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i <br /> Quarterly Monitoring and Sampling Report(Q3 2002) 6 <br /> Ranch Market 2 569 Santa Fe Road RiverbankCalifornia November 15 2002 <br /> • Conclusion <br /> Ten groundwater monitoring wells, one air sparge well, and four domestic water wells were <br /> sampled this quarter Groundwater elevation decreased an average 133 feet since April 2002 <br /> Referring to Table 3, an increase in the concentration of benzene, TPHg, and MtBE was <br /> observed in wells MW-1 through MW-4 and MW-7 MW-6, located upgradient of the former <br /> USTs, and MW-8, located cross gradient of the former USTs, did not contain benzene, TPHg, or <br /> MtBE above laboratory reporting limits this quarter Due to the minor concentration of benzene <br /> reported AS-1 that is screen from 40 to 45 feet bgs, it appears the dissolved petroleum <br /> hydrocarbons in the source area are present within the upper 10 feet of the saturated zone <br /> Remediation System Installation and Start-up <br /> As part of the remediation system installation, 24 remediation wells, and a soil vapor extraction <br /> (SVE) and ozone sparging remediation system, were installed at the site On September 26, <br /> 2002, the SVE system was started to check all system parameters and tune the catalytic oxidizer <br /> Influent and effluent SVE air samples were collected in the presence of a SJVAPCD inspector to <br /> confirm the system was in compliance with the Authority to Construct Permit conditions The <br /> air samples were sent to a California state-certified laboratory for analysis of TPHg, BTEX, and <br /> MtBE using EPA method 8260 The laboratory results, summarized in the table below and <br /> provided in Attachment 4, document the system is in compliance The SJVAPCD provided <br /> verbal approval to begin continuous system operation of SVE system An evaluation of system <br /> . performance will be summarized in future quarterly groundwater monitoring reports Details of <br /> the remediation well installation and system construction will be included in a report scheduled <br /> for completion in the fourth quarter 2002 <br /> Sampling Constituent(ppinv) <br /> POS TPHg Benzene Toluene Ethyl-benzene Total Xylenes MtBE <br /> INFL 2,200 49 70 9 6 70 <0 40 <br /> EFFL <5 0 0 13 020 <0 050 022 <0 10 <br /> Explanations <br /> TPHg=Total petroleum hydrocarbons as gasoline <br /> MtBE=Methyl-tert-butyl ether <br /> TPHg,BTEX MtBE via EPA Method 8260E <br /> Ppmv=Parts-per-nulhon by volume <br /> Due to damage of the ozone sparge skid during shipping additional repairs are required prior to <br /> start-up of the ozone sparge system <br /> File Ranch Market\RcportlRiverbank-02-3Q <br />