene 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 days(SRC), calculated from its rate constant of 8.1X10-12 cu cm/molecule-sec at 25 °C determined using a structure estimation method(3). 1,2-Diethylbenzene has the potential to undergo direct photolysis in air as it absorbs UV light at wavelengths in the environmentally significant range, >290 nm(4). |
|---|
