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QUARTERLY GROUNDWATER MONITORING MARCH 18 1988 WEGE and Lawrence Tank Testing (LTT) personnel collected quarterly groundwater samples from the five monitor wells at the site on March 18, 1998 See Appendix A for QA/QC, details, methods, procedures, abbreviations, and acronyms used in sampling and analysis DEPTH TO WATER MEASUREMENTS Depth to water was measured at all wells on March 18, 1998 The measurements were made from the surveyed elevation at the top of casing at each well using an electrical air/water interface probe (Table 1) No free product or product sheen was observed in any of the monitor wells COLLECTION AND CERTIFIED ANALYSIS OF GROUNDWATER SAMPLES Following depth to water measurements, WEGE and LTT personnel used a truck mounted vacuum lift pump and dedicated one inch diameter PVC tubing to purge each well of three volumes of water After purging, the wells were allowed to recover to at least 80% of their original well volumes A groundwater sample was then collected from each well with a polyethylene bailer and decanted with no headspace into two 40 ml VOA vials containing 0 5 ml HCL acid as a preservative The samples were delivered with accompanying chain of custody documentation to American Environmental Network (AEN) The certified laboratory (DHS 41172) analyzed the water samples from each monitor well for concentrations of TPH-G using EPA method 5030/GC-FID and . MBTEX, using EPA method 8020 DISPOSITION OF WASTEWATER The purged wastewater was contained on-site in labeled 55 gallon DOT approved drums This wastewater was transported by Evergreen Environmental Services to their recycling facility on April 3, 1998 under a non-hazardous waste manifest (see Appendix D) RESULTS QFQUARTERLY GROUNDWATER MONITORING GROUNDWATER GRADIENT AND FLOW DIRECTION Figure 4 shows the groundwater elevation gradient and flow direction determined from depth to water measurements at the five on-site monitor wells on March 18, 1998 The groundwater elevation has increased by an average of 7 03 feet at the five monitor wells since the previous quarterly monitoring round on December 5, 1998 The general flow direction has reversed when compared to previous measurements and now forms a south flowing ridge from MW2 towards MW5 The overall gradient is 0 001 feet/linear foot RESULTS OF CERTIFIED ANALYSIS OF GROUNDWATER SAMPLES The results of the certified analyses of groundwater samples collected from the five monitor wells on March 18, 1998 are shown in Table 1 Copies of the laboratory reports are included as Appendix C of this report • TPH-G concentrations ranged from a maximum of 5200 ug/l at MW 1 to less than the laboratory detection limits of 50 ug/1 at the remaining four monitor wells 2 Sanchez QM 3-98