Laserfiche WebLink
Regional Office <br /> 4585 Pacheco Boulevard <br /> ®INTERNATIONAL i � ;pA�iYtinez,California 94553-2233 <br /> TECHNOLOGY May 2, 1996 510-372-9100 <br /> CORPORATION :f.t' Fax:510-372-5220 <br /> -7 t;TlFr* ct NO: 765748 <br /> Mary Maeys <br /> San Joaquin County Public Health Services <br /> Environmental Health Division <br /> PO Box 2009 <br /> Stockton, California 95201 <br /> Planned Overexcavation Activities <br /> Pacific Bell Tank Replacement Project <br /> ?.3-00 Fight -Mile Road; Stockton, CsHfforma <br /> Dear Ms. Maeys: <br /> IT Corporation (PT) was retained by Pacific Bell to conduct oversite and verification sampling <br /> activities during the removal of two underground storage tanks from the above referenced Pacific <br /> Bell Property. The tanks consisted of one 4,000 gallon diesel fuel tank and one 10,000 gallon <br /> unleaded gasoline tank, which were removed on May 2, 1996 by representatives of Aronson <br /> Engineering. Two separate excavations (one for each tank) were dug, with two verification soil <br /> samples being collected beneath the diesel tank and three verification soil samples being collected <br /> beneath the unleaded gasoline tank. A mobile lab operated by Sparger Technology was onsite . <br /> to analyze the verification samples. Analytical results indicated the presence of unleaded gasoline <br /> in two of the three samples collected from the gasoline tank excavation (the sample collected at <br /> the east end and the sample from the center of the excavation floor possessed the gasoline <br /> concentrations. Petroleum contaminants were not encountered in the diesel tank excavation. <br /> It is the intention of IT to conduct overexcavation and a second round of verification sampling <br /> activities in the areas found to contain fugitive petroleum concentrations. A track excavator will <br /> be delivered to the cit-on May 2, 1996 in prep aratien for overexcavaa6)n eff£+rtc, to begin on May <br /> 3, 1996 at 0700. IT anticipates extending the depth of the excavation a maximum of 5.0 feet to <br /> (resulting in a maximum excavation depth of 20.0 feet below grade). The excavation side walls <br /> (east, and possibly north and south) may be extended a maximum of 2.0 feet beyond current <br /> limits, in the areas adjacent to the impacted soils. Overexcavation activities will be continued <br /> until no further visual, olfactory or field screening indications of petroleum contamination exists <br /> or the limits of the excavating equipment have been reached. Overexcavation activities will also <br /> be halted if it appears that any onsite structure may be undermined. <br /> A mobile laboratory will be onsite to analyze the second round of verification soil samples. <br /> Samples will be collected from the center of each new wall or floor excavated at a rate of 1/20 <br /> yd3 of soil removed. The samples will be analyzed for total petroleum hydrocarbons (TPH) as <br /> gasoline and benzene, toluene, ethyl benzene and xylenes (BTEX) using detection limits of 1.0 <br /> ppm for the TPH as gasoline and 0.005 ppm for the BTEX constituents. All results will be <br /> IT Corporation is a wholly owned subsidiary of fnternaL'onal Technology Corporation <br />