| Volatilization | The Henry's Law constant for 3-xylene is measured as 7.18X10-3 atm-cu m/mole(1). This Henry's Law constant indicates that 3-xylene is expected to volatilize rapidly from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 3.1 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 4.1 days(SRC). 3-Xylene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 3-Xylene is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 8.29 mm Hg at 25 deg C(3).
Literature: (1) Sanemasa I et al; Bull Chem Soc Jpn 55: 1054-62 (1982) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990) (3) Chao J et al; J Phys Chem Ref Data 12: 1033-63 (1983)
Literature: #An experiment which measured the rate of evaporation of m- and p-xylene from a 1:1000 jet fuel:water mixture found that it averaged 0.64 times the oxygen reaeration rate(1).
Literature: (1) Smith JH, Harper JC; pp.336-53 in 12th Conf Environ Toxicol: Behavior of Hydrocarbon Fuels in the Aquatic Environment (1980) |
| Soil Adsorption | A Koc value of 166 was measured for 3-xylene using sandy aquifer materials with an foc ranging from 0.0002 to 0.0225(1). Measured Koc values in soil have been reported to be 182(2), 166 and 275(3). According to a classification scheme(3), these Koc values suggest that 3-xylene is expected to have moderate mobility in soil. A Kp value (equilibrium-sorption coefficient) of 0.049 was measured for 3-xylene using a Borden soil column (98% sand, 0.29% organic carbon)(5). Benzene/toluene/xylene mixtures containing 3-xylene, were added to soil columns using aquifer material from the Cohansey aquifer (90% sand; 4.4% organic matter; pH-3.8); a partition coefficient of 8.74 was measured for 3-xylene(6). Adsorption coefficient values of 0.25, 0.23, and 0.02 were measured for 3-xylene, present in a benzene/toluene/ethylbenzene/xylene mixture, on montmorillonite, illite, and kaolinite (all with low to no organic carbon present), respectively, using a batch equilibrium technique(7). More 3-xylene vapor was sorbed by air-dry than oven-dry soil (Evesham clay; air-dry soil contained 37 g organic C, 350 g clay, and 60 g water/kg oven-dry soil) at relative vapor pressures of 3-xylene exceeding 0.6; this suggests that the planar 3-xylene molecule is either readily adsorbed by interlayer sites in the air-dry soil (more sites potentially available than in oven-dry soil) or, as it is a fairly soluble molecule, that some will dissolve in the water film in air-dry soil(8). 3-Xylene has been observed to pass through soil unchanged in concentration at a dune-infiltration site on the Rhine River(9). A soil leaching column study estimated a 3-xylene Koc of 282 using a chromatographic methodology(10).
Literature: (1) Abdul AS et al; Hazard Waste & Hazard Mater 4: 211-22 (1987) (2) Sabljic A; Environ Sci Technol 21: 358-66 (1987) (3) Schuurmann G et al; Environ Sci Technol 40: 7005-7011 (Supporting information) (2006) (4) Swann RL et al; Res Rev 85: 17-28 (1983) (5) Hu Q et al; Environ Toxicol Chem 14: 1133-40 (1995) (6) Uchrin CG, Katz J; Bull Environ Contam Toxicol 46: 534-41 (1991) (7) Li Y, Gupta G; Chemosphere 28: 627-38 (1994) (8) Nye PH et al; J Environ Qual 23: 1031-37 (1994) (9) Piet GJ et al; Quality of Groundwater Int Symp Proc Von Duijvanbouden W et al, eds. Studies Environ Sci 17: 557-64 (1981) (10) Xu F et al; J Environ Qual 30: 1618-1623 (2001) |
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