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(VATe A S S O C I A T E S I N C Petroleum hydrocarbon constituents were detected in soil samples collected from borings SBI and SB2. The highest reported constituent concentrations were observed in soil samples collected at 25.5 feet bgs in each of the borings. The highest concentrations of petroleum constituents at this depth were observed in SBI and include TPHg (9,500 mg/kg), toluene (65 mg/kg), ethyl benzene (82 mg/kg), and xylenes (470 mg/kg). The petroleum hydrocarbons appear to attenuate rapidly with depth as indicated greatest by soil samples from SBI at 45.5 feet bgs and S132 at 55.5 feet bgs which contained only trace amounts of petroleum hydrocarbons or none above the laboratory detection limits. Total lead was detected at 5.5 mg/kg from the soil sample collected form SBI at 25.5 feet bgs. Neither benzene, fuel oxygenate additives, or VOCs were detected above laboratory method detection limits in any of the soil samples analyzed. Petroleum hydrocarbon constituents, including TPHg and BTEX, were detected in groundwater samples collected from borings SB 1 and SB2. Only benzene, which was reported at concentrations of 7.6 ug/l and 12 ug/l exceeded California's Maximum Contaminant Level (MCL) for drinking water. In correspondence dated October 9, 1998, PHD/EHD requested additional work be performed at the project site. SCOPE OF WORK Planning and Permits ATC has completed the well installation permit application for the proposed subsurface investigation. The permit application and associated fees (check no. 2465) are attached to this workplan. ATC will also schedule field personnel and equipment, notify Underground Service Alert to locate underground utilities as required, and perform any other necessary field preparation and job start-up activities. Installation of Soil Borings and Monitoring Wells Three soil borings will be advanced employing stem hollow auger to depths of approximately 95 feet bgs or 15 feet past first encountered groundwater. Drilling will be conducted by a State licensed (C57) drilling company. A field geologist will be present to log soil samples. Descriptions of soil types encountered and sample collection intervals will be recorded on boring logs. Soil samples will be collected at five-foot intervals or at significant changes in the lithology. Each soil sample will be field screened with a Photoionization Detection (PID) meter or similar instrument and at least two samples from each of the three borings, based on field observations (i.e. odor, discoloration, PID readings), will be placed in a cooler with ice and submitted for laboratory analysis. w:\14885\reports\wkp1n.doc 2