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Future monitoring events will consist of the collection of groundwater samples and the measurement of water levels. Sample analytical data and maps depicting groundwater gradients and flow directions will be submitted to the DTSC within four weeks of the groundwater monitoring event (see Appendix D for the proposed project schedule). The reports will include the status of the groundwater characterization and be prepared in accordance with DTSC guidelines. 6.8 Proposed Petroleum Hydrocarbon Release Assessment Six proposed soil borings will be advanced by a Geoprobe direct push rig to assess soil and groundwater at the inferred locations of the 1991 petroleum hydrocarbon release as shown on Figure 9. Due to the narrative and map in the 1991 EDH Emergency Response Report and the resulting uncertainty of the location of the hydrocarbon release, the six borings will target pertinent Site features from the historic aerial photographs. Using the former features visible in the 1975 photograph in the Phase I report,two borings will be located near the white building near the center of the Site (referred to herein as the barn), two borings located north of the white building in the area with equipment, one boring near the possible residence with a septic tank along the eastern boundary, and one boring near the possible residence with a septic tank in the southeast corner of the Site. The soil borings will be continuously cored in order to review soil cores within acetate sleeves for petroleum hydrocarbon odor and/or discoloration and for the presence of imported or disturbed excavation backfill material. Boring logs will be generated to record lithology, presence of odors, indications of disturbed or excavation backfill material, field PID readings, driller observations, and sample collection information. Two soil samples from each location will be collected for VOC analysis within 5-gram plastic cartridges (25 grams of soil total)using EnCore sample T-handles in accordance with EPA Method 5035. Following collection of the Encore samples, a six-inch long portion of the acetate sleeve will be cut with the handsaw, capped, labeled, and stored for analysis of TPH, PCBs,PAHs, and LUFT metals. Grab groundwater samples will be collected within first encountered groundwater anticipated to be at 10 to 12 feet bgs. The collection of the two soil gas samples associated with the petroleum hydrocarbon assessment is described in Section 6.4.1. Soil borings and grab ground water boring locations will be backfilled with granular bentonite and capped with concrete or asphalt patch. Sampling and Analysis Workplan Tracy Corners Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Project Number SM14-129814 Docket Number HAS-VCA 14/15-108 August 15,2016 Page 28