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16 On July 12, 1993, an area 20 feet by 35 feet at the south end of the excavation was deepened to a depth of approximately 23 feet Confirmation soil and grab groundwater samples were collected on July 12, 1993 at the locations shown on Figure 4 Samples were placed on ice, transported under chain-of-custody documentation to Sparger Technology and analyzed for TPHg and BTEX The samples contained TPHg and BTEX above method detection limits Analytical data are summarized in Table 3 According to the results of confirmation soil samples (WIf, August 1993) residual hydrocarbon contaminated soil is mainly confined to the north end of the excavation The excavation was subsequently backfilled and paved with asphalt 4.2.1 Stockpiled Soil The soil generated duringthe tank removals and the overexcavation activities was stockpiled to the north of the site The soil was stored on visquene plastic until samples could be collected to determine its disposition On December 4, 1994, soil samples were collected from the locations shown on Figure 5 The samples were placed on ice and transported under chain-of-custody documentation to Argon Laboratories in Ceres, California The samples were composited in the laboratory at 4 to 1 and analyzed for TPH& TPHd, and BTEX The samples contained no detectable concentrations of TPH& TPHd, or BTEX Analytical results are summarized to Table 4 The soil stockpile is estimated to be approximately 1,600 cubic yards On April 4, 1996, Smith Environmental personnel collected 18 soil samples from the stockpiled sod Samples were placed on ice and transported under chain-of-custody to Argon Laboratories The samples were composited in the lab at 2 to 1 ratio and analyzed for TPHg, TPHd, and BTEX The samples contained no detectable concentrations of TPH& TPHd, or BTEX Analytical results are summarized in Table 4 and laboratory reports are contained in Appendix C 4.3 Assessment of Soil Contamination On October 10 and 11, 1994, RESNA personnel supervised advancement of five soil borings (SB2, SB3, MW 1, MW2, MW3) at the site to depths ranging from approximately 15 to 30 feet below grade Three of the borings, NMI, MW2, and NM, were completed as groundwater monitoring wells The boring locations are shown on Figure 2 ' Drilling was conducted by Spectrum Exploration, Inc (C57# 512289) utilizing a hollow stem auger drill ng A field geologist continuously fogged all drill cuttings and cored soil samples Descriptions of soil types encountered and sample collection intervals are included on the bonng/well logs in Appendix D Cored soil samples were collected at five foot intervals using a 2-inch diameter split-spoon sampler containing three brass tubes A photo ionization detection ' meter (PID) was used as a field screening device for the detection of petroleum hydrocarbon vapors in drill cuttings and cored samples Soil samples collected at approximately 10 5 and 16 feet below grade were selected for laboratory analysis Soil samples were placed on ice and transported under chain-of-custody to Argon Labs for analysis The samples were analyzed for TPHg, TPHd, and BTEX The analytical results for soil are summarized in Table 5 w 1943371cbs=doe 3 • SMTH 1