ABSTRACT
Natural attenuation is considered as a potential remedy at the very first step of the process, and many of the most critical decision points rely on a conceptual understanding of contaminant degradation in the subsurface. There has been a historical prejudice against the reliance on natural attenuation for site remediation because the latter is perceived to be a "no-action" or "walk-away" solution to environmental contamination. The most comprehensive cleanup protocol that includes consideration of natural attenuation is that of Wiedemeier et al. for the cleanup of fuel hydrocarbons at Department of Defense (DOD) facilities. The overall approach of the Air Force Center for Environmental Excellence (AFCEE) protocol emphasizes the iterative development of a conceptual model of natural attenuation, and stress is placed on assembling multiple lines of evidence for natural attenuation. There is no protocol for demonstrating natural attenuation of metals. Nor can the protocols for natural attenuation of organic contaminants be used without modification as templates.
