Use of Mass Flux Measurement Pre- and Post-Remediation

Several technical and policy questions are being debated regarding the utility or futility of attempts to aggressively treat DNAPL source zones even though several field-scale demonstrations have shown that in-situ remediation technologies can extract or destroy a large fraction (70-90+%) of the contaminant mass. Can the spatial extent and contaminant mass distribution present in the source zone be reliably characterized? If so, what fraction of the DNAPL mass should be extracted or destroyed? Which source cleanup technologies perform the best? Which site attributes are useful in optimizing the design and implementation of source remediation? What benefits in risk or liability or cost reduction can be achieved from partial mass depletion of the source? What are the likely negative impacts of aggressive source remediation attempts? What are the appropriate metrics for site evaluation and remedial performance? Are appropriate methods available to measure these metrics? What are the long-term stewardship needs at DNAPL sites where the source is either partially depleted or physically contained? These questions will be explored, using recent results from theoretical analyses and data from field studies, to assess the benefits of partial source depletion at DNAPL sites. New approaches being developed and tested for establishing the source and plume strength as a robust metric for site assessment and remediation effectiveness will be presented.