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' In March 2002, a 2,000-gallon diesel UST was removed from the site The UST was located about 120 feet from the former heating oil UST and had contained fuel for an emergency backup ' power generator During removal activities, groundwater was encountered at a depth of approximately 12 feet below surface grade (bsg) A soil sample collected from the north end of ' the excavation contained 13 parts per million(ppm) of total petroleum hydrocarbons as diesel (TPH-D), and a sample collected from the pipeline trench contained 5 0 ppm TPH-D A groundwater sample collected from the excavation contained 130 parts per billion(ppb) of TPH- D (IT, 2002b) Stockpiled soils were used to backfill the UST excavation following removal ' activities Analytical results of the soil and groundwater samples are presented in Tables 2 and 3, and depicted in Figures 3 and 4 In September 2002, at the request of the SJCEHD, six direct-push soil borings were made on both sides of the 2,000-gallon diesel UST, along the fuel piping system, and in the direction of ' groundwater flow Analysis of the soil samples detected TPH-D in one of the borings at a concentration of 2 7 ppm No benzene, toluene, ethylbenzene, and xylenes (BTEX) constituents ' or methyl tertiary butyl ether(MTBE) were detected in any of the soil samples (IT, 2002c) The soil analytical results are summarized in Table 4 and depicted in Figure 5 Copies of the boring lie logs are included in Appendix B Groundwater was encountered during boring activities at depths ranging from 11 feet to 14 feet rbsg Analysis of groundwater samples collected from three of the borings detected TPH-D at concentrations ranging from 50 ppb to 390 ppb No BTEX constituents or MTBE were detected in the samples Groundwater analytical results are summarized in Table 5 and depicted in Figure 6 In April 2003, a site conceptual model (SCM) was completed for the site by Shaw The results of the SCM indicate numerous UST systems existed on nearby properties The majority of these UST systems were located to the south, in the anticipated upgradient direction Subsurface impact was confirmed upon removal of several of the UST systems Contaminants from some of these former UST systems may have impacted groundwater conditions at the SBC site (Shaw, 2003a) In July 2003, three monitoring wells were installed at the site The wells were screened from 8 to ' 23 feet bsg, i e , across the water table Soil samples were collected from depths of 10 and ' CNCDISHAREIUS11V4-0001 doc 2