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ATC Associates, Inc Project No 99975 7501 <br /> sampled after 80 percent or greater recovery Turbidity, dissolved oxygen and oxidation- <br /> reduction potential of the samples were also measured Appendix A contains copies of the <br /> Purge/Sampling Worksheets <br /> ' To minimize potential cross-contamination between wells, all measuring, purging and <br /> sampling equipment was washed in an non-phosphate detergent solution, rinsed with tap <br /> water, and then rinsed with distilled water prior to sampling each well <br /> ' The sampling procedures for each monitoring well consisted of extracting well water with <br /> a clean Teflon rm bailer attached to a clean nylon cord Water collected for analysis of TPHg <br /> ' and BTEX was decanted into 40-milliliter glass vials with Teflon'rm-lined septa The <br /> samples were preserved with hydrochloric acid and acidified to a pH of approximately 2 0 <br /> All samples were labeled and placed in a refrigerated cooler with the chain-of-custody <br /> document Samples transported to the laboratory were analyzed within the specified holding <br /> time Samples stored overnight at ATC were refrigerated at a temperature of <br /> ' approximately 4°Celsius <br /> • The groundwater samples were analyzed for TPHg utilizing EPA Method 8015M, for BTEX <br /> ' and MTBE utilizing EPA Test Method 8020,and for TBA,MTBE,DIPE,ETBE and TAME <br /> utilizing EPA Test Method 8260 One trip blank was submitted with the samples for <br /> analytical quality control <br /> • Groundwater produced during purging and samp ling was contained in 55-gallon drums and <br /> temporarily stored at the site <br /> 3.0 RESULTS <br /> ' 3.1 Analytical Results <br /> ' A summary of all groundwater analytical results to date, including the most resent (and <br /> previously unreported) April and August 1998 results, are presented in Table 2 The August <br /> 1998 analytical results are also shown on Figure 3 The results are further discussed under <br /> ' Section 4 0 <br /> 3.2 Groundwater Elevations and Gradients <br /> ' A summary of the groundwater elevation measurements from current ATC and previous OST <br /> monitoring is shown on Table 3 Groundwater elevation contours for the April 1998 results are <br /> ' presented in Figure 4a Although Figure 4b shows the groundwater elevations plotted for the <br /> August 22, 1998 measurements, the elevations are not contoured Copies of the field <br /> purge/sampling worksheets are included as Appendix A Historical groundwater elevation data <br /> and groundwater gradients are included in Appendix B <br /> Groundwater Monitoring and Remediation Status Report Page 2 <br />