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DATA GAP ASSESSMENT WORK PLAN AND PATH TO CLOSURE REVIEW Chase Chevrolet, 424 N. Van Buren Street Proposed Scope of Work January 2, 2018 advanced and soil is collected in the auger bucket thereby filling the soil sample sleeve with minimal disturbance and little to no volatilization of petroleum hydrocarbons. Soil samples from soil borings SB-1 and SB-2 will also be collected at depths of 10, 15, 20, and 25 feet bgs and retained for analyses using acetate sleeves inserted into the direct-push rods. Additional samples with elevated PID readings may be retained for analyses. The soil samples selected for laboratory analysis will be retained in 2-inch diameter by 6-inch long stainless-steel sample sleeves or acetate sleeves, sealed with Teflon® sheets and plastic caps, then labeled and placed on ice in an insulated container for delivery under proper chain- of-custody (COC) protocol to a California Department of Health Services (DHS)-certified lab. Soil samples will be analyzed for the presence of GRO by Environmental Protection Agency (EPA) Method 8015M; and benzene, toluene, ethylbenzene, and total xylenes (collectively, BTEX), MTBE, and naphthalene by United States Environmental Protection Agency (US-EPA) Method 8260B. 4.7 GRAB GROUNDWATER SAMPLE COLLECTION AND ANALYSIS To avoid cross contamination and minimize sediment in accumulating in the grab groundwater sample, a second boring will be advanced adjacent to soil borings SB-1 and SB-2. Since the water samples will be collected within 2 to 3 feet of previous boring, they will also be labeled as SB-1 and SB-2. The drive rods will be advanced at least 5 feet into groundwater at depth of 20 to 25 feet bgs and a water level meter will be used to monitor for the presence of water in the outer drive rods prior to retracting the rods from approximately 25 to 15 feet bgs, just above groundwater. The boring will remain open for approximately 1 hour and the depth to water will be monitored and recorded on the field data sheet. If sufficient water is present in the boring, a grab groundwater sample will be collected from the borehole using a small diameter disposable Teflon ® Bailer, if possible. If no appreciable groundwater is accumulated within the first hour, the boring will remain open and will be secured temporarily from surface traffic overnight. The following day the groundwater level will be measured in the boring and a grab groundwater sample will be collected, if possible. Grab groundwater will be bailed from the temporary well, decanted from the bailer into 40-milliliter (mL) VOA vials preserved with hydrochloric acid (HCI), and capped. Each VOA vial will be checked to ensure no bubbles are present, labeled, placed on ice in an insulated container, and transported under proper COC documentation to a California State-certified laboratory. Following collection of the grab groundwater sample, the borehole will be tremie grouted from total depth to grade with neat cement grout. The boring will be completed at the surface with concrete to match existing grade. The grab groundwater sample will be analyzed for the presence of GRO by EPA Method 8015M, and BTEX, MTBE, and naphthalene by US-EPA Method 8260B. A quality control trip blank (QCTB) VOA will provided by the laboratory to accompany the samples. Stantec arn \\us1312- f02\workaroup\ 1857 \ active \ 185703766 \ 05 Jeport_deliv \ deliverable \ work_plan \ 185703766_20180102_424_van_buren_work_plan_final.docx 4.3