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ATC Associates Inc. <br /> 1117 Lone Palm Avenue, Suite B <br /> (: <br /> Modesto,California 95351 VATC <br /> 209-579-2221 <br /> A S S O C I A T E S I N C . fax:209-579-2225 <br /> Sample Analysis <br /> Selected soil samples will be immediately placed on ice and delivered under chain-of-custody <br /> documentation to a State-certified laboratory for analysis. Samples will be analyzed for total <br /> petroleum hydrocarbons as gasoline (TPHg) by EPA Method 8015B and BTEX and fuel <br /> oxygenates by EPA Method 8260B. <br /> Soil Vapor Extraction Testing <br /> Vapor samples will be collected through a 1/4-inch Teflon sample line connected to a stainless steel <br /> wellhead fitting, and will be collected in Tedlar sample bags. Teflon tubing will be used to <br /> minimize sample loss through adsorption and the possibility of distorted results from sample lines <br /> contaminated by previous test runs. <br /> ATC proposes utilizing high vacuum extraction in an effort to further evaluate soil vapor <br /> extraction as a viable option to remediate the vadose zone soils. High vacuum extraction will be <br /> conducted using the new vapor extraction well as the source well and existing monitoring and <br /> remediation wells MW1 through MW5, VW1, VW2 and VW3 as observation wells. The <br /> remedial action will be conducted as three events each of a duration of approximately five days <br /> for a total of three months. Vacuum influence and depth to water will be monitored at the <br /> observation wells to evaluate the radius of vacuum influence and groundwater draw down. <br /> During the remedial action, the soil gas oxygen concentration will be monitored using a <br /> GasTechTM combustible vapor analyzer. The volatile fuel hydrocarbon (VFH)concentration will <br /> also be monitored with a photo ionization detector (PID). Soil gas samples will collected in <br /> Tedlafrm bags or Summa canisters for laboratory analysis for VFH, BTEX and MTBE using <br /> EPA Test Method TO-14. <br /> Based on measured depth to groundwater at the site, ATC does not anticipate recovering <br /> groundwater during the vapor extraction events. Any moisture recovered in the knockout drum <br /> during the remedial action events will be recorded. Depth to groundwater measurements will be <br /> collected from surrounding observation wells at periodic time intervals. <br /> The high vacuum extraction will be conducted using mobile extraction equipment having a <br /> liquid-ring blower and associated flow rate and pressure measuring equipment. A thermal <br /> oxidizer will be utilized to treat the extracted vapors. Following completion of the high vacuum <br /> extraction events, ATC will evaluate the information and provide recommendations. <br /> sA14885\workp1ans\wkp1n 11-20-06.doc 5 <br />