Volatilization | The Henry's Law constant for octadecane is estimated as 1.9X10-2 atm-cu m/mole(1) from its vapor pressure, 3.41X10-4 mm Hg(2), and water solubility, 6.0X10-3 mg/L(3). This Henry's Law constant indicates that octadecane is expected to volatilize rapidly from water surfaces(4). 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)(1) is estimated as 1.7 hours 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)(1) is estimated as 6.3 days(SRC). However, adsorption to suspended solids and sediment is expected to attenuate volatilization(SRC). The estimated volatilization half-life from a model pond is greater than 2 years if adsorption is considered(5). Octadecane has a vapor pressure of 3.41X10-4 mm Hg and exists as a liquid under environmental conditions; therefore, octadecane may volatilize from dry soil. Literature: (1) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Nov 9, 2016: http://www2.epa.gov/tsca-screening-tools (2) Jensen TS; PhD Thesis: Petroleum hydrocarbons: compositional changes during biodegradation and transport in unsaturated soil. Roskilde, Denmark: Ministry of the Environment and Energy, National Environmental Research (1994) (3) Yalkowsky SH, et al; Handbook of Aqueous Solubility Data. 2nd ed., Boca Raton, FL: CRC Press p. 1184 (2010) (4) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990) (5) US EPA; EXAMS II Computer Simulation (1987) |
Soil Adsorption | The Koc of octadecane is 2.2X10+7(1). According to a classification scheme(2), this Koc value suggests that octadecane is expected to be immobile in soil. Literature: (1) Jensen TS; PhD Thesis: Petroleum hydrocarbons: compositional changes during biodegradation and transport in unsaturated soil. Roskilde, Denmark: Ministry of the Environment and Energy, National Environmental Research (1994) (2) Swann RL et al; Res Rev 85: 17-28 (1983) |