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23 February 1998 <br /> AGE-NC Project No 95-0130 <br /> Page 2 of 5 <br /> 22 GROUND WATER SAMPLING <br /> Theround water levels in monitoring wells MW-1 through MW-5. VW-1C, VW-2A and VW-3A <br /> g .. g <br /> were allowed to recover for a minimum of one hour prior to sample collection Ground water <br /> samples were collected utilizing disposable polyethylene bailers and new nvlon rope Sufficient <br /> ground water sample was collected from each well to fill three 40-m1 EPA-approved VOA vials <br /> I containing 0 5 ml I S% hydrochlor is acid as a preservative for the samples Care was taken to ensure <br /> that visible air bubbles were not present in the VOA vials after filling and capping Ground water <br /> sample containers were labeled x\ith the \N ell designation date, time, and sampler s initials <br /> 2 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br />' Each ground water sample was logged on a chain-of-custody form, placed ill a chilled container and <br /> transported to a California state-certified laboratory for analysis in accordance with EPA method <br />' 8015M for total petroleum hydrocarbons quantified as gasoline (TPH-g) and in accordance with <br /> EPA method 8020 for volatile aromatics (benzene toluene ethyl benzene and \ylene BTE&X) with <br /> meth}1-tertiary butyl ether (MTBE) and in accordance with EPA method 8260 for,,olatile organics <br /> (including oxygenates) The laboratory report (Castle Analytical Laboratory Ref erence No 1379 and <br /> McCampbell Analytical Inc Lab I D 84465 to 84472) and chain-of-custody forms are presented in <br /> Appendix B <br /> 3.0 FINDINGS <br /> 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> The depths to growid watei from v ells MV1-1 through MW-5, VW-1C, VW-2A and VW-3A were <br /> measured between 47 12 and 48 18 feet beloNx the top of well casings Bem een September 1997 and <br /> December 1997 dLpth to ground eater increased all average 0 01 feet at the site The ground water <br />' eleNation data for MW-1 though MW-5 during December s ground water monitoring event is <br /> depicted in Figure 3 4 <br /> During the December 1997 monitoring eNent ground eater Naas between 12 88 and 2 60 feet above <br /> the top of screened intervals from monitoring N\ells MW-1 through MW-5 As a result, the screened <br /> intervals from these wells are completely submerged and may not yield water samples fully <br /> representative of gi ound water conditions near the top of the saturated zone,where fuel h3 di ocai bons <br /> -,\ould be expected to have the greatest impact <br />' In December 1997, the gradient \gas calculated to be 0 006 ft/ft or approximately 31 feet per mile <br /> 4th ant tit GtoFnriru»mcn1a1 Inc <br /> 1 <br />