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Kennedy/Jenks Consultants <br /> PRIVILEGED & CONFIDENTIAL <br /> 4.0 DISCUSSION <br /> A total of 16 soil gas samples were collected and analyzed during this soil gas survey. <br /> Based on these results, the concentrations of PCE in the soil gas samples collected from 5 <br /> feet bgs are highest immediately south of the Beckman Building and appear to decrease in <br /> all directions from Sampling Point#3. For soil gas samples collected from 18.5 to 22 feet <br /> bgs, the highest concentrations appear to be to the south of the area investigated as par <br /> of this study. <br /> The results of this soil gas survey indicate that the concentrations of PCE are greater in the <br /> samples collected from 18.5 to 25 feet bgs than the samples collected from 5 feet bgs with <br /> the exception of samples collected from Sampling Points SPm3 and SP 7, where this trend <br /> is reversed. The presence of PCE in shallow groundwater in the vicinity of the Beckman <br /> Building was documented in the URS report. <br /> The results of this soil gas survey also generally agree with data on PCE concentrations in <br /> soil gas samples detected by URS Consultants, Inc. (URS) from depths of approximately 5 <br /> feet bgs. The results of the FRI conducted at Guild indicate elevated concentrations of <br /> PCE at a depth of 5 feet along the main sewer line located in the alley south of the <br /> Beckman Building (running east to west and buried at a depth of approximately 5 feet). <br /> This study detected elevated PCE concentration in the soil gas sample collected at 5 feet <br /> bgs from Sampling Point SP#B along the sewer line. <br /> The soil gas results from the samples collected at 5 feet bgs as part of this survey <br /> corroborate the PCE detected in the soil samples recently collected from a similar depth at <br /> the Site by Kleinfelder. Figure 2 presents the locations of and PCE concentrations in the <br /> soil samples collected by Kleinfelder. However, the distribution of PCE in soils as <br /> interpreted by the soil sampling results, reported in micrograms per kilogram of soil, do not <br /> directly compare with the distribution of PCE in soils as interpreted by the soil gas sampling <br /> results, reported in ug/I. The difference in the comparison is most evident along the <br /> western boundary of the Beckman Building property. <br /> ��,�;,:_�_• 5 95270-4.01 <br /> 9951.9527r,4.01.uod:-m c doc <br />