ITRC Publishes New Resource on Integrated DNAPL Site Characterization and Tools Selection (ISC-1)
Sites contaminated with dense nonaqueous phase liquids (DNAPLs) and DNAPL mixtures present significant environmental challenges. Despite the decades spent on attempts to characterize and remediate DNAPL sites, substantial risk remains. Inadequate characterization of site geology and the distribution, characteristics, and behavior of contaminants has limited the success of many remediation efforts; however, amassed experience and applied research have resulted in a better understanding of the complexity of subsurface geologic conditions.
This guidance document reviews the current knowledge of DNAPLs and their subsurface behavior. Using an integrated site characterization (ISC) approach that emphasizes adequate data resolution to fully characterize a site, this document describes how to align data on contaminant distribution, geology, and groundwater flow at a spatial resolution appropriate to the site-specific remedial objectives. With improving understanding of subsurface contaminant behavior, both existing and new tools and techniques can be used to measure physical, chemical, and hydrologic subsurface parameters to better characterize the subsurface.
This document synthesizes the knowledge of DNAPL site characterization and remediation and provides guidance on simultaneous characterization of contaminant distributions, hydrogeology, and attenuation processes to allow for improvements in the following areas:
- assessment of ongoing contaminant exposures;
- quantification of contaminant transport, storage, and attenuation patterns;
- prediction of future exposures that would occur without intervention;
- prediction of changes in future exposures that would occur in response to remedial actions; and
- selection and design of remedial actions.