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C A M B R I A Mr Steven Shih
<br /> • June 20, 2005
<br /> ANALYTICAL RESULTS
<br /> Table 1 summarizes soil analytical results, and Figures 2, 3, and 4 present the TPHg, benzene,
<br /> and MTBE analytical data The laboratory analytical reports are included in Attachment B A
<br /> summary of the data is presented below
<br /> Compliance Sampling: The six samples (TP-1-19 through TP-6-19) collected from the UST
<br /> excavation did not contain any detectable TPHg,BTEX, or MTBE
<br /> Samples collected from beneath three of the dispensers (D-1-5, D-2-5, and D-3-5) contained 850,
<br /> 10,000, and 7,300 parts per million (ppm) TPHg, respectively No benzene or MTBE was
<br /> detected in these samples, although reporting limits were elevated Sample D-4-5 did not contain
<br /> any detectable TPHg,BTEX, or MTBE
<br /> Three samples collected from beneath product piping (P-1-5, P-2-5, and P-3-5) contained 220,
<br /> 2,300, and 3,800 ppm TPHg, respectively No benzene or MTBE was detected in these samples,
<br /> although reporting hnuts were elevated Soil sample P-7-5 contained 0 011 ppm MTBE The
<br /> other samples (P-4-5 and P-6-5) collected beneath product piping did not contain detectable
<br /> TPHg, benzene, or MTBE
<br /> The 12 samples collected from the pea gravel stockpiles (PG-1 through PG-12) did not contain
<br /> any detectable TPHg, BTEX,or MTBE
<br /> Over-Excavation Sampling- Of the 17 samples collected from the excavation near the north and
<br /> eastern dispensers, 10 (D-3-12, S-8-12, 5-9-12, 5-10-12, S-11-12, 5-12-7, 5-13-7, 5-15-4,
<br /> 5-16-7, and 5-17-11 5) contained TPHg at concentrations ranging from 14 to 11,000 ppm, 7
<br /> (D-3-12, 5-8-12, 5-10-12, 5-11-12, 5-15-4, 5-16-7, and 5-17-11 5) contained benzene from
<br /> 0 020 to 10 ppm, and 3 (5-13-7, 5-14-7, and 5-15-4) contained MTBE from 0 013 to 0 042 ppm
<br /> Note that the soil from sample locations 5-13-7 and S-15-4 was removed during the over-
<br /> excavations activities (as indicated by shading in Table 1) Therefore, the only sample containing
<br /> detectable MTBE that remains in place beneath the site is 5-14-7 (0 013 ppm) The highest TPHg
<br /> was detected in soil sample 5-8-12, located northwest of the eastern dispenser Samples collected
<br /> near the northern dispenser indicate that over-excavation was effective in removing TPHg,
<br /> benzene, and MTBE from that area
<br /> Of the four samples collected in the vicinity of the western dispenser, one sample (5-1-7)
<br /> contained 17 ppm TPHg and 0 081 ppm benzene All four of these samples contained MTBE at
<br /> concentrations ranging from 0 0057 to 0 11 ppm, with the highest concentration in sample 5-1-7
<br /> 4
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