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A <br /> Quarterly Summar- Report <br /> First Quarter 1997 <br /> 1 <br /> Former Unocal Service Station 2859 <br /> 1665 Pacific Avenue <br /> Stockton, California <br /> County STID 4 None <br /> County San Joaquin <br /> BACKGROUND <br /> Underground storage tanks removed in March 1988 From March 1988 through <br /> November 1994, a total of 12 on-site and 3 off-site borings were drilled, 4 on-site moni- <br /> toring wells, 3 on-site soil vapor extraction (SVE) wells, and 5 off-site monitoring wells <br /> were installed Analytical results indicate that soil near the eastern dispenser island <br /> contains gasoline hydrocarbons and groundwater has been impacted with gasoline <br /> hydrocarbons A work plan to initiate a 6-month SVE test was submitted on July 14, <br /> 1995 A 30-day public notification for air permitting was initiated, and an air permit to <br /> construct was received in December The SVE remedial system was constructed in <br /> January 1996 The S%E pilot test was run from January through November 1996 The <br /> pilot test indicate that SVE has been successful at removing nearly 2,800 pounds of <br /> hydrocarbons However, analysis of the mass removal trend also indicated that the <br /> incremental benefit of continued operation had been lost <br /> RECENT QUARTER ACTIVITIES <br /> Quarterly groundwater monitoring and sampling were performed in February The SVE <br /> remedial system was decommissioned and removed from the site Unocal submitted a <br /> remedial action performance summary for the reporting period of October through <br /> December 1996 Unocal also subniitt�d an argument that the site is suitable for closure as <br /> a low risk groundwater case <br /> NEXT QUARTER ACTIVITIES <br /> Second quarter 1997 groundwater monitoring and sampling will be performed <br /> 3100405A/1Q97QSR 1 Apnl 18, 1997 <br />