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' Stantec <br /> L & M OPERABLE UNIT- THIRD QUARTER 2010 SITE STATUS, REMEDIAL SUMMARY, <br /> AND GROUNDWATER MONITORING REPORT <br /> Groundwater Monitoring and Sampling <br /> October 27, 2010 <br /> 2.2 LABORATORY ANALYSIS <br /> 1 Groundwater monitoring of L&M OU wells during the third quarter 2010 was performed by <br /> Stantec. Stantec's standard procedures for groundwater monitoring and sampling are <br /> ' presented in Appendix B. Collected groundwater samples were submitted under <br /> chain-of-custody (COC) documentation to Kiff Analytical, a state certified laboratory located in <br /> Davis, California and were analyzed for 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 RDA wells during the third <br /> quarter 2010. <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 Laboratory Validation forms, COC documentation, and field data sheets for the third <br /> ' quarter 2010 monitoring and sampling event performed by Stantec are presented in <br /> Appendix C. Gauging data provided by Wallace-Kuhl for the RDA in UOU and MOU wells are <br /> ' included in Appendix D. <br /> 2.3 THIRD 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 /> ' 5.09 ft below mean sea level (MSL) in well DPE-6 to 4.68 ft above MSL in well MW-30 (Table 3 <br /> and Figure 2). Groundwater flow direction during the third quarter 2010 was observed in two <br /> sections of the site (northeast and southwest). Along the northeast portion of the site, <br /> ' groundwater flow direction was to the south-southeast with an approximate hydraulic gradient of <br /> 0.024 foot per foot (f tft). In the southwestern part of the site, groundwater flow direction was to <br /> the northeast with an approximate hydraulic gradient of 0.01 ft/ft. Historical gradient data are <br /> summarized in Table 8; vertical gradients are summarized in Table 9. A groundwater elevation <br /> contour map of the July 19, 2010 monitoring event is included as Figure 2. <br /> ' 1A`RdewateATW Stockton(Pa.[2A-0415J1ReponslQMR120101301013o1OQSSRQRSRQMR Stockton FINALAM 2.2 <br />