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Quarterly Summary Report <br /> Fourth Quarter 1994 <br /> Unocal Bulk Plant 0788 <br /> 8203 East 11*h Street <br /> Tracy, California <br /> City/County ID #: 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. Pacific Environmental Group, Inc. <br /> (PACIFIC) installed groundwater Monitoring Wells U-1 through U-3 on October 24 <br /> and 25, 1990. Wells U-4 through U-6 and exploratory soil Borings U-A through U-C <br /> were installed in May 1991. On-site Wells U-7 and U-8 and off-site Wells U-9 and U-10 <br /> were installed in March 1992, as described in PACIFIC's Soil and Groundwater <br /> Investigation Report, dated June 11, 1992. A Remedial Action Plan(RAP) was <br /> submitted on March 18, 1993. A work plan for implementation of the RAP was <br /> submitted on July 13, 1993. System design was completed June 18, 1993. Air emissions <br /> permit application was approved by the San Joaquin Air Pollution Control District in <br /> July 1993. The bulk plant was permanently closed and all related activities ceased on <br /> December 1, 1993. The aboveground tanks, loading racks, and garage structure were <br /> removed from the site in September 1994. <br /> RECENT QUARTER ACTIVITIES <br /> Quarterly groundwater monitoring and sampling were performed on November 8, 1994. <br /> Soil excavation and ex-situ bioremediation, and soil vapor extraction were considered as <br /> potential remedial strategies. A report documenting a soil and groundwater investigation <br /> was submitted on December 1, 1994. Remedial alternatives were evaluated and soil <br /> vapor extraction/air sparging were selected as the preferred alternative for site . <br /> remediation. A work plan which documents the remedial evaluation and presents the <br /> implementation plan and schedule was submitted on December 30, 1994. <br /> NEXT QUARTER ACTIVITIES <br /> Quarterly groundwater monitoring and sampling will be performed and documented. <br /> Upon approval of the preferred remedial strategy, air permit modifications will be <br /> submitted. Remedial system design will be initiated. <br /> CHARACTERIZATION/REMEDIAL STATUS <br /> Soil contamination delineated? Yes. <br /> Dissolved groundwater delineated? No. <br /> 31000103/4Q94QSR 1 January 13, 1995 <br />