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Flag City Chevron • - 2 - • 22 November 2004
<br /> 6421 Capitol Avenue, Lodi
<br /> b. If metals of concern (Cr"', etc.) are not detected in samples, or general minerals (SO4, etc.)are not
<br /> present at levels favorable for adverse reactions in saturated soil,then you may proceed to item d.,the
<br /> Pilot Study phase, after final approval of the GE report. Note that all GE, BST and Pilot Study analytical
<br /> detection limits must be sufficiently low to test the theories proposed in the Reports and provide
<br /> comparisons to Water Quality Goals. You will continue to monitor groundwater during the Pilot Study
<br /> for the know petroleum hydrocarbon contaminants and general parameters (dissolved oxygen,pH,
<br /> specific conductance,temperature).
<br /> C. If metals of concern(Cr 6+, etc.) are detected, or minerals of concern (SO4, etc.) are detected in samples
<br /> at potentially harmful levels, then a BST will be conducted to show which contaminant(s) are produced;
<br /> and whether the produced contaminant(s)will persist after termination of ozone injection,using the
<br /> graphed slope of the declining contaminant(s) concentrations versus time to calculate a decay rate(time
<br /> to revert to non-detect). If a contaminant(s)is produced and persistent(does not degrade with time),
<br /> provide that information in a report for my review. If contaminant(s)produced are not persistent,
<br /> provide a BST Report containing modifications to the approved Pilot Study work plan monitoring
<br /> program, specifically, the frequency of analyses needed to confirm contaminant decay rates as calculated
<br /> from BST analytical evidence.
<br /> d. During the Pilot Study phase, groundwater sampling and analyses will be conducted immediately before
<br /> startup of the ozone injection system, and at intervals of one and 2 hours afterwards, in order to validate
<br /> all contaminant(s) analyses and proposed decay rates, if applicable. If a BST is not required prior to the
<br /> Pilot Study,then analyze at least once before and 1 hour after startup of ozone injection. Additional
<br /> Pilot study sampling schedules should be proposed in the Pilot Study Workplan.
<br /> e. Install data loggers in selected monitoring wells to record changes in dissolved oxygen,pH, specific
<br /> conductance, and temperature during the Pilot Study. The test data will be helpful to determine the
<br /> effectiveness of ozone injection.
<br /> f. Submit two Reports, each 30 days after completion of the IOS BST and the Pilot Study. The Pilot Study
<br /> Report may be submitted with the Addendum, or as a separate report/workplan if AGE recommends
<br /> other remedial options.
<br /> Please procure the appropriate drilling permit and give San Joaquin County Environmental Health
<br /> Department and myself at least 3 working days notice prior to commencement of fieldwork. You may
<br /> contact me at (916) 464-4615 with your questions or comments.
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<br /> i;!' James L. Barton, R.G.
<br /> Engineering Geologist
<br /> cc: Mr. Mark Owens, UST Cleanup Fund, SWRCB, Sacramento
<br /> Mr. Mike Infuma, San Joaquin County Environmental Health Division, Stockton
<br /> Mr. Scott Rishwain, Rishwain& Rishwain, Stockton
<br /> Mr. Ben Guzman, San Joaquin County Municipal Utilities, Stockton
<br /> Mr. David Lamm, McDonald's Corporation, 2700 Gage Lane, Lincoln, CA 95648
<br /> Mr. Timothy J. Cuellar, Advanced GeoEnvironmental, Incorporated, Stockton
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