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15 July 2002 AGE -NC Project No 96-0232 Page 12 of 21 3 4 2 Laboratory Results of Ground Water Samples During the June 2002 sampling event, TPH-g was not detected in any of the analyzed water samples, however, TPH-d was detected in samples collected from MW -9B, MW -9C, MW -10A, MW -10C, MW -1013, MW -11C, MW -11D MW -12 (A through D), and MW -13 (A through D) at concentrations as high as 430 ,ug/l (MW -12A), TPH-mo was detected in water samples collected from MW -10A and MW -12A at concentrations of 260 ,ug/l and 350 1.4g/1, respectively The laboratory reports noted that the TPH-d sample chromatograms had no recognizable patterns and/or a few isolated peaks Based on further laboratory review of the TPH-d sample chromatograms, the laboratory further indicated to AGE that with the exception of MW -12A and MW -13A, the TPH-d detections did not have typical diesel characteristics, and that the detected chromatogram peaks were possibly the result of biological interference (Appendix H) BTEX constituents were not detected in any of the samples collected during the June 2002 sampling event However, MTBE (utilizing EPA Method 8021B) was detected in water samples collected from wells MW -7, MW -8A, MW -11B, MW -11D, MW -12A, MW -13A, EW -4, EW -5, EW -8 and EW -10 at concentrations as high as 200 µg/l (MW -8A) MTBE (utilizing EPA Method 8260M) was detected in water samples collected from monitoring wells MW -7, MW -8A, MW -9A, MW -11A, MW -11B, MW -11D, MW -12A and MW -13A at concentrations as high as 250 µg/l (MW -8A), isoconcentration maps displaying the estimated extent of dissolved MTBE in First Zone and Second Zone aquifer are depicted in Figures 16 and 17 MTBE was detected in water samples collected from extraction wells EW -4, EW -5, EW -6, EW -8 and EW -10 at concentrations as high as 29 4g/1 (EW -4), an isoconcentration map displaying the estimated extent of dissolved MTBE in the area of the ground water extraction wells is depicted in Figure 18 1,2 -DCA and TBA were detected at well MW -13A at concentrations of 2 2 ,ug/l and 17 4g/1, respectively No other constituents of concern were detected above laboratory reporting limits in the water samples collected during the second quarter sampling event Analytical results of ground water monitoring well samples are summarized in Tables 5 and 6 The laboratory reports (McCampbell Analytical Inc work order nos 0206240 and 0206271) and chain -of -custody forms are presented in Appendix H 4.0• ADDITIONAL NPDES SAMPLING REQUIREMENTS An RWQCB waste water discharge permit (NPDES permit no CAG915001) for discharge was issued to Flag City Chevron by RWQCB letter dated 06 November 2000 In accordance with the Advanced GeoEnvironmental, Inc