ARCHIVED REPORTS_ANNUAL 2009 GROUNDWATER MONITORING AND SAMPLING REPORT

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Mr.M. Scott Mansholt-CEMC Annual 2009 Groundwater Monitoring and Sampling Report April 15, 2009 Alden Park Page 4 of 6 • Site Wells in Program: MW-1, MW-3 through MW-12, MW-14 through MW-16, MW-18, MW-20, and MW-21. • Wells Containing SPO: MW-1, MW-3, MW-5,MW-6, MW-15, MW-16,MW-18, MW-20, and MW-21 have historically contained SPO. MW-5 and MW-21 contain oil- absorbent(oleophilic) socks that are monitored quarterly. Vacuum extraction of SPO from the remaining wells is performed on a quarterly basis. • Depth to Groundwater at Site: Ranged from 10.91 feet below top of casing (btoc) in MW-8 to 13.72 feet btoc in MW-11. Depth-to-groundwater measurements collected to date from these wells indicate that the average depth to groundwater at the site is 11.19 feet btoc. • Calculated Groundwater Elevation: Ranged from 38.87 feet above mean sea level (MSL) in MW-7 to 41.81 feet above MSL in MW-12. Groundwater elevation measurements collected to date from these wells indicate that the average groundwater elevation at the site is 41.58 feet above MSL. • Approximate Groundwater Flow Direction/Gradient: Predominantly toward the north northwest at 0.003 ft/ft, which is consistent with historic groundwater flow-gradient site data. SAMPLING MW-4, MW-7, MW-8,MW-10, MW-11, and MW-12 were purged by the regulatory-approved, low-flow minimal drawdown method using a low-flow submersible pump with dedicated polyethylene tubing following depth-to-groundwater measurements. MW-9 and MW-14 were purged using the three-volume purge method because draw down exceeded 0.33 feet. Measurements of pH, specific conductance, temperature, oxygen-reduction potential, turbidity, ' and dissolved oxygen water-quality parameters were recorded during the purge process. Groundwater samples were collected after water-quality parameters stabilized (stabilization criteria are presented on the field data sheets). The groundwater samples were'decanted into laboratory-provided bottles, which were labeled, sealed, and placed immediately into an ice- cooled container for delivery to Lancaster Laboratories, Inc. (Lancaster), under SAIC chain-of- custody protocol. Lancaster is a California-certified laboratory (ELAP#2116). Samples were not collected from MW-1, MW-3, MW-5, MW-6, MW-15, MW-16, MW-18, and MW-20 due to the presence of SPO. A sample was not collected from MW-21 due to the presence of sheen. GROUNDWATER ANALYTICAL RESULTS Groundwater samples collected on January 15 and 16, 2009, from MW-4, MW-7 through MW-12, and MW-14 were analyzed for the following COPCs: • TPHd (Cto-C25), using U.S. Environmental Protection Agency (EPA) Method 8015B; and • PAHs using EPA Method 8270C with large-volume injection.