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Mr Harlin Knoll San Joaquin County Environmental Health Division 20 February 2001 ON Page 3 In December 1998, QST drilled soil borings BFS-1 and BFS-2 to collect sail and groundwater samples in the vicinity of the three closed-in-place USTs A report d 19 February 1999 of this field activity and analytical testingresults t aced SJCEHD Figure 2 in this report Shows the boring locations Four soil omitted to the analyzed at sample depths from 13 5 and 20 5 feet below grade in BFS-1 and 1 were 18 5 feet below grade from BFS-2 The sample results were non-detect ford 15 5 to toluene, ethylbenzene, and xylenes (BTEX), MTBE, other ox benzene, Field photoionization detector (PID) readings also showed negligible,tless thanalcohols Of volatiles from soil samples Groundwater was encountered in these bor4 ppmvt approximately 28 feet below grade A grab groundwater sample collected from iborin t BFS-1 contained TPHg at 4,200 µg/l and BTEX at 220 µg/I, 400 µ 1, 340 g 1,500 pg/l, respectively MTBE was also detected in groundwater from burin g l' and concentration of 0 at a 78 µg/l Of the gasoline-related compounds listed above, lonly xylenes were detected in a groundwater sample collected fromy boring BFS-2 (0 55 µg/!) These results would indicate that soil impacts from TPHg identified in the 199 FE is limited to the immediate area of FE's 1997 slant borings 7 work by In January 2000, Orion installed three groundwater monitoring wells (MVV-1 and MW-3) in the vicinity of the former USTs A report detailing the well i and 2, and groundwater sampling was submitted to the SICEHD on 7 July 2000 nralJ well d from locations are shown on Figure 2 One soil sample was selected and analyzed he well r boring during drilling activities The soil sample from MW-1, at a depth of 2 feet below m each grade, contained the only detectable concentration of MTBE at 99 micrograms kilogram (µ g/kg) This is several orders of magnitude below the EP per Preliminary Remediation Goals (PRG) of 37,00Q A Region 9 November MTBE in industrial soils The soil samples analyzed from rMW 2evised and MW-3 2000, for were below detection limits at depths of 35 and 15 feet below grade, respectively MTBE and BTEX were not detected in any of the other soil samples analyzed from the TPHg borings In January and May 2000, groundwater samples from well MW-1 (inst former source area) did not contain detectable amounts of TPHg orBTEXd near the amount of MTBE was detected in MW-1 at a concentration of 7 9 A small round of sampling and 4 D µg!l during the second round U psamplingientµg/1 during the first contained TPHg concentrations of 91 µg/l during the first round Of land 42 µg/l from the second round MTBE was not detected in MW-2 in either round of sampling The samples from cross-gradient well MVV-3 did not contain detectable concentrations of TPHg, BTEX, and MTBE during all rounds of groundwater sampling S\BFS\STOCKT0N\LTR\LTR007 DOC 2/20/01