ARCHIVED REPORTS_ANNUAL 2009 GROUNDWATER MONITORING AND SAMPLING REPORT

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Attachment C:Data Usability Summary and Laboratory Analytical Reports Representativeness Representativeness was assessed through the evaluation of method blank samples; trip, field, and rinsate blank samples; chain-of-custody forms; preservation; and holding times. The results were also compared to the laboratory's MDLs and LOQs. Method Blank Results ' Laboratory method blanks were evaluated for any detections above the laboratory MDL. Data were not qualified if a target compound was detected in the method blank and not detected in a sample result. The PAH method blank associated with sample MW-9-W-090116 had several analytes detected between the LOQ and the MDL; however, no analytes were detected in the sample except for pyrene. The pyrene result was greater than 5 times that found in the blank, so no qualifiers were applied. The method blank associated with sample MW-8-W-090115, MW-12-W-090115MS, and MW-12-W-090115MSD had trace amounts of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene. Only sample MW-8-W-090115 reported results less than 5 times the amount found in the blank; results were flagged E for each of the analytes. Laboratory Fuel Notes for TPHd Analysis Lancaster reports that the observed sample gas chromatogram pattern is not typical of the #2 fuel/diesel pattern, and elutes later in the diesel range for samples MW-7-W-090116 and MW-9-W-090116. Analytical results were flagged E. Field Quality Control Results Field QC samples were not taken for this location during this event. Chain-Of-Custody Forms ' Sample analytical results were evaluated for agreement with the chain-of-custody form. The evaluation determined that all samples were received at the laboratory in the appropriate containers and in good condition with the chain-of-custody form filled out properly. 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 with the exception of sample MW-9-W-090116 PAH results. The laboratory mistakenly spiked the original extract from the sample and re-extracted the sample outside of its holding time; therefore, all results were flagged E for sample MW-9-W-090116 PAH results. Reporting Limits Data reported for this sampling event were reported with the laboratory MDLs. The MDL �. represents the lowest concentration point where an analyte can be positively identified, but the quantitation is an estimate. The LOQ is the lowest concentration of an analyte in a sample that the laboratory can report with precision and accuracy. Analytes that were reported between the MDL and LOQ for this data set were qualified J as estimates.