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Technical Memorandum April 7, 2017 Page 3 Alert was contacted. Following review of the utility locations on W Tokay Street, the area along the south side of W Tokay Street in the bike lane between the addresses of 116 and 120 W Tokay Street was selected for CPT-38 (Figure 1). This location was selected due to its proximity to the GWET system and its position along the projected centerline of the LCP. Additional internal data review by Langan identified a CPT from 2004 located on the corner of W Tokay Street and S School Street, thus rendering the proposed CPT on the corner of Spruce Street and S School Street to be redundant. Hence, only CPT-38 was advanced. Permits for the work (see Attachment A) were obtained from San Joaquin County Environmental Health Department (boring permit) and the City (encroachment permit). A description of the work and results are presented below. Advancement of CPT-38 and Grab Groundwater Sampling On February 8 and 9, 2017, CPT Inc. (C-57 license number 884827) advanced CPT-38 to a depth of 116.8 ft-bgs. Based on the subsurface stratigraphy, two adjacent CPT borings were advanced to depths of 85 and 114 ft-bgs for collection of discrete grab groundwater samples. Advancement of the CPTs was completed under supervision of a Langan licensed Professional Geologist. Prior to advancement, each location was hand augered to a depth of 5 ft-bgs. The results of the CPT investigation are discussed below: During advancement of the CPT, difficult conditions were encountered at several depth intervals, consistent with depth intervals previously characterized with stiff, fine-grained soils; Groundwater was first encountered at approximately 51 ft-bgs; The CPT log shows the greatest thickness of coarse-grained intervals above 40 ft bgs. Coarse-grained intervals below the water table were recorded from 52 to 56, 84 to 88, 98 to 99, and 113 to 114 ft-bgs; and Refusal was encountered at 116.8 ft-bgs, consistent with the presence of stiff, fine-grained soils. The CPT log (Attachment B) was examined and two groundwater sampling depths, 84 to 85 ft-bgs and 113 to 114 ft-bgs, were selected. The CPT rig was moved approximately three feet and a grab groundwater sample was collected from separate borings using a hydropunch-like sampler. Samples were decanted directly into HCL-preserved 40-milliliter vials. The sealed and labeled samples were placed in an ice cooler and submitted to McCampbell Analytical laboratory of Pittsburg, California under chain-of-custody protocol. The groundwater samples were analyzed for HVOCs using United States Environment Protection Agency Method 8260B. Results are presented below; laboratory analytical reports are provided in Attachment C: Sample CPT-38-1 (collected at 84 to 85 ft-bgs) had a reported concentration of PCE of 380 tg/L; and Sample CPT-38-2 (collected at 113 to 114 ft-bgs) had a reported concentration of PCE of 120 tig/L. WEST YOST ASSOCIATES o A213 \ 17-17-37 wp LPEDW-7RLocation \ 040517_2M