Technology Description

The data-driven approach to be demonstrated is consistent with National Research Council recommendations for "multiple lines of evidence" and "footprint" approaches, complements existing guidance for assessing the natural attenuation of dissolved plumes, and incorporates the SZNA screening-level modeling tool development previously supported by the Department of Defense. It builds on the fundamental understanding of SZNA mechanisms and translates those into practicable site-specific guidance. While previous work focused on petroleum hydrocarbons, the approach is easily generalized to both DNAPL and mixed DNAPL/LNAPL sites. The SZNA assessment approach includes three basic levels of data collection and reduction, referred to as Group I, Group II, and Group III data and analyses. Group I will focus on measurements that provide evidence that SZNA is occurring, Group II measurements include additional information necessary to estimate the current overall SZNA rate, and Group III measurements are focused on evaluating the long-term implications of SZNA for temporal changes in source zone residual composition, source zone groundwater quality, and vapor migration impacts. Ultimately, users will identify the questions of interest and then collect the corresponding data.