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test. A trip blank was also placed in the cooler, together with the soil and groundwater samples, to verify any contamination while the samples were in transit from the site to the laboratory. To ensure the integrity of the samples, the cooler was sealed with a custody seal. BC Analytical informed CRC that the seal was intact and the samples were in good condition when they received them. 4.5 Groundwater Sampling and Monitoring One (1) groundwater sample was collected from each borehole. After the last sample was obtained between depths of 10 and 12 feet bgs, the probe rods, with a conical steel tip at the leading end, were lowered into the borehole. From the bottom of the borehole (12 feet bgs), the rod string was pushed 3 feet within the saturated zone. The conical tip was unlocked (released) and the probe rods were retracted 2 feet allowing water to recover within the exposed section of the borehole. A section of 3/8-inch Teflon tubing, connected to a small portable pump, was then inserted through the probe rods. After 15 to 30 minutes elapsed in order for for the water to recover, the battery-powered portable pump (Portable Masterflex, 12 VCD, 2.5 amperes pump) was started and water flowed through the tubing. Two (2) 40-milliliter (ml) VOA glass vials were filled with the water sample. A new set of Teflon tubing was used in every sampling round to prevent cross-contamination. The sample was labeled, double-bagged in a plastic bag, placed in a cooler with blue ice and entered onto a chain of custody form. The water sample from each of the boreholes was observed to be cloudy to murky (due to the presence of clay). However, no odor or discoloration which might infer the presence of petroleum hydrocarbon and/or VOCs was noted. The groundwater samples were analyzed for VOCs by EPA Method 8010. CRC monitored the depth to the groundwater in each borehole during the site investigation. The initial water measurement was conducted in the morning after the sampling. The second measurement was performed in the afternoon before the boreholes were backfilled. CRC used a Water Level Indicator (Slope Indicator Co.) which was provided with a light and sound alarm system. A flashlight bulb and a beeping sound were activated when the probe came in contact with the groundwater. The depth to groundwater was read on the graduated (0.01 foot) tape attached to the probe. CRC observed in the afternoon measurement that the groundwater receded 0.4 foot (4.8 inches) in borehole 132 and to 1.75 feet in borehole 131. Maximum drop of the groundwater was recorded in boreholes 131 (1.75 feet) and 133 (1.25 feet), where sandy, coarse to gravelly clay (SC) was encountered. 4.6 Decontamination of Coring and Sampling Tools All coring and sampling tools were decontaminated before and after coring to prevent cross contamination between boreholes. Soil materials adhering to the coring and sampling tools and liners were removed with a brush and the CRC Environmental Risk Management, Inc. Project#2100-217-2 American Savings Bank 150 West 10th Street May 1995 7 Tracy, California