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V Y.d T C A S S O C I A T E S I N C t✓ age from Jurassic (205 million years before present) to Recent (present time) and include both marine and continental deposits. The subsurface geology encountered at the Geoprobe® borings GP1, GP2, and GP3 generally consisted of clay, silt, and sand from the ground surface to a depth of approximately 16 feet bgs, the maximum depth explored. Clay was encountered in each boring from the surface to approximately 6 feet bgs. Sandy Silts were logged from the sample interval of 9 to 11 feet bgs in each boring. Each boring had sand with varying amount of silt and/or gravel from depths between 14 to 16 feet bgs. Gregg's stratigraphic interpretation of the CPT data indicate variable layers of clayey silt and silt were encountered from approximately 5 feet bgs to approximately 12 feet bgs. Alternating intervals of sandy silt, clayey silt, clay, and sand was encountered from approximately 12 feet bgs to 21 feet bgs. A relatively thick sequence of alternating intervals of silt, clayey silt, silty clay, and clay were encountered from approximately 21 feet bgs to 47 feet bgs and was underlain by alternating layers of sand and gravelly sand to approximately 57.9 feet bgs. A copy of Gregg's Presentation of Cone Penetration Test Data is included in Appendix C. 3.2 Hydrogeology V Water level measurements were collected from groundwater monitoring wells MW-1 through MW-6 during the first quarter 2004. The depth to water ranged from 7.58 to 9.28 feet below top �.� of well casing elevation. Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site flowed in a northerly direction. The average hydraulic gradient on January 12, 2004, was calculated to be approximately 0.003 ft/ft or approximately 16 feet/mile. The data indicate a groundwater gradient that is generally consistent with previous groundwater gradients observed at the site. 4.0 ANALYTICAL RESULTS 4.1 Soil Analytical Results r Soil samples collected from borings GP2, GP3, and CPT1 contained no detectable concentrations of TPHg, BTEX, or oxygenate fuel additives. The soil sample collected from boring GP1 at approximately 10.5 feet bgs contained concentrations of TPHg, ethylbenzene, and total xylenes at 7.0 milligrams per kilogram (mg/kg), 0.052 mg/kg, and 0.14 mg/kg, respectively. No other analytes were detected in these samples. No TPHg, BTEX, or fuel oxygenates were detected in V the sample collected from boring GPI at 15.5 feet bgs. Analytical results of soil samples are summarized in Table 1. 4.2 Groundwater Analytical Results r, The groundwater samples collected from borings GPI and GP2 contained detectable concentrations of TPHg and BTEX. The groundwater sample collected from boring GP3 ..i contained no detectable concentrations of TPH or BTEX. The groundwater sample from boring CPT1 at approximately 19 feet bgs contained detectable concentrations of TPHg and BTEX. The sAl786 Rreportslsum2004.doc 5 v