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Tosco Corporation,a subsidiary of Plulltps Petroleum Company 3 Tosco Station#11192, 1403 Country Club lane,Stockton,CA March 4,2002 atmosphere DPE tests were performed on well MW-7 for 4 hours, MW-3 for 3 hours and simultaneously on wells MW-3 and MW-7 for 100 hours The total DPE time was approximately 107 hours Physical and chermcal parameters including applied vacuums, groundwater, soil vapor total system and well field extraction flow rates, total depth to groundwater, and flame ionization detector(FID) readings were monitored throughout the DPE event Vacuum gauges were placed at nearby monitoring wells in order to monitor the pressure gradient induced by each respective extraction well DPE test data is summarized in Table 1 During each day of testing, influent vapor samples were collected from the DPE system influent vapor stream Groundwater samples were collected from monitoring wells MW- 3 and MW-7 on the first day of the test, December P, 2001 and on the last day of the test, December 7th, 2001 Air and water samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX compounds), and methyl tert-butyl ether (MtBE) by EPA Methods 8015 and 8020 Air samples were also analyzed for volatile oxygenates using EPA Method 8260B Results of these analyses are presented in Tables 2 and 3 Certified laboratory analytical reports and chain-of-custody documentation data are presented in Attachment A DPE RESULTS During the 4-hour DPE event for well MW-7, the applied vacuum was 25 inches of N. mercury(inches of Hg), vapor extraction flow rates ranged from 14 17 cubic feet per minute (cfm) to 17 00 cfm The groundwater extraction flow rate was 0 4 gallons per minute (gpm) Groundwater elevations for observation wells MW-1 and MW-11 increased by 0 06 feet, well MW-4 increased by 0 03 feet, and wells MW-5 and MW-6 did not show any sigiuficant changes in groundwater elevations FID readings collected from the vapor extracted from well MW-7 ranged from 322 parts per million by volume (ppmv) to 500 ppmv Applied vacuum, vapor extraction flow rates, groundwater extraction flow rates, and influent FID readings are presented in Table 1 During the 3-hour DPE event for well MW-3, the applied vacuum was 25 inches of Hg, vapor extraction flow rates ranged from 27 49 cfm to 33 41 cfm The groundwater extraction flow rate ranged from 0 5 gpm to 4 0 gpm Groundwater elevations for wells MW-6 and MW-11 decreased by 0 02 feet, wells MW-1 and MW-4 decreased by 0 05 feet, and well MW-5 decreased by 0 07 feet FID readings collected from the vapor extracted from well MW-3 ranged from 1,500 ppmv to 3,000 ppmv Applied vacuum, vapor extraction flow rates, groundwater extraction flow rates, and influent FID readings are presented in Table 1 During the 103-hour DPE event for wells MW-3 and MW-7, the applied vacuum was 25 inches of Hg, and vapor extraction flow rates ranged from 10 90 cfm to 22 57 cfm The groundwater extraction flow rates ranged from 16 gpm to 9 0 gpm Groundwater elevations for observation well MW-1 decreased by 0 11 feet, well MW-6 decreased by 0 12 feet, well MW-4 decreased by 0 14 feet, well MW-5 decreased by 0 15 feet, and well MW-11 did not show any significant changes in groundwater elevation FID