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1 <br /> ATC Associates, Inc Project No 99975 7501 <br /> All wells were purged until dry or until four well-volumes of groundwater were removed <br /> The purged water was monitored for temperature, pH and conductivity Purging was <br /> ' considered complete when these parameters had stabilized When possible,the wells were <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 "m bailer attached to a clean nylon cord Water collected for analysis of TPHg <br /> ' and BTEX was decanted into 40-milliliter glass vials with Teflonrm-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 One trip blank was submitted with the <br /> samples for analytical quality control <br /> ' Groundwater produced during purging and sampling 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)December 1998 results, are presented in Table 2 and are also shown on <br /> ' Figure 3 The results are further discussed under 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 December 1998 results <br /> are presented in Figure 4a The groundwater elevations were also measured on January 26, <br /> 1999 Corresponding groundwater contours are presented in Figure 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 1 <br /> 1 <br />