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rHistorical Background Den's Auto Repair Page 2 of 3 PREVIOUS SITE ASSESSMENT AND SAMPLING ' On 23 June 1997, three soil probe bonngs (B-1 through B-3) were advanced at the site Three additional soil borings(B-4 through B-6)were advanced and completed as ground water monitoring ' wells on 08 to 11 September 1997, boring B-4 (MW-1) was established at the western edge of the station parking lot,bon-rig B-5 (MW-2)was advanced at the north end of the drive way entrance to the parking lot,and boring B-6(MW-3)was advanced at the east edge of the parking lot Analytical ' results of soil samples collected from the soil borings indicated that • Hydrocarbon-impacted soil was present in the vadose zone(above the water table)below the ' former UST location, within the saturated zone in the vicinity of the newly installed well MW-1, and distributed in the capillary zone Soil encountered at 35 feet bsg in the boring established for well MW-1 was not impacted by detectable concentrations of petroleum hydrocarbons, while soil at depths between 43 and 70 feet bsg was impacted by petroleum hydrocarbons ' . The impacted soil encountered between 43 and 70 feet bsg in MW-1 appears to be part of a significant,undefined plume,possibly associated with the former dispenser island more than Ile Impacted soil encountered in the former UST cluster may extend,at depth,to the MW-1 area, but the lower hydrocarbon concentrations in the former UST cluster suggest otherwise No I soil contamination was encountered in boring B-2, which extended only to 35 feet bsg The groundwater monitoring network has been monitored twelve times since September 1997 Over that time span, the highest concentrations of dissolved hydrocarbons have been detected in well IMW-1,at the western edge of the site The lateral extent of dissolved hydrocarbons is not yet defined to the north of wells MW-1 and MW-2 CPT LITHOLOGIC INVESTIGATION ' On 12 and 13 November 2002,three soil borings(CPT-1,CPT-3,and CPT-4)were advanced on-site and off-site utilizing CPT technology Lithologic data was collected from these three borings Soil ' borings were advanced to collect grab ground water and soil samples from selected depths Soil boring CPT-2 was advanced without a CPT sounding(Figure 2) IGround water samples were collected from the CPT borings at the following intervals • CPT-1 was sampled between 84 feet and 88 feet bsg and between 1 I I feet and 115 feet bsg, ' • CPT-2 was sampled between 76 feet and 80 feet bsg and between 111 feet and 115 feet bsg, . G CPT-3 was sampled between 51 feet and 55 feet bsg, between 71 feet and 75 feet bsg, ' Advanced GcoEnvironmental,Inc I