SITE INFORMATION AND CORRESPONDENCE

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FEB 28 '95 04:38PM CL--RWITER GROUP CLEARWATER C R Ci 11 t', [ N C. • In the sample collected at 12.5 feet below grade in boring EP-SB-6-12-5: This boring was advanced in the vicinity of the fOn er dispenser isLand, Immediately in front of the service station building. Results of lab analysis of this soil sample indicated the presence of 3,100 ppm TPH as gasoline. The boring was not drilled past this depth. As documented in the Resna CAP, results of analysis of soil samples -colleted from all other borings in the vicinity of the former tanks indicated that soil in these areas contained no gasoline-range hydrocarbons, and apparently had not been impacted by gasoline hydrocarbons. • In a soil sample collected during drilling of the borehole for MW-1: Results of lab analysis indicated that this sample, collected at 41.5 feet below ground surface (bgs , contained 2,90a ppm of TPH as gasoline. Traces of hydrocarbon constituents were detected at other depths in the boring (below 41.5 feet). No samples. were collected in the interval above 41.5 feet, though field measurements indicated the possible presence of significant concentrations of hydrocarbons in the interval from 10-25 feet bgs. MWA is located close to EP-S]3- 6, near the formex dispenser island. No concentrations of gasoline constituents ' were'detected in soil samples collected from any of the other monitoring well 'borings. Ih soil samples collected from two of the dnree borings for.the vapor extraction wells. Lab analysis detected 1.3 ppm TPH as gasoline in a sample collected from 15.5 feet bgs in the boring, for VW 2, 1.5 ppm. TPH as gasoline in a say nple collected at 15.5 feet and 1.1 ppm (0.1.0 ppm over the method detection fi nit) in a sample collected at 45.5 feet in the boring for BTW-3. • In vapor samples collected during a.pilot vapor extraction test: Moderate concentrations of TPH as gasoline were detected in samples collected during the test on VW-2, low concentrations in samples collected during the test on 'BTW-3, and trace concentrations in samples collected during the test on VW-1. • In a groundwater sample collected from MW-I during the first sampling event, immediately after well installation: Samples collected from MW-1 during quarterly visits following this first event, and from all other monitoring wells have been shown by laboratory analysis to be free of hydrocarbon conta►minati6n. Following the completion of the site characterization, Resna installed three vapor extraction wells (mentioned above) in the locations shown an the attached :map. The wells were all completed at approximately 50 feet bgs, and screened frorn 20 - 50 feet. Each of the wells was drilled through the backfill of the former tank excavation. While it is assumed that backfill materiat was compacted during backfilling, the former excavation was not resurfaced. It should aLVo be- noted that a unit of fine-grained material was observed in most borings, beginning at approximately 40 feet bgs. Sediments.above'this unit were documented as more coarse-grained- 2