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+a1s Page 5 San Joaquin County November 6, 2008 Project Number 99008-008321.03 soil samples are collected. Soil cores will be field screened for volatile organic compounds (VOCs)with a photoionization detector(PID). The soil cores will also be examined for soil classification and described on detailed boring logs in general conformance with the Unified Soil Classification System (USCS). Bureau Veritas proposes to collect soil samples for possible chemical analysis from Borings BV-1 and BV-2 at approximate four-foot intervals during drilling (i.e. 4, 8, 12, 16, and 20 feet bgs). Exact soil sampling depths will be determined based on field observations, drilling conditions, soil core recovery, and the particular soil analytical laboratory method that will be performed. Retrieved sample sleeves will be cut from plastic liners, sealed with Teflon tape and plastic end caps, labeled with identifying information, and stored in a pre-chilled ice-chest awaiting transportation to the laboratory. Selected soil samples for chemical analysis (discussed in Task 3)will be recorded onto a chain-of-custody (COC) document; remaining soil samples will be placed on hold by the laboratory pending additional analysis (if necessary). Grab-Groundwater Sampling According to information in the Phase I ESA, groundwater is anticipated to be encountered at approximately between 25 and 30 feet bgs. Bureau Veritas will attempt to collect four grab-groundwater samples (BV-3 through BV-6) using one of the following methods: • Bureau Veritas will attempt to collect grab-groundwater samples from the borings using a closed- system Hydropunch@ sampler. The Hydropunch®sampling tool will be advanced beyond the drill bit into undisturbed soil, and the sampling tool will be retracted thereby exposing the screen and allowing water to flow into the sampling chamber. • If groundwater is slow to enter the borehole, Bureau Veritas will install a temporary, one-inch- diameter, slotted-screen, schedule 40 PVC casing into the open borehole approximately 2 to 4 feet below first encountered groundwater. A peristaltic pump with new polyethylene tubing or a single-use disposable bailer will be used to obtain the grab-groundwater sample (if encountered). Upon retrieval, the grab-groundwater sample will be transferred directly into appropriate sample containers provided by the analytical laboratory. The grab- groundwater samples will be sealed, labeled and placed in a pre-chilled ice chest for delivery to the laboratory. Chain-of-custody records will be completed and accompany the grab-groundwater sample shipments to the laboratory. Soil Vapor Sampling Bureau Veritas proposes to collect soil vapor samples along the southern property boundary (Borings BV- 4 through BV-6). Upon completion of the borings to the desired depth, active soil vapor samples are proposed to be collected at approximate depths of 5 and 15 feet bgs. The soil vapor sampling will be conducted in accordance with the guidance provided in the Regional Water Quality Control Board (RWQCB) Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater (RWQCB, 2005), California Department of Toxic Substances Control/Los Angeles RWQCB Advisory— Active Soil Gas Investigations(DTSC/LARWQCB, 2003), and DTSC's Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air(DTSC, 2005). SAES\PROJECTS\3-Chicago[99](15-16)\Walgreen Repo rts\99008-008321.01 Stockton\P2\Workplan.doc