SITE INFORMATION AND CORRESPONDENCE_1993-2003

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Draft Soils FS Memorandum -12- 14 September 1993 ' DDRW, Sharpe would be in the order of 1 to 2 months to complete this remedial alternative. This remedial alternative should be reevaluated and revised accordingly. r. Page 5-51, Section 5.2.2, Alternative 2C - Treatment Technologies - In-Situ Volatilization: This section states that testing indicated the soils of the South Balloon Area to be more permeable than the soils located in the Firefighting Training Area. The South Balloon Area was formally a landfill and was therefore, expected to exhibit different subsurface stratigraphy than the rest of the installation. It is unclear if the extent of the landfills, burial trenches, burn pits, etc. that have affected the subsurface stratigraphy (estimated areas and depths of disturbed soil or fill material) have been estimated. Boring logs and the ground penetrating radar investigations may provide sufficient information to make these estimates which should be summarized and presented in the FS. S. Section 6.0, Detailed Evaluation of Alternatives, Discussion: Alternatives for Lead and Chromium Contaminated Soil I C-Containment--Asphalt Cap: This alternative as summarized in Table 6.2-1 does not provide a permanent solution. In addition, the proposed design of the asphalt cap does not meet potential ARARs which address capping specification requirements. Therefore, this is not an acceptable alternative (see CVRWQCB Comment 10 on the February 1992 Draft Soils FS for additional comments). 2A-Treatment--Flration/Solidification: Conceptually, fixation/solidification is an acceptable alternative. However, a bench scale treatability study should be performed to demonstrate the effectiveness in fixing the contaminants of concern in order for the solidified material to qualify as an inert waste, as defined in Chapter 15. If this cannot be demonstrated, residual leachate may continue to threaten water quality and additional measures would be necessary to protect water quality. Without such a demonstration, the viability.of this alternative cannot be demonstrated prior to its selection as a remedial alternative. Other issues to consider include: 1. Process is very waste specific. Bench tests required to determine process applicability. 2. Organics content (e.g., > 15%) may interfere with metals stabilization process. 3. Variable soil conditions or waste distribution may result is inconsistent stabilization/treatment. 4. Commonly used analytical methods may not be sufficient to evaluate the effectiveness of the treatment process or long term stability of the treated matrix (Remedial Technologies Applications Matrix For Base Closure Activities, CA Military Base Closure Environmental Committee, April 1993).