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i 4 0 RESULTS 4 1 Depth to Groundwater and Hydraulic Gradient The depth to groundwater on January 27 was between 37 and 38 feet, which is one foot greater than the depth in June 2004 (Table 1) Most of the wells are 40 feet deep, meaning that less than 3 feet of water were present in each well The calculated elevation of the water table is approximately 22 feet below sea level Figure 3 illustrates the hydraulic gradient and general direction of groundwater flow As in previous quarters the contours indicate that the prezometric surface slopes eastward 4 2 Analytical Results Hydrocarbon concentrations in January xNere quite similar to those measured in June 2004 in most wells although Total Petioleum Hydrocarbon concentrations increased Volatile aromatic concentrations (benzene toluene, etc ) remained in the range of 1-3 parts per billion (micrograms per liter), but TPH-g concentrations increased by 10% or more (Table 2) The laboratory report noted that the TPH-g chromatograms differed fiorn standard gasoline chromatograms The laboratory has noted this in previous samples as well, such as in June 2004 One possibility rS that the gasoline has degraded somewhat and is skewed toward the heavy hydr ocarbon range In VM-3, for instance, TPH-g concentrations have been above 100 ppb on several occasions but BTEX compounds have not been detected Another possibility is that non-gasoline hydrocarbons • are present Chlorinated hydrocarbons, typically used in cleaning solvents,were detected in samples that were collected in 1996 and 1997 Currently, solvents are not part of the analytical protocol practiced at the site 5 0 REMEDIATION ACTIVITIES Installation of the soil vapor extraction system was delayed in the second half of 2004 due to delays in receiving payment and reimbursement from the State Underground Tank Cleanup Fund Piogram Some of the financial problems were resolved late in the year,,and a thermal oxidation extraction system was mobilized to the site on February 3, 2005 A crane was hired to unload the equipment which was placed next to the garage building in the southwest corner of the site in the drum storage area An electrical panel for controlling the equipment was previously installed in this area during the second quarter of 2004, and Pacific Gas & Electric Company connected it to the existing power grid in January 2005 The area is enclosed by the perimeter fencing around the site so no additional enclosure has been constructed 5 0 CONCLUSIONS Groundwater monitoring in the first quarter of 2005 supports the data collected in 2003 and 2004 eegarding the direction of groundwater flow and the extent of groundwater contamination Both 3