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samples. Analytical parameters included in these analyses are listed in <br /> Attachment 2. <br /> Without an understanding of the ground-water flow path(s) at NCS Stockton, <br /> implementation of a ground-water sampling plan will result in the collection of large quantities <br /> of random information. The amended ground-water analyses discussed above will provide data <br /> that can help focus any subsequent RI activities, including a base-wide sampling plan. <br /> 4) Future RI/FS activities should consider other potential sites not listed in the reports cited <br /> by this memorandum. It has been the Department's experience that investigations are <br /> sometimes focused too quickly on known sources of contamination. Eventually, other <br /> sources are discovered and added to the RI/FS, usually causing program delays and cost <br /> overruns. <br /> The interim site investigation is concerned with evaluating the hydrogeology of NCS <br /> Stockton. A clear understanding of the hydrogeology will facilitate identification of additional <br /> sources of contamination, if any are present. The identification and investigation of additional <br /> contaminant sources is not part of this interim site investigation. Serendipitous discovery of <br /> previously unrecognized contaminant sources should not be discouraged. Such discoveries are not <br /> unusual at locations where records are poor and historic activities were not performed in an <br /> environmentally sensitive manner. <br /> 5) When well clusters are constructed, it is recommended that the deepest well be continuously <br /> logged. <br /> The deepest borehole in each cluster of wells or piezometers will be logged continuously. <br /> 2.2 SPECIFIC DHS COMMENTS <br /> 1) A synthetic (non-organic) polymer is recommended as an option for use with mud-rotary <br /> drilling. All information regarding synthetic polymers is requested for review. This <br /> material should receive the Department's approval prior to its usage. <br /> If the mud rotary drilling technique is selected, the use of synthetic (non-organic) <br /> polymers will be examined as an alternative to traditional drilling muds. Available information <br /> regarding any polymer will be submitted for DHS review and comments prior to beginning field <br /> work. <br /> 5 <br />