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Kennedy/Jenks Consultants <br /> 5.4.7 OU-2 AOI 7 Soil Samples <br /> As described in Section 2, AOI 7 includes the "support" area where various support facilities <br /> were located. Soil samples collected from AOI 7 were analyzed for Title 22 metals, TPHd, <br /> TPHmo, VOCs, and SVOCs. <br /> 5.4.7.1 OU-2 AOI 7 Soil Samples — Metals <br /> Analytical results for the Title 22 metals are summarized in Table 6 with the respective PRGs <br /> and CHHSL values. <br /> Beryllium, selenium, silver, and thallium were not detected at concentrations exceeding <br /> analytical reporting limits in any of the 20 soil samples collected from AOI 7. Antimony was <br /> detected in four samples, mercury was detected in two samples, and molybdenum was detected <br /> in three samples. Cadmium concentrations in three samples slightly exceeded the residential <br /> CHHSL but not the residential PRG. <br /> Two surface soil samples contained concentrations of lead exceeding residential PRG and <br /> CHHSL values but not the industrial PRG or CHHSL values. The other 18 soil samples <br /> contained lead at concentrations less than residential PRG and CHHSL values. The lead <br /> concentrations were typically highest in the surface soil samples collected from the five borings, <br /> and decreased with increasing depth. <br /> Similar to other portions of OU-2, arsenic concentrations in the 20 soil samples collected from <br /> AOI 7 ranged from 1.4 to14 mg/kg. <br /> 5.4.7.2 OU-2 AOI 7 Soil Samples — Organic Compounds <br /> As shown in Table 7, TPHd and TPHmo were detected at concentrations exceeding analytical <br /> reporting limits in samples from the five borings advanced in AOI 7. Elevated concentrations of <br /> TPH occurred only in samples only from OU2-A017-S5. At a depth of 6.5 feet bgs, the soil at <br /> OU2-AO17-S5 changed color from brown to gray with black specks and had a hydrocarbon odor <br /> (see Appendix A). The TPHd and TPHmo concentrations in this boring increased with <br /> increasing depth, with maximum concentrations of 3,900 mg/kg of both TPHd and TPHmo <br /> detected in sample OU2-AO17-S-5-10/11. <br /> VOCs were detected at concentrations exceeding analytical reporting limits in three samples <br /> from Boring OU2-AO17-S4 and one sample from Boring OU2-AO17-S5. VOCs detected in <br /> Boring OU2-AO17-S4 include PCE and trichloroethene (TCE) at concentrations less than the <br /> respective PRGs. The PCE concentrations in Boring OU2-AO17-S4 decreased with increasing <br /> depth. VOCs detected in sample OU2-AO17-S-5-10/11 include acetone, sec-butylbenzene, and <br /> naphthalene, all at concentrations less than the respective PRGs. <br /> ' The SVOC phenol was detected in sample OU2-AO17-S-1-0/0.5 at a concentration of 1.1 mg/kg <br /> and sample OU2-AO17-S-1-5/6 at 0.13 mg/kg. These concentrations are less than the <br /> residential PRG. <br /> • <br /> DRAFT Phase I Remedial Investigation Report Page 28 <br /> Former Tracy Railyard, Tracy, California <br /> g:\is-group\admin\jobW510565777.18_uprr109-reportsld rpAtext.doc <br />