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w <br /> OCalifornia Refional Water Quality Control Board <br /> Central Valley Region <br /> Winston H.Hirkox Steven T.Butler,Acting Chair 9 <br /> Secretary for Sacramento Main Mee - Gray Davis <br /> Environmental Internet Address: http:!/www.swmb,c .gov/-mgcb5 - t. Governnr <br /> Protection 3443 Routier Road,Suite A,Sacramento,California 95827-3003 <br /> Phone(916)255-3000•FAX(916)255-3015 <br /> 18 February 1999 <br /> Mr. Donald Bradshaw <br /> Levine Fricke Recon, Inc. <br /> 1900 Powell Street, 12th Floor <br /> Emeryville, CA 94608-1827 <br /> REVIEW OF DRAFT PHASE 77 IRA, MEETING SUMMARY, LINCOLN CENTER, STOCKTON, <br /> SAN JOAQUIN COUNTY <br /> I am in receipt of the 27 January 1999 Draft Phase II Interim Remedial Action Detail Plan prepared on <br /> behalf of the Settling Dry Cleaning Defendants (SDCDs) for Lincoln Center in Stockton. My review of <br /> the document is found in the enclosed memorandum. In general, the plan is well written and <br /> comprehensive. <br /> On 11 February 1999, a meeting was held at the Regional Board to discuss comments about the Detail <br /> Plan. The meeting was attended by Board staff, representatives of the SDCDs, the SDCD's consulting <br /> firm (Levine-Fricke-Recon; LFR), and representatives of Lincoln Properties Limited. Several issues <br /> were raised at the meeting including the need to validate the model used to calculate the soil vapor target <br /> cleanup level, the need for additional indoor air monitoring, and a request that the Department of Toxic <br /> Substances Control (DTSC) review the calculations used to determine the soil vapor target cleanup <br /> level. Lincoln Properties also has concerns about the overall system design; I understand that the <br /> SDCDs, LFR, and Lincoln Properties will be meeting separately to finalize the design. <br /> I do not believe that it is necessary at this time to collect additional soil vapor data to further validate the <br /> model. An interim remedial measure is being proposed, and any necessary fine-tuning can be proposed <br /> as part of the final Remedial Action Plan. However, additional indoor air monitoring may be justified in <br /> order to ensure that an adequate number of soil vapor extraction wells are installed. Because people <br /> working in certain buildings at Lincoln Center are currently exposed to soil vapor containing excess <br /> concentrations of PCE, this extra monitoring should not delay the implementation of the remedial action. <br /> An alternative to additional indoor air monitoring is to add more soil vapor extraction wells around the <br /> buildings. <br /> As we discussed on 18 February, a suggestion has been made to remove all references to the health risk <br /> assessment from the Draft Interim Detail Plan and instead base the soil vapor target remedial goal on <br /> groundwater protection. This is acceptable because the document shows that when the soil vapor is <br /> remediated to a level which will protect water quality, then it will also be fully protective of human <br /> health. In addition, the final Health Risk Assessment(HRA) will contain an evaluation of the health <br /> effects of the hazardous substances moving from the soil vapor into buildings and the final remedial goal <br /> California Environmental Protection Agency <br /> ea Recycled Paper <br />