As-found concentration
As-found concentration means the concentration measured in samples collected in-situ (i.e., prior to being moved or disturbed for cleanup and/or disposal) from environmental media or material, unless otherwise specifically provided. For example, media must not be disturbed, nor may they be diluted (e.g., excavated, placed on a pile, and sampled after such placement), before characterization sampling is conducted. Sampling media in piles and existing accumulations would be considered as-found if the media were already in piles when the site was first visited by the responsible party, such as during the redevelopment of abandoned properties with historic PCB contamination. The as-found concentration is distinct from the source concentration, which is the concentration of the PCBs in the material that was originally spilled, released, or otherwise disposed of at the site.