MODELING OF THE GASEOUS-DIFFUSION COEFFICIENT IN THE PRESENCE OF NAPL

Gas phase diffusional resistance (D-0/D) was measured using packed soi l columns containing a fixed relative saturation of dodecane with vary ing moisture contents. Argon was chosen to serve as an inert gas phase tracer. Dodecane was used to simulate an immobilized NAPL in the soil subsurface. Results indicated that filling of soil pores by either li quid water or liquid dodecane has a similar effect on the gas phase di ffusional resistance. A previously developed diffusion model was modif ied to account for total liquid (water and NAPL) saturation and compar ed with the experimental data. (C) 1998 Elsevier Science B.V. All righ ts reserved.