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Work Plan for Expedited Additional Site Assessment Tracy Corners Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Proposal Number P14-129814.4 May 5,2015 Page 13 Based on borings advanced during the January 13, 2015 investigation, the underlying subsurface consists predominantly of brown, dense, damp clay with some medium sand (CL) from the ground surface to approximately 10 feet below ground surface(bgs).At 10 feet bgs,the subsurface consists predominantly of brown and red, well- graded wet gravels (GW). Groundwater was encountered during this investigation at approximately 10 feet bgs. Based on review of the State Water Resources Control Board GeoTracker database,two leaking underground storage tank sites are located approximately 1,000 feet and 2,000 feet northeast of the subject property. Groundwater data from 2005 and 2010 associated with these sites, respectively, indicate groundwater has consistently flawed north-northeast at these locations. Objective Proposed soil boring locations are shown on Figure 1.The objective will be to collect groundwater samples at locations that will allow further understanding of the lateral extent of the PCE plume(and other related and potential volatile organic compounds[VOCs])to be able to anticipate the scope-of-work and costs that may be required to assess and/or remediate the cumulative VOCs in groundwater that are attributable to the former use of PCE at the Quality Cleaners. An additional objective is to assess the potential presence of TPH-cc and benzene, toluene, ethylbenzene, and total xylenes (BTEX) along the northeast subject property boundary contiguous with the historical address of 3301 North Tracy Boulevard. Proposed Approach The field work is anticipated to be performed over two days. The first day will be used to collect at least ten grab groundwater samples using a direct push Geoprobe and analyzing the samples with an onsite mobile laboratory. The assumption that ten groundwater samples could be collected will depend on drilling conditions. Ultimately, the actual locations and number of borings will be dependent on the data obtained from the mobile laboratory. Soil, groundwater, and soil gas samples associated with assessing potential impacts from historical impacts related to 3301 North Tracy Boulevard will collected during the second day of field work. Samples obtained during this portion of the assessment will be transported to a fixed laboratory and analyzed within five business days of the samples being logged at the laboratory. The concept as to how the work might be accomplished is as follows: • Use USA North and a private utility locator to clear boring locations and attempt to define the alignment of the sewer lateral associated with the dry cleaners suite; • Groundwater samples will be analyzed onsite by a mobile laboratory; • Collect two groundwater samples along the sewer lateral alignment depending on the length of the sewer lateral alignment. Review of the attached figure from the Phase I suggests it's possible