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I J. -29 December 1998 ,� AGE-NC Project No. 95-0106 -Page 3-of 4 Neither TPH-g nor BTEX weredetected in the�ground water samples from monitoring wells MW-2,' ' MW-3,• MW-5, MW-6 (upper) and MW-7. 'Analytical results,of ground water "samples are �. summarized-on Table 5. • Analysis by' EPA Method $260m did not detect oxygenated fuel additives in any of the•water samples analyzed- Thefollowing compounds were detected.by EPA Method aS260 in the water sample collected' from well MW-4: isopropyl-.benzene at. 14'ulo, n-propyl benzene at'3.1 µg11, naphthalene at 35 ug/l, 1,2,4-trimethyibenzene,ai 1'60 ug/,1,- 1,3,5-trimethyl benzene at 28 pg/l and vinyl acetate at 47-/t g/1. In addition, 140 ugll.benzene, 22 Iig/l toluene; 1..40 ug/l ethylbenze'e and ',. '180-µg/i total.xylenes'were detected-in the sample: These,concentrations are-similar'to tholes detected in the MW-4.,sample collected duringthe previous:monitoring event, The sample collected from monitoring well MW-I yielded 3.5µg/l benzene,as analyzed,by.EPA Method 8260..The BTEX concentrations detected;by'EPA,Method 8260'are presented in',Table 6. The laboratory ' - reports(MAI Laboratory IDs 99316 and 99317 through 99323),QA/QC and chain=of---custody forms x` ' ,are included in Appendix B. 4."0.' " SUMMARY/CONCLUSIONS The'following,conclusions were drawn from the results of the-site investigation: ; ' .The ground water , dient on 24 November 1998 was calculated to be an average of 0.0042 -ft/ft directed north-northwesterly. g •, Ground water elevation atthe site decreased an average 0.66feet since the:last,quarterly . ' monitoring event._ Dissolved petroleum hydrocarbons:were detected'in the samples from., • m well MW-1 located on-site..arid well :MW,=4, located off-site.�and down-gradient (north) of the former UST excavation ; •.: - Oxygenated scompounds were•not,detected in any of.the ground'water samples by EPA ' Me'thod,8260m: J Low,concentrations:of VOCs were 'detected in the water.samples collected from MW-4 and MW1 1' • The concentraiionsuof analytes detected in the ground water sample from MW-4 were,similar ` to the concentrations"detected during the May 1998 monitoring event.", _ •' -The concentrations of benzene detected in the.ground water samples collected from'MW-1 and MW-4-exceed the California.Maximum Contaminant Level (MCL) of`1 s l Advanced CeoEnvironmcntal,Inc.