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PRIVILRED & CONFIDENTIAL • TPH-g and BTEX were not reported in groundwater samples collected from monitoring wells MW-1 or MW-3; • TPH-g was reported in the groundwater samples collected from MW-2 and MW-4 at concentrations of up to 3.4 ppm; • TPH (Carbon Range C8-C44+) was also reported in the groundwater sample collected from MW-2, at a concentration of 2.3 ppm; • Benzene was reported in the groundwater samples collected from MW-2 and MW-4 at concentrations of 1.2 ppm and 11 ppm, respectively; and • MTBE was not reported in the soil or groundwater samples collected. Subsequent to the September 1997 Additional Phase II Subsurface Investigation, the SJCEHD requested that an additional soil boring be installed down-gradient from groundwater monitoring wells MW-2 and MW-4. Building Analytics submitted a Work Plan for the Additional Soil Boring and Quarterly Groundwater Monitoring to the SJCEHD on May 4, 1997, which was approved with continents on January 20, 1998. Final approval was issued after the SJCEHD received reports from adjacent LUST sites on July 20, 1998. 1 OBJECTIVE AND SCOPE OF WORK The first objective was to perform an additional assessment of subsurface soil conditions beneath the subject site to further investigate the potential source of contamination. The second objective was the further investigation of on-site groundwater conditions to further assess the extent of the known groundwater contamination. To accomplish the objectives, Building Analytics performed the following tasks: a. Submitted a Work Plan and Well Permit to the SJCEHD; b. Marked the boring location and called Underground Service Alert (USA) to perform utility clearance; c. Advanced one soil baring to a maximum depth of 80 feet bgs down-gradient from groundwater monitoring wells MW-2 and MW4; ' d. Collected soil samples continuously to a depth of approximately 80 feet bgs, and submitted selected samples for analysis of TPH, BTEX and fuel oxygenates in accordance with Environmental Protection Agency (EPAj Methods 8015M (TPH) and 8260 (BTEX and fuel oxygenates). Additionally analyzed selected soil samples for permeability, porosity, bulk density, moisture content, organic carbon content and grain size distribution in accordance with the appropriate American Society for Testing and Materials (ASTM) standards; e. Collected one groundwater sample from the newly installed soil, and submitted the sample for analyses of TPH, BTEX and fuel oxygenates in accordance with EPA Method 8015M (TPH), and EPA Method 8260 for BTEX and fuel oxygenates; 3 199075-WKB.Stnckton Ph.]]and Quart.Groundwater