Behavior assessment model for trace organics in soil. IV: Review of experimental evidence

Experimental evidence supporting the environmental screening model of Jury et al. (1983) is reviewed and discussed. For several laboratory studies of volatilization, initial and boundary conditions matched those used in our model and simulations were run. In all cases, good agreement was found between predicted and measured volatilization losses, with and without accompanying water evaporation. When five chemicals of widely differing volatility were exposed to identical experimental conditions, the model correctly predicted the relative loss behavior observed. The convective mobility predictions of the model were shown to be consistent with several laboratory studies of compound leaching, as long as the water flow rate was slow enough (< 0.01 cm/s) to ensure equilibrium between the solution and adsorbed phases. The Millington and Quirk tortuosity model used in our representation of the soil diffusion coefficient was found to give a good prediction of the water content dependence of the effective diffusion coefficient observed in several studies. The thickness of the stagnant boundary layer predicted from our similarity assumption was shown to be consistent with the apparent thickness inferred from several laboratory and field measurements of volatilization.