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y `.r01 A S S O C I A T E S I N C On February 18, 1999, a geologist from ATC Associates supervised the installation of three groundwater-monitoring wells from 39 to 41 feet bgs. Soil borings MWl, MW2, and MW3 were completed as two-inch monitoring wells. One soil sample from each boring was collected and after the groundwater monitoring wells were developed one groundwater sample was collected from each well. Soil and groundwater samples contained detectable concentrations of petroleum hydrocarbons. Results are summarized in ATC's Summary Report of Additional Subsurface Investigation, dated June 1, 1999. On September 12, 2001, and October 4 and 5, 2001, a geologist from ATC Associates supervised the advancement of six soil borings, SB7 through SB 12, to approximately 20 to 25 feet bgs and one CPT boring to approximately 45 feet bgs. Analytical results of soil samples indicated no detectable presence of petroleum hydrocarbons or fuel oxygenates. One groundwater sample was collected from each boring at the depth groundwater was first encountered. Groundwater samples indicated no detectable presence of petroleum hydrocarbons or fuel oxygenates. Results are summarized in ATC's Summary Report of Supplemental Subsurface Investigation, dated January 4, 2002. On July 16, 17, and 18, 2002 an aquifer test was conducted over a 48-hour period by extracting groundwater at a generally constant rate from well MW 1. The test was performed to determine the aquifer properties and the radius of influence for groundwater pumping. The groundwater extraction pilot test yielded a pumping rate of approximately 4.76 gpm and a ROI of up to 85 feet. Results are summarized in ATC's Feasibility Study Report, dated December 12, 2002. SCOPE OF WORK Bi-Weekly Groundwater Extraction ATC proposes to perform ten bi-weekly groundwater extraction events, estimated up to 18 hours per event, from monitoring well MW 1 to serve as interim remediation. Prior to beginning groundwater extraction, ATC personnel will measure depth to water in all on-site wells. ATC will collect one groundwater sample from well MWl at the beginning of the groundwater extraction and just prior to completion of groundwater extraction. The groundwater samples will be placed on ice and will be transported under chain-of-custody to a State-certified laboratory. The samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethyl benzene, and xylenes (BTEX), and methyl tertiary butyl ether (MTBE) by EPA Methods 8015/8020. If MTBE is detected in any groundwater sample by EPA Method 8020, the sample will be further analyzed for oxygenate fuel additives by EPA Method 8260 to confirm the results. A pump equipped with a flow meter, totalizer, and discharge hose will be installed into well MWl. A submersible pump equipped with a flow meter capable of reading flows up to 10 gallons per minute (gpm) and a discharge hose will be installed in well MWl. ATC will use a generator to supply power to the pump. wAwordpro\14981\Reports\workpin interim remed.doc 2