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A=ntec v �> No Further Action Request Report Chevron and ARCO Commingled Plume No. CP0034 April 10, 2012 SVE and AS systems were activated on January 1, 1995 and May 5, 1995, respectively. The SVE system was comprised of 14 SVE wells (V-1 through V-12 and E-6) and an Airex Katox 100 catalytic oxidizer. The SVE system was shutdown on March 1, 2001, due to low influent concentrations. Prior to shutdown, the SVE system removed approximately 4,897.2 lbs of GRO, 61.3 lbs of benzene, and 4.5 lbs of MTBE. The AS system consisted of eight AS wells (S-1 through S-6, S-8, and S-9) and a 7.5-hp blower (MD Pneumatics Model 3202). The AS system was shutdown on April 12, 2007 with the approval of SJCEHD. Historical remediation data for the SVE and AS systems are included in Appendix D. SVE Radius of Influence A radius of influence (ROI) test was performed for the SVE system operated at Chevron facility 94275 and documented in Addendum To Corrective Action Plan, submitted by Geraghty & Miller, Inc on October 9, 1997 (Table 6-1). The test involved performance of a step test of varying vacuums and measuring the induced vacuums observed in nearby wells. Documentation for a ROI test could not be found for ARCO facility 2133. To estimate a conservative value for the ROI of both the Chevron and ARCO facilities, Stantec utilized the minimum vacuum applied during the step test for Chevron facility 94275 (approximately 40 inches of water column). This applied vacuum was also observed during operation of the SVE system at ARCO facility 2133. Based on Table D-1 and Figure D-1 (Appendix D), a ROI for Chevron facility 94275 was calculated to range between 28 and 59 ft. ROI was estimated using the point at which the trend line for the induced vacuum was approximately 1% of the applied vacuum at the extraction well. Based on this evaluation, a conservative estimate of at least 25 ft ROI is assumed to have been present at ARCO facility 2133. 2.5. DISTRIBUTION OF RESIDUAL HYDROCARBONS AND OXYGENATES 2.5.1. Distribution of Hydrocarbons and Oxygenates In Soil The lateral and vertical extent of �etrolP�m hydrocarbons in soil has been delineated Historical soil analytical data shows that petroleum hydrocarbon impacts to the soil beneath the Chevron facility were mainly limited to the southern portion of the site in the vicinity of the former USTs and current and former dispenser islands. Petroleum hdrocar bon iMDacts_toJf►e soil beneath the _ARCO fac l ty._were.mainlyJimited-to-the shallow depths.iri_the_vidnity-of-the-dispenser islands in the northern port on 4f the_,slte.at�slP,nth of ar�pr�ximateLy-thr.eeJt.b_gs,_and.at.greater depths of approximately)_5_to_2Q_fLbgs in the soulhern._portion of the site to_the_south_and southwest of the USTs. Soil isoconcentration contour maps for GRO,, DRO, benzene, and MTBE at different depth intervals populated with historical soil analytical data are included as Figures 5 through 20. 94275 NFAR 2012.doc 9