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Stantec <br /> April 30, 2010 <br /> Page 2 of 14 <br /> Reference: First Quarter 2010 Site Status, Groundwater Monitoring and Remedial Summary Report-Stockton <br /> Terminals Technical Committee Facilities <br /> more than 97 percent, while in treatment zone well TS/MW-1 B concentrations decreased by more <br /> than 99 percent. <br /> Two pilot studies are in progress on the Tesoro Terminal. Baseline metals data were collected from <br /> four wells as part of the Hydrogen Peroxide Injection (HPI) Pilot Study. HPI and evaluation <br /> monitoring commenced during March 2010. As part of the Oxygen Injection (OI) Pilot Study, "D" <br /> zone wells TS/MW-3DR and TS/MW-4D were installed and developed during March 2010. The <br /> new wells will be sampled and surveyed, and a helium tracer test will be conducted during second <br /> quarter 2010. <br /> Interim remedial work is being conducted on the BP/ARCO Terminal in a proactive response <br /> following a fourth quarter 2008 fire-foam release at the terminal. During first quarter 2010, <br /> approximately 3,220 gallons of groundwater were removed from 16 wells potentially impacted by <br /> the release. <br /> Recommendations and Proposed Activities: <br /> • Continue groundwater monitoring and sampling to facilitate ongoing evaluation of dissolved <br /> hydrocarbon concentration trends and the effectiveness of remedial efforts. <br /> • Direct Kinder Morgan Energy Partners (KMEP) to resurvey wells (southeast of the Tesoro <br /> Terminal) to enable continued compatibility of groundwater elevation data with the STTC <br /> and ST services well networks resurveyed during October 2008. <br /> • Continue operation and maintenance (O&M) of the upgraded East and West Systems and <br /> monitoring of groundwater wells in the ozone-injection monitoring program. <br /> • Overpurge BP/ARCO Terminal wells with methylene blue active substances (MBAS) <br /> concentrations greater than the California Secondary Maximum Contaminant Level (MCL) of <br /> 500 micrograms per liter (pg/1), during any of the last four quarters. Sample downgradient <br /> Port of Stockton wells for MBAS as requested by the RWQCB. <br /> • Continue activities associated with the OI and two-phase HPI pilot studies on the Tesoro <br /> Terminal. <br /> 2.0 COMPLETED WORK SUMMARY <br /> Quarterly groundwater monitoring and sampling was conducted on and adjacent to the STTC <br /> terminals (Figure 1) during first quarter 2010 in accordance with the MRP and Stantec's standard <br /> procedures (Appendix C). Well construction details are presented in Table 2. <br /> During first quarter 2010, 47 "A" zone, 20 "B" zone, 17 "C" zone, and 9 "D" zone wells were gauged <br /> (Tables 3 to 5). Groundwater samples were collected from the monitoring well network on <br /> February 1 through 5 (Tables 6 to 8). Well AR/MW-14B was inaccessible due to terminal activities <br /> and was not sampled during first quarter. Wells TO/R-5 and TO/MW-1 were flooded due to recent <br /> rains and could not be sampled. Sixteen BP/ARCO wells were overpurged prior to sampling <br />