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3 <br /> CHRONOLOGY <br /> Tri-Valley Growers page 2 <br /> 26,200 Galt Rd., Thornton CA. <br /> 11/28/94 Consulting firm,RAH, drilled and sampled seven (7) soil borings (SB-1 [20 degree; <br /> angle]through SB-7) around Forklift area. Three of sixteen soil samples contain <br /> detectable petroleum concentrations to <20'bgs (TPH-G at 5.1 to 2,700 mg/kg). <br /> Groundwater sample from SB-1 reported TPH-G at'12,000,000 ug/l and Benzene at <br /> 77,000 ug/1. <br /> 02/10/95 RAH advanced hand augers (HA-1, 2&3) inside Forklift repair shed. Very low <br /> levels of soil contamination detected. Groundwater samples "not analyzed" for <br /> TPH-D. HA-2 most contaminated groundwater sample with TPH-G at 400 ug/l. <br /> BTEX at 6, 2.8, 8.8, and 6.4 ug/l respectively. RAH concludes groundwater laterally <br /> defined and impacted under floor of shed at least to 17 feet laterally,but not more <br /> than 28'. <br /> 04/18/96 Consulting firm, SECOR, drills SB-8, 9, and IOM' forklift area. Only SB-10 detects <br /> any petroleum contamination in soil. Groundwater samples concluded to be "non- <br /> representative" of subsurface conditions since `grabbed'through open hollow stem <br /> augers. Unable to locate actual results. <br /> 03/26-27/98 Consulting firm,Harding-Lawson&Associates (HL.A),drills three Hydropunches <br /> (SII'-1 to HP-3) in forklift area as directed by PHS-EHD to define vertical limits of <br /> soil plume. HP-2 detects highest soil contamination to 21'bgs but does not collect <br /> another soil sample until 35.5'bgs, and it is non-detect. All three HP's detect <br /> groundwater contamination,with HP-2 reporting TPH-G at 17,000 ppb at depth of <br /> 31'bgs (no soil sample at this depth to support or deny submerged source contention <br /> by PHS-EHD). PHS-EHD does not concur with HLA conclusion of plume <br /> definition and site qualified for.No Further Action. MW-7 to be placed in-"T 4&5" <br /> former location. Proposed five foot screened interval at to be placed somewhere <br /> between 30-40'bgs. <br /> 03/26/98 HLA analyzes HP-2 groundwatersample for five (5) fuel oxygenates and 1,2-DCA. <br /> No detectable oxygenates by EPA Method 8260. <br /> 04/30/99 HLA installs MW-7 in "74& 5" former location with screened interval at 30'-40'bgs. <br /> Soil samples collected at 25',and 30'bgs were non-detect for petroleum and <br /> oxygenates. First water sample on May 5, 1999 showed TPH-G at 620 ug/l and <br /> Benzene at 1.9 ug/l <br /> 06/08/99 MW-7 sampled and TPH-G at 160 ug/lwith Benzene below 0.5 ug/l. <br /> a <br />