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SUBSURFACE SOIL AND GROUNDWATER ASSESSMENT REPORT PROJECT BACKGROUND AND PREVIOUS ASSESSMENT The site is the former location of the University of the Pacific (UOP)Physical Plant on the north side of Mendocino Avenue within the UOP campus UOP moved its main campus to its present location in Stockton in approximately 1924 The former Physical Plant building, Central Receiving Building,and Electric Shop located south, southeast and southwest of the site have been remodeled for use as classroom buildings UOP recently removed a Custodial Warehouse and a shed formerly located to the east of the site UST REMOVAL, APRIL 7, 2000 As part of current renovations and construction of new facilities, UOP removed a 4,400 gallon unleaded gasoline UST on April 7, 2000, under pen-nits issued by SJCEHD (#022179) and the City of Stockton Fire Department(#00-91) Deltech Geotechnical Inc performed the UST removal and Ground Zero Analysts, Inc conducted the required soil sampling All removal and soil sampling activities were observed by and completed under direction of Michael Kift and Vidal Pedraza of SJCEHD Excavated soil from the tank pit (including pea gravel and soil) was used as backfill The former UST location is now beneath a newly paved staff and student parking lot (Figure 2) Documentation prepared during the UST removal is included with this report as Appendix A Soil samples were collected beneath the northern end of the tank at 13 feet below ground surface (bgs)and beneath the southern end of the tank at 13 feet bgs Additional soil samples were obtained from stockpiled soil No groundwater was encountered during tank removal activities The SJCEHD requested soil samples be analyzed for total purgeable petroleum hydrocarbons as gasoline (TPHG), benzene,toluene,ethylbenzene and xylene(BTEX),MTBE, di-isopropyl ether(DIPE) ethyl tertiary butyl ether(ETBE), tertiary amyl methyl ether(TAME), and tertiary butyl alcohol (TBA) Soil samples collected from the bottom of the UST tank cavity contained only detectable levels of MTBE,xylenes, and one detected concentration of TBA,as summarized below in Table I SOIL AND GROUNDWATER ASSESSMENT, JULY 2000 Upon review of soil sample results collected during the UST removal, SJCEHD requested that UOP conduct an investigation to determine the lateral and vertical extent of soil and groundwater potentially impacted by MTBE ESA submitted the Soil Investigation Workplan to complete this work to the SJCEHD on June S, 2000 for review, and UOP received workplan approval from Ms Carol Oz (SJCEHD)on June 19, 2000 The full report of this investigation was submitted to the SJCEHD and is titled Subsurface Sail and Groundwater Assessment Report, University of the Pacific, 1081 West Mendocino Avenue, dated August 25, 2000 ESA installed five soil borings on July 5, 2000 at the former UST location, as shown on Figure 3 Soil boring TP-i was placed in the center of the fomier excavation to assess soil and groundwater conditions beneath previously excavated areas ESA placed TP-2 through TP-5 approximately 15 feet from TP-1 along the previous excavation perimeter TP-4 and TP-5 were intended to assess soils and groundwater conditions at either ends of the former UST Reportedly, the former Addmonat Groundwater Assessment Report 3 ESA 120025 2 Marsh 26 2001