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Mr. Michael Desso - 3 - • 22 February 2005 Nestle USA, Inc. believes only arsenic and antimony may be mobilized by the push-pull tests. Nestl6 needs to fully assess this potential impact before Regional Board staff can agree that in situ carbohydrate- enhanced bioremediation can be implemented to treat the entire 25,000 ftZ Industrial Avenue hotspot or any other Nest16 hotspots. Nestle should assess baseline concentrations of metals and monitor for a full suite of metals during push-pull tests and the longer-term pilot test recommended in General Comment 1. 10. Monitoring data collected during the 1999/2000 permanganate pilot test shows the horizontal groundwater gradient in the Upper Aquifer beneath the Industrial Avenue property is very small when the extraction wells are not operating. The permanganate did not appear to move in the six months following injection and pumping had to be implemented to mix the permanganate throughout the target treatment area. Furthermore, the permanganate should have been completely utilized in 4 to 6 months, but it persisted for more than 12 months. Please confirm that the problems encountered (or lessons teamed) during this pilot study were reviewed and considered in preparation of the Draft Work Plan. Specific Comments 1. Page 5, Subtask 3a: Briefly explain how the tracer will be added to the well and mixed to provide a uniform concentration throughout the test interval. 2. Page 6, Subtask 3b: This section indicates the injection solution will contain 1%carbohydrate. This percentage appears to be low, so explain how this amount was determined to be optimal for the push-pull test. Also,please explain how the molasses will be mixed with the treated groundwater effluent and bromide tracer prior to injection. 3. Table 1: Some of the proposed analyte reporting limits in this table are too high. For example, the proposed reporting limits (RLs) for cVOCs are 1 to 2 orders of magnitude higher than the RLs that Nestle' achieves under the existing long-term groundwater-monitoring program. Revise the RL for cVOCs to 0.5 gg/L and the RL for sulfate to 1 mg/L. Also, add a full suite of metals to this table with RLs equal to or less than the lowest applicable water quality objectives or the lowest RLs that can be achieved with EPA analytical methods. Chloroform is a Nestle' CoC that is commonly detected in M-1 A, so please add it to the VOCs that will be tested/reported. If you have any questions, please contact me at(916) 464-4733 (mpierce(a,waterboards.ca.aov). Marcus L. Pierce, C.Hg. Engineering Geologist