Laserfiche WebLink
' 1. Complete the installation of a ground water monitoring system at the pit. <br /> 2. Investigate the source of TCE in ground water in the vicinity of the pit. <br /> 3. Determine the vertical and horizontal extent of TCE in ground water beneath <br /> the pit. <br /> ' 4. Determine the aquifer characteristics of the water-bearing zone beneath the <br /> pit. <br /> ' Procedure <br /> To complete the remedial investigation of the Pit 8 area, LLNL intends to install <br /> ' an additional downgradient monitoring well and possibly other wells to monitor the <br /> extent of TCE in ground water beneath the site. The well(s) will be constructed, <br /> developed, and hydraulically tested according to the protocol described in previous <br /> ' sections. Water samples will be collected and analyzed for VOCs, tritium and metals. A <br /> records search and field sampling will be done to determine the source of TCE in ground <br /> water. <br /> ' TASK 14 - REMEDIAL INVESTIGATION AT PIT 9 <br /> Purpose and Rationale <br /> ' The purpose of this task is to complete the remedial investigation of the inactive <br /> Pit 9 area. Monitoring well K9-1 monitors ground water quality downgradient from the <br /> ' pit. Inactive water supply well W3, located approximately 1200 feet downgradient from <br /> the pit, contains ground water having up to 24 ppb of 1,2-dichloroethane (1,2-DCA). By <br /> September 1988, LLNL plans to: <br /> ' 1. Complete a records search to establish the history of Pit 9 and the well W3 <br /> area. <br /> ' 2. Complete the installation of a ground water monitoring system at the pit. <br /> 3. Determine if ground water contamination exists beneath Pit 9. If contamin- <br /> ation is found, determine its vertical and horizontal extent. <br /> 4. Determine the aquifer characteristics of the water-bearing zone beneath the <br /> pi t. <br /> ' 5. Determine if water in well W3 is in hydraulic continuity with water beneath <br /> Pit 9. <br /> ' Procedure <br /> ' To complete the remedial investigation of the inactive Pit 9 area, LLNL intends <br /> to install three additional monitoring wells to implement a complete ground water <br /> monitoring system in the pit area. The wells will be constructed, developed, and <br /> hydraulically tested according to protocol described previously. Water samples will be <br /> ' collected and analyzed for tritium, VOCs and metals. The hydrogeology in well W3 will <br /> be assessed to determine if Pit 9 may be a source of the 1,2-DCA in the well. Other <br /> potential sources for the 1,2-DCA in well W3 will be evaluated. <br /> ' -10- <br />