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' Bank of Stockton - Cutter Lumber Site Page 4 <br /> Quarterly Groundwater Monitoring Report <br />' Project No 102 2 <br /> October 29,2003 <br />' labeled, inserted into foam holders and placed in an ice chest cooled to 4°C for <br /> transport to the laboratory <br />' Gasoline contaminated purge & rinseate water generated during the activities <br /> described above was stored in poly drums located on the site American Valley <br />' Waste Oil will remove this material prior to the next scheduled depth to water <br /> measuring event <br />' 2.2 Groundwater Sample Analyses <br /> Groundwater samples were analyzed as follows <br /> Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method <br /> 5030/8015(m) <br /> • Benzene Toluene, Ethylbenzene and total Xylene (BTEX) and MTBE by EPA <br /> method 602 <br />' The detection limits are included in the summary analytical data table (Table 2) <br /> Detectable levels of gasoline range petroleum hydrocarbons and/or BTEX <br /> compounds were found in all 6 water samples that were collected <br /> 2.3 Field Data <br /> IleThe field data for this groundwater monitoring event are summarized in <br /> Appendix B and Table 1 The level of groundwater has fallen more than three <br /> feet since the groundwater monitoring event completed on June 17, 2003 The <br /> 1 bearing and gradient of groundwater flow was calculated using a 3-point <br /> solution for wells MW-6, 10 & 11 At the time of this current event, the recent <br /> pilot vapor extraction and sparge test was in the process of being completed As <br />' a result of these activities, the groundwater level in MW-6 was 3 feet shallower <br /> than normal and not representatives of normal conditions For this reason the <br />' MW-6 water level was not included in the groundwater gradient map (Figure 3), <br /> or in the 3-point solution Instead a 3-point solution based on MW-7, 8B and 11 <br /> was used The historical calculations of gradients and directions ate <br />' summarized in the following table <br /> Table. Groundwater Gradient, 2002 & 2003 <br />' Date Gradient, Direction/Slope <br /> March 20, 2002 N660E, 0 0028 ft/ft <br /> June 17, 2002 N490E, 0 0033 ft/ft <br /> September 12, 2002 N620E, 0 0041 ft/ft <br /> December 20, 2002 N420E, 0 0030 ft/ft <br /> March 24, 2003 N480E, 0 0040 ft/ft <br />' July 17, 2003 N811W, 0 0037 ft/ft <br /> September 22, 2003 N460E, 0 0044 ft/ft <br /> Calculation based on MW-7, 8B and 11 <br /> 1 2937 Veneman Ave ,#13240 Geo-Phase Environmental Inc Phone (209) 569-0293 <br /> Modesto, CA 95356 Fax (209) 569.0293 <br />