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W GI[, <br /> Souitbiwest, 11inc. <br /> SJCEHD had numerous files for the Shell Stockton terminal located at 3515 Navy Drive, <br /> adjacent to Parcel 12. Elevated petroleum hydrocarbon levels are present in unsaturated soil, <br /> saturated soil and groundwater throughout most of the facility. Groundwater monitoring has been <br /> ongoing since 1990, and remediation via groundwater extraction has been ongoing since 1995. <br /> Groundwater samples were collected in May 2007; the wells closest to the Parcel 12 boundary <br /> indicate elevated concentrations, and the southwest groundwater flow direction is such that <br /> impacted groundwater is possibly present beneath the south end of Parcel 12. <br /> A few documents referred to "Navy Monitoring Well W-19" which was reportedly located on <br /> Parcel 12. These documents were usually dated 2001 or earlier. No monitoring well was <br /> observed at the subject site during the site visit on January 7, 2008. <br /> The Nustar facility located at 3505 Navy Drive was first used as a bulk facility in 1938. In 1989 <br /> British Petroleum acquired the site. Tosco Refining Company(Tosco) acquired the site from BP <br /> in 1994 and transferred ownership to ST Services in October 1998. Valero (now know as <br /> Nustar) acquired the site in 2005 and is the current operator. Since 1998 the facility has been <br /> reportedly used only for diesel storage. In April 2004 a 2,000 to 5,000-gallon fuel release was <br /> reported. Soil and groundwater beneath the site is impacted by petroleum hydrocarbons, MTBE <br /> and oxygenates. Remediation consisting of groundwater extraction and treatment started in 2003 <br /> and ended in 2006. Installation of an oxygen injection system is planned. <br /> A quarterly monitoring report for the Third Quarter of 2007 for Nustar indicated that petroleum <br /> hydrocarbon impacted groundwater is present on site and has migrated offsite to the southwest. <br /> 5. PROPOSED FIELD ACTIVITIES <br /> The site assessment will include advancing Geoprobe soil boring in four locations at the south <br /> end of the property, as shown on Figure 2. Soil samples will be collected at approximately 4 <br /> feet and 8 feet below grade (or just above groundwater, which ever is shallower), and one <br /> groundwater grab sample will be collected from each boring. The soil sampling depths may vary <br /> slightly in order to obtain two unsaturated soil samples per boring. <br /> The field activities will be performed in accordance with the Tri-Regional Board Staff <br /> Recommendations for Preliminary Investigation and Evaluation of Underground Storage Tanks <br /> guidance document dated April 16, 2004. The work will be performed under the supervision of <br /> a California Professional Geologist. <br /> 792. PRI.01 Page 3 February 28, 2008 <br />