| Volatilization | The Henry's Law constants for 1- and 2-methylnaphthalene are 5.14X10-4 and 5.18X10-4 atm-cu m/mole, respectively(1). These Henry's Law constants indicate that methylnaphthalenes are expected to volatilize from water surfaces(2). Based on these Henry's Law constants, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 5.5 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)(3) is estimated as 5.3 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column(SRC). The estimated volatilization half-life from a model pond is 23 to 78 days if adsorption is considered(4). The Henry's Law constants for 1- and 2-methylnaphthalene indicate that volatilization from moist soil surfaces may occur(SRC). Methylnaphthalenes are not expected to volatilize from dry soil surfaces(SRC) based upon vapor pressures of 0.067 mm Hg(5) and 0.055 mm Hg(6) for 1- and 2-methylnaphthalene, respectively.
Literature: (1) Altschuh J et al; Chemosphere 39: 1871-87 (1999) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990) (3) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Jan 5, 2015: http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm (4) US EPA; EXAMS II Computer Simulation (1987) (5) Macknick AB, Prausnitz JM; J Chem Eng Data 24: 175-8 (1979) (6) Karyakin NV et al; Zh Fiz Khim 42: 1814-16 (1968)
Literature: #The Henry's Law constant for 1-methylnaphthalene is reported as 5.14X10-4 atm-cu m/mole(1). This Henry's Law constant indicates that 1-methylnaphthalene is expected to volatilize 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 5.5 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 5.3 days(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 23-41 days if adsorption is considered(3). 1-Methylnaphthalene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 1-Methylnaphthalene is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 0.067 mm Hg(4).
Literature: (1) Altschuh J et al; Chemosphere 39: 1871-87 (1999) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990) (3) US EPA; EXAMS II Computer Simulation (1987) (4) Macknick AB, Prausnitz JM; J Chem Eng Data 24: 175-8 (1979) |
| Soil Adsorption | Using a structure estimation method based on molecular connectivity indices(1), the Koc of methylnaphthalenes can be estimated to be 2530(SRC). However, 1-methylnaphthalene has reported Koc values of 2290(2) and 4400(3) and 2-methylnaphthalene has a reported Koc value of 4350(2) and measured Koc value of 8500(3). According to a classification scheme(4), these Koc values suggest that methylnaphthalenes are expected to have slight to no mobility in soil.
Literature: (1) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Jan 5, 2015: http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm (2) Sabljic A et al; Chemosphere 31: 4489-514 (1995) (3) Sabljic A, Protic M; Bull Environ Contam Toxicol 28: 162-5 (1982) (4) Swann RL et al; Res Rev 85: 17-28 (1983)
Literature: #A log Koc value of 3.36 was reported in soil(1). An average log Kp for 1-methylnaphthalene of 1.96 was determined from 17 measurements(2). The log Koc values for 1-methylnaphthalene in 88 sediment samples were 2.76-5.78(3). According to a classification scheme(4), these Koc values suggest that 1-methylnaphthalene is expected to have slight to no mobility in soil. The logarithmic sorption coefficient of 1-methylnaphthalene to snow was 5.79(5).
Literature: (1) Schuurmann G et al; Environ Sci Technol 40: 7005-11 (2006) (2) Vowles PD, Mantoura RFC; Chemosphere 16: 109-16 (1987) (3) Hawthorne SB et al; Environ Toxicol Chem 25: 2901-11 (2006) (4) Swann RL et al; Res Rev 85: 17-28 (1983) (5) Roth CM et al; Environ Sci Technol 38: 4078-84 (2004) |
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