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California Regional Water Quality Cohtrol Board <br /> Central Valley Region <br /> Terry Tamminen <br /> Robert Schneider,Chair ,� 7 <br /> - <br /> Secreta for Arnold Schwarzenegger <br /> Secretary Sacramento Main Office L 1 `-' ``' Governor <br /> Environmental Internet Address: http://www.swrcb.ca.gov/rwgcb5 <br /> Protection 11020 Sun Center Drive#200 Rancho Cordova,CA 95670-6114 OCT <br /> Phone(916)464-3291 0 5 2004 <br /> ENV1ROM WEit►; HLALTH <br /> 4 October 2004 PERMIT/SERVlCrS <br /> Mr.Ken Hillard <br /> 7-Eleven Corporation <br /> P.O. Box 711 <br /> Dallas,TX 975221-0711 <br /> FIELD TEST PROGRAM FOR EVALUATION OF OXIDATION CAPACITY OF GROUNDWATER, <br /> 7-ELEVENSTORE#14177, 2725 COUNRTY CLUB BOULEVARD,STOCKTON, SA V JOAQUIN COUNTY, <br /> I reviewed two documents, dated 22 July 2004 and 31 August 2004, titled Field Test Program for Evaluation of <br /> Oxidation Capacity of Groundwater(Reports), and submitted by SECOR International Inc. (SECOR) on behalf <br /> of 7-Eleven Corporation. The 22 July 2004 Report provides a Workplan for a Pilot Study utilizing batch oxygen <br /> injection into a new 2"well(I-1) from a compressed gas bottle into the aquifer, to enhance degradation of <br /> petroleum hydrocarbons. The 31 August 2004 Report uses analytical results of dissolved metals and general <br /> minerals from a groundwater sample from monitoring well MW-1 (located 5 feet from I-1), to produce theoretical <br /> calculations in a geochemistry evaluation. Based on the evaluation, SECOR concluded that a Bench Scale Study <br /> is not necessary prior to the Field Pilot Study. <br /> The Workplan is tentatively approved as written with the following conditions: <br /> • SECOR must collect and analyze one representative soil sample from the oxygen injection target zone at <br /> the site. Soil analyses will repeat the previously groundwater analytical suite, so that the revised <br /> geochemical evaluation(GE)report may compare the results of the soil and groundwater, and thoroughly <br /> discuss the expected worst-case scenario reactions, i.e., 100% conversion of constituents of concern into <br /> contaminants,reporting the chemical reactions in molar concentrations. <br /> • If metals of concern (Cr 6+, etc.) are not detected, or general minerals (SO4, etc.)are not present at levels <br /> favorable for adverse reactions in saturated soil, then you may proceed to the Pilot Study after final <br /> approval of the GE report. Note that all Pilot Study analytical detection limits must be sufficiently low to <br /> test the theories proposed in the Reports and provide comparisons to Water Quality Objectives in the GE <br /> report. You will continue to monitor groundwater during the Pilot Study for the know petroleum <br /> hydrocarbon contaminants and general parameters (dissolved oxygen,pH, specific conductance, <br /> temperature). <br /> • If metals of concern(Cr 6+, etc.) are detected, or minerals of concern(SO4, etc.) are detected at potentially <br /> harmful levels,then a Bench Scale Test(BST)will be conducted to show which contaminant(s) are <br /> produced; and whether the produced contaminant(s)will persist after termination of oxygen injection, <br /> using the graphed slope of the declining contaminant(s) concentrations versus time to calculate a decay <br /> rate (time to revert to non-detect). If a contaminant(s) is produced and persistent,provide that <br /> information in a report for my evaluation. If contaminant(s)produced are not persistent,provide a BST <br /> Report containing modifications to the Pilot Study monitoring program, specifically,the frequency of <br /> analyses needed to confirm contaminant decay rates as calculated from BST analytical evidence. <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />