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Kennedy/Jenks Consultants <br /> 6.2.5 Conclusions for OU-2 <br /> Total lead exceeding industrial CHHSL values was present in one surface soil sample. Arsenic <br /> was present in nine soil samples at concentrations exceeding background levels. These <br /> samples were typically collected from surface or near-surface soils. Other metals are not <br /> considered chemicals of further interest in OU-2. <br /> Given the activities which historically occurred in OU-2, the presence of TPH in soil in all of the <br /> AOls in OU-2 is not unexpected. The elevated TPH concentrations frequently occurred in <br /> samples collected from surface or near-surface soils. <br /> TPHd was found in all four groundwater samples from OU-2, however the samples were not <br /> filtered prior to analysis. Although relatively elevated concentrations of TPHd and TPHmo were <br /> present in the groundwater sample collected from AOI 7, it is anticipated that filtration and/or <br /> silica gel cleanup of future groundwater samples would reduce the TPH concentrations in <br /> groundwater. <br /> VOCs and SVOCs in soil are not chemicals of further interest in OU-2. VOCs in groundwater <br /> also are not chemicals of further interest. TPH in soil, and potentially groundwater, in OU-2 may <br /> require further evaluation. The highest TPH concentrations in shallow soil in OU-2 were found in <br /> AOI 4 (former ponds), AOI 5 (former oil tank and associated facilities) and AOI 6 (former <br /> roundhouse). <br /> 6.3 Operable Unit 3 <br /> Three soil borings were advanced in OU-3 and two soil samples from each boring were <br /> rcollected and analyzed for TPH, lead and arsenic. Although the total lead concentrations in <br /> each of the three <br /> ive to lead concentrations in the deeper sample from <br /> near-surface samples were elevated relat <br /> each boring, none of the lead concentrations exceed industrial PRG or CHHSL values. The <br /> near-surface soil sample collected from Boring OU3-S1 also contained elevated concentrations <br /> of TPH and arsenic. The arsenic concentrations in the other five soil samples appear to be <br /> consistent with background arsenic concentrations in soil at the Railyard. <br /> Consistent with findings from the other OUs, analytical results from all three soil borings indicate <br /> that concentrations of TPH, lead and arsenic in soil decrease significantly with increasing depth, <br /> indicating that the chemical impact is typically limited to near-surface soils. <br /> Three reconnaissance groundwater samples were previously collected in and adjacent to OU-3. <br /> Analytical results from these samples indicate that elevated concentrations of TPH are present <br /> in groundwater in the southwestern portion of OU-3 (Geocon 2005). <br /> 6.4 Operable Unit 4 <br /> 6.4.1 Findings <br /> Four soil borings were advanced in OU-4 and two soil samples from each boring were collected <br /> and analyzed for TPH, lead and arsenic. One soil sample was also analyzed for VOCs and <br /> DRAFT Phase I Remedial Investigation Report <br /> Page 42 <br /> Former Tracy Railyard, Tracy, California <br /> g:\is-group\admin\job\0510565777.18_uprr\09-reports\d rpt\text.doc <br />