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preserved VOAs supplied by the analytical laboratory. The sample containers will be sealed, labeled, stored on ice in a thermally-insulated cooler, and then transported under chain-of- custody protocol to a state-certified analytical laboratory. All reusable groundwater sampling equipment will be thoroughly washed with a Liqui-Nox solution, rinsed with tap water, and then rinsed with distilled water prior to each use. The completed borings will be filled and sealed with a grout mixture consisting of neat cement, in accordance with SJCEHD and California Department of Water Resources (DWR) requirements. The soil and groundwater samples will be analyzed for TPH-g, BTEX, MTBE, and TBA by EPA Method 8260B. 4.3 WELL INSTALLATION Based on the results of the direct-push investigation, ETIC proposes to install two 2-inch diameter groundwater monitoring (MW-2A and MW-5) at the Site. The proposed locations of well MW-2A is shown on Figure 12. ETIC proposes to install the two wells west of the sidewalk. The City of Stockton Public Works Department has indicated that the area west of the sidewalk is considered to be private property. During the November 2006 investigation,groundwater was first encountered in soil borings Cl and C3 between 47.5 and 48 feet BGS. The grab groundwater samples collected from boring C1 (located within the boundaries of the former UST excavation) and C3 (located north of the excavation) contained elevated concentrations of TPH-g and BTEX. Well MW-2A will be installed near well MW-2 and former soil boring Cl. The well is not expected to exceed 60 feet in total depth and will be screened appropriately to intersect the flowing sand encountered below approximately 47 feet BGS. The well will be used to monitor groundwater quality within the flowing sand. The well will be constructed with 4-inch diameter casing to accommodate a submersible pump for aquifer testing or potential groundwater extraction should that be necessary. Groundwater monitoring data indicate that the majority of the residual contamination is limited to the vicinity of the former UST excavation. TPH-g has been detected only in groundwater samples collected from well MW-2 since 2003. However, the highest concentration of TPH-g in grab groundwater samples collected during the November 2006 investigation was detected in the sample from former boring C3, generally north and cross-gradient of the former UST excavation. The installation of a monitoring well generally north of boring C3 is necessary to assess the lateral extent of contamination north-northwest of the former UST excavation. The proposed location of the well will be dependent upon the results of the direct-push SI.-Cmur-SCM and Rev.R1 WP 2007.09 15