Theme: 10. Characterization, Fate and Transport

Topic Area: 10f. High-Resolution Site Characterization (HRSC)

Formatted Title:

Reassessment of Site Conditions Based on Quantitative High-Resolution Site Characterization (qHRSC)

Background/Objectives:

Historical operations at a manufacturing facility resulted in the release of trichloroethene (TCE) to groundwater. Traditional environmental investigation activities were utilized to develop a conceptual site model and delineate chlorinated volatile organic compound (cVOC)-impacted groundwater. An agency-approved Remediation Work Plan (RWP) was developed proposing groundwater treatment utilizing RPI CAT100^® reagent, with quantitative high-resolution site characterization (qHRSC) proposed to collect additional data for development of the injection design.

Approach/Activities:

The qHRSC was completed in three separate stages. Each stage consisted in the collection of soil and groundwater samples. Soil samples were collected every two vertical feet to depths of approximately 25 feet below grade. Shallow and deep groundwater samples were collected at each exploratory location. Soil samples were analyzed for cVOCs and groundwater samples were analyzed for cVOCs, anions, and dissolved gases for the determination of reagent mass loadings throughout the proposed injection area. A total of 551 soil and 110 groundwater samples were collected and analyzed.

Results/Lessons Learned:

A 3-dimensional contaminant mass model was utilized to interpret the qHRSC analytical results. The qHRSC identified an additional source area, present at significantly greater concentration and mass than that which was previously discovered during the initial RWP investigation. The lateral and vertical extents of the proposed injection treatment area were adjusted to account for the findings of the qHRSC. Without completion of the qHRSC the additional source area would have been undiscovered and groundwater remediation would have failed at the Site.

Steven Irvin

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(Group 2, Poster Board #116) Reassessment of Site Conditions Based on Quantitative High-Resolution Site Characterization (qHRSC)