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r ' Mr Ron Rowe February 9, 2000 dispenser island The area was subsequently over-excavated to a depth of 18 feet, which was the maximum depth possible with the equipment available, and resampled The analytical results from the sample collected from 18 feet below grade(fbg)contained 43 parts per indhon(ppm)benzene and 0 250 ppm methyl tert-butyl ether(MTBE) The excavation, sampling, and analytical results were summarized to Cambria's July 25, 1996 Tank Removal and Soil Sampling Report MW-1 Installation: In March 1998,Cambria installed one groundwater monitoring(MW-1)well near the southeast dispenser island MTBE was detected in three of the soil samples,with a maximum concentration of 11 0 nulligrams per lalogram (mg/kg) at a depth of 27 5'-29'fbg Methanol was detected in two of the samples, with a maximum concentration of 6 6 mg/kg at 27 5'-29'fbg CPT Investigation: August 17, 1998, Cambna advanced 10 cone penetrometer testing (CPT-1 to CPT-10)to define the presence and extent of hydrocarbons and MTBE in the soil and groundwater beneath the site The depths of the CPT ranged from 43 8 to 53 6 ft bgs • None of the contaminants, with the exception of MTBE, are present m ground water beyond the source area near the southeastern dispenser MTBE in ground water has been delineated vertically to the west to the detection limit by borings CPT-6,CPT-7,CPT-8,and CPT-9, to the southwest by boring at CPT-10,and to the northeast by boring at CPT-3 In the source area,MTBE concentrations in ground water decrease rapidly with depth CPT Investigation#2 In April, 1999,Cambria installed two groundwater monitoring wells(MW-2, MW-3),two groundwater monitormg/extraction wells(EW-1,EW-2)and five CPT borings at the site referenced above The purpose of the well installations was to investigate the horizontal and vertical extent of hydrocarbons,determine the groundwater flow direction,and for possible future groundwater extraction The purpose of the CPT borings was to investigate the horizontal and vertical extent of hydrocarbons to the south and southeast of the site The horizontal and vertical extent of TPPH,BTEX,MTBE, and methanol in soli were defined by the CPT boring installations during this phase and previous phases of the investigation - The lateral extent of hydrocarbons in eround water tc dPfinpd to the nnrth o.,,,tk .-A southeast by this investigation,and to the southwest and west by this and previous phases of the investigation To the east in boring CPT-12, MTBE concentrations decrease with depth, 2