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17 June 2002 <br /> AGE-NC Project No 99-0559 <br /> IPage 6 of 7 <br /> I 100µg/1,respectively,the remaining BTEX compounds were detected at concentrations of 0 64µg/1 <br /> toluene (MW-6E) and 140 µg/l toluene and xylene (MW-7E) MTBE was detected utilizing EPA <br /> Method 8260 Modified, at concentrations of 5 0 µg/1 (MW-6E) and 11 µg/1 (MW-7E), other fuel <br />' oxygenates were not detected <br /> The analytical results of current as well as historical ground water samples are summarized in <br /> Table 2 Iso-concentration maps displaying the estimated distribution of dissolved benzene and <br /> MTBE in the hydrologic units are depicted in Figures S through 12 The laboratory reports (CTEL <br /> I D nos 0202-091-1 to 3 and 0202-099-1 to -20), quality assurance and quality control (QA/QC) <br /> reports and chain-of-custody forms are included in Appendix B <br /> I4.0. SUMMARY AND CONCLUSIONS <br /> Based on data collected during the monitoring event, AGE concludes <br /> • Thegr ound water flow direction for HU1 and HU2 was south-southwest,while ground water <br /> flow direction for HU4 was southeasterly Ground water flow direction in the three deeper <br /> lie hydrologic units appeared to flow northwest to north-northwest <br /> • Free product continues to be present in well MW-2, located in the area of the USTs <br />' 0 The highest concentrations of petroleum hydrocarbons detected at the site were present in <br /> the ground water momtonng well samples completed in HU1 and HU2, and HU3 and HU4 <br /> The maximum concentrations were detected in samples from wells MW-1 through MW-4 <br /> and MW-7, near the former UST release <br /> • Overall, the concentrations of TPH-g and BTEX compounds in the HU5 samples collected <br />' from well MW-7 increased from the previous quarter <br /> • Concentrations of MTBE remain high in Upper and Lower HU5 water samples from well <br />' MW-5, located at the western edge of the site <br /> • The lateral extent of impacted ground water has not been defined at the site <br /> I • The vertical extent of impacted ground water is not delimited in the area of the former USTs, <br /> benzene at concentrations above the California Minimum Contaminant Level and low <br /> concentrations of MTBE have been detected in water samples from deep-screened wells <br />' MW-6 and MW-7 <br /> Advanced GeoEnvironmental,Inc <br />