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Q Limited Phase 11 Subsurface Investigation Report 902-908 East Scotts Avenue Stockton,California a ntea g ro u p Antea Group Project No. UPR82572A 3.1.1 Site Reconnaissance On March 23, 2012, Antea Group inspected the 906 East Scotts Avenue building, which had been inaccessible during the recent Phase I ESA reconnaissance. The 18,000-square-foot building is currently vacant, but reportedly was most recently used as an auto body repair shop. The majority of the interior was an open warehouse area with concrete floors. An oil/water separator was observed in the middle of the western half of the warehouse. Floor drains and de minimis staining was observed on the eastern side of the building. There is a small, vacant office area located in the northwestern corner of the warehouse consisting of three carpeted offices, two tiled bathrooms, and a costumer entrance area. Locations of the floor drains and oil/water separator are depicted on Figure 2,with photographs of the observations included in Appendix A. 3.1.2 GPR Survey Antea Group contracted an independent locating service utilizing ground-penetrating radar (GPR) to screen the subsurface for any potential subsurface features in the common courtyard area located on the central portion of the site. This was to verify that no undocumented subsurface features (e.g., underground storage tanks) were present beneath large asphalt patches noted during the initial site reconnaissance. The courtyard area covered during the survey is included on Figure 2. The GRP survey did not reveal any unusual features or disturbances within the area surveyed. 3.1.3 Utility Locate Prior to drilling, Antea Group marked all proposed soil test boring locations and contacted Underground Service Alert North (USA) to clear the boring locations of publicly-owned underground utilities. An independent locating service was contracted to clear the boring locations of private subsurface utilities or other obstructions. In addition to locating the private utilities,the locators also traced oil/water separators'discharge piping to ensure connection to the sanitary sewer system. The oil/water separators are located in the 906 and 908 East Scotts buildings and both discharge to the sanitary sewer(Figure 2). 3.2 Soil Boring Installation and Sampling 3.2.1 Soil Boring Installation On April 12-13, 2012, Cascade Drilling, L.P. (Cascade), supervised by an Antea Group geologist, advanced 20 soil borings using a hand auger and a truck-mounted, direct-push (Geoprobe°) rig. After coring the concrete or asphalt surface at each pre-marked location 131 through B20 (Figure 2), Cascade advanced each boring with a hand auger to five feet bgs, with the exception of 138, 1314, 1317, and 1320, which were advanced to two or three feet bgs. Cascade personnel used a hand auger to collect samples for soil screening and analysis and to ensure no subsurface obstructions were present in the upper five feet. Cascade advanced five borings (133, 66, 1313, 615, and 618) to 10 feet bgs utilizing the direct-push rig. To prevent cross-contamination during drilling and sampling activities, field personnel decontaminated any reusable components using an Alconox° scrub followed by double rinsing. 4 www.anteagroup.com