ARCHIVED REPORTS_2011 REVISED FEASABILITY STUDY

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Nestle USA, Inc.—Ripon, CA January 28, 2011 2011 Revised Feasibility Study pilot boring for well M-25C2 at depths between 38 and 56 feet bgs. The TCE concentration from a deeper groundwater sample (74 feet bgs) at the same location was 31 pg/L, but slightly higher in the A subzone samples from the same location (210 and 170 pg/L at 88 and 99 feet bgs, respectively). TCE concentrations in deeper samples from M-25C2 were much lower (6 and 10 pg/L between 163 and 186 feet bgs)""' Additional characterization of COCs in groundwater beneath the Site to depths of approximately 100 feet bgs, and west of the Site, was conducted by Geomatrix Consultants, Inc. (Geomatrix) in August and December 2005. Of the 54 depth- discrete groundwater samples collected by Geomatrix (including three duplicate samples), seven were reported to contain TCE concentrations (> 1,000 pg/L), all from beneath the Site at depths between 40 and 60 feet bgs TCE concentrations were at least one order of magnitude lower in deeper samples (from 60 to approximately 100 feet bgs). This spatial distribution of shallow, relatively high concentrations of TCE suggests an onsite release of TCE-impacted shallow groundwater beneath a relatively small area of the Site extending from the former warehouse and water treatment building northward towards former supply well N-1, and does not extend east beyond the location of former supply well N-3. Figure 2 through Figure 6 within the April 2006 Initial Testing and Characterization Report from Geomatrix show this vertical distribution of TCE impacts beneath the site.xx'v 6.1.2 519 S. Stockton Avenue Site Following the discovery of TCE in groundwater samples from Site production wells, Nestle investigated additional possible off Site source areas by conducting a series of soil vapor surveys. The 519 South Stockton Avenue site was suspected as a possible source area, with COC impacts thought to be related to the presence of City sewer lines immediately to the east. In 1992, Nestle installed a SVE system at 519 South Stockton Avenue based on results from 1989 and 1991 soil gas surveys. In 1999, Nestle installed a groundwater extraction and treatment system at the 519 South Stockton Avenue location. A modified version of that groundwater extraction and treatment system has operated through September 2009, with influent concentrations ranging from 5.3 to 150 pg/L TCE at E-2 and 15 to 70 pg/L TCE at E-6. As of April 2009, groundwater sample results collected from monitoring wells in the area of the Stockton Avenue site range from concentrations below detection limits (0.5 pg/L) at monitoring wells M-8A and M-91B, to 17 pg/L TCE at monitoring well M-813. 6.1.3 City of Ripon Wastewater Treatment and Disposal Plant (WWTP) The City of Ripon WWTP is located just north of the River and west of Highway 99 (Figure 3). The RWQCB oversees the WWTP and has issued Waste Discharge Requirements Order No. 94-263 (WDR) governing operations at the WWTP. The City of Ripon is assessing the possibility of increasing the permitted non-industrial discharge limit of 1.4 million gallons per day (MGD) to 2.18 MGD, in order to accommodate anticipated population increases in the area. 14