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S E C O R ----- - -- - • Ms Anastasia Duarte-Wilkinson February 4, 2004 Page 2 during this monitoring event The groundwater elevation decreased an average of approximately 0 38 feet since the last sampling event in July 2003 The groundwater flow direction during this reporting period was predominantly toward the south/southwest with a hydraulic gradient of 0 06 feet per foot(ft/ft) A summary of groundwater level data measured through October 20, 2003 is presented in Table 1 Copies of field observations documenting work performed at the site are presented in Attachment 1 GROUNDWATER ANALYTICAL RESULTS The distribution of groundwater sample analytical results obtained from monitor wells at the site on October 20, 2003 is presented on Figure 3,and summarized 1n Tables 2 and 3 With the exception of a concentration of MTBE reported in MW-9 at 1 5 micrograms per liter (ug/L), TPHg, BTEX, and fuel oxygenates were reported below method detection limits in all wells sampled Monitor well MW-1 was not sampled due to the presence of 0 01 foot of LPH Monitor wells MW-5 and MW-10 were not sampled, MW-5 was reported dry, and MW-10 contained an insufficient quantity of water to sample Attachment 2 contains photocopies of the laboratory analytical report and the chain-of-custody fora LPH is monitored and removed(if necessary)from MW-1 by hand bailing methods and the use of a passive, down-hole petroleum skimmer LPH was not removed from MW-1 this quarter,due to the small quantity in the well A total of approximately 62 gallons of LPH has been removed from MW-1 since Its detection in February 2000 Until this quarter, LPH had not been detected in MW-1 since July 2002 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 SVE wells (W-1, W-3 through W-8), two groundwater monitor wells modified for SVE(MW-1 and MW-3),and four AS 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)approved an air permit for the site SOIL VAPOR EXTRACTION On September 16,2003,the SVE/AS system was shut down following the receipt of verbal authorization from the SJCPHD, and has remained off-line through the fourth quarter 2003 The SJCPHD approved the non- operation of the system as a result of low soil vapor influent concentrations Since the SVE/AS system began operation in December 1999, a total of approximately 38,894 pounds of gasoline and 233 2 pounds of benzene have been removed and treated at the site 1\Time OiKLockeford\OMRs12001-20031Lockeford 04-03 doc SECOR lntemational Incorporated