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1 <br />' 27 October 2003 <br /> AGE-NC Project No 98-0450 <br /> Page 13 of 17 <br />' 5 2 1 Confirmation Ground Water Sample Analysis <br /> Following sample collection,the samples were placed in laboratory-supplied containers,labeled and <br /> were transported under chain-of-custody to CalTech Environmental Laboratories (CTEL), a <br /> California Department of Health Services (DHS)-certified laboratory <br /> The water samples were analyzed for <br />' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> ' Method 5030/8015 Modified, <br /> • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and the fuel additives methyl <br /> tertiary-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), <br /> ' tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), ethylene dibromide (EDB), <br /> 1,2-di chloro ethane (1,2-DCA), methanol and ethanol in accordance with EPA Method <br /> 8260 Modified <br /> 1 <br /> All nnseate generated during drilling activities was containerized in properly labeled DOT-approved <br /> '• 55-gallon drums, and was stored on-site in an area lacking public access The soil borings were <br /> backfilled over its entire depth with a bentonite/portland cement grout mix <br /> ' 5 2 2 Analytical Results of Confirmation Ground Water Analysis <br /> ' MTBE was detected in two ground water samples(CB 1 and CB2)down-gradient of the former UST <br /> location,at a concentration of 2 0 ug/l and 1 3 gg/1,respectively TPH-g was also detected in sample <br /> ' <br /> CBI at a concentration of 60 µg/1 No other target analytes were detected in the samples analyzed <br /> Confirmation water sample analytical results are included in Appendix C <br /> 5 3 CONFIl2MATION GROUND WATER MONITORING <br /> ' At the directive of the EHD, a ground water monitoring event was conducted on 29 August 2003, <br /> the depth to ground water in each monitoring well was measured to the nearest 0 01-foot utilizing <br /> a Solinst water level meter Ground water monitoring wells BMW-1 through BMW-5 (site wells) <br /> ' <br /> and-MW-5-(off-site well) were monitored and sampled The ground water elevation was then <br /> calculated by subtracting the measured depth to ground water from the surveyed casing elevations <br /> (Table 7) Ground water elevations were later plotted and contoured on a scaled site map (Figure 6) <br /> ' After water levels were measured, approximately 26 gallons (a minimum of three casing-water <br /> volumes perwell)ofwaterwere purged from wells BMW-1 and BMW-2 utilizing a Watterra inertial <br /> Advanced GeoEnvironmeelal,Inc <br /> 1 <br />