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Ms. Anne C. Conner September 22, 2009 3 The site reconnaissance also confirmed the presence of water supply wells CSD-1, WSD-1 and ZFD-1, and staff gauges WS SE-4, -5, -6 and -72. Water supply well TCD-1 was not found, and ZFD-1 was concluded not to be a PG&E water supply well. Water supply wells CSD-1 and WSD-1 are in active use by PG&E and therefore would not be decommissioned. The staff gauges would be removed as part of the site closure process. INITIAL DISCUSSIONS WITH SJCEHD MSE contacted SJCEHD to discuss the requirements for well decommissioning. SJCEHD requirements are found in Well Standards (SJCEHD, 2005). Because CVRWQCB rescinded the WDR based on concurrence that the site COCs are no longer found at concentrations above background, SJCEHD would approve the decommissioning of wells and piezometers by pressure grouting rather than by overdrilling(MSE, 2009c). SJCEHD also provided a schematic for the subsurface protective cement grout cap to be placed over the top of the pressure grouted wells and piezometers (called a"mushroom cap"), and requested that grout be a 9-sack mix of neat cement rather than a mix of cement and bentonite. MSE also discussed with SJCEHD the results of the site reconnaissance. SJCEHD agreed to perform a records search on several of the wells and piezometers (P-6A, WP-1, ZFD-1 and TCD-1) so that MSE could prepare an accurate Request for Bid. In the absence of available and accurate survey data, MSE also agreed to attempt to locate P-6A and WP-1 by clearing and scraping the surface around their approximate locations and looking for evidence of the piezometers. In addition, MSE requested any additional well completion data that SJCEHD might have on wells (e.g., borehole diameter and annular space)based on permits that could be found in County records. However, no permits and additional well construction details were found in SJCEHD records. SOIL MOUND SAMPLING AND ANALYSIS AND EVALUATION OF RESULTS On June 1, 2009 MSE collected samples from the four soil mounds to establish their disposition and for preparing an accurate Request for Bid. Two two-point composite samples were collected and were labeled "Composite East" (for the two eastern soil mounds) and "Composite West" (for the two western soil mounds). MSE submitted the samples under chain of custody to McCampbell Analytical in Pittsburg CA, a California Department of Health Services-certified analytical laboratory, for 24-to 48-hour turnaround on analysis. Laboratory analysis was requested for COCs listed in the rescinded WDR(barium, sulfate, sodium, chloride and pH) that could have potential toxicity characteristic. Attachment 2 to this report provides the chain-of-custody record and analytical results and Table 2 summarizes the results and provides composite sample averages for each COC. The averages in Table 2 were compared to Pond 3 subsurface soil data presented in Table 6-1 from the 2007 Annual Groundwater Monitoring Report(MSE, 2008). These comparisons are also shown in Table 2. Z Note WSSE-4, -6 and-7 had not been measured since 1999,2007 and 1995,respectively. The WSSE-4 and-6 staff gauges were found lying on their sides and the WSSE-7 staff gauge was surrounded by tall vegetation.