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Mr.Harlin Knoll May 16, 2001 Page 3 Project No. 2007-0065-01 SAMPLING, ANALYSIS, AND MONITORING PROGRAM RESULTS Groundwater samples were collected from 11 monitoring wells on February 23, 2001 and forwarded to Alpha Analytical, Inc. for analysis. Samples were analyzed for total petroleum hydrocarbons as gasoline (TPHG) using United States Environmental Protection Agency (USEPA) Method 8015B/DHS LUFT Manual, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX compounds) and five oxygenates (methyl tertiary butyl ether [MTBE], tertiary butyl alcohol [TBA], diisopropyl ether [DIPE], tertiary amyl methyl ether [TAME], and ethyl tertiary butyl ether [ETBE]) using USEPA Method 8260B. Certified Analytical Reports with chain-of-custody documentation are included in Appendix C. A summary of the groundwater analytical data is presented in Table 2 and Figure 3. Petroleum hydrocarbons and fuel oxygenates were not detected above laboratory reporting limits in the samples collected from monitoring wells MW-1, MW-2, MW-6, MW-9, and MW-10, consistent with the previous sampling event. Concentrations of TPHG, benzene, and MTBE decreased in the samples collected from wells S-1, S-2, and MW-8 since the previous sampling event. The highest concentrations of TPHG • (2.3 mg/l) and MTBE (2,300 ptg/l) were detected in the sample collected from monitoring well S-1. The highest concentration of benzene (16 µg/l) was detected in offsite monitoring well MW-4. Concentrations of TPHG, BTEX, and MTBE detected at monitoring well MW-4 increased since the previous sampling event. MTBE was detected in monitoring well MW-7 at a concentration of 3.2 �tgll. TBA was detected in the samples collected from monitoring wells S-1 (2,900 µg/l) and MW-3 (25 µg/1). SOIL VAPOR EXTRACTION SYSTEM Stratus operated and maintained the SVES during first quarter 2001, under an authority to construct (ATC) issued by the SJVUAPCD. The system startup was conducted on August 15, 2000. The SVES consists of a 150 cubic feet per minute catalytic oxidizer with a 5 horsepower blower. Soil vapors are extracted from the subsurface by the blower and abated in a catalytic oxidizer before discharge to the atmosphere. Tables 3, 4, and 5 show the operating time, flow rates, analytical results of air samples , and the mass extraction and emission rates of the SVES. Field data sheets are presented in Appendix B. Figure 4 presents changes in influent TPHG concentrations and cumulative mass removed since startup. During the first quarter 2001, 8 site visits were conducted to monitor, optimize system performance and conduct maintenance. Influent and effluent air samples were collected on January S, 2001, February 6, 2001, and March 7, 2001 and forwarded to Alpha OTroject FileslUSA Gaso1ine100651Qtr1y1U5A 0065 1Q01.doc 5TKATU5