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i. j kwoo v Kennedy/Je *9I Chuen Mr. Tom Terrill Reynolds and Brown 26 January 1987 Page Three Undisturbed soil samples were collected at five toot intervals using a 2. 5-inch outside diameter California Modified Drive Sampler. The sampler was driven 18 inches below the bottom of the auger bit using a 140-pound hammer which fell over a 30--inch interval. Each sampler was equipped with three 1. 5-inch diam- eter, 6-inch long brass liners for preservation and handling of collected samples. The sampler and brass liners were steam cleaned initially and between subsequent uses to minimize cross-contamination of samples. J One liner from each sample drive was preserved for chemical analysis. These liners sample were covered on each end with teflon sheets, capped with vinyl end covers, and sealed with plastic tape to minimize the loss of volatile constituents. These samples were chilled and transported to Kennedy/Jenks/ Chilton' s Laboratory Division for analysis. Chain of custody forms were maintained throughout sample collection and trans- port. Two soil samples from each boring were selected for chem- ical. analysis. Headspace analysis for the presence of organic vapors was also performed in the field on a separate soil sample from each sam- pler interval . A portion of the soil sample selected for head- space analysis was extruded into a pre-cleaned glass jar which was covered with aluminum foil and allowed to sit in a warm area for five to ten minutes. The head space (the space in the jar above the soil sample) was then monitored for total organic vapors by inserting the intake tube of a Foxboro Model 128 por- table organic vapor analyzer through the aluminum foil. The maximum organic vapor concentration detected was recorded. Headspace organic vapor monitoring was performed as a field method for evaluating the presence of petroleum product in soil , as well as a criterion for selecting soil samples for laboratory analysis. Boring logs that describe subsurface lithology using the Unified Soil Classification System, depths of sampled intervals, mea- sured groundwater levels and details of well construction are presented in Attachment B. The first two borings, Bl and B2, (see Figure 1 ) , were drilled to a depth of 15 feet, which was the depth of the first soil sample collected below the water table. The third boring , B3, was drilled to a depth of 20 feet. This was done because head- space monitoring detected organic vapors in the sample from 10