ARCHIVED REPORTS_XR0005810 - Laserfiche WebLink

Home Browse Search

' 09 July 1999 AGE-NC Project No 95-0137 Page 3 of 4 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION ran Depth to round water at the site ed from 15 20 to 16 55 feet below surface grade(bsg)The data p g g indicates an average increase of the relative ground water elevation at the site of 0 8 feet over the quarter The relative ground water elevation ranged from 82 79 to 84 21 feet The relative ground water elevation in each well and the hydraulic gradient were calculated from these data ' The ground water flow was directed toward the north and specifically toward the well north of the Jimco Truck Stop truck wash (MW-7) A significant ground water gradient was noted under the truck wash The ground water gradient was shallow on the RFS site compared to the Jimco portion of the site and was directed toward the northwest ' Historically, ground water flow direction at the site has vaned from north to northwest, consistently at a low gradient Figure 3 illustrates the contoured relative ground water elevations as measured on 25 May 1999 1 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in the ground water samples from wells MW-1 though MW-8 and vapor/air- sparging wells VW-1 and VW-2 at concentrations as high as 8,100 micrograms per liter(ug/l) TPH- ' d was detected in same ground water samples at concentrations up to 120,000µg/l (MW-6) The maximum concentration of benzene and toluene were detected in the sample from ground water monitoring well MW-2 at a concentration of 880µg11 and 27 ,ug/1, respectively Ethylbenzene and xylenes were detected at maximum concentration in samples collected from wells VW-la and MW-2 ' at 590µg/l and 730 µg/l, respectively Moderate range concentrations(4 0µg11 to 590µg/1) of BTEX compounds were detected in samples from wells MW-1 and MW-3 through MW-8 and also detected in the vapor wells VW-1 and VW-2, respectively MTBE was detected in the ground water sample collected from well MW-3 at a concentration of 2 0 µg11 DIPE and TBA were detected in the samples from the wells at the site at concentration up to 4 7 µg/l and 140 µg11, respectively ' Analytical results from ground water samples for each monitoring event analyzed by EPA Methods 8015 Modified and 8020 are summarized in Table 2 Analytical results for ground water samples analyzed by EPA Method 8260 Modified are summarized in Table 3 The laboratory report (MAI Lab ID Numbers 12073 through 12084), quality assurance and quality control (QA/QC) and chain- of-custody are included in Appendix B AdrQirced GeoEn%rronmental,Inc 1