ARCHIVED REPORTS XR0009134 - Laserfiche WebLink

Home Browse Search

' 15 July 2002 AGE-NC Project No 97-0301 ' Page 4 of 5 ' gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify ground water flow direction • Ground water elevation increased at the site an average 1 69 feet between the December 2001 and the March 2002 ground water monitoring events, the increase of ground water elevation is probably due to seasonal fluctuation 1 • The ground water elevation at the site was within the screened intervals of wells MW-6 and MW-7, which yielded samples fully representative of shallow ground water conditions, however, the water level in wells MW-1 through MW-4 were approximately I foot above the screen interval(drowned)during the March 2002 monitoring event The ground water elevation at well MW-5 was approximately 50 feet above the screen interval and yielded a sample more representative of deeper ground water conditions • Substantial concentrations of dissolved TPH-mo have previously been detected in water samples collected from well MW-4(screened 30 to 50 feet bsg) and from well MW-5 (screened ' 80 to 90 feet bsg), indicating that there is a limited area impacted with TPH-mo in the area assessed • The core of the dissolved petroleum hydrocarbon plume appears to be located in the area of jig wells MW-1 and MW-7, analysis of ground water samples collected from MW-I 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 March 2002, AGE recommends • 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 Inc site (3105 South El Dorado Street) A Feasibility Studies and Monitoring Well Installation Work Plan was submitted to the EHD on 09 April 2002 and approved by the SJCEHD by letter on 22 Apnl 2002, however, based on a telephone conversation on 17 June 2002 with Mr Bob Trommer of the UST Cleanup Fund, the scope of work for ' the above referenced work plan does not appear to be acceptable to the UST Cleanup Fund Therefore, AGE will delay scheduling any of the above field until mutual agreement is made between AGE, SJCEHD and the UST Cleanup Fund ' Advanced GeoEnvironmcntat Inc