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T Mr. Robert McClellon October 31, 2007 Page 2 In December 2005, a vapor extraction pilot test was conducted to evaluate the feasibility of installing a permanent landfill gas extraction system. During this test,vapor samples were collected from the two extraction wells and analyzed for volatile organic compounds(VOCs). Analytical results of these samples confirmed the presence of VOCs where the total VOC concentration in each of the vapor extraction wells was less than 5 ppmv.Based on these results,VOC constituents could be present in groundwater.To assess the presence or absence of VOC constituents in the groundwater,three ground- water monitoring wells were installed at the site on June 12,2006. Following the installation of the groundwater monitoring wells, groundwater samples have been collected quarterly and analyzed for VOCs. In a meeting on May 24, 2007,Mr. Ross Atkinson of the Regional Water Quality Control Board (RWQCB) Central Valley Region concurred with the recommendation in the Quarterly Monitoring Report dated April 30, 2007, to suspend the groundwater monitoring activities for VOCs.As per Mr. Atkinson's request, groundwater samples have been collected and analyzed for metals and general minerals(only total dissolved solids [TDS] after the first event)since the fourth quarter of 2006. FIELD ACTIVITIES The following two sections describe the monitoring activities completed during the third quarter of 2007 and the removal activities for the excess passive soil vapor extraction trench material completed during the week ending September 28,2007. Quarterly Monitoring Activities During the third quarter of 2007, landfill gas concentrations were measured within the gas-migration monitoring probes,extraction wells, and passive vents every month. The quarterly groundwater monitoring activities were completed on September 20,2007. Using a handheld portable landfill gas monitor,each gas-migration monitoring probe, each extraction well,and each passive vent was measured for methane,oxygen,and carbon dioxide. These measure- ments were recorded in a field log book. Groundwater samples were collected from the three monitoring wells using the following procedures: • The water level from each monitoring well was measured using an electronic water level sounder. • Prior to groundwater sample collection, each well was purged using a bailer.During purging, groundwater parameters(pH,temperature,and conductivity)were recorded on the Monitoring Well Sampling Data form(Attachment 1)at least once per well casing volume. Purging was completed when the groundwater parameters had stabilized to within 10 percent. The purged water was placed in 55-gallon drums. • A groundwater sample, collected from each well using a bailer was placed into the analytical laboratory-prepared sample containers. K:\Wprocess\25532\WorldEnterprise\Quarterly Rpt\2007\3Q07\103107.doc