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�J Groundwater elevation data for December 17, 2004, indicate a groundwater flow direction <br /> aprimarily to the south at a gradient of about 0 01 to 0 008 (Table 2 and Figure 3) Groundwater <br /> flow direction and gradient for fourth quarter 2004 are consistent with those during previous <br /> aquarters <br /> 3.2 LABORATORY RESULTS <br /> The following sections provide an evaluation of the quality assurance/quality control results for <br /> the laboratory analyses and present analytical results Copies of analytical reports for the <br /> groundwater samples collected for the fourth quarter 2004 groundwater monitoring event are <br /> included in Appendix B <br /> Q3.2.1 Quality Assurance/Quality Control Evaluation <br /> Groundwater samples collected by WGR for wells MW3-1, MW3-2, MW3-3, MW3-4, MW3-5, <br /> and MW3-6 were received by MAI on December 20, 2004 Holding times for the requested <br /> analyses were met Recoveries of surrogate spike samples were within laboratory quality control <br /> alimits <br /> 3 2 2 Analytical Results <br /> Analytical results for quarterly groundwater monitonng parameters are presented in Table 3 <br /> Historical analytical results for grab groundwater samples collected from soil bonngs are <br /> included in Table 4 During fourth quarter 2004, groundwater samples from four of the six <br /> sampled groundwater monitoring wells had detectable concentrations of TPHg or BTEX <br /> i <br /> Historical and fourth quarter 2004 TPHg concentrations in groundwater samples collected from <br /> the site soil borings and monitonng wells are plotted and contoured on Figure 4 <br /> Groundwater wells MW3-4 and MW3-5 are background wells, wells MW3-1, MW3-2, and <br /> MW3-3 are completed near the former UST, and well MW3-6 is a downgradient well Low <br /> concentrations of TPHg and BTEX compounds have been detected occasionally in groundwater <br /> samples from background wells MW3-4 and MW3-5 (Table 3) However, during the fourth <br /> quarter 2004 monitonng event, TPHg and BTEX were not detected in groundwater samples from <br /> wells MW3-4 and MW3-5 During the fourth quarter 2004 monitoring event, TPHg and BTEX <br /> were detected in groundwater samples from monitoring wells MW3-1, MW3-2, MW3-3, and <br /> MW3-6 Groundwater samples from the downgradient well and the wells near the former UST <br /> consistently have detections of TPHg and BTEX compounds (Table 3) Methyl tertiary butyl <br />