SITE INFORMATION AND CORRESPONDENCE_1997

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Lincoln Center * 2 3. Municipal well COS-11 is to be added to the monitoring well network and sampled on a semi- annual basis by EPA method 8260A beginning with the first quarter 1998. 4. If desired, monthly water level measurements may be discontinued and replaced with quarterly measurements. Surface Emission Isolation Flux Chamber Investigation Sampling Plan (13 October 1997) 1. This workplan is to collect data to be used for the health risk assessment(HRA). I informed Levine-Fricke-Recon(LFR) in early October that Board staff does not review HRAs, and therefore, staff cannot review or approve the flux chamber proposal. 2. The SDCDs needs to deride which State agency (Office of Environmental Health Hazard Assessment or Department of Toxic Substances Control)they prefer to use for review of the HRA. If DTSC is the choice (as indicated verbally), then the responsible parties need to begin the contracting process immediately. Monitoring Well MW-21 Evaluation and Recommendations (16 October 1997) 1. We did not receive the 7 May 1997 letter to Lincoln Properties which contained revisions to the workplan. Therefore, we did not approve the work described by this report. In the future, all workplans, addendums, and revisions are to be sent to Board staff in time for review and comment. 2. I approve the proposal to abandon well MW-21. 3. The new B zone well is a cluster with screens at three discrete intervals of the B zone. The first round of analytical results show that the first two intervals of the B zone are highly contaminated while the third is not. How are the other B zone wells constructed? Will the B zone data be skewed if different wells are screened across different intervals of this zone? 4. Once again, the lab sheets show that chemicals other than the "Hazardous Substances"were detected. However,these chemicals were not tabulated or discussed in the report. Future reports are to contain a tabulation of all detected chemicals. Project Update Meeting(29 October 1997) 1. LFR is to continue collecting grab groundwater samples until the PCE plume has been defined to 0.5 µg/1. We are specifically concerned about the SDCD's decision not to pursue the upgradient extent of contamination in the B zone. 2. Staff expressed concerns that the investigation is continuing without direct Board oversight. The SDCDs stated that staff will be invited to the monthly "periodic meetings" (as defined in the Consent Decree), and that staff will receive all notifications of field activities. We also asked that the progress meetings be held on a more frequent and regular basis. 3. The SDCDs are to obtain staff's approval before installation or destruction of any monitoring well.