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CRYSTAL CREAMERY STOCKTON WKA No. 1628.10 February 5, 2000 Page 3 The average depth-to-groundwater encountered in the wells during the pilot tests was 14.8 feet bsg. During the first pilot test utilizing VEWI as the vapor extraction well, three influent soil gas samples VEW14, VEWI-II and VEWI-III were obtained at 30 minutes, 2 hours and 4 hours, respectively. During the second pilot test using well VEW3 as the vapor extraction well,three additional influent soil gas samples VEW34,VEW3-II, and VEW3-III were obtained at 30 minutes, 2 hours and 3-112 hours,respectively. The samples were obtained by connecting I-liter Tedlar bags to the influent sampling port of the blower. The samples were submitted under chain of custody to a California-certified laboratory for analysis of Total Petroleum Hydrocarbons. (TPH) as gasoline using Modified EPA Method 8015,Benzene, Toluene, Ethylbenzene, and Total Xylenes(BTEX) and Methyl-tent-Butyl ether using EPA Method 8020. A photoionization detector(PID)was used to measure influent hydrocarbon vapor concentrations from vapor extraction well VEW1 and VEW3 during the pilot tests. PID readings during the F_ <, pilot tests ranged from 0.2 molar parts per million(ppm) to 9.5 molar ppm. TPH as gasoline, MTBE,benzene, and ethylbenzene were not detected in soil gas samples VEWI, VEWI-III, and VEW3-I through VEW3-III. Results of laboratory analysis revealed TPH as gasoline in soil gas sample VEW1-11 at a concentration f�6 � molar ppznlTot I Xylenes were detected in sample VEWI-I at a concentration of0.053 mppm and toluene was detected in all the samples at concentrations ranging from 0.051 molar ppm to 0.12 molar ppm. During the test, an average differential vacuum pressure of approximately 40 inches and 36 inches of H2O were measured at vapor extraction wells VEWI and VEW3,respectively. A vacuum extraction flow rate of approximately 250 to 280 standard.cubic feet per minute(scfin) was observed in the extraction well. Vacuum pressure and time were measured at the extraction and observation wells using Magnehelic pressure gauges. The maximum observed vacuum pressure drawdowns in VEW2 and VEW3 during the first pilot test were approximately 2.2 and 1.6-inches of H2O,respectively. The maximum observed vacuum pressure drawdowns in wells VEWI and VEW2 during the second pilot test were approximately 1.5 and 0.7-inches of HO, respectively. Graphical representation of vacuum pressure drawdown over time and distance are included as Appendix A. WALLACE KUHL F-ASq®CiATES IM-,