Association of Hazardous Substances with Sources
Associating hazardous substances with individual sources is important in several respects. The association of a hazardous substance with sources at a site can form the basis of attributing a significant increase in pathway contaminant concentrations to the site, fulfilling the requirements for an observed release. Any hazardous substances associated with sources at a site are, by inference, associated with the site and could potentially form the basis for evaluating the numerous substance-specific HRS factors, e.g. toxicity, mobility, persistence, and bioaccumulation potential. However, in general, only those hazardous substances that are associated with sources with non-zero containment values for the pathway in question can be used in the pathway scoring.
Hazardous substances, pollutants, and contaminants associated with a source can be identified using:
- Sampling data;
- PRP records, labels, and manifests;
- State or Federal records and permits;
- Information on site operations; and/or
- Historical records.
- If a hazardous substance can be documented as being
present at a site (for example, by labels, manifests, oral or written
statements), but the specific source(s) containing that hazardous substance
cannot be documented, the hazardous substance can be considered present in
every source at the site (in the absence of definitive evidence to the
- Because individual samples of contaminants may be successfully refuted during public comment, it is important that all hazardous substances associated with every source (with non-zero containment) at the site be identified at the time of proposal.
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