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I <br /> amec , <br /> with information from nearby sites associated with the HPP (TAOC Tracy Pump Station and <br /> Alden Park; Geomatrix, 2006). <br /> 2.3 PREVIOUS INVESTIGATIONS IN EASTERN PORTION OF TRACY RAIL YARD <br /> Kennedy/Jenks and AMEC have conducted soil and groundwater investigations in the eastern <br /> portion of the Tracy Rail Yard site (A0I-4 and A0I-5) since 2005 (Kennedy/Jenks, 2006 and <br /> AMEC, 2010). Soil and groundwater sampling locations and petroleum hydrocarbon analytical <br /> results from these past investigations are shown on Figures 3 and 4. Analytical results from <br /> these past investigations for the A0I4 and A0I-5 portions of the Tracy Rail Yard site are <br /> included in Appendix A. <br /> During previous investigations in A0I4 and A0I-5, Kennedy/Jenks and AMEC observed <br /> evidence of petroleum-affected soil, and elevated concentrations of total petroleum <br /> hydrocarbons (TPH) were detected in soil samples from several borings(Figure 3) at depths <br /> up to 18 feet bgs in the vicinity of the former TAOC pipeline. The highest concentrations of <br /> TPH in soil were generally detected near the HPP and near the terminus of the OVP. Elevated <br /> concentrations of TPH were detected in several groundwater samples in the vicinity and <br /> downgradient of the former TAOC pipeline (Figure 4). <br /> Benzene, toluene, ethylbenzene and xylenes (collectively referred to as BTEX)were not <br /> detected in soil samples collected from A0I4 and A0I-5 except for one detection of benzene <br /> at 0.0005 milligrams per kilograms(mg/kg) in the soil sample collected from boring TRY-11 at <br /> 6.0 bgs (Figure 3). This concentration was J-flagged as it was reported between the laboratory <br /> method detection limit and the laboratory reporting limit. BTEX was not detected in <br /> groundwater samples collected from A0I4 and A0I-5 (Figure 4). <br /> Volatile organic compounds (VOCs)were not detected in soil samples collected in 2005 by <br /> Kennedy/Jenks with the exception of tetrachloroethene at one location and acetone at three <br /> locations; these constituents are not associated with the HPP. VOCs were not detected in <br /> groundwater samples collected in 2005 by Kennedy/Jenks. <br /> Polynuclear aromatic hydrocarbons (PAHs) were detected at low concentrations in all the soil <br /> samples collected from A0I-4 and A0I-5 by AMEC in 2009. With the exception of phenol at <br /> one location, semi-volatile organic compounds were not detected in the samples collected by <br /> Kennedy/Jenks in 2005. Low concentrations of certain PAHs were detected in groundwater <br /> samples collected by AMEC from TRY-1 and from TRY-3 at 25, 30, and 48 feet bgs. <br /> AMEC Geomatrix, Inc. <br /> X:\16000s\161130\4000\OffSiteEastWP 061511\1 txt,cvrs,Itrs\text.docx 3 <br />