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2.3 PHASE II INVESTIGATION <br /> WES performed a Phase II soil investigation in October 1997 This involved <br /> 1 advancement of three shallow soil borings (B-2 through B-4) in the vicinity <br /> of the former UST Boring B-2 was drilled just west of the former UST <br /> location Borings B-3 and B-4 were drilled to the southwest, near the former <br /> location of a battery storage area All boring locations are shown on <br /> Figure 2 <br /> Analytical results (Table 2) indicated that soil in the vicinity of the former <br /> tank was impacted by total petroleum hydrocarbons in the gasoline range <br /> (TPH-g) TPH-g was detected in boring B-2 at concentrations of 17,000 <br /> and 13 milligrams per kilogram (mg/kg) at depths of 16 5 and 215 feet <br /> bgs,respectively In the 16 5 feet bgs sample, benzene was not detected <br /> over the elevated reporting linut of 62 mg/kg, however,toluene, <br /> ethylbenzene, and xylenes were detected at concentrations of 570,300, and <br /> 1,700 mg/kg,respectively Benzene, toluene, ethylbenzene, and xylenes <br /> (BTEX) were detected in the 215 feet bgs sample at concentrations of <br /> 0 017,0 069, 0 013, and 0 076 mg/kg, respectively Although the samples <br /> from borings B-3 and B-4 were not analyzed for TPH-g, the lack of BTEX <br /> in these samples suggests that TPH-g was not present The results of the <br /> Phase 11 investigation were presented in a 11 November 1997 letter report <br /> prepared by WES entitled, Phase II Hazardous Materials Report, Parcels 5 and <br /> 6, Stockton Multimodal Station Site <br />' 2.4 SOIL AND GROUND NATER CHARACTERIZATION <br /> On 5 November 1997, an Underground Storage Tank Unauthorized <br /> Release form was submitted by San Joaquin County to the State Water <br /> Resources Control Board in response to the analytical results of the <br /> samples collected during the Phase II investigation In a 5 December 1997 <br /> letter,San Joaquin County notified UPRR that the 936 East Weber site had <br /> been placed m the Local Oversight Program and that UPRR had been <br /> designated as the primary responsible party <br /> In May 1998,ERM completed a soil and ground water characterization to <br /> further characterize the lateral and vertical extent of TPH-g impact to soil in <br /> the vicinity of the former UST and evaluate potential TPH-g impact to <br /> ground water The results of the characterization were presented in a report <br /> entitled, Soil Investigation Report- 936 East Weber Avenue - Stockton, California <br />' (ERM, August 1998) <br /> For this investigation, ERM collected 12 soil samples and two grab ground <br /> water samples from borings B-5 and B-6 Boring B-5 was located in the <br />' ERM 5 9343 50/UPRR/07/11/02 <br />