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Attachment B: Data Usability Summary and Laboratory Chemical Analytical Report Preservation and Holding Times Samples were preserved in the field as appropriate,were received at the laboratory within the acceptance temperature criterion of 4+2 °C, and were prepared and analyzed within specified holding times. The sample preservations,when required by the analysis,were less than the acceptance pH limit of 2. Laboratory Fuel Notes for TPHd Analysis The laboratory noted that the observed hydrocarbon fuel pattern for TPHd analysis in sample WFSMW-I-W-060503, and its field duplicate WFSMW-I-WD-060503, included#2 fuel/diesel and an additional pattern that elutes later in the target carbon range. Individual peaks also eluted within the target carbon range. TPHd were reported at 190 gg/L in sample WFSMW-I-W- 060503, and 160 µg/L in field duplicate sample WFSMW-I-WD-060503. The samples were also silica-gel cleaned prior to the analysis and TPHd were not detected after the silica-gel cleanup. This indicates the TPHd results were likely biased high due to biogenic material,which was removed during silica-gel analysis. Completeness Completeness is defined as the number of valid results(i.e.,those not rejected)divided by the total number rejected. Based on this evaluation of the data against the QC objectives,the percentages of valid data for each method and matrix are 100 percent. Comparability Based on the data evaluation, it was concluded that the data are comparable with other laboratory data for similar samples and sample conditions. The sample collection techniques,EPA test methods, detection limits, analytical laboratory,units of measure, and sample preparation procedures were selected to ensure data comparability. Summary Based on SAIC's evaluation, all analytical data are usable as qualified for the purpose of determining chemical concentrations in groundwater at the site. The result for naphthalene detected in the equipment rinsate blank,QA-R-060503,was qualified J because the concentration was between the laboratory MDL and reporting limit. The final result for this sample is 0.019 Jµg/L. Unless noted otherwise,analytical data collected in support of this investigation are considered precise, accurate,representative, complete, and comparable, and they may be used for their intended purposes.