| Geology |
| Factor |
Effect |
| Lithology |
Geologic factors control mechanisms and direction(s) of contaminant migration, the presence and nature of completed pathways to potential receptors, nature and accessibility of source zone(s), and the remedial approaches that are likely to be successful. |
| Homogeneity/heterogeneity |
| Orientation, extent, and continuity of geologic units |
| Composition |
| Hydrology |
| Factor |
Effect |
| Depth to groundwater |
Hydrologic factors control whether contaminants will affect groundwater or surface water, mechanisms and direction(s) of contaminant migration, the presence and nature of completed pathways to potential receptors, nature and accessibility of source zone(s), and the remedial approaches that are likely to be successful. |
| Permeability |
| Direction(s) and rate(s) of groundwater movement |
| Presence/absence of preferential flowpaths |
| Presence/absence of confining units |
| Thickness of water-bearing unit |
| Distance to surface-water bodies |
| Surface drainage characteristics |
| Precipitation |
| Groundwater recharge |
| Source Zone |
| Factor |
Effect |
| Contaminant(s) |
The nature of the contaminants affects the degree of potential hazard, and their physical and chemical properties control the interactions of the contaminants with the environment, characteristics of contaminant migration, and contaminant fate. Location and size of the source zone affect its accessibility and the remedial approaches that are likely to be successful, Source-zone mass affects the decision regarding whether to attempt source-zone removal/reduction (i.e., reduction of mass in a source zone containing little mass may not be cost-effective). |
| Contaminant mass |
| Contaminant concentrations |
| Vertical and lateral extent |
| Volume |
| Groundwater Plume |
| Factor |
Effect |
| Contaminant(s) |
The nature of the contaminants affects the degree of potential hazard, and their physical and chemical properties control the interactions of the contaminants with the environment, characteristics of contaminant migration, and contaminant fate. Location of the plume with respect to potential receptors, and contaminant concentrations within the downgradient parts of the plume, affect the selection of remedial approaches that may be necessary or desirable. |
| Contaminant concentrations |
| Vertical and lateral extent |
