SITE INFORMATION AND CORRESPONDENCE

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Mr. Robert Garcia • • 29 January 2004 Leprino Foods, Inc. 2 In Phase 2, LFC would continue hydraulic control of groundwater by pumping, install additional injection points along the fenceline, and install injection points within the source area to enhance the rate that SPH dissolves into the groundwater, thereby accelerating the removal rate of the SPH. Path to Closure LFC states that it will attempt to meet the numerical diesel cleanup standard of 10 mg1I(emphasis added) set by the Regional Board, but if this is not attainable within a reasonable active remediation period, it proposes using non-numerical cleanup criteria. These criteria include ensuring that polluted groundwater will not reach potential receptors, human health is protected, natural attenuation mechanisms will continue to reduce remaining hydrocarbons in the groundwater, and a good-faith effort is made to reduce hydrocarbon mass while minimizing the potential for long term treatment if the benefit to water quality is diminishing. LFC then proposes specific criteria under which active remediation and monitoring would terminate. Changes to Monitoring and Reporting Program LFC proposes to change the MRP to require semi-annual monitoring, eliminate wells MW-7, RW-4A, MW-5 and MW-14A from the program, terminate pumping from recovery well RW-4A, and abandon well RW-4A. Comments 1. Figure 1 of the Proposal shows the cone of depression created by EW-2 is continuing to increase, and Figure 2 of the Proposal shows proposed injection point O-1 lies within the cone of depression created by EW-2. Therefore, the oxygenated water will flow towards the extraction well, not towards the monitoring points. Proposed injection point 0-2, upgradient of RW-1, appears to lie in the stagnation point between the local groundwater flow to the northwest and the EW-2 cone of depression in which the flow would be southeast. Therefore, it is not clear which direction the oxygenated groundwater will flow from 0-2. The oxygen injection points need to be located further downgradient and outside of the EW-2 cone of depression to treat the offsite plume. 2. Phase 1 of the Proposal is essentially a pilot study for oxygen injection, because only two injection points would be installed. Injection point 0-1, upgradient of RW-2, would be monitored by three monitoring points spaced 8, 16 and 24 feet downgradient, to provide information on effectiveness of treatment in the downgradient direction. However, there is a lack of monitoring points side-gradient to the injection point. Assuming that the injection points will be moved further downgradient to treat the offsite plume, side-gradient monitoring points are needed to confirm the theoretical dispersion lateral to the groundwater flow. 3. Regarding site cleanup levels, State Board Resolution No. 68-16 ("Antidegradation Policy")requires the Board in regulating discharges to maintain high quality waters of the state until it is demonstrated that any change in quality will be consistent with maximum benefit to the people of the State, will not unreasonably affect beneficial uses, and will not result in water quality less than that described in plans and policies (e.g., quality that exceeds water quality objectives). The water quality limit for TPHd, based on taste and odor, is 0.1 mg/l, not 10 mg/l as stated in the Proposal.