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SECTION 5.0 RESULTS AND DISCUSSIONS 5.1 GROUNDWATER SAMPLING RESULTS 5.1.1 Vertical Groundwater Sampling Results The results of the groundwater quality parameters and inorganic compounds (nitrogen as nitrate and sulfate) for wells MW-6 and VW-2 are presented in Table 5-1 The specific conductivity, temperature, and turbidity results were consistent with typical groundwater quality parameters The pH results were low in both wells (less than 4 5) Lower pH measurement may have been due to meter calibration errors Dissolved oxygen concentrations were measured in water samples brought to the surface, the results (approximately 7 5 mg/L) were consistent with dissolved oxygen concentrations in surface water bodies rather than insitu oxygen concentrations in groundwater (typically less than 5 mg/L) The saturated oxygen concentration in water (i e , water that is exposed to air) with a water temperature between 17 and 18°C is approximately 8 mg/L, which is slightly above the measured dissolved oxygen concentrations from the two wells (i e , 7 5 mg/L) Additionally, the inorganic results for nitrogen as nitrate (non-detect) and sulfate (7 2 to 22 mg/L) were consistent with anoxic to anaerobic conditions The discrete vertical groundwater analytical results for TPH-g, BTEX, and MTBE for wells MW-6 and VW-2 are presented in Table 5-2 and are graphically shown on Figure 5-1 The analytical laboratory reports, including chain-of-custody documentation, are provided in Appendix E The results for well VW-2 show a significant decrease in TPH-g, BTEX, and MTBE concentrations in groundwater with depth from 47 to 61 feet bgs The analytical results were not significantly different at 61 and 67 5 feet bgs in well VW-2 Historically, the highest concentrations of TPH-g and BTEX in groundwater were detected in 1996 in well VW-2, when groundwater was at a depth of 60 6 to 63 2 feet bgs (see Table 3-3) The highest concentrations of TPH-g and BTEX in soil were observed at a depth of 46 feet bgs (see Table 3-2) TPH-g and BTEX were not detected 2n soil samples collected below 50 feet bgs at the time of well installation in 1996 The results for well MW-6 show an overall decrease in TPH-g concentrations in groundwater with depth from 46 to 71 feet bgs, although the TPH-g concentration in the sample collected from 59 5 feet bgs is greater than that from 46 feet bgs The results for well MW-6 show a slight crease in MTBE concentrations with depth from 46 to 71 feet bgs Concentrations of MTBE were not detected in well MW-6 at 46 bgs Benzene, toluene, and xylenes were detected in the samples collected at 59 5 and 7I feet bgs The samples collected in well MW-6 indicate a slight decrease in concentrations of xylenes from 59 5 to 71 feet bgs, while the benzene and toluene concentrations showed a slight increase from 59 5 to 71 feet bgs Historically the highest concentration of TPH-g and BTEX in groundwater were detected in well MW-6 during the July S 1PROJ1410401000411YYARMMAINTYARUSADOC 5-1 UNS Greiner Woodward Clyde