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No VOCs were detected in the travel blank or laboratory method blank. To verify these finding, the County directed GLA to collect a second set of samples. Groundwater elevations were measured, and groundwater samples were collected from each of the three temporary wells on November 2, 2011. The results of the second tests were similar to the first, as follows: Table 4 Phase I Verification Sample Analytical Results VOC Concentrations from samples taken November 2,2011(µg/L) Groundwater Well ID Elevation.(ft) DCDFM PCE TCFM Total VOC MW-9 230.77 2.6 0.66 1.5 4.76 MW-10 1 220.06 1 0.52 0.88 0.40(trace) 1.8 MW-11 216.57 2.9 -71 1.3 0.15(trace) 4.35 No VOCs were detected in the travel blank or laboratory method blank. These results verify the preliminary sample results and suggest a northeasterly migration of VOCs from the CHSL. As shown above, the analytical results presented above indicate estimated trace to low, quantifiable levels of VOCs in samples from each of the Phase I temporary wells. The distribution of VOCs did not allow for determination of the extent of VOCs, and as a result, these wells were abandoned, and step-out wells were constructed. 4.3.4 Phase I Temporary Well Abandonment The Phase I temporary wells were abandoned on December 19 and 20, 2011, in accordance with California Well Standards (DWR Bulletin 94-70). The well casing was extracted, and the filter pack and bentonite chip seal were removed by overdrilling using an 8.5-inch outer diameter hollow-stem auger. After the well materials were removed, the annular space was backfilled using a cement slurry composed of eight to nine 47-pound bags of Type II-V Portland cement mixed with 55 gallons of water. The grout was pumped into the annular space using a tremie pipe to minimize potential bridging. The grouting volumes used to abandon the Phase I temporary wells are as follows: MW-9—260 gallons, MW-10—240 gallons, MW-11 — 240 gallons. Abandonment was conducted under the supervision of GLA's field geologist and an inspector from San Joaquin County Environmental Health Department. 4.4 PHASE II EMP FIELD WORK I The presence of trace and low, but measurable concentrations of VOCs in samples from the Phase I temporary wells required that "step-out" wells be constructed to better assess the extent of VOC impacts to the upper aquifer. These wells were constructed as part of the Phase II field work, which also included drilling and sampling of temporary EMP Report—Phase I1Geo-Logic Page ■ 9 ' Corral Hollow Sanitary Landfill ASSOCIATES August 21,2012