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0 0 <br /> Wendy L. Cohen -2- 1 November 1993 <br /> 2. The work plan proposes to drill seven hydropunch boreholes for soil and ground water <br /> sampling. <br /> I recommended that at least one borehole be drilled in the vicinity of AST 2 and along the <br /> pipelines from the ASTs to the sumps. I also stated that the general approach should be to go <br /> radially from the hotspots until the zero line of contamination is defined. <br /> 3. The work plan proposes to take a maximum of three soil samples in the vadose zone. <br /> I recommended that soil samples in the vadose zone also include sections of stratigraphic <br /> change. In addition to the vadose zone samples, I suggested that at least one sample each in <br /> the unsaturated and saturated zones be taken for grain size analysis which should be obtained <br /> prior to designing the wells. <br /> 4. The work plan proposes to backfill the boreholes after collecting samples. <br /> I recommended that the boreholes be backfilled only after the results have been confirmed, <br /> particularly samples which define the zero line of contamination. <br /> 5. The work plan proposes testing all soil and ground water samples for TPH as hydraulic oil <br /> (TPH-HO); selected soil samples for U.S. EPA Method 8270, 8010, and 8020 constituents; <br /> ground water from EWs for selected metals, oil and grease, and U.S. EPA Method 601 and <br /> 602 constituents. The ground water samples from the MWs will be analyzed for TPH-HO. <br /> I recommended that the selected soil samples also be analyzed for TPHD and TPHG. The <br /> EW samples should also be tested for TPHD, TPHG, complete suite of metals, and general <br /> minerals. The rationale for this request is that all this information is necessary to determine if <br /> other contaminants are present in addition to TPH-HO and TPHD. The information also is <br /> needed prior to designing the remediation system. The MWs should be sampled for the same <br /> constituents that are present in the EWs. <br /> Mr. David Meade of Condor documented the above agreements through the attached 22 October <br /> 1993 letter. I visited the site on 26 October 1993 and passed on to Mr. Meade your comment <br /> regarding the 48-hour waiting period after well development before sampling. He said the 48-hour <br /> waiting period is part of their ground water sampling protocol and will be observed at LOR <br />