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I11 November 2002 AGE-NC Project No. 95-0106 Page 3'of 4 . Neither TPH-g nor BTEX compounds were detected in the ground water samples from monitoring . ' wells MW-2, MW-3, MW-S, MW-6 (upper), MW-6 (lower) and MW-7. MTBE was not detected in any of the ground water samples. Analytical results of ground-water ' samples are summarized on Table 2. The laboratory report (MAI Lab ID 0209391-001.A through- 02.09391-008A), QA/QC and chain-of-custody are included in Appendix C. 1 4.0. SUMMARY AND CONCLUSIONS ' The following conclusions were drawn from the results of the site investigation: • The ground water was generally northward on 24 September 2002, and gradients were ' calculated to range from 0.007 toward the north-northwest to 0.005 toward the northeast. • Dissolved petroleum hydrocarbons were detected in ground water samples from monitoring ' well MW-4, located down-gradient off-site from the.former UST excavation, and MW-1 located just north of the former UST area. �- ' . BTEX compounds were detected in the water samples collected from MW-4 and MW-1. The concentrations of benzene in the samples exceeded the State of California maximum contaminant level (MCL) of 1 µg/1 for drinking water. ' Analytical data from monitoring wells MW-2 and MW-7 limits the horizontal extent of dissolved hydrocarbons south and east of the site, respectively. Analytical data from wells MW-3 and MW-6 limits the extent of dissolved hydrocarbons northeastward of the site. '. Analytical data•from monitoring well MW-5 limits the extent of dissolved hydrocarbons north-westward of the site. The extent of dissolved hydrocarbons to the west is not ' completely defined at this time. • Continued detection of TPH-g and BTEX in ground water samples collected from the off--site well MW4 indicates that the plume of impacted ground water has migrated off-site towards ' the north, however, the general lack of detection of hydrocarbons in the MW-7, MW-6, MW-5 and,MW-3 wells shows that the plume is not wide-spread and has not migrated northeast of MW-4 or northwest of the former UST pit. The extent of the•plume around MW-4 is constrained by data from MW-6 toward the north- northeast, MW-5 toward the southwest and MW-7 toward the east relative.to MW-4. The ' northwestern extent of the plume from MW-4 isnot well constrained. ' The results of this and previous monitoring events and previous soil investigations leads AGE to conclude.that: ' Advanced CeoEnvironmental,Inc.