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VJ1 « as 18: ;31 0508 897 8578 LPC %1INAKU. RIA RIDDLE & 1SOLA <br /> 003/017 <br /> Patrick D,Riddle <br /> Michael Buck <br /> Page 2 <br /> ENVIRONMENTAL <br /> PROJECT CONTROL <br /> Appendix A contains the full laboratory data sheets for the results summarized <br /> in the three attached tables. In addition, Appendix B is a technical <br /> memorandum evaluating the quality of the volatile data for three of the <br /> compounds of concern. Pacific Analytical Laboratory does not routinely screen <br /> incoming samples for concentration ranges. Initially, all the samples were <br /> introduced into the analyzer undiluted, which resulted in some analytes <br /> exceeding the instruments capabilities. These samples were diluted and re- <br /> analyzed. Some of these diluted samples contained compounds still beyond the <br /> range of the instrument and were diluted again. As a result, the laboratory <br /> reported more than one concentration for some samples for one or more <br /> compounds. The report in Appendix B explains the process used to determine <br /> which of the results is the most representative and any systematic difficulties <br /> during the analysis. The results are presented in Table 1, with the appropriate <br /> qualifiers as footnotes, explaining the qualifier. No data assessment was <br /> requested for the other compound of concern, vinyl chloride; all of the results <br /> reported, for samples and blanks, diluted or undiluted, contained no detectable <br /> vinyl chloride, at a Method Detection Limit of 0.2 gg/L (parts per billion). <br /> As you can see, some of the results are considered estimations due to various <br /> laboratory and sample conditions. Environmental Project Control has <br /> conducted a review of the results, compared them to the historical analyses, <br /> considered the location of wells, and believes the level of uncertainty associated <br /> with the results from most of the wells is appropriate for the purpose for which <br /> these samples were collected: that is, to draft an up-to-date Remedial <br /> Investigation / Feasibility Study (RI/FS) Work Plan. However, some <br /> uncertainty exists, and we may recommend that certain wells be sampled again <br /> early in the process of conducting the RI/FS in order to make the best decisions <br /> about locations of additional monitoring wells. <br /> Should you have any questions or comments on this data,please call me. <br /> File: 21.01/Correspondence <br />