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GEOMATFI1X field water quality parameters were monitored and the clarity of the water was observed. Groundwater samples were collected in laboratory-prepared containers, sealed, labeled, and placed immediately in an ' ice-cooled chest for subsequent delivery to the laboratory using chain-of-custody procedures. ' 5.0 LABORATORY ANALYSIS Soil samples collected from the confirmation soil boring (SB6) were analyzed for BTEX using EPA ' Method 8020, TPH-G using a modified version of EPA Method 8015, and TPH-D also using a modified version of Method 8015, in accordance with the work plan. The TPH-D analysis was performed using standard procedures and also with a silica gel cleanup performed prior to analysis. The laboratory quantified the results of the Method 8015 analyses against a diesel standard as requested and reported the presence of hydrocarbons in the TPH-D range in this sample; however, the laboratory indicated that ' the chromatographic signature of the material present in the soil samples showed a non-typical diesel pattern. Laboratory services were provided by American Environmental Network (AEN) of Pleasant Hill, California. AEN is certified by the State of California to perform hazardous waste analyses. Analytical data sheets provided by the laboratory are included in Appendix C. ' In order to evaluate the type of petroleum hydrocarbons present in soil beneath the site, a soil sample collected during the additional characterization from boring SBS at a depth of 25 feet was submitted to a laboratory for fingerprint characterization by capillary gas chromatography. This sample had the greatest indication (based on field evidence, such as odor, discoloration, and OVM results) of the presence of petroleum hydrocarbons of the samples collected from that boring. Fingerprint characteri- zation was performed by Friedman & Bruya, Inc. (FBI) of Seattle, Washington. FBI is certified by the State of California to perform these analyses. Results of the fingerprint characterization indicate that the ' petroleum hydrocarbons in soil beneath the site are gasoline and not diesel. The sample was then analyzed for BTEX using EPA Method 8020 and for TPH-G using a modified version of EPA Method ' 8015. Analytical data sheets provided by the laboratory are included in Appendix C. Based on the results of fingerprint characterization, the remaining soil samples collected at the site ' submitted for laboratory analysis were also analyzed for BTEX using EPA Method 8020 and TPH-G using a modified version of EPA Method 8015. Laboratory services were provided by AEN. Analytical data sheets provided by the laboratory are included in Appendix C. In order to be consistent with, and confirm, the results of the groundwater monitoring performed by Geomatrix- in-May-,1995;=which=indicated-that diesel-was-not- present-in-groundwater, groundwater— --=--- samples collected on 17 November 1995 were analyzed for BTEX using EPA Method 8020 and TPH-G and TPH-D using modified versions of EPA Method 8015. To reduce the likelihood of false positives for TPH-D, groundwater samples were analyzed for TPH-D as follows: a standard sample with no preparation, a sample filtered using a 0.45 micron filter, and a sample filtered and treated with a silica 5