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Mr. Robert McClellon July 29, 2010 Page 2 extraction wells was below 5 ppmv. Based on these results, VOC constituents could be present in groundwater. To assess the presence or absence of VOC constituents in groundwater, three groundwater monitoring wells were installed at the site on June 12, 2006. Following the installation of the groundwater monitoring wells, groundwater samples were collected quarterly and analyzed for VOCs. Mr. Ross Atkinson of the Regional Water Quality Control Board (RWQCB) Central Valley Region requested that groundwater samples be collected and analyzed for metals and general minerals (only total dissolved solids [TDS] after the first event) starting in the fourth quarter of 2006. In a meeting on May 24, 2007, Mr. Atkinson concurred with the recommendation in the Quarterly Monitoring Report dated April 30, 2007, to suspend the groundwater monitoring activities for VOCs. FIELD ACTIVITIES Landfill gas concentrations were measured within the gas -migration monitoring probes, extraction wells, and passive vents, and the quarterly groundwater monitoring activities were completed on June 8, 2010. Using a handheld portable landfill gas monitor, a GEM 2000, each gas -migration monitoring probe, each extraction well, and each passive vent was measured for methane, oxygen, and carbon dioxide. These measurements were recorded in a field logbook. Groundwater samples were collected from the three monitoring wells using the following procedures: • The water level within 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 or the monitoring well was bailed dry. The purged water was placed in a 55 -gallon drum, pending disposal. • A groundwater sample, collected from each well using a bailer, was placed into the analytical laboratory -prepared sample containers. • Groundwater samples were labeled and placed in an ice chest with ice. The ice chest was shipped to EMAX Laboratories, Inc. in Torrance, California, under proper chain -of -custody procedures for selected dissolved metals analyses by United States Environmental Protection Agency (EPA) Method 6010/6020/7470 and TDS analysis by EPA Method 160.1. RESULTS Soil Vapor. The methane concentrations measured during the quarter in the gas -migration monitoring probes were zero percent (%) in all probes and both vapor extraction wells. Methane concentrations measured in the vapor extraction wells were 2.3% in EW -1 and 3.2% in EW -2. Methane concentrations measured in the passive vents were 3.6% in VP -1, 4.9% in VP -2, 5.9% in VP -3, and 5.1% in VP -4. Oxygen concentrations measured at all sample locations during the quarter ranged from 0% to 17.3%. H:\Wprocess\25532\WorldEnterprise\Quarterly Rpt\20102Q 10\2Q 10_0729 I O.cbc