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1 23 April 2002 • AGE-NC Project No 97-0301 Page 4 of 5 i • The ground water elevation at the site was within the screened intervals of wells MW-1 through MW-4,MW-6 and MW-7,which yielded samples fully representative of shallow ground water conditions The ground water elevation at well MW-5 is approximately 50 feet above the screen interval(drowned)and yielded a sample more representative of deeper ground water conditions • The core of the dissolved petroleum hydrocarbon plume appears to be located in the area of wells MW-1 and MW-7, 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,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 5.0. RECOMMENDATIONS Based upon data collected during December 2001, AGE recommends lie Continued ground water monitoring utilizing wells MW-1 through MW-7 The next quarterly ground water monitoring event should be performed concurrently with the California Tank-Line IInc site (3105 South El Dorado Street) A Feasibility Studies and Monitoring Well Installation Work Plan was submitted to the SJCEHD on 09 April 2002 and approved by the SJCEHD by letter on 22 April 2002, the scope of work included installation of one ground water extraction well, two soil vapor extraction (SVE) wells, one air sparge ' well,one ozone sparge well, four multi-level ground water monitoring wells,performance of a 24-hour ground water aquifer pumping test, performance of an eight-hour SVE pilot test, performance of a 48-hour in-situ air sparging (IAS) pilot test, performance of a 24-hour SVEJAS pilot test and ' performance of a four-week ozone spargirig pilot test Upon pre-approval by the UST Cleanup Fund, AGE will schedule field work with the SJCEHD 6.0. LIMITATIONS ' Our professional services were performed using that degree of care and skill ordinarily exercised by environmental consultants practicing in this or similar localities The findings were based upon analytical results provided by an independent laboratory Evaluation of the hydrogeologic conditions ' at the site for the purpose of this investigation was made from review of previous consultants reports . and a limited number of available data points (ground water samples) and subsurface conditions may Advanced GeoEnvironmentni,Inc