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S E C O R Ms Anastasia Duarte-Wilkinson January 30, 2003 Page 2 The groundwater elevation decreased approximately 0 86 feet since the last sampling event In July 2002 The groundwater flow direction during this reporting period is toward the south/southwest with a hydraulic gradient of approximately 0 02 ft/ft A summary of data regarding groundwater levels measured through November 12, 2002 is presented in Table 1 Copies of field observations documenting work performed at the site are presented in Attachment I GROUNDWATER ANALYTICAL RESULTS The distribution of groundwater sample analytical results obtained from monitor wells at the site on November 12, 2002, is presented on Figure 3 and summarized in Table 2 The highest concentration of petroleum hydrocarbons is in the vicinity of monitor well MW-1 TPHg and benzene concentrations were below method detection limits for all wells during this monitoring event,with the exception of MW-1 MTBE concentrations ranged from 0 60 micrograms per litter(ug/L)in MW-9 to below method detection limits in monitor wells MW-1 through MW-4, MW-6, MW-7, MW-8 and MW-10 this quarter Attachment II contains photocopies of the laboratory analytical report and the chain-of-custody form It should be noted,monitor well MW-5 was not sampled this quarter because the well was dry On November 12, 2002, LPH was not detected In MW-1 during this monitoring event and therefore was sampled LPH continues to be monitored and removed(if necessary)from MW-1 by hand bailing methods and the use of a passive, down-hole petroleum skimmer on a weekly basis A total of approximately 62 gallons of LPH has been removed from MW-1 since its detection in February 2000 PURGE WATER • Purge water generated during groundwater purging is currently contained on-site in Department of Transportation rated 55-gallon drums pending removal to a disposal/recycling facility SITE REMEDIATION Construction of a soil and groundwater remediation system was completed at the site in December 1999 The remediation system consists of seven soil vapor extraction (SVE) wells (W-1, W-3 through W-8), two groundwater monitor wells modified for SVE(MW-1 and MW-3)and four air sparge wells(AS-1 through AS-4) with catalytic oxidation treatment A Site Plan depicting the locations of the remediation wells, subsurface piping,and remediation equipment compound Is Included as Figure 4 Initial start-up air discharge compliance testing was completed on December 13, 1999 The San Joaquin County Valley Air Pollution Control District (SJVAPCD) has approved an air permit for the site SOIL VAPOR EXTRACTION During site visits,SECOR monitored system parameters and collected appropriate Influent soil vapor samples Air samples were collected on October S. 2002, November 5, 2002, and December 3, 2002 Based on the influent soil vapor samples analytical results,approximately 149 pounds of gasoline were removed and treated at an average extraction rate of 51 scfm for this reporting period A total of approximately 38,785 pounds of gasoline has been removed and treated at the site since the SVE system began operation The soil vapor analytical results and system efficiency results are Included as Attachment III i 1 Mme 0 LL.ockefordQ402 doe SECOR Intemational Incorporated