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Mr. Kyle Christie February 27, 1995 Page 4 .J cleaning water (also stored in 15 labeled 55-gallon DOT drums) was removed from the site by Integrated Wastestream Management. Lithology The lithology of each borehole was classified by collecting soil samples every 5 feet to the total depth of each borehole using a 2-inch-diameter by 18-inch-long California split spoon sampler. Borehole logs are presented as Appendix C of this report. The lithology of the boreholes is generally similar to that of existing-monitoring wells and soil boreholes at the site. The upper 20 feet consists of silts and clays with zones of fine to medium sand. From 20 feet to the total depth of the boreholes (30 feet), the lithology consists of fine to medium sand with minor coarse sand and fine gravel lenses identified in some of the boreholes. Results During sampling, each borehole was monitored for the presence of hydrocarbons using a photoionization detector (PID). The PID readings are recorded on the borehole logs. Generally, the highest PID readings were recorded on soil samples collected in the unsaturated zone immediately above static groundwater. This indicates that the hydrocarbons are generally limited to the saturated zone and the capillary fringe. Samples were collected above groundwater in the boreholes for laboratory analysis. With the exception of boreholes VES-7, S-1, and S-3, two soil samples from each borehole were submitted for laboratory analysis. Samples from boreholes VES-7, S-1, and S-3 were not submitted to the laboratory because the soil quality in this area has been characterized with samples collected during previous investigations. Soil samples from eight boreholes were submitted to Sequoia Analytical Laboratory (a California certified and ARCO contracted laboratory) in Sacramento, California under proper chain-of-custody procedures. Each borehole soil sample was analyzed for benzene, toluene, ethylbenzene, and xylene (BTEX), and for total petroleum hydrocarbon as gasoline (TPH-G) by EPA Methods 5030/8020 and 8015 Modified. Table 2 presents a summary of laboratory analytical results for all soil samples collected from this site to date. The most recent sample results are in bold print. A complete laboratory report for the September sampling is included as Appendix D of this report. Hydrocarbons were not detected in either of the two soil samples collected from borehole VES-2. Hydrocarbons were identified in soil samples collected immediately above the saturated zone in all of the other boreholes. One or more hydrocarbon constituents were identified at concentrations slightly above the laboratory detection limit in the soil samples collected at a depth of approximately 5 feet in boreholes VES-3, VES-4, and VES-5 (near the pump islands). The highest TPH-G concentration (470 ppm) was identified in the sample 02724l95\E:\7524'RFPOR-TS 1524-011-1 QMS-PS2200