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i 22 July 2003 AGE-NC Project No 97-0301 tPage 4 of 5 ' • Ground water elevation generally increased at the site an average 0 96 feet between the December 2002 and the March 2003 ground water monitoring events The increase in ground water elevation is probably due to seasonal fluctuation ' • The ground water elevation at the site was generally only 1 to 2 feet above the screened intervals of wells MW-1 through MW-7, and should yield samples fully representative of shallow ground water conditions,however,the water level in well MW-5 was approximately ' 48 feet above the screen interval and yielded a sample more representative of deeper ground water conditions ' • The core of the dissolved petroleum hydrocarbon plume appears to be distributed near the location of well MW-1, at well MW-7 and north to a yet an undetermined distance downgradient Analysis of ground water samples collected from MW-1 and MW-7 suggest ' the core of the plume is impacted by TPH-g, TPH-d, TPH-k, BTEX and 1,2-DCA • Substantial concentrations of dissolved TPH-mo have previously been detected in water t samples collected from well MW-4 (screened 30 to 50 feet bsg) and from well MW-5 70�6r (screened 80 to 90 feet bsg),indicating a limited distribution of TPH-mo in the area assessed MW-4&,w� MW-7alsa • • BTEX and 1,2-DCA concentrations in ground water samples MW-1 and MW-7 were rrv� ' substantially above their respective Maximum Contaminant Levels in drinking water • Very low concentrations of MTBE,EDB and TBA have been detected at MW-1 indicating ' that there is only a minor impact of these components • The vertical extent of dissolved petroleum hydrocarbons is not fully defined at the site, the ' lateral extent of the dissolved petroleum hydrocarbon plume is not fully defined toward the southeast, east and northeast of the current area bound by wells MW-1 through MW-7 1 50. RECOMMENDATIONS ' Based upon data collected during March 2003, AGE recommends • Continued ground water monitoring utilizing wells MW-1 through MW-7 The next quarterly ' ground water monitoring events are tentatively scheduled for September and December 2003 or after the installation of any new wells and should be performed concurrently with the California Tank-Line Inc site (3105 South El Dorado Street) 1 A Work Plan for installation of three on-site multi-level wells was submitted to the SJCEHD on 09 ' April 2002 and approved by the SJCEHD by letter on 22 April 2002 Installation of the monitoring wells is scheduled to occur July14 through July 18, 2003 Advanced GeoEnvironmental,Inc