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<br /> !_ y May 1997 � 7;
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<br /> AGE-NC ProJect N6.95-0 128 r3r `
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<br /> 23OROUND WATER,SAMPLE COLLECTION
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<br /> Upon`stabilization, awater sample was. collected from each purged well using a new; clean, _
<br /> T .. .,. - •.; 3 ., ,y_;:'. _ - i•• moi_.- f '3R"
<br /> 4 'disposable plastic bailer Immediately upon retrieval;`samples weire transferred into,clulled 40 m1 Lam'
<br /> IEPAapproved�VOA, ials containing O S rnl 1'8%hydrochloric acid'and into a 1-lv er amber bottle- ,-
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<br /> Satriples were`placed in a chilled container and transported under chain of=custody to!1vlc Campbell,
<br /> i Analytical Inc.:(MAI)4n Pacheco -California .All samples were analyzed in accordance wrth EPA -
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<br /> methods.503018015m for TP-H rg,TPH d and iri-accordance with EPA methods 602 for1BTE&X and
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<br /> MTBE _ 47 . Or14t
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<br /> 3.-1 `GROUND WATER-ELEVATION AND GIiADIENTrs
<br /> The casing elevation_of'each �Svell'was surveyed relative to a City,of Stockton benchmark, The r
<br /> _ elevation of.ground.water'in:eachwell' vas calculated by subtract�rig the ground.v+�ater depth from
<br /> the surveyed casing;elevationpThe deptliof ground water, casing elevations andground elevations
<br /> are:depictedon.Table,,2 - Ground Water Elevations `The.hydrau-ic gradient__was deterinrned by�s
<br /> fie, contouririg the;ground water}e�levation in each well
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<br /> Ground water.gradient was'calculate'cl'to b6--approximately . 0034'5 ft/ft.directed 22 Eon11i" y a
<br /> northern.end of,the-sife and calculated to be approxirinately 0 00246 ftfft directed N i6° E�ori the
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<br /> �x ;central and eastern,portions.of the'site The ground water elevation contours on clic site areillustrated
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<br /> in Figure,3 w Ground Water Elevation �: t 3 5 4 _ z{
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<br /> 3 3'-2t -ANALYTICAL RESULTS OF .GROUND NATER!SAMPLES �. r SAL � � ']
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<br /> TPH-g and TPH d_were defectei in the:water;sample'collected from well VW 1:at concentrations
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<br /> of 130;000 and.48,000 yg/1 C icrogranns_perliter or.parts-per billion�nppl ), respectively B-TE&X x
<br /> compounds were also detected m the same ground water sample at concentrations up to�23,000 ppb`'
<br /> v While; MTBE was also detected tz the Baine sample at concentration of
<br /> ,g- �:'• __° TPH.g --and TPH,d' :were detected- m r'monitonng, wellsMW4
<br /> ('A conceritrations.as great as`1 tovlooO:ppb{TPH g,MW 6,located a'tthe nortfiem boundary;of the site)
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<br /> SBTE&X constituents were also detected in each monitored well at concentrations as High as:22,000:
<br /> — 'ppb{toluene, MW 6):,MTBE was also detected in.each monitored°well, locally at concentrations up ;. 4.
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<br /> t6,'5;800'ppb (IvIW.6). Analytical results 0,fground.water;samples are sumii arized-on Table 3 r
<br /> s Analytical'Results'of Ground Water Samples. The laboratory report {MAI Laboratory lD 75411
<br /> through 7'54'1"5) wQAIQC report aiid chain-of ciistocl- are included=
<br /> .. y as Appendix C .- �
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<br /> ikr IV
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