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1 <br /> • 28 November 2003 <br /> AGE-NC Project No 95-0109 <br /> Page 2 of 7 <br /> In December 1993, a low pressure blower was installed and connected to the seven vapor wells and <br /> four monitoring wells to introduce an oxygen source (air) in preparation to innoculate wells with <br /> hydrocarbon-consuming bacteria In August 1994, in-situ bioremediation began at the site by <br /> full-scale inoculation with hydrocarbon-consumingbacteria-Details ofwell inoculation canbe found <br /> in the GeoAudrt-prepared Quarterly Report -September 1994, dated 18 October 1994 <br /> In May and September 1998 and January 1999 hydrogen peroxide was added to selected wells to <br /> increase dissolved oxygen concentrations and promote biodegradation The most recent soil borings <br /> were advanced in February 1999,to assess the progress of the in-situ bioremediation Results of the <br /> investigation indicated that 90% of the hydrocarbons impacting soil had been remediated A <br /> summary of in-situ bioremediation can be found in the AGE-prepared Quarterly Report-March and <br /> June 1999 dated I I August 1999 , f ' <br /> Further background information including the site history, description and results of previous <br /> investigations are detailed in the Problem Assessment Report (PAR) dated 31 July 1991, prepared <br /> by PES Environmental,Inc , and in the AGE-prepared reports Quarterly Report-March 1996 dated <br /> 19 April 1996, Quarterly Report-March and June 1999 dated 11 August 1999, Cone Penetrometer <br /> • Testing Report, dated 19 February 2002 and Quarterly Report - Fourth Quarter 2002, dated, <br /> 20 January 2003 <br /> 3.0. SCOPE OF WORK <br /> The gasoline additive 1,2-DCA has been detected in"first"groundwater in the down-gradient well <br /> MW-16 over the past four quarters and in eastern perimeter well MW-7 over the past six quarters <br /> 1,2-DCA was also detected in western perimeter well,MW-11 during the third quarter 2003 <br /> However, the detection of 1,2-DCA MW-11 has not been confirmed by additional sampling <br /> Based upon the detection of 1,2-DCA in wells MW-7 and MW-16, AGE proposes the installation <br /> of two additional monitoring wells for the lateral assessment of 1,2-DCA <br /> • One well located approximately 40 feet east of MW-7,within the Geweke Property parking <br /> area, and <br /> • One well located approximately 75 feet south of MW-16, withmg the City of Lodi right-of <br /> way in Walnut Street - <br /> If 1,2-DCA is detected in MW-11 during the fourth quarter 2003 sampling event,one additional well <br /> will be installed approximately 30 feet west of MW-11 The scope of work for installation of <br /> • monitoring wells will include the following tasks <br /> Advanced GeoEnvironmentai,Inc <br /> w <br /> r i 1 <br />