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0 <br /> ~� CLEARWATER <br /> G x o v r <br /> Emvrronmeatal Services <br /> below ground surface (bgs) Soil samples were analyzed for total petroleum hydrocarbons as <br /> gasoline (TPHg), as diesel fuel (TPHd), as kerosene (TPHk), and as motor oil (TPHmo) <br /> Samples were also analyzed for benzene, toluene, ethylbenzene, and total xylenes (BTEX) The <br /> highest concentrations of TPHg, TPHd, and BTEX were detected at 5,700 milligrams per <br /> kilogram (mg/kg) TPHg, 50 mg/kg TPHd, and 48 mg/kg benzene TPHk and TPHmo were not <br /> detected in any of the four samples <br /> On September 25, 1997, Clearwater supervised the drilling of six soil borings to depths from 32 <br /> to 38 feet bgs Three of the borings were converted to groundwater monitoring wells (MW-1 <br /> through MW-3) Soil samples collected from four of the six borings contained detectable <br /> concentrations of petroleum hydrocarbons The highest concentrations of TPHg (570 mg/kg) <br /> and benzene (4 0 mg/kg) were detected in the sample from SB-2 at a depth of 25 feet bgs <br /> Groundwater samples collected September 29, 1997 from all three monitoring wells contained <br /> detectable concentrations of dissolved petroleum hydrocarbons The highest concentrations of <br /> TPHg (32,000 micrograms per liter [gg/L]) and benzene (2,200 µg/L) were detected in the <br /> sample from monitoring well MW-1 Low concentrations of TPHd were detected in soil samples <br /> from SB-5 (11 mg/kg) and SB-6 (2 mg/kg), and in the groundwater sample from MW-1 (300 <br /> gg/L) Subsequent groundwater sample results have been non-detect for all three wells and with <br /> approval from the SJC/EHD, analysis for TPHd has been discontinued Results of these efforts <br /> were presented in Clearwater's Subsurface Investigation Report, dated November 20, 1997 <br /> Based on these initial investigation results, the SJC/EHD requested additional monitoring wells <br /> be installed to better define the aerial extent of soil and groundwater contamination After <br /> discussion with Ms Lori Duncan of the SJC/SJC/EHD, Clearwater submitted the Workplan for <br /> Site Investigation dated November 18, 1998 An addendum to the workplan, dated December <br /> 10, 1998, was submitted in response to SJC/EHD comments The workplan and addendum were <br /> approved by the SJC/EHD on December 15, 1998 <br /> In January 1999, Clearwater supervised the installation of three additional groundwater <br /> monitoring wells (MW-4 through MW-6) to delineate the extent of dissolved-phase <br /> ZB178C/3rdQtr 2004 Monitoring Rpt 2 October 8,2004 <br />