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6ETTLER - RYA N IN C. SOIL BORING REPORT at Former Unocal Station No 0123 1034 Central Avenue Tracy, California a Report No 240073 03-1 INTRODUCTION This report presents the results of a subsurface investigation performed by Gettler-Ryan Inc (GR) at the above referenced site The work was performed at the request of Unocal Corporation (Unocal) to further evaluate the distribution of residual petroleum hydrocarbons in soil and groundwater downgradient of the subject site The scope of work performed included preparing a site safety plan, obtaining the required soil boring and encroachment permits, advancing one soil boring to 16 feet below ground surface (bgs), collecting soil and grab groundwater samples for chemical analysis, analyzing the soil and grab groundwater samples, and preparing a report documenting the work This work was originally proposed in GR Report #240073 03, Work Plan For Additional Subsurface Assessment, dated October 5, 1999 The Work Plan was approved by San Joaquin County Environmental Health Division (SJCEHD) on October 22, 1999 (copy of approval attached in Appendix A) SITE DESCRIPTION _ The site is located on the southeast corner of the intersection of Central Avenue and 11"' Street in Tracy, California (Figure 1) The site was reportedly an operating Unocal service station from 1920 through 1962 Two underground storage tank (UST) complexes have existed at the site A cluster of three USTs was located at the northern property boundary adjacent to 116' Street, and a second cluster of three tanks located to the south that was active at the time of closure in 1962 Other station facilities consisted of a station building, a dispenser island, and one waste oil UST The property was purchased by Bank of America in 1962 All subsurface and aboveground facilities have been demolished and removed from the site (except for one UST at the northern property boundary that was abandoned in place) The site is currently an asphalt-paved parking lot owned by and servicing the Wells Fargo Bank located immediately to the south Pertinent site features are shown on Figure 3 PREVIOUS ENVIRONMENTAL ACTIVITIES A limited subsurface investigation was conducted by L M Swift for Wells Fargo and is detailed in a Phase I Report dated March 29, 1994 The investigation included an underground electronic survey of the parking lot to determme if any abandoned USTs existed beneath the site, and exploratory borings to- collect soil and groundwater samples The underground survey detected no large metal anomalies, and concluded that there were no USTs beneath the site However, hydrocarbon-impacted groundwater was detected in the northern portion of the site 6747 Sierra Court , Suite J Dublin , California 94568 ( 925 ) 551 - 7555