FIGURE 1-1 Hypothetical DNAPL release site. In addition to residual and pooled DNAPL sources, the figure depicts vapor-phase contaminants in the unsaturated zone and a plume of dissolved and sorbed contamination in the saturated zone downgradient of the DNAPL. Note that the residual DNAPL is more likely to occur in sparse pools and fingers, rather than in the massive bodies inferred in the picture.
SOURCE: NRC (2005a); adapted from Cohen et al. (1993).
FIGURE 1-2 Schematic of possible post-remediation trajectories for plume behavior. The y axis could be any decision variable used to measure the remedial objective (e.g., the contaminant concentration at a point of compliance).