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GeoHydrologic Consultants, Inc.
<br /> grade by North American Technical Services on January 9, 2008. Relative density was
<br /> measured at 5 locations at 98%, 95%, 97%, 99%, and 99%relative densities. Copies of
<br /> the bulk density test results for the backfill material and a summary of in place measured
<br /> densities is included in Appendix H.
<br /> Photo documentation of the entire UST removal process is included in Appendix I.
<br /> 3.4 UST Tank Pit, Stock Pile and Dispensers Soil Sampling Activities
<br /> Soil samples could not be collected from the tank pit at the time of tank removal because
<br /> of safety concerns regarding slope stability associated with the excavation which
<br /> prevented collection of the required soil samples with the backhoe bucket or any other
<br /> method, due primarily to excessive amount of pea gravel in the excavation. Soil samples
<br /> from beneath the dispenser pans could not be collected during dispenser removal
<br /> activities since there was a concrete footing beneath each dispenser pan extending to a
<br /> depth of approximately 9 feet below grade that prevented collection of these samples as
<br /> proposed. These tank pit and dispenser area soil samples were later collected using
<br /> geoprobe and hollow-stem auger method,as described later.
<br /> Following removal of the USTs, piping,and dispenser, soil samples from stockpiled soil
<br /> (SP-1-W, SP-1-MI, SP-1-M2, SP-I-E, SP-2-S, SP-2-M1, SP-2-M2, SP-2-N, SP-3-E, SP-
<br /> 3-M1, SP-3-M2, SP-3-W, SP-4-W, SP-4-E) and the fuel line trench(P-1-15, P-1-35, P-1-
<br /> 55, P-1-75)were collected on December 11, 2007 for analyses(Figure 3). GHC collected
<br /> these samples onsite at the direction of the SJCEHD inspector in brass rings. These soil
<br /> samples were analyzed by Alpha Analytical, Inc. of Sacramento, California(stockpiled
<br /> soils), and Associated Laboratories of Orange, California, (fuel trench soils)which are
<br /> certified laboratories for the analyses performed, for TPHg by EPA Method 8015
<br /> Modified and BTEX, MTBE, DIPE, ETBE,TAME, and TBA by EPA Method 8260B.
<br /> Soil samples results for the samples collected from UST stockpiled overburden and
<br /> dispenser trench soils did not contain detectable concentrations of any of the analytes of
<br /> concern. These soil sample results are summarized in Table 1 and a copy of the
<br /> laboratory report and chain-of-custody documents are included in Appendix D. After
<br /> receiving the soil sample results, Tafoya backfilled the UST pit and dispenser trenches
<br /> with the stockpiled overburden and dispenser trench soils,and clean pea gravel.
<br /> GHC collected soil samples from soil borings which were installed beneath the dispenser,
<br /> and confirmation UST soil samples from beneath each end and middle of the three UST's
<br /> on February 6 through 8, 2008, and March 6, 2008. Soil boring permits were obtained
<br /> from SJCEHD prior to conducting the sampling activities. A copy of the signed-off
<br /> boring permits are included in Appendix G. Soil samples collected from beneath each
<br /> dispenser and the majority of the UST bottom samples were collected with a geoprobe
<br /> hydraulic push rig operated by Test America Drilling. The remaining UST bottom
<br /> samples(USTIM-21.5, UST3M-22, and UST3M-N-21)were collected through borings
<br /> completed with a hollow-stem auger drill rig operated by Test America Drilling, where
<br /> replacement wells were to be installed. Mr. Michael Infurna of SJCEHD was present
<br /> during sampling activities with the exception of sample UST3M-22. This sample was
<br /> TOC 172 UST Removal Report Final Page 10
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