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1 <br /> 1 l 1 1 it I <br /> I <br /> r 1 <br /> 1 I <br /> 06 December`2002 1 <br /> AGE-NC Project No 97-0333 <br /> Page 8 of 9 <br /> 1 1 , <br /> • Free-floating petroleum product has been encountered at wells MW-2, MW-6 and EW-1 <br /> during the December 2001 and the August 2002 ground water monitoring events Free- <br /> floating petroleum product was not encountered in any wells during the February and May, <br /> ' 2002 monitoring events " <br /> 1 , <br /> The results of interim ground water pump-and-treat remediation between 06 June and 26 September <br /> ' 2002 are as follows <br /> • Between 06 June 2002 and 26 September 2002,the pump-and-treat system was in operation <br /> for approximately 76 days and processed approximately 240,109 gallons of water AGE <br /> estimates that an average 3,159 gallons of water was discharged per day during this time <br /> • Between 19 August and 24 September 2002,interim ground waterpump-and-treat operations <br /> t were suspended at the site for maintenance of the pump-and-treat carbon media vessels <br /> 1 <br /> • Dissolved MTBE was detected from grab samples collected at the influent end of the <br /> treatment system at concentrations between 6,700 gg/l and 13,000 lig/l (Table 2) <br /> • Laboratory analysis of four grab water samples collected at the effluent end of the pump- <br /> and-treat system did not detect any constituents of concern above state maximum <br /> contaminant levels(MCL's),however,TBA was detected during thl August and September <br /> II 1 <br /> 2002 sampling events at concentrations as'high as 340 µg/1 (Table 2) 1 <br /> 1 <br /> • Between 06 June 2002 and 26 September 2002, approximately 19 6 pounds of MTBE was <br /> removed from extracted ground water(Table 1), since system initiation,the estimated total <br /> ' mass removed is approximately 166 4 pounds of MTBE <br /> I E ' <br /> I ` <br /> 1 5.0. RECOMMENDATIONS <br /> , I <br /> ' Based upon the results of the third quarter 2002 investigation, AGE recommends <br /> • Continued quarterly,ground'water monitoring utilizing wells MW-1 through MW-6 for <br /> charactenzation of ground water conditions on the site r ; <br /> • Future groundwater sampling should include full EPA Method 8260 <br /> • Continued ground water extraction (interim ground water remediation) from well EW-1 <br /> A work plan,addendurn,dated 03 April 2002,was submitted to the EHD for installation of additional ;f! <br /> ' shallow and deep-screened(multi-level)groundwater monitoring wells,the EHD approvedthe work <br /> I plan addendum by letter dated 03 Apri12002 Between 23 September and 04 October 2002, seven ; <br /> IE II R! <br /> AdvancedG <br /> � eoEnvironmental,Inc <br /> i III'' <br /> 1 I <br /> t <br />