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0 TC lk ATE S I N C . 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 supervised the advancement of six soil borings, SB7 through SB 12, to approximately 20 to 25 feet bgs and one cone penetration test (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 - 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 (ROI) 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. Interim remedial action activities consisting of groundwater extraction were conducted at the site from July 8 to December 4, 2003. A total of approximately 50,060 gallons of groundwater were extracted from MW 1 during 11 groundwater extraction events conducted from July 8 to December 4, 2003. Groundwater extraction at monitoring well MW1 was conducted in an attempt to reduce petroleum hydrocarbon concentrations in groundwater in the vicinity of MW 1. SAMPLING ACTIVITIES On March 2, 2004, ATC personnel collected groundwater samples from monitoring wells MW1, MW2, and MW3. The locations of the monitoring wells are shown on Figure 2. Prior to collection of groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in groundwater purged from the monitoring wells and recorded. A minimum volume of three well casings was purged from each well prior to sampling. The wells were allowed to recover and samples were collected from each well using disposable bailers. The groundwater samples collected from each well were submitted to State-certified Argon Laboratories (ELAP Cert. No. 2359) for chemical analyses of total petroleum hydrocarbons as gasoline (TPHg) utilizing EPA Method 801513; benzene, toluene, ethylbenzene, xylenes (BTEX) utilizing EPA Method 8021B; and gasoline oxygenates/additives including methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether(ETRE), di-isopropyl ether(DIPE), tertiary butyl alcohol (TBA), tertiary amyl ether (TAME), 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB) by EPA Method 8260B. Groundwater well purge and sample logs are contained in Attachment 1. s Aenvironmenta111498 RReportAl QR-04.doc 2