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USTs, subsurface hydraulic hoists and oil/water separators". Additionally,historical aerial photographs dated 1957 through 2002, depicted what appeared to be several small commercial structures located along the western and southern boundary of the subject site but the specific uses of these structures were not made apparent during the assessment. Krazan also reported that the Quick-N-Save facility at 2057 EI Dorado Street, located approximately 288 feet north-northwest of the subject site is listed on the LUST database as the location of a November 23, 1999 unauthorized release of gasoline that impacted soil and groundwater. The groundwater flow direction was assumed to be to the east. Krazan conducted a Geotechnical Investigation which included installing six (6) soil borings on the site. They described upper native soils and fill material as clayey gravel, sandy gravel, sandy silty clay, sandy clayey silt, and silty sand. The clayey soil has a high shrink-swell potential. Previous structures were located on the site and the site is surrounded by existing developments. Buried structures associated with these developments such as underground utilities extend onto the site. Groundwater was encountered at approximately 31 feet below surface grade (bsg). The groundwater flow direction was not determined. SCA Environmental Engineering(SCA)performed exploratory trenching and soil sampling at the site to investigate the suspected on-site USTs.? Nine (9) trenches were installed along the west side of the site and eight (8)trenches were installed in the east side of the site. SCA reported that four(4)USTs are present in the southwest portion of the site. Buried debris was also reported in the area. SCA reported there were two (2) 1000-gallon USTs on the south side and two (2) 5,000-gallon USTs on the north side. They noted liquid pooling on the west side of one UST. SCA collected soil samples near the USTs and other areas of the site and analyzed the samples for a variety of compounds. SCA reported total petroleum hydrocarbons (TPH) as gasoline and lead in soil near the USTs, and TPH as diesel and motor oil, low levels of DDT and DDE, and arsenic in fill on the east side of the site. SCA also identified large amounts of buried debris in the eastern portion of the site. In July 2008 ROKEN conducted a groundwater investigation which included a combination of direct-push and rotary drilling methods to collect groundwater samples from 10 temporary sample locations at the site. Groundwater was encountered at a depth of approximately 26 feet below ground surface, and temporary PVC casing was installed at each sample location to keep boreholes open and facilitate collection of groundwater samples. Water samples were analyzed for volatile organic compounds (VOCs), gasoline range organics (GRO), diesel range organics(DRO), motor oil range organics (MORO), LUFT 5 Metals(Cadmium, Chromium,Nickel,Lead,Zinc), and semi volatile organic compounds (SVOCs). The sample results confirmed that gasoline constituents are present in subsurface areas in the northwest and southern portions of the site. Documented releases at off-site sources (Quick-N-Save market)may have contributed to the gasoline compounds detected in s Geotechnical Engineering Investigation,Proposed Dorado Court,2154 South El Dorado Street,Stockton, California,Project No.032-06015,Krazan&Associates,Inc.,January 22,2007. 7 Exploratory Trenching and Soil Sampling,Dorado Court,Stockton,California,SCA Project No.F8311,SCA Environmental Inc.,April 19,2007. 8 Phase II Environmental Site Investigation,2154 S.El Dorado Street,Stockton,CA,ROKEN Engineering Services,July 14,2008. 4