1,1-Dichloroethylene

The Henry's Law constant for 1,1-dichloroethylene is reported as 0.0261 atm-cu m/mole(1). This Henry's Law constant indicates that 1,1-dichloroethylene 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 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). 1,1-Dichloroethylene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of 1,1-dichloroethylene from dry soil surfaces may exist based upon a vapor pressure of 600 mm Hg(3).