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Geosyntec'' consultants former Village Cleaners suite. Intermediate soil vapor samples were collected every 15 feet across the Site. Concentrations of PCE were reported in soil vapor samples at a maximum concentration of 1,160 µg/l_ in the intermediate soil vapor samples. The highest concentrations of PCE were reported in intermediate soil vapor samples collected around newly installed soil vapor probe SG-100. Deep soil vapor samples were also collected along the sanitary sewer lateral and in the southern part of the northern parking lot. PCE was reported at a maximum concentration of 895 pg/L in these deep soil vapor samples and the highest concentrations of PCE in deep soil vapor were generally in samples collected along the sewer lateral (LFR, 1999). 2.4 Remedial Action, Optimization and Confirmation Sampling To address COC impacts in soil vapor, a soil vapor extraction system (SVE) system was installed at Lincoln Center in 1999. The SVE system comprised 35 SVE wells (SVE-1 through SVE-35) screened from 10 to 30 bgs. Five SVE wells(SVE-3 through SVE-7)were located in the northern part of the Site by SG-100 and screened between 10 and 30 feet bgs. SVE-3 and SVE-4 were located approximately 80 feet north and 110 feet north-northwest of newly installed SG-100, respectively; SVE-5 was located approximately 100 feet west of newly installed SG-100, across the sanitary sewer lateral, SVE-6 was located approximately 100 feet south of newly installed SG-100; and SVE-7 was located approximately 50 feet east of newly installed SG-100 (Figure 2). While the SVE system was in operation, soil vapor was extracted from the SVE wells using a 2,000-standard-cubic-feet-per minute (scfm) positive displacement blower installed at the treatment system compound (TSC). At the TSC, soil vapor was treated using two vapor-phase granulated activated carbon (GAC) vessels connected in series prior to being discharged to the atmosphere. The SVE system was in continuous operation from September 1999 through June 2013 and removed approximately 7,500 pounds of PCE over 14 years of operation. The mass removal rate decreased significantly within the first few years of operation and remained relatively flat thereafter. After operation of the SVE system was no longer cost effective, multiple phases of optimization occurred in 2012 and 2013 and in situ soil vapor samples were collected to confirm the cleanup goals had been met. The California Human Health Screening Levels(CHHSLs)were used as cleanup goals at that time. The commercial CHHSL for PCE was 603 gg/m3. During a soil vapor sampling event in May 2012, PCE was reported in soil vapor samples collected from SG-1, located approximately 50 feet northwest of the newly installed SG-100,at a concentration of 3,000 µg/m3, above the commercial CHHSL. SVE system optimization testing was conducted at SVE-3, SVE-5 and SVE-7 following the sample collection. Optimization testing occurred between November 2012 and February 2013 and included three events of short-term pulsing of the three SVE wells. Soil vapor samples were collected from SVE-5 at the beginning and end of each pulsing period. Confirmation soil vapor samples were collected following the optimization testing. Concentrations of PCE reported in SVE-5 at the beginning of each pulse period ranged from 17 pg/m3 to 1,600 gg/m3 and concentration of PCE reported in SVE-5 at the end of each pulse period ranged from 0.28 µg/m3 to 3,900 µg/m3. The confirmation soil vapor sample collected from SG-1 after the optimization in 2013 had a concentration of PCE of 600 µg/m3, below the CHHSL of 603 pg/m3. 202012 Lincoln Center Soil Vapor Assessment Work Plan 3 December 2020