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I Bank of Stockton - Cutter number Site Page 4 Quarterly Groundwater Monitoring Report ' Project No. 102.2 May 13,2005 labeled, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory. Gasoline contaminated purge & rinseate water generated during the activities described above was stored in poly drums located on the site. American Valley ' Waste Oil will remove this material prior to the next scheduled depth to water measuring event. ' 2.2 Groundwater Sample Analyses Groundwater samples were analyzed as follows: • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method ' 5030/8015(m). Benzene Toluene, Ethylbenzene and total Xylene (BTEX) and MTBE by EPA method 602 1 1 The detection limits are included in the summary analytical data table (Table 2). Detectable levels of gasoline range petroleum hydrocarbons and/or BTEX ' compounds were found in 5 of 6 water samples that were collected. 2.3 Field Data lie The field data for this groundwater monitoring event are summarized in Appendix B and Table 1. The level of groundwater has risen about 3 feet since the groundwater monitoring event completed on December 23, 2004. The ' bearing and gradient of groundwater flow was calculated using a 3-point solution for wells MW-6, 10 & 11. The historical calculations of gradients and directions are summarized in the following table: Table: Groundwater Gradient, 2004 & 2005 Date Gradient; Direction/Slope ' March 16, 2004 N3711E, 0.0047 ft/ft June 7, 2004 N48°E, 0.0042 ft/ft September 1, 2004 N600E, 0.0052 ft/ft December 23, 2004 N23°E, 0.0034 ft/ft March 17, 2005 N390E, 0.0047 ft/ft ' * Calculation based on MW-7, 813 and 11. ' 2937 Veneman Ave.,#B240 Geo-Phase Environmental Inc. Phone (209) 569-0293 Modesto, CA 95356 Fax(209) 569-0293