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Quarterly SummaryReport _ <br /> Fourth Quarter 1995 <br /> Former Unocal Bulk Plant 0788 <br /> 8203 East I I th Street <br /> Tracy, California <br /> City/County ID 4: Unknown <br /> County: San Joaquin <br /> BACKGROUND <br /> A partially buried 5,000-gallon transmission fluid storage tank was removed on <br /> December 13, 1989; and analysis of soil samples indicated low levels of petroleum <br /> hydrocarbons. The San Joaquin County Public Health Services Department requested <br /> additional investigation on January 30, 1990. Since 1990, 10 groundwater monitoring <br /> wells have been installed to assess soil and groundwater conditions. A Remedial <br /> Action Plan (RAP) recommending soil vapor extraction and air sparging was submitted <br /> on March 18, 1993. A work plan for implementation of the RAP was submitted on <br /> • July 13, 1993. The bulk plant was permanently closed and all related activities ceased <br /> on December 1, 1993. The aboveground tanks, loading racks, and garage structure <br /> were removed from the site in September 1994. In December 1994, Unocal proposed <br /> a site remedial strategy which included soil vapor extraction and enhanced <br /> biodegradation. Groundwater monitoring and sampling are performed on a semiannual <br /> schedule. <br /> RECENT QUARTER ACTMT]ES <br /> Semiannual groundwater monitoring and sampling were performed in February 1996. <br /> Due to continued low-to-non detect concentrations of dissolved hydrocarbons in site <br /> wells, Unocal reevaluated remedial alternatives for the site, based on the"interim <br /> guidance" issued by the State Water Resources Control Board. In a letter'dated <br /> January 23, 1996, PACIFIC, on behalf of Unocal, recommended a site remedial <br /> strategy that includes passive bioremediation, continued groundwater monitoring, and <br /> .off site assessment to delineate the lateral extent of dissolved hydrocarbons in <br /> groundwater. <br /> NEXT QUARTER ACTrVfMS <br /> No activities are anticipated. <br /> 310001104 95 SR <br /> Q Q 1 January 18, 1996 <br />