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*ARR ASSOCIATES <br /> Environmental Engineering and Geohydrology <br /> March 30, 2006 RECOV D <br /> APR 4 Z00d <br /> Mr. Mark Adams, Trustee ENVIRONIVENT HEALTH <br /> Lincoln Center Environmental Remediation Trust PERMIT/SERVICES <br /> 137 Park Place <br /> Richmond, CA 94801 <br /> Subject: Feasibility Study for the Lincoln Center Site, Stockton <br /> Dear Mr. Adams: <br /> On behalf of Lincoln Properties Ltd. (LPL), Farr Associates submits this letter regarding its <br /> oversight and monitoring of the subject work conducted by the Lincoln Center Environmental <br /> Remediation Trust (LCERT) at Lincoln Center, Stockton (Site). The comments in this letter <br /> cover two important issues: 1. The persistently high levels of volatile organic compounds <br /> (VOCs) east of the "Historical Source Area," and 2. The slow pace of LCERT's progress toward <br /> completion of the Site Feasibility Study and selection of the final site remedy. <br /> We would like to acknowledge LCERT's progress in Site investigation and the implementation <br /> of significant interim remedial actions (IRAs). The groundwater extraction and treatment IRAs <br /> provide a significant degree of control in limiting the migration of VOCs in groundwater, and the <br /> soil-vapor extraction IRA has been effective in removing a substantial mass of VOCs from <br /> unsaturated sediments at the Site. Despite the substantial progress, much remains to be done. . <br /> LCERT has recognized the persistence of VOCs in the "Historical Source Area," located in the <br /> western portion of Lincoln Center near Benjamin Holt Drive, and has conducted several pilot <br /> studies and special investigations to support the selection and design of remedial actions for this <br /> area. However, high concentrations of VOCs (principally tetrachloroethene - PCE) in <br /> groundwater east of the "Historical Source Area" (the Eastern Hot Spot) are not receiving any <br /> special attention, even though the PCE concentrations observed in this area are similar to those <br /> observed in the "Historical Source Area." <br /> The existing site data are sufficient to conclude that persistently high PCE concentrations have <br /> been observed in the Eastern Hot Spot. Selected PCE concentrations observed in groundwater <br /> east of the "Historical Source Area" are as follows: <br /> 6016 Princeton Reach Way • Granite Bay, California 95746 Tel. (916) 781-9327 • Fax (916) 781-9357 <br />