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Phase H Additional Subsurface Investigation Tracy Comers Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Project Number 14-129814.3 January 27,2015 Page 14 access Geoprobe Model 4020M drill rig and advanced borings B3 and B4 with a direct-push, truck- mounted Geoprobe Model 5410 drill rig. Drilling rods and sampling equipment were decontaminated between samples and borings to prevent cross-contamination. Boring Locations Borings Bl and B2 were advanced in the interior of the dry cleaning facility. Borings B3 and B4 were advanced in the exterior of the dry cleaning facility. Boring Bl was to the southwest of the dry cleaning machine. Boring B2 was advanced adjacent to the west of the boiler room. Boring B3 was advanced approximately 20 feet southwest of the rear door of the property. Boring B4 was advanced approximately 15 feet southeast of the rear door of the property. Boring placement was limited due to presence of machinery in the interior of the property as well as a sewer line in the exterior portion of the property. Refer to Figure 3 for a map indicating boring locations. Sampling Depths Borings Bl, B2, and B4 were advanced to a terminal depth of 12 feet bgs. Boring 'B3 was advanced to a terminal depth of 16 feet bgs. Soil samples were collected from borings Bl, B2, and B4 at 5 and 10 feet bgs. Soil samples were collected from boring B3 at 5, 10, and 15 feet bgs. Groundwater samples were collected from temporary well points screened from 9—12 feet bgs in boring B2 and from 8— 12 feet bgs in borings B3 and B4. A groundwater sample was not collected from boring Bl as it was not a part of the proposed scope of work. Soil Sampling Methodology Borings Bl and B2 were overlain by concrete, which was penetrated using a concrete coring attachment advanced by a hand-held power drill. Borings B3 and B4 were overlain by concrete,which was penetrated using a concrete coring attachment advanced by the direct-push drill rig. Soil samples from borings Bl and 62 were collected using a 3-foot long by 2-inch diameter MacroCore sampler with a 3-foot long acetate liner,which was advanced by the direct-push drill rig using 3-foot long by 1.5-inch diameter drill rods. The sampler was driven into the subsurface to allow undisturbed soil to enter the open MacroCore barrel and retrieved in 3-foot intervals to recover the soil-filled liners. Soil samples from borings B3 and B4 were collected using a 4-foot long by 2-inch diameter MacroCore sampler with a 4-foot long acetate liner,which was advanced by the direct-push drill rig using 4-foot long by 1.5-inch diameter drill rods. The sampler was driven into the subsurface to allow undisturbed soil to enter the open MacroCore barrel and retrieved in 4-foot intervals to recover the soil-filled liners. Soil samples were prepared for laboratory analysis by cutting an approximately 6-inch long section of the liner using a hacksaw. Samples from the lower half of the liner were capped on either end with Teflon tape and plastic caps. The capped liners were labeled for identification and stored in an iced-cooler. The soil in the upper half of the liner was visually inspected for discoloration, monitored for odors, classified in accordance with the Unified Soil Classification System (USCS), placed in a sealable plastic bag, and field- screened with a photoionization detector (PID) calibrated to isobutylene. None of the collected soil PARTNER