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the site, across Pacific Avenue Two source tests, of two hours each, were conducted on MW8 The well is near the leading edge of the plume and results Indicate that a two hour vacuum extraction once a week will help control the migration of the plume and will enhance biodegradation by removing CO2 and enhancing oxygen transfer while limiting hydrocarbon removal to less than 0 1 pound per week Mr. Mark Schonhoff of San Joaquin Valley Unified Air Pollution Control District, evaluating this source test as it pertains to air quality conditions in the Stockton area and has allowed Wickland to perform the weekly two hour venting of this well The weekly venting of MW8 commenced on Janaury 25, 1995 and lasts a duration of two hours The average flow rate calculated during during these venting events is 64 cfm with an average vapor stream containing 0 111 mg/L as gasoline and 2 1% carbon dioxide, see Table 4 The above results show that the weekly two hour venting of MW8, is removing excess carbon dioxide and allowing oxygen transfer to occur A calculated 2 14 pounds of gasoline range hydrocarbons has been removed from MW8 as of December 19, 1995 , see Table 4 and Appendix A - Field Notes MW8 VENTING PROCEDURES We are using LTT vacuum trucks to pull an estimated 7 - 10 feet of water vacuum on MW8 , for 2 hours weekly and exhaust directly to atmosphere This vacuum generates a flow rate of approximately 64 cfm COLLECTING SAMPLES The sample is obtained from a sample port located, prior to the vacuum pump from a sample port on the flow meter orifice Sterile poly tubing was used to attach a one liter tedlar bag, fitted with a special septum "valve' and tubing bib, to the sample port The sample port is on the vaccum side of the pump and therefore a vacuum greater than the well vacuum must be exerted on the outside of the tedlar bag to "fill" the bag with the vapor sample A special vacuum box, in which the tedlar bag is sealed Inside, is used to exert a high vacuum to the exterior of the bag, thereby pulling a sample into the bag Once the tedlar bag is filled, its valve is closed and locked and the appropriate label is placed on the baa The label shows the date, time, sample ID# and analyses to be run and the sampler' s initials The tedlar bag samples are then placed within a cooler, and are hand delivered to WEGE' s laboratory that same day The vapor sample is then infected into an FID (Flame Ionizing . Detector) chromatograph and the resulting chromatogram compared to standard chromatograms of known TFH (Total Fuel Hydrocarbons, gasoline) and BTEX (benzene, toluene, ethylbenzene, and xylenes) PAGE 3 R603 UPDATE-42 1/11/96