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Monrtonng Well Installation and VET Report—Former Unocal Station#2859,Stockton,CA July 30,2001 vacuum Each day the speed setting was vaned between 1,800 and 2,600 RPM Propane was used as a secondary fuel source for the engine when extracted petroleum concentrations were not high enough to act as the sole fuel source Well casing, screen interval, and distance from the vacuum source are shown on Table 3 Laboratory influent air samples were collected near the beginning, middle, and end of the test each day,except on,tune 20, 2001, where only two samples were collected due to the engine overheating and shutting down Analytical data are summarized in Table 4 The VE test monitoring data are summarized in Table 5 On June 18, and 21 and soil vapors were extracted from well VW-1 This well is slotted from 18 to 43 feet bgs On June 19 soil vapors were extracted from well VW-2 This well is slotted from 24 to 53 feet bgs On June 20, and 22 soil vapors were extracted from well VW-3 This well is slotted from 10 to 26 feet bgs Observation wells MW-1, MW-2,and MW-3 are slotted from 20 to 50 feet bgs Observation well MW-6 is slotted from 20 to 60 feet bgs The test ran for approximately 8 hours each day The groundwater level at the time of the test was approximately 24 feet bgs Pilot Test Results On June 18 and 21,2001, system flow rates from well VW-I ranged from 8 7 to 14 9 standard cubic feet per . minute (scfm) The applied vacuum ranged between 2 and 8 inches of water column (inches) The highest vacuum level recorded in any of the observation wells during the test of well VW-1 was 0 09 inches in well MW-2 The measurable vacuum in the observation wells was between 0 00 and 0 08 inches Test results were fairly consistent over the two days of the test on this well On June 19, 2001, system flow rates from well VW-2 ranged from 8 to 14 scfm The applied vacuum ranged between 2 and 5 inches The highest vacuum level recorded in any of the observation wells during the test of well VW-2 was 0 20 inches in well MW-3 The measurable vacuum in the observation wells was between 0 00 and 0 08 inches On June 20 and 22,2001,system flow rates from well VW-3 ranged from 8 to 14 scfin The applied vacuum ranged between 1 and 6 inches The highest vacuum level recorded in any of the observation wells during the test of well VW-3 was 0 20 inches in well MW-3 The measurable vacuum in the observation wells was between 0 00 and 0 08 inches This data suggests a very limited lateral radius of influence No significant level of vacuum (greater than 0 20 inch)was recorded in any of the observation wells during the test The shortest distance between a test well and an observation well was 10 feet between wells VW-2 and VW-3 The greatest vacuum recorded on an observation well was 0 20 inches in well MW-3 during the test of wells VW-2 and VW-3 During the pilot test,the influent to the IC engine was sampled The highest influent petroleum hydrocarbon concentrations were from well VW-3 Concentrations as high as 311 parts per million by volume(ppmv)of TPHg and 2 2 ppmv of benzene were reported Lower influent concentrations were reported from wells VW-1 and VW-2 No detectable concentrations of MtBE were reported in any influent samples Extraction rates for VW-3 were between 0 01 and 0 8 pounds of TPHg per day at varying test conditions The extraction rates for VW-1 and VW-2 were between 0 01 and 0 7 pounds of TPHg per day Complete sample and extraction rate data are provided in Table 6 24007204-1 6