ARCHIVED REPORTS XR0000679 - Laserfiche WebLink

Home Browse Search

' 11 August 2003 AGE-NC Project No 96-0232 ' Page 10 of 15 3 4 13 Secondary Aquifer Zone ' Ground water elevation vat on data collected in the Secondary Aquifer Zone(85 to 105 feet bsg)at the Flag ' City Chevron site inferred a southeasterly flow and a northwesterly flow towards a southwest-orient trough, the orientation of the trough vers west-northwest in the vicinity of the Rocky's Restaurant site The ground water trough appears to terminate at a significant ground water depression in the ' area of Three B's Truck Plaza wells MW-9C and DW-1 (Figure 6) Ground water gradients were approximately 0 01 ft/ft or less near Three B's Truck Plaza well MW-9C and 0 001 ft/ft or less in the area of Flag City Chevron wells MW-8B and MW-9B 3 4 14 Primary Aquifer Zone 1 Ground water flow in the Primary Aquifer Zone (130 to 150 feet bsg) appeared to be similar to the flow pattern established in the overlying Secondary Aquifer Zone Ground water gradients were ' approximately 0 02 ft/ft or less near Three B's Truck Plaza well MW-9E and 0 001 ft/ft or less in the area of Flag City Chevron wells MW-8C and MW-9C (Figure 7) 3 4 2 Laboratory Results of Ground Water Samples During the June 2003 sampling event, TPH-d was detected in the samples collected from MW-2, MW-12A and EW-7 at concentrations of 160 µg/l,320 µg/1 and 76 µg/l, respectively, and TPH-mo was detected in the sample collected from MW-I2A at concentrations of 260 µg/1 The Iaboratory reports noted that the TPH-d sample chromatogram had no recognizable patterns The BTEX compound xylenes was detected in water samples MW-8B and MW-11C at concentrations of 1 7 µg/1 and 0 5 µg, respectively MTBE (utilizing EPA Method 8260M) was detected in water samples collected from monitoring wells MW-6B,MW-8A,MW-9A,MW-11A,MW-11B,MW-11 D,MW-12B,MW-13A andMW-15 through MW-18 at concentrations as high as 290 gg/l(MW-8A), isoconcentration maps displaying the estimated extent of dissolved MTBE in First Zone and Second Zone aquifer are depicted in Figures 8 and 9 In addition, MTBE was detected in water samples collected from extraction wells EW-1, EW-2, EW-4, EW-5 and EW-7 through EW-10 at concentrations as high as 26 Ag/1 (EW-4 and EW-5) No other constituents of concern were detected above laboratory reporting limits in the water samples collected during the second quarter 2003 sampling event Analytical results of groundwater monitoring well samples are summarized in Tables 5 and 6 The laboratory reports (McCampbell j Advanced GeoEnvironmental,Inc