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t <br /> ATC Associates Inc <br /> v 1117 Lone Palm Avenue, Scute B <br /> Modesto, California 95351 <br /> 209-579-2221 <br /> Fax 209-579-2225 <br /> ASSOCIATES I NC <br /> None of the analytes of interest were detected in the groundwater samples collected from MW8, <br /> MW9, or the on-site domestic well <br /> Figures I through 20 graphically present the historic relationship between the groundwater <br /> elevation trends and selected dissolved chemicals of concern for MW1, MW2, MM3, MW4, <br /> MW5, MW6 and MW9 <br /> iHistonc groundwater monitoring and analytical data are summarized in Table 2 and laboratory <br /> data are contained to Attachment 2 <br />' REMEDIATION SYSTEM ACTIVITIES <br />' Soil Vapor Extraction System Monitoring <br /> On September 6, 2005, ATC performed start up of the SVE in the presence of a SJVAPCD regulator <br />' The system operated approximately 10 hours a day, however due to noise complaints by on-site <br /> residents of the temporary generator, the SVE was started and turned off daily by field technicians On <br /> Febzuary 20, 2006, PG&E completed primary electrical service feed to the system and the portable <br /> generator was taken off-line <br /> Monthly parameters monitored in the field include soil vapor extraction flow rates, induced vacuum <br />' responses at on-site wells, hydrocarbon vapor concentrations as measured with a phototoiuzation <br /> detector (PID), and total hours of system operation System monitoring data are contained in <br /> Attachment 3 Vapor samples for laboratory analysis are transported under chain-of-custody <br />' documentation to SunStar Laboratories, Inc (Environmental Laboratory Accreditation Program <br /> Certification No 2250)in Tustin, California, and analyzed for volatile organic compounds (VOCs)by <br />' EPA Method TO-14 <br /> At time of startup (September 2005), analytical results for the influent sample detected TPHg <br />' vapors at a concentration of 21,000 parts per million by volume (ppmv) TPH9 results for the <br /> effluent were measured at 11 ppmv These values represent a 99 95 percent destruction efficiency <br /> for the SVE at time of startup During each monthly sampling event since system startup, <br />' petroleum hydrocarbons have been detected in each vapor extraction well and influent sample, <br /> although at reduced concentrations compared to the initial startup event <br /> Quarterly Vapor Sample Analytical Results <br /> TPHg and BTEX were detected in the vapor samples collected from vapor extraction wells VW1 <br /> through VW4 and the influent sample dunng each system monitonng and samplwg event TPHg and <br /> BTEX have been detected in the effluent sample during past sampling events, but are within the <br /> requirements of the San Joaquin Valley Air Pollution Control Ihstnct permit to operate Vapor sample <br /> S 1625881031quarterlyl2-nd qtr-2006 doc 5 <br />