| Umweltverhalten | TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 4,900(SRC), determined from a structure estimation method(2), indicates that 1,6-dimethylnaphthalene is expected to have slight to no mobility in soil(SRC). Volatilization of 1,6-dimethylnaphthalene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 4.2X10-4 atm-cu m/mole(SRC), using a fragment constant estimation method(3). 1,6-Dimethylnaphthalene is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.46X10-2 mm Hg(4). A 54.5% loss after 7 days in a marine water die-away study with sediment inoculum from Dunstaffnage Bay, Scotland(5), indicates that biodegradation may be an important fate process in the terrestrial environment.AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 4,900(SRC), determined from a structure estimation method(2), indicates that 1,6-dimethylnaphthalene 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 4.2X10-4 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 6 hrs and 6 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 51 days if adsorption is considered(5). According to a classification scheme(6), an estimated BCF of 520(SRC), from an estimated log Kow of 4.3(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is high(SRC). A 54.5% loss after 7 days in a marine water die-away study with sediment inoculum from Dunstaffnage Bay, Scotland(9), indicates that biodegradation may be an important fate process in the aquatic environment.ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,6-dimethylnaphthalene, which has a vapor pressure of 1.46X10-2 mm Hg at 25 °C(2), is expected to exist primarily as a vapor in the ambient atmosphere. Vapor-phase 1,6-dimethylnaphthalene 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 5 hrs(SRC), calculated from its rate constant of 6.34X10-11 cu cm/molecule-sec at 25 °C(3). Based upon aqueous photolysis data for 1- and 2-methylnaphthalene(4), 1,6-dimethylnaphthalene may undergo direct photolysis in the atmosphere(SRC). |
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