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1 <br /> MA <br /> April 15, 1993 Working To Restore Nature <br /> 1 ARCO Service Station No 2076, Lodi, California <br /> Results of analyses of soil samples indicate that residual hydrocarbons have been delineated <br /> at the site Residual hydrocarbons were identified and remain in place beneath the former <br /> underground storage tanks and dispenser islands Based on laboratory analyses, residual <br /> 1 <br /> hydrocarbons were detected near the former underground storage tanks at a depth of 11 <br /> feet below grade in borings B-14 and B-16 Residual hydrocarbons were detected near the <br /> dispenser islands to a depth of 6 feet below grade, however, TPHg at concentration of 1 1 <br /> I parts per million (ppm) was detected at a depth of 31 feet below grade in boring B-15 <br /> Laterally, residual hydrocarbons appear to be limited to the former underground storage <br /> tanks and to the vicinity of the dispenser islands The lateral extent of the hydrocarbons <br /> directly east of the former tank cavity and beneath the station budding has been inferred <br /> I <br /> based on data gathered from borings B-10 and B-11 (Plate 6) <br /> Free-Phase Hydrocarbons in Ground Water <br /> Results of subjective analyses of ground-water samples collected during the ground-water <br /> monitoring events indicated floating product has not been present at the site since <br /> monitoring began (Table 6) <br /> Dissolved Hydrocarbons and Selected Chemicals in Ground Water <br /> 1 Laboratory analyses indicated detectable concentrations if dissolved gasoline (TPHg) and <br /> BTEX compounds were not present in ground-water samples collected from monitoring <br /> wells MW-1 through MW-4 Total and fecal coliform bacteria were not detected at <br /> concentrations above laboratory reporting limits from the water sample collected from well <br /> MW-4, however, nitrate (4 3 ppm) was detected to the water sample from well MW-4 The <br /> analytical results are summarized in Table 7 Based on these laboratory results, ground <br /> water beneath the site has not been impacted by hydrocarbons Appendix C contains the <br />► laboratory reports and Cham of Custody Records <br /> -5 10 <br /> 1 <br />