ARCHIVED REPORTS_PHASE II ENVIRONMENTAL SITE ASSESSMENT

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WGIR, • Soulthwest, linin. from B-1 with a concentration of 170 mg/Kg. TPH-mo was also detected in the two backhoe excavation samples, 5-3-3' and S-6-1.5', at concentrations of 7.6 and 16 mg/Kg, respectively. TPH as gasoline (TPH-g) was detected in nine of the one-foot boring samples at concentrations ranging from 2.1 to 4.4 mg/Kg, all below the ESL, but was not detected in the excavation samples or deeper boring samples. The chromatograms indicated strongly aged gasoline and significant diesel range compounds with no recognizable pattern. TPH as diesel (TPH-d) was detected in all 1-foot boring samples except B-11 and B-18 and was also detected in the 1.5-foot excavation sample, the 3-foot sample from B-8 and the 5- foot sample from B-1. Detectable TPH-d concentrations ranged from 1.8 to 450 mg/Kg with the highest concentration found in B-9. TPH-d levels exceeded the ESL in the 1-foot samples from B-4, B-9 and B-13. The chromatograms indicated significant diesel and oil range compounds with no recognizable pattern. The concentrations of TPH-d, TPH-mo and petroleum O&G detected in the one-foot samples are shown on the site plan presented as Figure 4. . The VOC acetone was detected in one-foot soil samples from B-1, B-8, B-9, B-13 and B-17. The compounds 2-butanone (MEK) and styrene were detected in the one-foot sample from B- 13, and MEK and naphthalene were detected in the one-foot sample from B-17. These were the only detections of VOCs and all were well below the applicable PRGs. The only SVOCs detected were bis(2-ethylhexyl) phthalate and butyl benzyl phthalate which were found in the one-foot sample from B-13 at concentrations of 100 and 27 mg/Kg, respectively, which are below PRGs. 10.2 Groundwater Analytical Results The results of laboratory analysis of the groundwater grab samples collected from the temporary casings installed in the borings on May 14, 15 and 16, 2008 are summarized in Table 2. The laboratory analytical reports for the groundwater samples are included as Appendix B. The applicable primary maximum contaminant levels (MCLS) for drinking water, as outlined in Title 22 of the California Code of Regulations, are listed in the right column of Table 2. In cases where MCLS are not established, the California Department of Health Services (DHS) notification levels are given or, in the case of petroleum hydrocarbons, San Francisco RWQCB ESLs are listed. • 704. PRI.05 22 July 21, 2008