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CRYSTAL CREAMERY STOCKTON <br /> WKA No. 1628.10 <br /> February 5, 2000 <br /> Page 5 <br /> Prior to initiating the test, static water levels and dissolved oxygen were measured at the air <br /> sparging wells. Depth-to-groundwater measured in the wells prior to testing ranged from 12.27 <br /> feet below well casing to 12.39 feet below well casing and dissolved oxygen levels ranged from <br /> 0.1 to 0.5 mg/l. Furthermore,prior to performing the test the wells were purged of <br /> approximately three well volumes of groundwater. Product, sheen or petroleum hydrocarbons <br /> were not detected in the air sparging wells. Water samples ASI-W1, AS2-W1, and AS3-W1 <br /> were then obtained from wells AS 1,AS2, and AS3,respectively. Subsequent to the sparging test <br /> water samples ASI-W2,AS2-W2, and AS3-W2 were obtained from wells AS 1,AS2, and AS3, <br /> respectively. The samples were submitted under chain of custody to a California-certified - <br /> laboratory for analysis of TPH as gasoline,BTEX, and the fuel oxygenates Tert-Butanol,Methyl <br /> tert-•Butyl Ether, Di-isopropyl Ether, Ethyl tert-Butyl Ether, and Tert-Amyl methyl Ether <br /> (oxygenates) using EPA Method 8260B. <br /> During the test, an average air injection pressure of approximately 6.5 psi and a flow rate of <br /> approximately 10 scfin were measured at air sparging well AS 1. The maximum observed water <br /> mounding in wells AS2,AS3 and MW4 was 0.05 inches in wells AS2 and MW4 and 0.07 inches <br /> in AS3. Initial dissolved oxygen levels in wells AS2,AS3, and MW4 were 0.3, 0.2 and 0.4 parts <br /> per million. Positive pressure was initially measured at 0.6 inches in well VEW1 and 0.00 inches <br /> of water in wells VEW2 and VEW3. <br /> As the test progressed, dissolved oxygen levels increased significantly in wells AS2, AS3 and <br /> MW4. Additionally, an increase in positive pressure to 3.8, 0.4 and 0.8 inches of water was <br /> observed in wells VEW1,VEW2 and VEW3,respectively. Results of laboratory analysis did not <br /> reveal concentrations of petroleum hydrocarbons or oxygenates in either the baseline or post-test <br /> groundwater samples. Graphical representation of dissolved oxygen over time and distance, <br /> depth-to-water over distance and time as well as positive pressure over time are included as <br /> Appendix A. <br /> Vapor extraction and air sparging effectiveness was determined through interpretation of <br /> measured observation well variable response over test duration and is discussed in the conclusion <br /> F _-;- section of this report. Tabulated results of chemical analysis and complete laboratory analytical <br /> "INK <br /> WALLACE•KU¢IF. <br /> PY ASSOCIATE.;IN' <br />