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GEOMATRIX After sampling, the boreholes were filled from the bottom with a neat cement-bentonite grout using a polyvinyl chloride (PVC) pipe The grab groundwater sample was labeled, placed in a chilled-ice chest, and delivered under chain-of-custody procedures to Agriculture and Priority Pollutant Laboratories (APPL), Inc , of Fresno, California, for laboratory analyses of BTEX, 1,2-dichloroethane (12DCA), and oxygenates using U S Environmental Protection Agency ' (EPA) Method 8260B, for TPHg using U S EPA Method 8015, and dissolved lead using U S EPA Method 6010B, as requested by the PHS/EHD Oxygenates included MtBE, diisopropyl ether(DIPS), ethyl tert butyl ether(ETBE), and tert amyl methyl ether(TAME) 3.2 INSTALLATION OF MONITORING WELLS ' Analytical results indicate that BTEX, 12DCA, TPHg, and oxygenates were not detected in the grab groundwater sample collected from B3-14, except for DIPE, which was reported at 0 88 micrograms per liter (gg/L), a concentration near the laboratory's practical quantitation limit of 0 5 gg/L (described in further details in Section 4 4) Since DIPE has not previously ' been detected in any of the site samples and no TPHg was detected in this sample, it is thought the detection may be a false positive Based on these results, a monitoring well deeper than 40 feet bgs is not warranted at this site, and as such, was not installed during this assessment On February 11 and 12, 2003, three shallow monitoring wells were installed outside of the ' estimated limit of affected groundwater (Figure 2) in accordance with the PHS/EHD-approved work plan (Geomatrix, 2002c) The purpose of these wells is to monitor the lateral extent of ' affected groundwater at the site Spectrum Exploration, Inc , of Stockton, California, provided the monitoring well installation services The borings for the three wells were advanced to a ' depth of about 24 5 feet bgs using a CME-85 drill rig equipped with 8-inch diameter hollow- stem augers Soil samples were collected at 5-foot depth intervals from the ground surface to about 20 feet bgs and continuously from 20 to 24 5 feet bgs for field screening and lithologic ' logging Field screening and lithologic logging were conducted as described in Section 3 1. ' First groundwater was encountered at about 20 5 to 22 feet bgs in a sandy layer found in all three bonngs (discussed in Section 4 2) Based on this information and the data from previous ' site investigations, the monitoring wells are constructed of about 9 feet of 2-inch diameter PVC blank casing with about 15 feet (from about 9 to 24 feet bgs) of 0 02-inch machine- slotted PVC well screen Filter pack, comprising No 3 Lonestar sand, was installed through the augers from the bottom of the boring to about 7 feet bgs (2 feet above the screen) After filter pack installation, the wells were developed by surging and bailing for at least one hour 1 11?R07ECrMWs16437 000/6437 08 doe 7 1