Ethylene Oxide

The Henry's Law constant for ethylene oxide is 1.48X10-4 atm-cu m/mole(1). This Henry's Law constant indicates that ethylene oxide 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 6 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 days(SRC). Ethylene oxide is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.31X10+3 mm Hg(3). Although no data on the volatilization of ethylene oxide from soil could be found, a study of the dissipation of ethylene oxide from fumigated commodities gave half-life values of 4 hr to 17.5 days(4).