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Mr. Ron Rowe March 9, 1998 Page 3 t,. Two generalized geologic cross sections(A-A' and B-B')are presented on Figure 4. These cross sections are intended to depict the generalized geologic conditions and differentiate between intervals dominated by coarser-grained sediments (sand and gravel)and intervals dominated by fine-grained sediments (silt and clay). The coarser-grained strata are those expected to store and transmit groundwater,while the fine-grained deposits are not expected to store or transmit significant quantities of groundwater. Interpretation of CPT data indicate that sediments underlying the Site to the maximum depth explored consist of relatively unconsolidated,interbedded,gravel, sand,silt, and clay. Based on their occurrence at comparable depths, individual sand and gravel horizons have been correlated across portions of the Site(see Figure 4); however,it is unknown whether these sand layers are laterally continuous across the Site or on a regional scale. The upper 30 to 45 feet consist of fine-grained sediments (predominantly silt and clay). Beneath the fine- grained layer are interbedded coarse-and fine-grained layers to the total depth explored. Two relatively thick (7 to 9 feet thick) coarse-grained layers were encountered at 43 to 50 feet and 79 to 88 feet bgs. Similar interbedded sediments were encountered at comparable depths in CPT-2 and CPT-3 soundings advanced at the Site. Although a Site-specific flow direction for the Site cannot be confidently established without a minimum of j three monitoring wells or piezometers, information on groundwater flow patterns at the adjacent property I indicate the regional direction of groundwater flow is towards the southeast. During the December 1997 CPT investigation, a total of seven PPDT tests were performed in soundings CPT-1 through CPT-3. The PPDT measures the time required for the static pare pressure to reach an equilibrium value. In general, the more permeable the sediments the more rapidly the pore pressure will equilibrate. As expected,results of the PPDT show relatively rapid dissipation rates at depths where coarse-grained layers were determined by CPT soundings. Groundwater and Soil Analytical Results Chemical analytical results for groundwater samples are presented on Table 1. Groundwater and soil laboratory analytical data reports and chain-of-custody records are provided as Attachment B. TPHg concentrations of 1,400 parts per billion(ppb) and 2,800 ppb were observed in the groundwater grab samples collected from CPT-1 at 84 and 106 feet bgs,respectively. Benzene concentrations of 100 and 260 ppb were observed in the groundwater samples collected from CPT-1 at depths of 84 and 106 feet bgs, respectively. Concentrations of toluene, ethylbenzene, and xylenes were also observed in the groundwater grab samples from CPT-1 at depths of 84 and 106 feet bgs and are presented on Table 1. MTBE was not detected above the detection limit in the two groundwater grab samples from CPT-1. TPHg, BTEX, and MTBE were detected above the detection limits in the soil sample collected from CPT-1 at a depth of 125 feet bgs. A TPHg concentration of 17,000 ppb was observed in the groundwater grab sample from CPT-2 at a depth of 82 feet bgs. TPHg concentrations were not observed above the detection limits in the groundwater grab samples collected at 32 and 102 feet bgs in CPT-2. Benzene concentrations of 0.9 and 4,600 ppb were observed in the groundwater samples collected from CPT-2 at depths of 32 and 82 feet bgs, respectively. Benzene concentrations were not observed above the detection limit in the groundwater grab sample collected at 102 feet bgs. Concentrations of toluene,ethylbenzene, and xylenes were observed in the groundwater grab sample collected at 82 feet bgs from CPT-2 and are presented on Table 1. Concentrations of toluene, ethylbenzene, and xylenes were not observed above the detection limits in the groundwater grab samples collected from CPT-2 at depths of 32 and 102 feet bgs. MTBE was not observed above the detection limits in all three groundwater samples collected from CPT-2. HASPPBISTOCKTONICPTSURV2.RPT SECOR International Incorporated