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Nestl6 USA Inc. - 2 - 28 June 2005 This response does not address how Nest16 intends to revise the Draft Work Plan in order to clarify the purpose of the initial testing and whether a second work plan will be submitted for the pilot-scale test. Also, it appears that Nestl6 may proceed from very limited testing to a"pilot-scale" system that may operate as the long-term remedy for the source area. Any long-term remedies that involve injection of amendments into local groundwater will likely require Waste Discharge Requirements (WDRs). Nestl6 needs to revise the Draft Work Plan to fully-address the original comment provided in the Regional Board staff letter dated 22 February 2005. We can't approve implementation of the pilot-scale test without submittal of a report detailing the results of the initial testing and characterization program and submittal of a Draft Pilot-Scale Work Plan for our review/approval. General Comment 3 Regional Board staff has found that many food-grade products that are used as substrate for enhancing bioremediation of CAHs contain relatively high concentrations of metals. The substrate should be tested for a full suite of metals and the results need to be provided to Regional Board staff for review prior to substrate injection. Although the matrix of molasses substrate may necessarily elevate the quantification limits of some metals,Nestl6 needs to instruct their contract laboratory to provide the lowest possible reporting limits. EPA Methods 1631 and 7199/1636 should be used for mercury and hexavalent chromium unless matrix problems prevent analysis using these methods. Nestle response: Information regarding the molasses that will be used at the site is attached. According to the company from which we purchase food-grade molasses, mercury and chromium have not been detected during their annual testing. A representative sample of the molasses solution that will be injected in the pilot test will, however, be analyzed for mercury and hexavalent chromium prior to injection. We have been informed by the laboratory that due to the presence of molasses in the solution, the samples cannot be analyzed using the low-level methods proposed in your letter. We propose analyzing the samples of the solution for hexavalent chromium using EPA Method 7196(standard detection limit of 10µg/L) and for mercury using EPA Method 7471 (standard detection limit of 0.2 µg/L). We will instruct the laboratory to achieve the lowest possible detection limits, however.detection limits may be raised due to the presence of molasses. The reporting limits in the attached test results for molasses are very-high-and only a few metals were tested. Nest16's response does not indicate the sample of molasses will be analyzed for a full suite of metals. Nestl6 must submit the sample of molasses to a Department of Health Services certified laboratory for analysis for a full suite of metals. The suite of metals should include aluminum, antimony, arsenic,barium, beryllium,boron, cadmium, chromium(total), cobalt, copper,hexavalent chromium, iron, lead, magnesium,manganese, mercury, molybdenum, nickel, potassium, selenium, silver, sodium, thallium, vanadium, and zinc. General Comment 9 The Draft Work Plan states one of the objectives of the push-pull tests is"assessing the potential for reducing conditions to mobilize trace metals that may be present in subsurface soils", but does not discuss how this will be accomplished. The proposed target analytes in Table 1 suggest that Nestl6 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 ft2 Industrial Avenue hotspot or any other