ARCHIVED REPORTS_XR0011931 - Laserfiche WebLink

Home Browse Search

' 20 March 2006 • AGE-NC Project No 95-0130 ' Page 12 of 13 as 27,000 µg/l from well MW-7B (Table 4) TPH-g was not detected in well MW-5 for the ' second consecutive quarterly monitoring event, likely representing a retraction of the dissolved ground water plume Additionally, the deepest detection of dissolved TPH-g and ' BTEX was in the sample collected from well MW-6E (137-142 feet) The approximate extent of dissolved TPH-g is depicted in Figures 5 and 7 • Although an overall trend of decreasing MTBE concentrations has been evident at the site, an even more rapid decline of MTBE concentrations was evident from the December 2005 sampling event from wells MW-6B (50-55 ft), MW-7B (50-55 ft), VW-2A (43-63 ft) and VW-3A (43-63 feet) The rapid decline of dissolved MTBE concentrations could be attributed to the recent addition of wells of VWAC, VW-2A and VW-3A to the interim ground water pump-treat system in August 2005 The highest concentrations of dissolved MTBE were detected from VW-3A at 18 pg/l, the approximate extent of dissolved MTBE is depicted in Figures 6 and 8 • The highest concentration of 1,2-DCA was detected in sample MW-7B at 180 gg/l, ' significant concentrations of 1,2-DCA were detected or have consistently been detected from wells MW-3, MW-6(B-D), MW-7(B-D), MW-8, VW-1B, VW-1C, VW-2A, VW-2B and VW-3A, indicating a significant 1,2-DCA-impact to ground water at the site 1 • • TAME was not detected in any ground water samples during December 2005, however, significant concentrations of TAME were previously detected from wells MWA through ' MW-3, MW-6(B-E),MW-7(B-D),V WAC,VW-2A and VW-3A at concentrations as high as 750 µg11 (MW-6B), indicating a significant TAME-impact to ground water at the site • TBA and EDB were not detected in any of the analyzed water samples, however, they had ' been detected previously TBA had been detected in wells MWA, MW-2, MW-3, MW-5, VW-1 C,VW-2A,VW-2B and VW-3A, suggesting a minor TBA-Impact to ground water at the site EDB had been detected from wells MW-7B, VW-1B, VW-1C and VW-2A at concentrations significantly above the DHS's Maximum Contaminant Level (MCL) in drinking water ' • The high concentrations of petroleum hydrocarbons detected in samples collected from wells MW-6(B and C),MW-7(A and B),VW-1 C,VW-2A and VW-3A indicated that these wells are within or near the dissolved petroleum hydrocarbon"core area"of the plume (Figures 5 ' through 8) • The lateral and vertical extent of the dissolved petroleum hydrocarbon plume is not known ' toward the northwest,northeast,east and southeast of the area bound by we11s MW-1 through MW-7 (Figures 5 through 8) ' Based on SVE remediation data collected between 07 September and 07 December 2005, AGE concludes Advanced GeoEnviroameatai,Inc