SITE INFORMATION AND CORRESPONDENCE

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Mr. Mike Desso - 2 - • 15 September 2008 Nestle USA Inc. 2. Stockton Avenue Site. There are not enough monitoring wells screened in the Intermediate Aquifer near the Stockton Avenue treatment system to verify the large groundwater extraction system capture zone shown by piezometric contours drawn on Figures 4-1 through 4-4 of the Annual Report. In fact, only onsite monitoring well M-8C is within 800 feet of the extraction wells. The next closest wells in order of approximate distance from the extraction wells are: M-1 8C1 800 feet north-northwest, M-6C 1, 100 feet north-northeast, M-24C1 1,200 feet west, and M-11C1 1,200 feet southeast. None of these are close enough to depict the influence on the piezometric surface suggested by the contours on the figures.. Several wells should be proposed for installation in the Intermediate Aquifer near the Stockton Avenue groundwater extraction wells. There are not enough monitoring wells screened in the Shallow Aquifer to monitor the piezometric groundwater surface near the Stockton Avenue treatment system. As with the Intermediate Aquifer monitoring network, only onsite well nest M-8A/8B is close to the extraction wells. The next closest well nests in order of approximate distance from the extraction wells are: M-9A/96, 650 feet west; M-18A/186, 800 feet north-northwest; M-22A/22B, 850 feet northeast; M-6A/613, 1,100 feet north-northeast; and M-11A/11B, 1,200 feet southeast. Several wells should be proposed for installation in the Shallow Aquifer near the Stockton Avenue groundwater extraction wells. 3. City Wastewater Ponds. Concentration trends of trichloroethene (TCE) and it's breakdown products in monitoring wells near the City treatment ponds may give clues to concentrations observed south of the Stanislaus River. Nestle should study the trends in Upper Aquifer monitoring wells including M-23A and M-32A, and Intermediate Aquifer monitoring wells including M-30C1, M-31C1, and M-32C. Concentrations of CDCs have been reported in the domestic well depicted on Figures 6, 7, and 8 of the Annual Report between monitoring wells M-32A and M-34A. The domestic well is screened within the Upper Aquifer and the concentration of TCE on 8 May 2008 was 6.5 µg/L. Therefore, it is reasonable to assume that the 0.5 and 5 µg/L TCE concentration contours on Figure 6 extend from the wastewater ponds, across the river, and beyond the domestic well. Nestle should include the 8 May data on the figure and redraw the concentration contours accordingly. The concentration of cis-1,2-dichloroethene (DCE) on 8 May 2008 was 14 µg/L in the domestic well. Therefore, it is reasonable to assume that the 0.5, 5, and 10 µg/L cis-1,2-DCE concentration contours on Figure 7 extend from the wastewater ponds, across the river, and beyond the domestic well. Nestle should include the 8 May data on the figure and redraw the concentration contours accordingly. The concentration of vinyl chloride on 8 May 2008 was 1.3 µg/l_ in the domestic well. Therefore, it is reasonable to assume that the 0.5 µg/L vinyl chloride concentration contour on Figure 8 extends from the wastewater ponds, across the river, and beyond the domestic well. Nestle should include the 8 May data on the figure and redraw the concentration contour accordingly.