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Mr. Mike Desso • - 4 - • 15 September 2008 Nestle USA Inc. Other Comments The comments listed below address the following items: 5. California Department of Transportation (Caltrans) impacted irrigation well, 6. Migration of COCs northwest of the Former Facility, 7. Figure 2 well location map, 8. Groundwater flow and transport model, 9. Several text reference items, and 10. Reference corrections. 5. Caltrans well. Section 2.1, Item 7 summarizes Nestle's efforts to provide replacement water to the California Department of Transportation (Caltrans) for the impacted irrigation well on Manley Road in Ripon. Caltrans has denied Nestle access to replace the well with hookup to the City of Ripon (City) non-potable water system. Concentrations of COCs continue to decline in the well: concentration TCE has steadily dropped from a high of 6.3 micrograms per liter (µg/L) in April 2000 to a low of 0.75 4g/L in October 2007; concentrations of cis-1,2-DCE have dropped from a high of 190 µg/L in May 2002 to a low of 1.1 µg/L in April 2007. If Caltrans will not allow access, the Regional Water Board will not require Nestle to provide replacement water. 6. Northwest migration of COCs. The Annual Report cites conditions at City municipal well MW-10 as a measure of the effectiveness of the two operating Nestle groundwater treatment systems: "Municipal well MW-10 has not exhibited COCl above detection' limits over the course of the last 7 years of sampling from this well." However, it must be noted that in 2006 (after 5 years of sampling) breakdown products of TCE appeared and continue to be present in 2 water supply wells at Ripon Elementary School and Ripon Christian School. Although concentrations have not exceeded Public Health Goals published by the State of California and do not appear to be increasing rapidly, these school wells are located in the groundwater flow path between the Former Facility and MW-10. They are approximately 2,500 to 3,500 feet down-gradient of the Former Facility and 1,600 to 2,500 feet up-gradient of MW-10. 7. Well location map. Figure 2 should include a grid with lines drawn at intervals of approximately 1,000 feet and grid labels along the map margins. The font size used to depict the well names on the map should be significantly reduced (similar to the font of the vapor extraction [VE] wells at Industrial Avenue shown on the map). A well location key that references the location of each well using north-south and east-west grid coordinates should be added to the map. There appears to be sufficient space in thq upper right corner of the map to place such a key. The grid map should be included in future annual reports. 8. Groundwater model. The Annual Report's Section 1.10, presents assessment of the capabilities of the groundwater flow and contaminant transport model developed by ECM. Statements are made regarding plume migration based on model simulations. However, remedial action decisions should be made based on actual plume constituents of concern (COC) concentration data.