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46'Aust 2003 AGE-NC Project No. 98-01440 ' Page.3 of 4' . 3.2. ANALYTICAL RESULTS.OF GROUND WATER SAMPLES ' TPH-g was detected in the water samples.coll'ected from monitoring wells MW2 and MW5 at. ; "concentrations of 450 µg/land 110 µg/l,respectively. TPH-d was detected in the sample collected from monitoring well MW2 at a concentration of 230µg/l.- Benzene 30µg/l.Benzene was detected in the water samples-collected from wells MW2 and MW5 at concentrations of 8Q µg/1 and 7.2 µg11, respectively. The remaining BTEX compounds were detected in the.sa e-, samples at concentrations -as,high'as 3:4 µg/1 toluene, 7.4 µg/1 ethylbenzene and 4.6 µg/1-total xylenes. Additionally, 'toluene was detected in the sample `collected from well •MW7: at:a, I' concentration of 0.87 µg/1_,No other analyteswere detected at or above laboratory reporting limits in the water salnples•collected from the m6fiitoririg wells. A map showing the approximate extent 1 of dissolved benzene is presented in Figiire 5: Current and previous analytical results are summarized on Table 2. The laboratory report(MAI Lab. -ID No.0306372-001 through 0306372-009),QA/QC report and'chaiin-of-,custody form are included ' iii.Appendix B. 4.0. SUMMARY.AND CONCLUSIONS Based on the data collected during this monitoring period, AGE concludes: • Ground water elevations at the site in June 2003 ranged from 28.74 feet above mean sea level . (MSL) in well MW8 to 30.21 feet above MSL in well MWL The ground-water elevations at site increased'an average of 3.58 feet between the March 2003 and June 2003 sampling events. The.ground water at the,site was inferred to be flowing toward the north under an I : average gradient'or 0.009 feetifeet which is-consistent with the flow direction determined' during previous monitoring events' IThe highest concentration of.dissolved',hydrocarbons quantified as TPH='g and BTEX 'compounds extends northeast from USTs No. 4 and, 5. Dissolved hydrocarbons were encountered in 'the.,down-gradictit direction from the 'former USTs in samples from ' monitoring wells MW2 and-MW5.Hydrocarbon concentrations decreased tonon-detectable in the samples collected from wells M•W6 and MW8.Dissolved hydrocarbon concentrations remained non-detectable in samples from wells MW 1•; •MW3,a MW4 and MW9. The concentrations of benzene detected�in the water samples collected from-wells MW2 and .MW5 were above the,State' of California maximum contaminant level(MCL)of 1.0µg/1 for ' b'enzene in drinking water.'A map showing the.approximate extent of dissolved-benzene is . presented in Figure 5. Advanced CeoEnvironmental,Inc. .