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Stantec <br /> L & M OPERABLE UNIT- FOURTH QUARTER AND ANNUAL 2010 SITE STATUS, <br /> REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT <br /> Groundwater Monitoring and Sampling <br /> January 31, 2011 <br /> 2.2 LABORATORY ANALYSIS <br /> Groundwater monitoring of L&M OU wells during 4Q10 was performed by Stantec. Stantec's <br /> standard procedures for groundwater monitoring and sampling are presented in Appendix B. <br /> Collected groundwater samples were submitted under chain-of-custody (COC) documentation <br /> to Kiff Analytical, a state certified laboratory located in Davis, California and were analyzed for <br /> the following: <br /> • TPHd and TPHo by Environmental Protection Agency (EPA) Method 8015M <br /> • TPHg; benzene, toluene, ethylbenzene, and total xylenes (BTEX); fuel oxygenates <br /> (MtBE, di-isopropyl ether [DIPE], ethyl tertiary butyl ether [EtBE], TBA, tertiary amyl <br /> methyl ether [TAME], methanol, and ethanol); and volatile organic compounds (VOCs) <br /> by EPA Method 8260B <br /> • Semi-volatile organic compounds (SVOCs) by EPA Method 8270C <br /> • Dissolved metals by EPA 6000/7000 Series (during first and third quarters only per the <br /> MRP) <br /> Groundwater samples were not collected at the UOU and MOU in SRDA wells during 4Q10. <br /> Monitoring well construction details are presented in Table 2. Groundwater elevation and <br /> analytical data are presented in Tables 3 through 7. Certified laboratory analytical reports, <br /> Stantec Lab Validation forms, COC documentation, and field data sheets for 4Q10 monitoring <br /> and sampling event performed by Stantec are presented in Appendix C. Gauging data provided <br /> by Wallace-Kuhl for the SRDA in UOU and MOU wells are included in Appendix D. Electronic <br /> Deliverable Format (EDF) upload confirmations for the 4Q10 monitoring and sampling event are <br /> presented in Appendix E. <br /> 2.3 FOURTH QUARTER 2010 SHALLOW GROUNDWATER RESULTS <br /> 2.3.1 Shallow Zone Groundwater Gradient <br /> Groundwater elevations for shallow zone wells at the L&M OU, MOU, and UOU, ranged from <br /> 5.67 ft below mean sea level (MSL) in well DPE-6 to 4.29 ft above MSL in well MW-30 (Table 3 <br /> and Figure 2). Groundwater flow direction during 4Q10 was observed in two sections of the site <br /> (northeast and southwest). Along the northeast portion of the site, groundwater flow direction <br /> was to the south with an approximate hydraulic gradient of 0.023 foot per foot (ft/ft). In the <br /> southwestern part of the site, groundwater flow direction was to the east-northeast with an <br /> approximate hydraulic gradient of 0.011 ft/ft. Historical gradient data are summarized in <br /> Table 8; vertical gradients are summarized in Table 9. A groundwater elevation contour map of <br /> the October 18, 2010 monitoring event is included as Figure 2. <br /> I:\Tidewater\TW Stockton(Parcel 2A-0415)\Reports\QMR\2010\4010-Annual\4Q10 and Annual OSSRQRSRQMR Stockton_FINAL.doc 2.2 <br />