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Kennedy/Jenks Consultants <br /> Other soil samples were collected from the trenches near clay-tile pipes and the shallow metal <br /> pipe. These samples include OU5-AO112-TS-2-4, OU5-AO112-TS-3-6, OU5-AO112-TS-4-1.3, <br /> and OU5-AOl 1 2-TS-6-1.5. These samples were analyzed for TPHg, TPHd, and TPHmo. <br /> 5.7.3 OU-5 — Metals <br /> 5.7.3.1 Arsenic and Lead — Soil Borings <br /> The lead and arsenic results for the soil samples obtained from soil borings advanced in OU-5 <br /> are summarized in Table 11 and the total lead concentrations in shallow soil samples are shown <br /> on Figure 11. <br /> Concentrations of total lead ranged from 4.2 mg/kg to 780 mg/kg in soil samples collected from <br /> borings advanced in OU-5. With the exception of Borings OU5-AOI9-S20 and OU5-AO19-S22, <br /> the total lead concentrations in the surface samples were greater than the lead concentrations <br /> in the deeper samples. The highest lead concentrations are found in borings located mainly <br /> ' along the north side of OU-5 west of Avenue C, and in two borings in the central part of OU-5. <br /> Total lead concentrations in nine shallow samples in the northern part of OU-5 and two samples <br /> from central OU-5 exceeded the residential PRG and CHHSL values. None of the samples <br /> contained lead concentrations exceeding the industrial PRG and CHHSL values. <br /> Arsenic concentrations ranged from 1.8 mg/kg to 140 mg/kg in the soil samples collected from <br /> borings advanced in OU-5. With the exception of two borings (OU5-AOI9-S20 and <br /> OU5-AO19-S22), the arsenic concentrations in the surface samples were greater than the <br /> concentration from the deeper sample. The highest arsenic concentrations also occur mainly <br /> along the north side of OU-5 west of Avenue C, and in two borings in the central part of OU-5. <br /> Similar to soil samples from OU-2, arsenic concentrations in the soil samples from OU-5 exceed <br /> the residential PRG and CHHSL values. Soil boring samples with elevated concentrations of <br /> arsenic also contained elevated concentrations of lead, although the converse does not hold. <br /> The highest concentrations of both lead and arsenic in this set of samples were found in sample <br /> OU5-AO&S-8-0/0.5. <br /> Fragments of slag ballast were commonly observed on the ground in the northwestern part of <br /> OU-5. The greatest lead and arsenic concentrations were also found in this area. <br /> 5.7.3.2 Arsenic and Lead —Trenches and Test Pits <br /> The lead and arsenic concentrations in soil samples collected from the trenches and test pits <br /> are also included in Table 11. In AOI 11, higher concentrations of both lead and arsenic were <br /> found in the shallow (0.5 foot bgs) trench samples than in the sample collected from 3 feet <br /> depth. In the shallower samples, total lead concentrations ranged from 110 mg/kg to 530 mg/kg <br /> and arsenic concentrations ranged from 52 mg/kg to 110 mg/kg. The concentrations of lead and <br /> arsenic in the deeper sample were 7.6 mg/kg and 4.3 mg/kg, respectively. Similar to the soil <br /> boring samples, the highest concentrations of both lead and arsenic in the trench and test pit <br /> samples were found in the same sample. <br /> • <br /> DRAFT Phase I Remedial Investigation Report Page 33 <br /> Former Tracy Railyard, Tracy, California <br /> g:lis-groupladminljob10510565777.18_uprr109-reportslri rptltext.doc <br />