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I <br /> Mr Ron Rowe <br /> Page 3 <br /> r <br /> MTBE concentration of 14,000 ppb DIPE and TBA were detected in several wells at maximum <br /> concentrations of 41 parts per billion (ppb) (MW5) and 150 ppb (MW2), respectively. <br /> Groundwater Sampling Summary <br /> MTBE was not detected in any monitoring wells during the previous quarter. During this <br /> quarter, MTBE was detected in wells MW4 and MW9 In addition to the high MTBE levels <br /> in MW4, the hydrocarbon concentrations detected;n well MW4 have drastically increased since <br /> the previous quarter Since the groundwater flow direction has been consistently toward the <br /> east-southeast, these concentrations present in well MW4 do not appear to be related to onsite <br /> contamination <br /> Since this is the first quarter that oxygenates have been analyzed, it isn't possible to make <br /> conclusions regarding concentration trends However, the presence of DIPE and TBA in <br /> groundwater at this site seems unusual based on the letter from the Regional Water Quality <br /> Control Board, Central Valley Region dated August 1997 The letter suggests that in San <br /> Joaquin County DIPE has only recently been detected in groundwater and that TBA has only <br /> been detected at one location <br /> I <br /> VAM EXTRACTION SYSTEM ACTIVITIES j <br /> VES Startup 1 <br /> On November 4, 1997, Ground Zero performed the startup testing as required by the APCD <br /> Mr. Bruce Tuter of APCD was onsite to confirm the startup and testing Startup documentation <br /> was submitted to APCD under separate cover (January 7, 1998). <br /> Vapor wells VW2, VW5, and VW6 were online for the startup test Vapor wells VW 1 and <br /> VW4 did not have exposed screen interval Vapor well VW3 had only 9 feet of screen exposed <br /> above groundwater. Influent and effluent streams were monitored with a rented photoionization <br /> detector (PID) and recorded on the systems monitoring data sheet, included in Attachment C <br /> The influent and effluent PID readings were 500 parts per million (ppm) and 180 ppm, <br /> respectively Additionally, influent (Influ) and effluent (Eff) vapor samples were collected for <br /> Laboratory analysis <br /> i <br /> The vapor samples were submitted via courser under chain of custody protocol to Sequoia <br /> Analytical in Redwood City, California (FLAP #1210) The samples were analyzed for total <br /> purgeable petroleum hydrocarbons (TPPH) using modified EPA method 8015, and for benzene, <br /> toluene, ethylbenzene, and total xylenes (BTEX) using EPA method 8020 <br /> ro&, l"7 <br />