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' CreologicaI Technics inc. Page 4 Groundwater Monitoring Report Project No. 989.2 March 12,2004 Note: Vertical groundwater gradients from the previous three groundwater-monitoring events were exaggerated by an order of magnitude. The error was caused by an improperly formatted formula in the Microsoft Excell®spreadsheet. The attached vertical groundwater ' gradient table (Table 3) has the corrected information. Historical groundwater bearing and slope are summarized in Table 2 and a summary of ' vertical groundwater is included as Table 3 of Appendix A. A Rose Diagram is attached as Figure 4. 1 As required under AB2886, the depth to groundwater data was submitted electronically to GeoTracker on February 4, 2004, with confirmation number 3642257511. ' 2.2 Groundwater Analytical Results ' • Low concentrations of BTEX constituents were present in MW-1 and MW-4. No constituent of BTEX was found in the remaining monitoring wells. • Low concentrations of TPH-G were detected in MW-1 and MW-4. TPH-G was not ' present in any other monitoring wells. • Low concentrations of MtBE were present in MW-I, MW-4, MW-5, MW-6, MW-8 and MW-9. The levels are consistent with previous monitoring events. • Concentrations of MtBE in MW-I, MW-4, MW-5, MW-6, and MW-8 continue the decrease trend with each groundwater-monitoring event observed since September 2002. A plot of TPH-G versus groundwater elevation for MW-1 shows that generally the concentrations of TPH-gasoline fluctuate with groundwater elevation and that the ' overall concentrations have decreased two orders of magnitude over time. Historically, the fuel oxygenates DIPE, ETBE, TAME and TBA as well as 1,2 DCA and EDB have not been detected in any of the site's monitoring wells. This holds true for ' the new monitoring wells. These constituents are no longer analyzed in groundwater samples collected at this site. ' Laboratory Data Sheets are included in Appendix C. The data are summarized in Table 1 of Appendix A. Chart 1 is a plot of TPH-G versus groundwater elevation for MW-1. Chart 2 ' is a plot of MtBE versus groundwater elevation for MW-6. During purging of the monitoring wells, field measurements of the oxidation-reduction ' potential (ORP) of the water were taken using an YSI 3560 Flowcell meter. During this groundwater-monitoring event, dissolved oxygen was measured in all the wells using an YSI dissolved oxygen meter. These measurements are summarized in Table 4 of Appendix ' A and in the field logs of Appendix B.