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` In addition, a deeper boring was drilled at location G to evaluate the vertical extent of soil contamination and to obtain a groundwater sample, if possible. Location G was selected because it exhibited the highest soil gas concentration. An attempt was made to collect a groundwater sample from the boring by installing a 1 114-inch diameter perforated pipe in the boring for about 4 hours. However, the boring did not produce a sufficient amount of groundwater to obtain a sample. 4.1 Field Procedures Precision Sampling, Inc. (PSI) performed the drilling and sampling activities under the supervision of a the field engineer. PSI used a trailer-mounted hydraulic drive rig to obtain soil samples. After coring through the asphalt and concrete road surface, the soil was ,. continuously sampled with a 1 5/8-inch diameter sample barrel. Each boring was lithologically logged by the field engineer. The lithologic logs are included in Appendix B. The soil samples were collected in brass tubes, and the ends of each tube were covered with �. teflon tape. Plastic caps were placed over the ends of each sample tube and were taped to the tube with duct tape to seal the samples. Each sample tube was labeled with the following ' information: (1) project name, (2) sample identification, (3) sample location, (4) name of • the sampler, (5) sample time and date, and (6) requested analyses. The samples were stored in a chilled cooler and sent to Coast to Coast Analytical Services, Inc., a state-certified y analytical laboratory located in Benicia, California. The samples were sent under chain of custody procedures. Upon the completion of each boring, the borehole was backfilled with hydrated bentonite and the street surface was repaired with a cold asphalt patch. All downhole drilling and sampling equipment were steam cleaned prior to drilling, between borings, and after completion of drilling activities. Soil cuttings from the borings and the rinsate water from the steam L cleaning activities were contained in sealed drums and stored on the Union Pacific yard on Eighth Street. L 4.2 Analytical_Program Each soil sample was analyzed by Coast to Coast using EPA Test Method 8260, a gas L chromatograph/mass spectrometer (GC/MS) procedure. The concentrations of BTEX compounds, total petroleum hydrocarbons (TPH) as gasoline and TPH as diesel were quantified for each sample. The laboratory reports are contained in Appendix C. 1 4.3 Results L As indicated in the lithologic logs for each boring (Appendix B), the near surface soil (< seven ft bgs) at the site consists primarily of fine grained materials such as silty clay. The deeper boring SG (Plate B-4) indicates that the sand content increases in the depth interval from about 10 to 17 feet bgs. Table 1 presents the analytical results for the soil samples. In general, the results of the soil samples confirm the soil gas data, which indicate that soil immediately adjacent to and 1.. r�.�srocK rorr.so 4 f