SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Angelica Sandoval Marin [EH] From: Nuel Henderson [EH] Sent: Friday,January 23, 2015 3:13 PM To: 'Sheehan, Caryl@,Waterboards'; 'Trommer, Bob@Waterboards' Cc Adrienne Ellsaesser[EH];Angelica Sandoval Marin [EH] Subject: RE: GILLIES TRUCK,T0607700234, Claim 1129 Request for Teleconference Caryl and Bob, Adrienne and I can be available for a conference call regarding this site the afternoon of Monday, January 26, Tuesday morning January 27, all day Wednesday January 28, or the morning of Thursday January 29 or Friday January 30; you can select the time if any of these time periods work for you. We will be utilizing Adrienne's office and phone (209)468- 0343 for the call at our end. We have been working toward closing the site as should be evident from our recent letters and are just trying to tie up two main issues, especially as the site is in an area of high groundwater usage. In addition to the public water systems Adrienne noted below, a sensitive receptor survey in 2008 identified 28 water supply wells within a 2,000-foot radius of the site, of which 6 wells are 500 feet or closer to the site (the onsite well having been destroyed). We are trying to settle two issues at this time—an unassessed waste oil tank and identifying monitoring wells that may be destroyed by pressure grouting as opposed to being over-drilled, which can lead to considerable cost savings. Under our county ordinance, wells known or believed to be in areas of contamination must be over-drilled. As the last monitoring event was conducted in January 2011, it would be reasonable to assume a number of monitoring wells may have cleaned up over the last four years. The EHD identified 11 monitoring wells with favorable soil data and low TPHd concentrations that may have cleaned up. A work plan has been approved to sample these wells for TPHd and to analyze filtered samples for cadmium and zinc. In preparation for closing the site, the EHD discussed the site with a Central Valley Regional Water Quality Control Board (CVRWQCB) representative, who pointed out that we did not have the data related to a waste oil tank removed in 1986; this tank some 160 feet removed from the fuel USTs. The CVRWQCB was willing to accept data from nearby monitoring wells to resolve the issue and samples from two wells were analyzed for waste oil or unknown tank constituents. Unfortunately the samples yielded various metals; after filtering the samples zinc was still detected in the two samples and cadmium in one. As part of the sampling plan for the well destruction issue, water samples from the wells and one additional well(the well that had both cadmium and zinc) are to be filtered and analyzed for zinc and cadmium to demonstrate whether or not there may have been a release, the detected metals are background, or the detected metals were false positives due to lack of immediate filtering. The consultant proposed to advance a hand auger boring in the former waste oil tank pit and analyzed soil for the waste oil constituents, which the EHD has approved. After receiving the RDR with its closure recommendation, the EHD directed the consultant to proceed with the groundwater sampling as this is directly related to closing the site in a cost effective manner, but directed delaying sampling the soil until our agencies are in agreement as to how to proceed. To reiterate, the site had been in the initial stages of closure until the issue of the lack of assessment data for the waste oil tank came up: the consultant has been directed to conduct public notification of the pending closure, a work plan for well destruction is in progress and will be completed after the planned groundwater sampling event described above, the certified list of record fee title owners has been completed. The consultant informs me that the RP and he, the consultant, are ready to do these final tasks to close the site. Adrienne and I, and Angelica if available, look forward to discussing the site with you. Nuel Henderson, PG (209)468-3436 From: Adrienne Ellsaesser [EH] Sent: Tuesday, January 13, 2015 10:25 AM 1