ARCHIVED REPORTS_XR0007182 - Laserfiche WebLink

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S E C ® R • Mr Mark Chandler November 23, 2004 Page 2 surface(bgs) The groundwater potentiometric surface elevation averaged approximately 24 50 feet above mean sea level during this monitoring event The groundwater elevation decreased an average of approximately 0 59 feet since the last sampling event in April 2004 The groundwater flow direction during this reporting period was predominantly toward the south/southwest with a hydraulic gradient of 0 048 feet per foot(ft/ft) A summary of groundwater level data measured through July 23,2004 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 July 23, 2004 is presented on Figure 3, and summarized in Tables 2 and 3 With the exception of concentrations of TPHg,benzene, and MTBE reported in MW-1 at 1,100 micrograms per liter(ug/L),2 6 ug/L,and 0 6 ug/L and MTBE reported in MW-9 at 2 0 ug/L, TPHg, BTEX, and fuel oxygenates were reported below laboratory method detection limits (MRLs) in all wells sampled Attachment 2 contains photocopies of the laboratory analytical report and chain-of-custody documentation LPH is monitored and removed(if necessary)from MWA by hand bailing methods and the use of a passive, down-hole petroleum skimmer A hydrocarbon odor was reported in the well this quarter Until October 2003, LPH had not been present in the well since July 2002 A total of approximately 62 gallons of LPH have been removed from MWA 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 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 Since the SVE/AS system began operation in December 1999, a total of approximately 38,894 pounds of gasoline and 233 pounds of benzene have been removed and treated at the site On September 16,2003,the SVE/AS system was shutdown following the receipt of verbal authorization from the San Joaquin County Public Health Department(SJCPHD)and has remained off-line through the first quarter 2004 The SJCPHD approved the non-operation of the system as a result of low sod vapor influent concentrations At the request of the SJPHD on June 14,2004,SECOR restarted the remediation system due to the re-appearance of LPH in monitor well MWA The soil vapor analytical results and system efficiency results are included as Attachment 3 • I Mine Oif\LodcefordlQMRs120041Lodceford Q3-04 doc SECOR International incorporated