ARCHIVED REPORTS XR0001334 - Laserfiche WebLink

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u 1992 �AC�MA August 11, Working To Restore Nature ARCO Service Station 2168, Stockton, California PCB, HVO, TOG and Hexavalent chromium were below detection limits in the sample collected from boring B-7 near the waste oil tank. TEH (Cg - C30) were detected in sample S-40 S-B7 at 7 4 ppm; however, the laboratory report indicates that the sample does not F appear to contain diesel A cross section (Plate 23) was prepared to show the evaluated distribution of sediments and residual hydrocarbons in soil beneath the site from boring B-11 to boring B-3 (Plate 2) Sediments beneath the site are predominantly silt to clayey silt. The cross section shows that higher concentrations of residual gasoline hydrocarbons were detected in soil samples 1 collected near the dispenser islands than in samples collected near the underground storage tanks. Soil sample S-46 5-B8 was submitted to Raney Geotechnical of West Sacramento, California to evaluate the physical properties of the aquifer Results of the physical tests indicated a 1 specific gravity of 2 65 and a permeability of 9 0 X 10-7 centimeters per second. Sieve analyses of aquifer material indicated it is a silty sand. Plots of the sieve analyses are included in the attachments of this report. GROUND-WATER MONITORING AND ANALYSES Ole, On May 11, 1992, a technician from RESNA visited the site to take water-level measurements, conduct subjective analyses of ground water, and collect ground-water samples from wells MW-1 through MW-3 for laboratory analyses. The technician noted no floating product or sheen in the three wells Results of subjective analyses are presented in Table 3 Water purged from the wells was stored onsite to properly labeled 17-E steel drums pending the results of laboratory analyses. At ARCO's request, drummed water was removed and disposed of by Armour Petroleum Service and Equipment Corporation of Fairfield, California Results of Analyses of Ground-Water SaMples Water samples were analyzed for TPHg using modified EPA Method 8015 and BTEX using EPA Method 602. In addition, the water sample from well MW-2 was analyzed for TEH R using EPA Method 8015, TOG using EPA Method 413 2, and purgeable halocarbons using EPA Method 601 The water sample from well MW-3 was also analyzed for total and fecal coliform bacteria. Water samples were analyzed at Sequoia Analytical of Sacramento, California Results of water analyses are summarized in Table 4 and Table 5. t � 0526ccar 3ioo9-a 4