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ATC Associates Inc <br /> h 1117 Lone Palet Avenue, Suite B <br /> u Modesto, California 95351 <br /> ' 209-579-2221 <br /> A s s o c I A T E s I N C Fax 209-579-2225 <br /> ' None of the analytes of interest were detected in the groundwater samples collected from MWS, <br /> MW9 or the domestic well, DW <br /> ' Figures 7 through 20 graphically present the relationship between the groundwater elevation trend <br /> and hustoric dissolved petroleum hydrocarbons for monitoring wells MW1, MW2, MW3, MW4, <br /> MW5, MW6 and MW9 <br /> Historic groundwater monitoring and analytical data are summarized In Table 2 and laboratory <br /> data Is contained in Attachment 2 <br /> ' REMEDIATION SYSTEM ACTIVITIES <br /> ' Soil Vapor Extraction System Monitoring <br /> On September 6, 2005, ATC performed start up of the SVE system In the presence of a SJVAPCD <br /> ' regulator The system operated approximately 10 hours a day, however due to noise complaints by <br /> on-site residents of the temporary generator, the SVE system was started and turned off daily by field <br /> technicians On February 20, 2006, PG&E completed primary electrical service feed to the system and <br /> the portable generator was taken off-hne <br /> ' Monthly parameters monitored in the field Include soli vapor extraction flow rates, induced vacuum <br /> responses at on-site wells, hydrocarbon vapor concentrations as Treasured with a photoionlzation <br /> detector (PID), and total hours of system operation System monitoring data are contained in <br /> ' Attachment 3 Vapor samples are transported under chain-of-custody documentation to SunStar <br /> Laboratories, Inc (Environmental Laboratory Accreditation Program Certification No 2250) In <br /> Tustin, California, and analyzed for volatile organic compounds(VOCs)by EPA Method TO-14 <br /> ' At time of startup (September 6, 2005), analytical results for the influent sample detected <br /> vapors at a concentration of 21,000 parts per mllhon by volume (PPMv), representing 2 1% of <br /> ' free product TPHg results for the effluent were measured at 11 PPMv These values represent a <br /> 99 95% destruction efficiency for the SVE system at time of startup During each monthly <br /> sampling event since system startup, petroleum hydrocarbons have been detected In each vapor <br /> ' extraction well and Influent sample, although at reduced concentrations compared to the Initial <br /> startup event <br /> ' Vapor Sample Analytical Results <br /> TPHg and BTEX were detected In the vapor samples collected from the Influent sample during each <br /> system monitoring and sampling event TPHg and BTEX have been detected in the effluent sample <br /> during past sampling events, but are within the requirements of the San Joaqwn Valley Air Pollution <br /> 5154 2951000110&M11st-gtr-2006 doc <br />