ARCHIVED REPORTS_FIRST QUARTER 2011 STATUS SUMMARY REPORT

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Stantec First Quarter 2011 Status Summary Report Former Tosco Bulk Terminal No. 10013 April 29,2011 Six piezometers (P-1 through P-6)were installed in 2003 in the southwest portion of the site and offsite to monitor the effectiveness of the GWETS. Piezometers P-1 through P-3 were installed to monitor MW-8, and piezometers P-4 through P-6 were installed to monitor MW-14. Twelve oxygen injection points (IP-1 through IP-12) were installed in June 2007 under the oversight of EarthTech at locations nearby and surrounding monitoring wells MW-8 and MW-14. Nine of the injection points (I13-1 through IP-9) were installed at approximately 25 feet below ground surface (bgs) with 15 feet of 0.020-inch slotted casing from approximately 10 to 25 feet bgs (A-zone), and three injection points (IP-10 through IP-12)were installed at approximately 50 feet bgs with 15 feet of 0.020-inch slotted casing from 35 to 50 feet bgs (B-zone). Between December 17 and 21, 2007, mobile oxygen injection activities were initiated at the site. Between December 21, 2007 and June 20, 2008, there have been a total of twelve oxygen injection events completed on a bi-weekly basis. During each two-day event, oxygen injection into IP-1 through IP-12 was completed using bottled oxygen transported to the site by Stantec. The amount of oxygen injected into each well was 150 ft3 (13.4 pounds) per injection event conducted through April 24, 2008. During the oxygen injection events conducted in May and June 2008, 300 ft3 (26.7 pounds) of oxygen was injected into each well. Approximately 2,964 pounds of oxygen has been injected at the site during the pilot study activities between December 17, 2007 and June 20, 2008. On July 9 through 13, 2009, Stantec oversaw Cascade Drilling Inc. install four off-site oxygen injection wells (IP-14 through IP-17) and oversaw the destruction of seven off-site injection wells (IP-01, IP-04 through IP-09). Wells IP-14 through IP-17 was installed to enhance the potential effectiveness of the oxygen injection activities. On July 27 and 28, 2009, Stantec initiated the continuation of the oxygen injection pilot study to assess the continued effects of introducing oxygen into the targeted saturated zones beneath the sites. Utilizing wells IP-10, IP-11, IP-14 through IP-17, and MW-22 as remedial injection wells, 300 cubic feet(26.7 pounds) of oxygen were injected into each well on a bi-weekly basis. Oxygen injection activities were halted in December 2010. QUARTERLY MONITORING ACTIVITIES AND RESULTS Groundwater monitoring during the first quarter 2011 was performed in accordance with revised MRP No. R5-2004-0824, which is included as Appendix A. During the fourth quarter 2008, Stantec added to the frequency of selected monitoring points to better understand data trends and site characteristics. Monitoring wells MW-2, MW-3, MW-16, MW-17B, MW-18C, MW-20, MW-21B, and MW-22C are now monitored and sampled quarterly. In addition, monitoring wells MW-8 and MWA4 are now purged prior to sampling. 2