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CLEARWATER C, R O U 1' • Enveronrnentuf Servrcrs 8) in three of the soil borings All three wells were placed on the downgradient portion of the plume to help determine the downgradient extent of contaminants The hydropunch was performed in the former UST location to assess the vertical extent of groundwater contamination at 36 feet bgs Three soil borings were taken to define the lateral extent of soil and groundwater contamination on the northeastern portion of the site and assess possible off-site sources Three soil samples and one groundwater sample were analyzed from each boring Soil concentrations of TPHg and BTEX were detected only in boring MW-5B The highest soil concentration of TPHg (1,000 mglkg) was detected at 25 feet bgs in MW-513 This sample was also analyzed for TPH as Jet Fuel and found to contain 55 mg/kg Detectable concentrations of BTEX were present in soil samples collected from bonng MW-5B at 25 feet and 35 feet bgs MTBE was not detected by EPA method 8260 in any of the soil samples analyzed Groundwater concentrations of TPHg and BTEX were detected in borings SB-9, MW-5B, MW-7 and MW-8 The highest groundwater concentration of TPHg (9,700 µg/L) was detected in MW-5B MTBE was not detected by EPA method 8260 in any of the groundwater samples analyzed A dual-phase test well and air sparge point was installed at the site in February 2002 Remedial feasibility testing at the site was conducted during the week of March 10, 2002 The Well Installation and Feasibility Testing Report was submitted on May 9, 2002 From data collected during these activities, Clearwater developed and submitted a Corrective Action Plan dated November 20, 2002 to the SJC/EHD Beginning in June, 2000 groundwater in all monitoring wells has been sampled on a calendar quarterly basis These sampling events took place on June 6, 2000, August 28, 2000, November 14, 2000, February 13, 2001, May 30, 2001, August 22, 2001, October 11, 2001, February 14, 2002, May 10, 2002, September 30, 2002 Reports documenting these activities have been previously transmitted to the SJC/EHD by Clearwater OBJECTIVES In continuance of quarterly groundwater monitoring activities, the objectives of this current project were to gather groundwater samples from all monitoring wells at the site and to analyze the groundwater samples for hydrocarbon contamination In addition, an MNA study was initiated this quarter, and chemical parameters and groundwater samples were collected These data will serve for preliminary assessment of site suitability (discussed below) and as baseline GROUNDWATER MONITORING AND SAMPLING ACTIVITIES Groundwater monitoring and sampling activities were conducted on March 5, 2003 Groundwater elevation data were obtained from each of the monitoring wells utilizing an electronic water level indicator The water level indicator was thoroughly washed in an Alconox® soap bath and double rinsed with clean tap water prior to placement in each well to prevent possible water quality influence from exterior sources, and to prevent cross contamination Groundwater elevations were derived and are tied to established well surface elevation data (Table 1) ZB178C/1Q03 Monitoring Rpt 3 April 23,2003