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December.199$
<br /> AGE-NC Project No. 95=0106
<br /> Page 5;of 7
<br /> gyp• k :,: ". . . ,. ,.' .. • ,
<br /> .The laboratory report (MAI 'Laboratory.ID 88973 through 88977), quality assurance and quality`,
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<br /> control A/ C acid chain-of-custody are'included in'A• ' endix,D. .''
<br /> ' 4.3. RELATIVES GROUND WATER ELEVATION..AND GRADIENT
<br /> ' The relative groundwater elevation•in each well was calculated by'subtracting the'depth to ground
<br /> water from-the relative well'casing,elevations (Table 3). The relative groundwater elevation on-27
<br /> May 199$'was 0.1 l foot lower than during;the April monitoring event.The gradient was.calculated,
<br /> ` ;.
<br /> to be an average 0.0034 ft/ft`directed radially northward, ranging from northwest to!northeast..The
<br /> contoured ground water,elevation data from the site is illustrated:in Figure 3.= Relative Ground;
<br /> E .. Water Elevation. i.
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<br /> E4.4. : LABORATORYRESULTS OF GROUND WATER-SAMPLES``
<br /> Petroleum hydrocarbons were detected in the ground water samples collected from monitoring well.
<br /> E MW-4; located.down-gradient (north), ofAe former'UST excavation: TPH-g•was detected at a "
<br /> concentration of 2,900µg%1 "_BTEX compounds were detected at concentrations'of.'110'µg11;benzene;:,
<br /> 22 ,u toluene, 180'µg/1 ethylbenzene, and 220 ,ug/l xylenes. '
<br /> Neithei'TPH-g nor BTEX'were detected in the ground water samples from rnonitoririg wells Mw=1, -
<br /> MW-2sam.p
<br /> MW=3";.MW -,,.MW -6'(upper)-or MW-6 (lower)and MW-7.'Analytical results of-ground
<br /> E water les are,summarize d on Table 5.
<br /> EArialysis 'by EPA�Method 8260m'did not detect oxygenated fuel additives iny,any of'the water
<br /> samles:anal zed- Th w
<br /> p y e folio , rng.compounds were,detected by EPA'Method:8264 in the-.'water
<br /> ,sample collected'from well MW-4:'n-butyl,benzene'at'S 2'"µg11, sec=butyl benzene at 2.., kcg/l, tert-`
<br /> butyl::benzene at 26 µg/1,• 1.2-dichl6roethane, at 5 6'.;ug/l, isopropyl benzene at. 14 µg11, n-propyl
<br /> = benzene gat 29-,ug/1',:.naphthalene'at 10,0,48/1, 1;2,4 'tiunethylbenzene at. l90µg%1;•'-1;3;5-trimethyl
<br /> berizerie at 28 g/1 and vinyl"ac etate' at 17;µgll. The BTEX'and VOC'conceritrati6ns'd"etected by EPA
<br /> E Method 8260 are presented,in Table,6.-The l.aliofato"ry`.rep'ort (MAI L'aboratory.ID, $9753 through
<br /> 89760); QA/QC and chain f-c t d ;
<br /> -Q us o y`are inclilded,in Appendix E.
<br /> SA. SUMMARY/,CONCLUSIONS
<br /> The Pollowing'conclusions.were drawn fromithe results{ -of the site'investigation:'
<br /> I' impacted soil was detected in the..uppersaturated zone at the capillary-fringe approximately'
<br /> 30 feet east'of the-former UST on the''adjacerii property.'Hydrocarbon-impacted soil,wasrhot.
<br /> encountered in the same zorie 40 feeteast of the.former UST location.
<br /> ' r Ad ran;red CeoEn•ironmentnlonc.
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