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Page 4 Tracy Tire Fire Celeste Temple,Project Officer Environmental Sciences Consultants (N&M) in Irvine, California for analysis of permeability using American Society for Testing Materials Method D5084 (ASTM D5084), Atterberg Limits (ASTM D4318-95), and Sieve Analysis (ASTM D422-63). The results are summarized in Table 1 below. Table 1 Geotechnical Analytical Results Summar Atterberg Limits Sample Permeability USCS Soil Type LL PL I PI (cm/sec) G-1 (1'9"-2'9") 47 24 23 2.5 x 10-8 CL G-1 (6'0"-7'0") 45 24 21 3.8 x 10-7 CL G-1 (7'0"-7'8") 44 22 22 CL G-2 (5'0"-6'0") 39 21 18 CL G-2 (11'0"-12'0") — — — SW-SM __J Where: LL=Liquid Limit PI=Plasticity Index CL=Low-plasticity clay PL=Plastic Limit cm/sec=centimeters per second SW-SM=Well graded to silty sand N&M was unable to test the permeability of three of the five samples submitted, due to low sample volume. N&M was able to test the permeability of the two samples listed above, because a significantly smaller volume was required for testing of those consolidated, predominantly fine- grained samples. Thus, the permeability values shown in the table should represent the lowest of the soils. Because the samples were also classified as sand and gravel (see Attachment B), the permeability can be much greater, possibly as great as 1 x 10-' cm/sec. It is important to note that the permeability of the geologic materials varies widely, and that several clay layers may act to retard the transmission of groundwater infiltrating from the surface. In addition to the GeoprobeTM sampling, IWMB personnel excavated trenches using a trackhoe to provide an exposed cross-section for the START geologist to observe. The geologic materials observed were consistent with the samples collected using the GeoprobeTM: interbedded gravel, sand, silt, and clay. However, one trench was excavated to a depth of approximately 20 feet, and groundwater was observed at a depth of approximately 15 feet in the trench. At the request of the OSC, a groundwater sample (T-1) was collected and submitted to the laboratory of Curtis & Tompkins, Ltd. in Berkeley, California and analyzed for the contaminants of concern: volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), phenols, and metals. No VOC, SVOC, or phenol constituent was detected. Some metals of concern were detected. Laboratory analytical results indicated that the levels of arsenic and lead in the groundwater exceed the EPA Region 9 Preliminary Remediation Goals (PRGs) for these metals; however, no 1:\000610\SF389_0339TTRZXX\ITTzur30.799.wpd 10/17/99 6:56 PM