SITE INFORMATION AND CORRESPONDENCE_1997

Home Browse Search

RvineeFricke-Recon ENGINEERS,HYDROGEOLOGISTS 8 APPLIED SCIENTISTS installed primarily to characterize and monitor the vertical distribution of Hazardous Substances in the B-zone aquifer in the source area. MW-203B-1 is screened in the upper-most sand in the B-zone aquifer from approximately 92 to 95 feet below ground surface (bgs; 3 feet of screen). MW-203B-2 is screened from approximately 101 to 111 feet bgs (10 feet of screen) and MW-20313-3 is screened from approximately 123 to 128 feet bgs (5 feet of screen). Water-level data collected from these three discretely screened wells are not comparable with water-level data collected from the other B-zone monitoring wells. Water-level data and water quality data collected from the B-zone monitoring wells (with the exception of well cluster MW-203B) are comparable across the site. As part of the ongoing RI, LFR will be completing a more thorough evaluation of the sediments within the B-zone and their comparability between geographic locations. 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. We acknowledge the RWQCB's request to tabulate all detected VOCs and will provide these data in future reports, beginning with the fourth quarter 1997 quarterly groundwater monitoring report. PROJECT UPDATE MEETING (29 OCTOBER 1997) 1. LFR is to continue collecting grab groundwater samples until the PCE plume has been defined to 0.5µg/1. We are specifically concerned about the SDCD's decision not to pursue the upgradient extent of contamination in the B zone. As we discussed with Ms. Wyels on December 2, 1997, we recommend installing a pilot boring for the purpose of assessing the upgradient extent of Hazardous Substances in the B- and C-zones. Discrete groundwater samples will be collected from selected intervals in the B- and C-zones at this location. This proposal will be provided to the RWQCB in January 1998. 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. We acknowledge the RWQCB's request to participate in our monthly Periodic Meetings and will continue to plan these meetings to accommodate the RWQCB's schedule, whenever possible. We appreciate the RWQCB's attendance during our meetings on October 29, 1997 and December 2, 1997. We will also continue to provide the RWQCB with all notifications of field activities, as well as bimonthly status reports, and draft and final documents, as we have in the past. 3. The SDCDs are to obtain staffs approval before installation or destruction of any monitoring well. LV-Resp-RWQCB-Dec97-041I1:SRL