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laboratory detection limits for EPA method 8260 , as was performed by Superior Precision Analytical, Inc , see Update #29-Appendix A On March 6 , 1996 , quarterly ground water samples were obtained from all of the wells, see Table 1 and Appendix A These samples were collected by a WEGE Geotechnician and "Chain of Custody" delivered on ice to State certified testing laboratory, AMERICAN ENVIRONMENTAL NETWORK, INC DHS #1172, for chemical analyses These samples were analyzed for TPH and BTEX concentrations using EPA Methods 8015/5030 and 602 respecti-ely The next quarterly sampling will occur in June, 1996 GROUND WATER SAMPLE RESULTS This latest sample results showed levels declining at MW2 , MW3 , MW8 , and MW10 MW1 and MW12 showed slight increases, see Table 1, Figure 5, Figure 6-Charts and Appendix A VAPOR RECOVERY OPERATIONS AND RESULTS The original REMOX unit operated for 14452 hours out of a total of 21048 hours (690) From August 18, 1992 to March 5, 1996, the new replacement unit operated 18786 hours out of 31095 hours (600) During the site visit on June 7, 1995, excessive noise generating from the blower prompted the noon shut down of the REMOX unit The unit remained off until September 23 , 1995 At that time the blower was replaced with 2 DR 505 Rotron blowers and the system was restarted As of March 5, 1996 an estimated 74849 pounds of gasoline range hydrocarbons have been destroyed, see Table 2 , in Appendix C - Air Monitoring Report Since March 11, 1993 the vapor recovery/destruction has been declining when above 100 pounds per day of gasoline range hydrocarbons were being removed, down to 1 85 pounds per day on December 19, 1995 A request for Modification to the system was made , to remove the TO and replace it with activated carbon vapor scrubs This modification was approved, see Update #29-Appendix D On March 6 , 1996, start-up of the Carbon Adsorbtion system occ rreri see Appendix C MW-8 BIO-VENTING/OXYGEN TRANSFER On October 26 , 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 The vapor extraction system at Former Regal Station 603 , PTO # N- 1090-1-0 , was having only limited effect on the leading edge of zhe dissolved gasoline range plume that has traveled east from 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 PAGE 2 R603 UPDATE-43 3/25/96