A 2-D tank model was used to model the movement of DNAPL (tetrachloroethylene, TCE) in various soil conditions. TCE was dyed using Sudan V to produce strong red color to visualize its movement in the tank. The soil heterogeneities such as clay lenses, bedding planes, unsaturated-saturated zone are discovered to influence the migration pattern of DNAPL in soil.
Photo shows the migration of TCE in soil with clay lenses
The downward movement of TCE is retarded by the water table. It migrates laterally along the surface of the water table until its self weight (due to gravity) will overcome the capillary pressure and move to the bottom of the tank.