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1 <br /> TECHIAnrreport: 2123190 to Pfaff Consu8ing Company page 7 <br /> Report Of Analyses Of Samples From A Site Investigation At 5.31 South MacArthur Drive In Tracy,CA <br /> Performed For The Pratt Consulting Company On February 17-18th, 1990 <br /> Mr.John Pratt,owner of the Pratt Consulting Company,contracted wlih TECH/ART In February,19M to analyze <br /> additional samples collected by Mr. Pratt at a site In Tracy, California which was suspected of having received <br /> contamination from both gasoline and diesel fuel. <br /> Arrangements were made by TECH/ART for: analyses of the samples using a Photovac j0S50 with an Isothermal <br /> oven and a high performance capillary column,and field analysis quality assurance and control activitles. The <br /> site investigation was performed on 2/17-19/90. Samples were courlered from the site to the location of the <br /> Pnotovac,which was*set-up"in a hotel room within 0.5 mile of the site on 2/17/90,or which was at the TECH/ERT <br /> offices on 2/18-19/90. <br /> ACTIVITIES <br /> - Activities performed at the instrument set-up room near the site Included: <br /> Instrument checks(blanks), ■Sample analyses, <br /> ■Calibration rune, •Syringe checks(Injections of clean ale, <br /> ■Duplicate analyses, ■Sample container check runs. <br /> i <br /> OUALIT1f ASSURANCE ACTIVITIES <br /> QualW assurance activities Included the use of pure benzene,toluene, ethyl benzene and m-xyl ane and a cart[- <br /> fled gas mixture prepared by Scott Laboratories as callbranta. In addition,the Hampton gas-tight syringes were <br /> cleaned and checked for cleanliness prior to use,and 40 ml Teflon/slllcon rubber top-septa sample bottles were <br /> fused at all times. The carrier gas used was 'Ultra-Zero" grade compressed air which Es certified for low <br /> hydrocarbon and Ioe3r moisture content by Linde-Union Carbide. <br /> QUALITY CONTROL ACTIVITIES <br /> Instrument blanks were run at the beginning of each set of analyses. <br /> Callbratiors were performed using the Scott calibration gas,which contaim A methane,ethane, propane,butane, <br /> pentane,h:ixane,and heptane at concentrations of approximately 15 ppm each In dry nitrogen. Ps Scott gas Is <br /> furnished with an exact analysis certified to t 2%.) Calibration runs wero performed at Irregular intervals four <br /> times during the day. Checks of the pre-cleaned and other sampla bottles were performed by heating randomly- <br /> chosen empty bottles In o water bath to more than 50 Celsius and analyzing a sample of ga.. e.ftrawn from the <br /> bottle. <br /> Occasional check runs were performed with samples c4 diesel, leaded gasoline and urdeaded gasoline <br /> headspace vapor to ensure that Instrumental response was adegtuste and appropriate. Addltlona: check runs <br /> --- ---— --—-- -were rnada With samples of benzene;tdv®n®,snot"m=xylsria headspaca vapor to cWrm that retention,time drift -- - - --- -- —-- - <br /> had not exceeded narrowly-def[ned allowed limits. A factory-calibrated flowmetar was used to ensure consis- <br /> tency of carrier gas rate-of-flow. Duplicate analyses wee perfermad on 10%of the samples to provide another <br /> .. quality control check. <br /> f <br /> All quallt r control check results were satisfactory. <br /> FM <br />