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Ms.Kristi Shelton Page 4 of 6 • An attenuation projection of DCA in MW2 indicates that the DCA concentration in MW2 will fall below maximum contaminant level (MCL) in less than 15 years. An attenuation projection of DCA in MW2 is included as Figure 9. • A BIOSCREEN model was run for the DCA concentrations detected at the Site. The model predicts that the DCA plume will not migrate beyond the property boundary over the next 7 years. The groundwater model is included in Attachment C of Ground Zero's Second Quarter Groundwater Monitoring and Sampling Report dated July 21, 2010. Groundwater Analytical Results—Intrinsic Bioremediation Indicators Intrinsic bioremediation indicators were measured for four consecutive groundwater monitoring events and are summarized in Table 3 and briefly discussed in Ground Zero's Second Quarter Groundwater Monitoring and Sampling Report dated July 21, 2010. SUMMARY • Groundwater elevation has increased an average 8.82 feet since the November 6, 2009 groundwater monitoring event. • Since groundwater monitoring began in November 2008, the average groundwater elevation at the site is at the highest recorded levels. • During the February 4, 2011 groundwater monitoring and sampling event groundwater flow was toward the north-northwest. • Historically groundwater flow has been toward the north-northwest. • Groundwater flow rates are modest at the Site. During this monitoring event groundwater flow was calculated to be 0.0006 ft/ft. • No analyzed groundwater constituents have been detected above laboratory detection limits in MW3, MW4, and MW5 since groundwater monitoring began at the Site. • TPHg, TPHd, and benzene contamination in groundwater is limited to the area of well MW L • MTBE has been detected in MW2 in the last six consecutive monitoring events. The current MTBE concentration measured during this event was 1.3 µg/l,and below the MCL. • Detectable concentrations of DCA were reported in monitoring wells MW 1 and MW2. • Attenuation projections indicate DCA will reach the MCL in less than 15 years. • BIOSCREEN models are discussed in Ground Zero's Response to RWQCB Comments and Request for Case Closure dated September 22,2010. • Vapor intrusion issues are discussed in Ground Zero's Response to RWQCB Comments and Request for Case Closure dated September 22,2010. • Intrinsic bioremediation indicators suggest that there is strong evidence of active biologic remediation at the site and the details are discussed in Ground Zero's Second Quarter Groundwater Monitoring and Sampling Report dated July 21, 2010. • Ground Zero's Sensitive Receptor Survey was submitted to the RWQCB on January 3, 2011. • Previous subsurface and monitoring investigations have defined the vertical and lateral extent of both soil and groundwater contamination. G:\GROLINDZE\WCTOMATO\WCT-Investigation\Reports\QMR\2011\l QM201 l.doc