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1 05 September 2002 AGE-NC Project No. 95-0100 Page 5 of 9 ' hydrocarbon-impacted soil remediation alternatives were considered in the AGE's Corrective Action Plan (CAP), dated 06 December 1995. ' 3.6. SOIL-VAPOR EXTRACTION SYSTEM INSTALLATION ' AGE prepared a Remedial Action Work Plan, dated 17 March 1997, describing the installation and operation of a soil vapor extraction system. The SJC-EHD approved the plan on 21 March 1997. On 25 February 1998, soil vapor extraction commenced utilizing a King, Buck/Hasstech (KBH) ' thermal oxidation soil-vapor extraction unit(SVE).The initiation ofihe SVE operation was observed by representatives of the San Joaquin Unified Air Pollution Control District (A-PCD) and the SJC- EHD. tSoil-vapor samples were collected over the six months of operation to determine mass extracted and destruction efficiency. The SVE unit operated at varying rates during the observation period. Extraction flow rates were calculated to range fi•om 75 to approximately 90 scfm. Typically operation ' of the SVE averaged 85 scfin during the period. An induced vacuum (negative pressure) of approximately 15 to 20 inches ofwater was measured in the piping between the blower and extraction wells. An induced vacuum of approximately 0.15 inches was measured at well VW-2, a distance of t 20 feet from the extraction well VW-1. The soil-vapor samples collected are summarized in Appendix B. Oxygenated fuel additives were not detected in the samples. ' Approximately 96 gallons of gasoline were calculated to have been removed between 25 February and 28 April 1998, 169 gallons of gasoline were removed between 28 April and 06 June 1998, and 108 gallons of gasoline were extracted between 04 June and 30 June 1998. Approximately 59.9 gallons of gasoline were removed from the site during the third and portions of the fourth quarter of ' 1998. A total 433.5 gallons of hydrocarbons as gasoline were removed from the site. ' 3.7. CONFIRMATION PROBE BORING AND SAMPLING Following the termination of the VES,two confirmation borings were drilled in accordance with the ' approved Remedial Action Work Plan. On 1 I February 1999, two soil probe borings (CB1 and CB2) were advanced at the site under the observation of the SJC-EHD. Probe borings were advanced in the area of the former fuel dispenser ' island. Probe boring locations are shown on Figure 2. Probe boring CB 1 and CB2 were advanced at the northern and southern ends of the former dispenser island, respectively. Borings CB1 was advanced to a depth of 60 feet below surface grade (bsg) for the collection of a grab ground water- sample. Soil boring CB2 was advanced to a depth of 35 feet bsg.. Soil samples:were_collected at 5-._. _�- -"Y foot intervals, beginning at a depth of 5-feet bsg to a depth of SS feet bsg in boring CB1 and to a depth of 35 feet in CB2. 1 • Advanced GeoEnvironmentai,Inc.