Level of Contamination
At any target with hazardous substances present, there can be different levels of contamination. Targets can be subject to either actual or potential contamination. Actual contamination is established when there is an observed release of hazardous substances at a target location. The observed release can be established by either chemical analysis or by direct observation. Actual contamination is further divided into Level I and Level II based on the concentration of hazardous substances at the particular target. All other targets are considered subject to potential contamination.
Distinguishing among levels of contamination is important because it affects the factor values assigned to the nearest individual, sensitive environments, and population factors. It may also affect the waste characteristics factor category through its influence on the minimum factor value assigned for the hazardous waste quantity factor in a migration pathway.