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STATE OF CALIFORNIA—ENVIRONMENTAL PR(`- ^-TION AGENCY PETE WILSON,Governor CALIFORNIA REGIONAL WAS QUALITY CONTROL BOARD— OF CENTRAL CENTRAL VALLEY REGION 3443 ROUTIER ROAD,SUITE A El ,11g SACRAMENTO,CA 95827-3098 ff�r�I'�#1 PHONE: (916)255-3000 FAX: (916)255-30151!0,t� _ Ei f # ` 29 6 November 1995 Mr Donald Moore SECOR International Inc. 90 New Montgomery Street, Suite 620 San Francisco, CA 94105 REVIEW OF QUARTERLY GROUNDWATER MONITORING REPORT AND PROPOSAL FOR PASSIVE BIOREMEDIATION DEVICES,TOWER PARK MARINA, SAN JOAQUIN COUNTY Thank you for submitting the third quarter monitoring report for Tower Park Marina, which you have prepared on behalf of P.S. Marina Investors I. The report states that analytical results from Monitoring Well (MW)-3 show decrease in gasoline . (TPHg) and diesel (TPHd)compared with May 1995 results. Examination of Table 3 in the report shows that both gasoline and diesel remain higher,however,than reported in January 1995. Results from the other wells are relatively consistent with historical results. The report further states that the passive skimmer in MW-3 appears to be successful in removing floating product, based on decrease in measured thickness of the product. Product now occurs as a sheen in the well. In addition the report cites information from the manufacturer of the passive skimmer that the effectiveness of the device is severely decreased when product thickness is very thin or reduced to a sheen. Based on this information and on the measured thickness records, SECOR proposed to remove the skimmer from well MW-3, and to implement a free product and removal program. SECOR proposes to measure the free product thickness every two weeks, using an interface probe, and to remove ten casing volumes of product and impacted water. The report does not explain what will be done with the removed water and product,but it does state that product removed to date by the skimmer is contained on site. We request clarification on how the product is stored, for how long, and what is ultimately done with it. Based on a 3 November telephone conversation with you, we understand that the skimmer has now been removed. In addition to bailing product and impacted water from MW-3 on an as-needed basis, you propose to install passive remediation devices, consisting of a sleeve or sock containing an oxygen releasing compound(ORC), in wells MW-2,MW-3, and MW-4. The purpose of these installations is to enhance natural bioremediation.The technique does not have a long track record, but Board staff are aware of similar approaches being used at several other out of state sites. Based on our 3 November telephone conversation with.you, we understand that the particular