ARCHIVED REPORTS_REPORT OF ADDITIONAL SOIL AND GROUNDWATER INVESTIGATION

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GEOMATR • The soil and grab groundwater samples were submitted to Friedman and Bruya,Inc.,of Seattle, ' Washington, a Califomia-certified analytical laboratory,under Geomatrix chain-of-custody procedures. Soil samples were submitted for analysis for TPHc(Clo-C36 carbon range)using EPA ' Method 8015 Modified,PAHs using EPA Method 8270 SIM,and BTEX using EPA Method 8020. Grab groundwater samples were analyzed for TPHg(C6 to C12 carbon range)and TPHd(C10 to C24 carbon range)using EPA Method 8015 Modified,BTEX using EPA Method 8021B,and PAHs using EPA Method 8270 SIM. TPHd analyses were performed both with and without a silica gel preparation procedure to assess the presence of polar biodegradation byproducts in the groundwater ' samples. An aliquot of the sample from GMX-28(located within affected soil)was filtered by the laboratory with a 0.7-micron glass fiber filter prior to extraction and analysis to assess the presence of non-dissolved constituents adhered to particulates in the sample. Because the sample was collected within affected soil and it contained significant particulates,such interference from non-dissolved constituents was expected. Following collection of the soil and grab groundwater samples,the borings were backfilled with ' cement grout placed from the total depth of the boring to ground surface with a tremie pipe. '• 5.0 ANALYTICAL RESULTS TPHc,BTEX,and PAHs were not detected in the soil samples from GMX-23 and GMX-24. Soil ' sample analytical results are summarized in Table 3 and are presented on Figure 2. No BTEX,TPHg,or PAHs were detected in the grab groundwater samples from borings GMX-23 ' and GMX-24,which were collected downgradient of affected soil. Prior to the silica gel preparation procedure,TPHd was not detected above laboratory reporting limits in the sample from GMX-23, ' and was detected in the sample from GMX-24 at a concentration of 63 µg/1. Following a silica gel preparation procedure,TPHd was detected in both grab groundwater samples at concentrations of ' 127µg/1 (GMX-23) and 108 µg/l(GMX-24). However,TPHd was also detected in the method blank at a concentration of 116µg/1 and the laboratory indicated that these detections are likely due to laboratory contamination. In the grab groundwater sample from boring GMX-28,which was collected within the area of affected soil,toluene, and xylenes were detected at concentrations of 0.7 and 1.5 µg/l,respectively; and fluorene and phenanthrene(PAHs)were detected at concentrations of 0.3 and 0.2µg/l, ' respectively. TPHd was detected at a concentration of 620µg/1 prior to the silica gel preparation • procedure,and at 100µg/1 following a silica gel preparation procedure. TPHd was reported at 380 \\SF3\DEPTDATA\DOC_SAFE\60005\6115.007\DEC2000REPORT\BURNS SOILGW RPTNOV00_I.DOC 5