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II Ms Vicki McCartney April 4, 2406 i Page 2 vrn • Five Direct Push (DP) borings (GP-1 through GP-5) were made in August 2001' The borings were advanced ' to groundwater, and a discrete water sample was collected from each Three groundwater monitoring wells (MW-1 through MW-3) were installed in September 2000 (Figure 1) Quarterly groundwater monitoring and sampling was initiated in September 2000 In May 2002, one deep soil boring was made and two shallow sod borings were made and converted into monitoring wells MW-4 and MW-5 A dual-phase extraction (DPE) test was conducted from June 10 through 15, 2002 The DPE test was conducted by simultaneously extracting soil vapor and groundwater from well e MW-1 Four cone penetration tests (CPT) were conducted in September 2003 Discrete groundwater samples collected from HydroPuncho borings made adjacent to the CPT borings indicated the presence of methyl tert- ' butyl ether(MTBE) and benzene in groundwater northeast of the property beneath a city street In October 2004, Shaw submitted the Corrective Action Plan for Parkinson's Hammer 1-5 Arco(CAP) The CAP was tentatively approved, pending results from a deeper monitoring well located in the street east of the station and submission of contaminant mass calculations These activities are currently in progress Routine groundwater monitoring has been performed at the site since September 2000 There are five groundwater monitoring wells at the site, all with total depths of approximately 24 feet Groundwater Monitoring ' On October 17, 2005, groundwater samples and depth-to-water data were collected from monitoring wells MW-1 through MW-5 Groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX), 1,2-dibromoethane (EDB), 1,2-dichloroethane (1,2-DCA), and five gasoline oxygenates MTBE, di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert- amyl methyl ether (TAME), and tert-butyl alcohol (TBA) using U S Environmental Protection Agency(EPA) Methods 8015M/8021 B and 8260B Field and laboratory procedures are presented in Attachment 1 ' Certified analytical reports, chain-of-custody documentation, and field data sheets are presented in Attachment 2 ' Elevations and Gradient Groundwater elevations measured at the site were an average of 0 87 feet lower than measured in the ' previous sampling event of July 18, 2005 Groundwater flow was inferred to be to the northeast at an average gradient of 0 001, which was consistent with previous sampling events Groundwater elevation data are presented in Table 1 A groundwater elevation contour map based on the October 17, 2005, data is ' shown on Figure 1 Final Concentrations TPHg-range hydrocarbons were reported in samples from wells MW-1 and MW-3 at concentrations of 1,500 • micrograms per liter(µg/L) and 110 pg/L, respectively Benzene was reported in the samples from wells ' N 7-hPub18M01A A=\2005 RplsNQ4M4 da Shaw Environmental,Inc