ABSTRACT
Contaminants that have diffused into mineral grains or rocks in either the unsaturated or saturated zone. The migration of these phases could occur in the unsaturated or the saturated zone according to processes of diffusion, sorption and advection. Sorption to the surfaces of mineral grains within a rock occurs much like the sorption processes discussed in locus no. 4. In the saturated zone, the diffusing hydrocarbon may move between water-wet or contaminant-wet matrix grains into the aqueous or the liquid phase, while in the unsaturated zone, the diffusing hydrocarbon may move additionally between dry grains and into the vapor phase. Assuming that the petroleum derivatives considered here are nonreactive, then the reverse process, diffusion out of the rock matrix, ought to be described by the same equation in the saturated zone, where no significant discontinuity would exist between the matrix pore water phase and the fracture aqueous phase.
