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Figure 4 , represents the measurements obtained on December 12, 1994 Ground water gradient shows a relatively flat flow to the east, with a high mound at MW3 (probable a residual high in ground water caused from the vapor extraction at this well) MW-8 SOURCE TEST On October 28 , 1994 , a bio-venting source test was performed on MW-8 The purpose of this test was to evaluate the benefit of performing a once a week evacuation of the well to enhance oxygen transfer and remove residual CO2 Mr Mark Schonhoff of San Joaquin Valley Unified Aar Pollution Control District , is currently evaluating this source test as it pertains to air quality conditions in the Stockton area Presently the vapor extraction system at Former Regal Station 603 , PTO # N-1090-1-0, is having only limited effect on the leading edge of the dissolved gasoline range plume that has traveled east from the site, across Pacific Avenue Two sources 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 while limiting hydrocarbon removal to less than 0 1 pound per week We are proposing to utilize LTT vacuum trucks to pull an estimated 11 feet of water vacuum on MW8, for two hours once a week and exhaust directly to atmosphere This vacuum will generate a flow rate of approximately 20 cfm WEGE is also evaluating the need to change out BACT from Thermal Oxidation to Carbon Adsorbtion, in light of the lower amount of hydrocarbons found in the vapor stream and the cost savings of utilities, versus carbon change out SUMMARY There has been no evidence of floating product or product sheen on the ground water in MW1 since April 14 , 1992 and MW3 and MW10 since November 11, 1992 The last evidence of product , as a sheen in the condensate recovery system, was on March 1 , 1993 Vapor recovery has reduced the hydrocarbons in ground water significantly since the May 25, 1990 sampling, see Table 1 . Using benzene as an indicator, monitoring wells MWI , MW4 MW5, MW6, MW7 and MW9 have been reduced to below detection limits while the wells being utilized for vapor extraction (MW2, MW3 , and MW10) have been reduced by better than 95%, 99a and 99% respectively MWS increased from a reduced of approximately 56% (June-September, 1994) to a 220-. reduction as shown from the December 12 , 1994 sampling, this increase in contamination is most likely due to the down time of the REMOX unit during the months of October and November, 1994 Of the newly installed wells MW11 and MW12 , MW12 has shown a significant (92t) reduction PAGE 2 R603 UPDATE-35 1/17/95