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What is a Source?
Examples of sources include:
The following emphasize certain aspects of the HRS definition of source. The following are NOT sources for purposes of HRS scoring.
- Ground water plumes originating from known sources (such as a landfill);
- Surface water plumes originating from known sources (such as discharge pipes or overland runoff discharge areas);
- Areas of contaminated surface water sediments arising from discharges from known sources; and
- Volumes of contaminated ambient air.
The following ARE considered sources for purposes of HRS scoring:
- Ground water and surface water plumes of unknown origin;
- Areas of contaminated surface water sediments arising from direct placement (other than discharge) of waste materials into surface water bodies when the origin is unknown;
- Cylinders containing confined, gaseous hazardous substances; and
- Soils contaminated as a result of overland runoff, volatilization of ground water contaminants, or atmospheric deposition (from non-vehicular sources); and
Areas of observed soil contamination are sources. Sources need not contain waste materials. Materials that might not be considered a source if undisturbed, may become a source if excavated and moved (e.g., contaminated dredge disposal materials).
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