SITE INFORMATION AND CORRESPONDENCE

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Nestl6 USA hie. • - 5 - • 16 June 2005 anomalous and may have been misinterpreted. Revise this section and Figures 3-1 through 3-4. accordingly. 5. Page 10, Section 4.1.2: The first sentence of the second paragraph states that"well M-21 C clearly shows the influence of pumping from MW-11 in July 2003". It appears that"2003" should be "2004"in this sentence and this interpretation is unsupported. There is no well pumping data provided for MW-11 in the Draft Annual Report and Nestl6 did not measure the groundwater elevation in MW-11 in July 2004. Explain why this interpretation is correct or delete it. 6. Page 14, Section 4.3: The sentence at the top of the page states "VOC fluctuation may be partially attributed to natural attenuation, variations in rainfall, and equilibration with varying aquifer materials." Reductive dechlorination appears to be stalled at cis-1,2-DCE in the Upper Aquifer near EW-1 and Nestl6 has not provided any evidence that variations in rainfall affect plume concentrations. Delete this sentence. 7. Page 15, Section 5: In addition to conducting MK analysis,Nestl6 should also inspect the recent VOC data for trends because the MK test occasionally misses significant trends or identifies trends that are not supported by inspection of the data. Add data inspection to trend analysis and briefly describe it in this section. Also, describe the"stability test' in more detail. 8. Pages 15 and 16, Sections 5.1 through 5.3: While Regional Board staff believes the groundwater pump and treat operations that Nestl6 has conducted through July 2004 have been somewhat ineffective due to the low volume of groundwater pumped/treated, the reasons cited for reductions in VOC concentrations in this section do not include any remedial actions conducted by Nestl6. SVE operations conducted in the 1990s and groundwater pump/treat operations conducted to date must have contributed to the observed VOC reductions in monitoring wells near the two Nestl6 source areas. Regional Board staff recommends revising this section accordingly. The discussion of MK data implies reductive dechlorination is occurring and vinyl chloride is degrading to ethane or ethane. Nestl6 has not conducted a thorough study on natural attenuation or added a key natural attenuation parameter(dissolved oxygen)to the monitoring program as recommended by Regional Board staff. In addition,Nestle has not collected the data to demonstrate vinyl chloride is degrading to ethane or ethane and should limit discussion on natural attenuation in the Draft Annual Report until enough data has been collected to demonstrate complete reductive dechlorination is occurring. This section uses non-stable and unstable interchangeably in discussion of VOC trends in wells. A "non-stable trend" or"unstable trend" can have several meanings, so discussion of the MK results is confusing. Nestl6 should use terms like"significant increasing trend" or"significant decreasing trend" and avoid terms like "non-stable" or"unstable"when discussing data trends. 9. Page 16, Section 5.3: It is unclear how Nestl6 can conclude that TCE and cis-1,2-DCE concentrations in M-613 are"non-stable". Inspection of the data clearly shows a pronounced increasing trend, so revise this section.