Source Zone Delineation Demonstration Report - Triad Resource ...

1.3 Overview of Source Zone Delineation TasksThe delineation of the suspected source zone at OU 12 was conducted using a dynamic work planapproach. To ensure the project objectives were met, field operations were performed according to thefollowing strategy:Up-front systematic planning;Use of an adaptive (dynamic) sampling plan;On-site analysis and “immediate” availability of results using the DSITMS; andRapid on-site decision-making by the Core Technical Team and guided by real-time data.The primary tasks associated with the Source Zone Delineation Demonstration included the following:Task 1. Mobilization and Setup. The CPT truck was mobilized to the OU 12 site and the wirelinesampling tool system was prepared for field operations. The on-site laboratory consisting of the DSITMSalso was mobilized to the OU 12 site and initialized for field operations.Task 2. Wireline CPT Demonstration. The Wireline CPT investigation was conducted within thevadose zone and capillary fringe underlying the suspected source zone at OU 12. The investigationfocused on TCE analysis of vadose zone soils, since the TCE groundwater plume emanating from OU 12had been previously defined. Soil sampling began along a pre-determined sampling transect and one-footvertical intervals from the ground surface. Characterization of the spatial extent and magnitude of TCEcontamination in the vadose zone was concurrent with field sampling efforts. Iterative, short-delaymodeling of the extent of contamination provided field personnel with guidance for selecting newWireline CPT sampling locations.Task 3. Vapor Extraction/Monitoring Probe Installation. Soil vapor monitoring/extraction probes wereinstalled at seven locations in the suspected OU 12 source zone using direct push technology. At eachlocation, probes were installed from approximately 30 to 60 feet below ground surface (bgs) withscreened intervals ranging from 15 to 20 feet in length. Exact depths and locations were based uponreview of the Wireline CPT data collected during the project.Task 4. SVE Demonstration. The SVE system was constructed and operated for approximately 5 daysin the suspected source zone at the OU 12 site. The SVE system was operated at varied rates of flow todetermine vapor phase contaminant concentration profiles under both advective and diffusive dominatedflow regimes.March 2003 1-5 OU 12 Demonstration ReportFinal