ARCHIVED REPORTS_SECOND 2008 SEMI-ANNUAL GROUNDWATER MONITORING AND SAMPLING REPORT

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Data Usability Summary DATA QC OBJECTIVES SAIC evaluated project analytical data according to the following parameters in order to determine their usability: 1 • Precision • Accuracy • Representativeness • Completeness • Comparability DATA USABILITY SUMMARY The following sections summarize the findings of the data evaluation process. The following is a summary of the data verification and validation qualifiers used in the data evaluation: ualifier Description ' E Indicates the reported value is estimated due to associated QC results. J Indicates the reported value is an estimated concentration detected between the method detection limit(MDL) and limit of quantitation ' (LOQ). A summary of qualified data is provided in Table B-1. Data validation reason codes for all qualified data are also presented and defined on Table B-1. Precision and Accuracy The precision and accuracy of field and laboratory QC samples were evaluated. The calculated relative ' percent differences(RPDs)for field duplicate and MS/MSD pairs provided information on the precision of sampling and analytical procedures, and the RPDs for laboratory control sample/laboratory control sample duplicate(LCS/LCSD)pairs provided information on the precision of the analytical procedures. Evaluation of the percent recoveries (%Rs)of MS/MSDs,LCS/LCSDs, and surrogates provided information on accuracy. MS/MSDs ' Project-specific MS/MSDs were collected with the groundwater samples. All MS/MSD samples were with QC range with the following exceptions: The MS/MSD pair MW-5-WD-080717MS and MW-5- WD-080717MSD had TPH-DRO (C10-C25) percent recovery and RPD were outside the acceptance criteria. All associated samples MW-2-W-080717,MW-3-W-080717 and MW-5-W-080717 were flagged `E'. The MSD sample MW-6-W-080409MSD had Benzo(k)fluoranthene above the acceptance criteria however none of the associated samples had detections of this analyte so no flags were applied. When non project specific MS/MSD pairs were analyzed for QC proposes those samples were not evaluated in relation with matrix compliance in our samples. LCS/LCSDs A LCS was analyzed with each analytical batch of samples. All LCS/LCSD%Rs were within the laboratory control limits.The LCS analyzed with samples MW-2-W-080717,MW-3-W-080717, MW-5- W-080717 MW-5-WD-080717MS and MW-5-WD-080717MSD surrogate was above the QC criteria but its percent recovery was within acceptance range no flags were applied for this discrepancy. The LCS/LCD associated with samples QA-Pump-R-080409,MW-6-W-080409 and MW-7-W-080409 had Indeno (1,2,3-cd)pyrene and benzo(g,h,i)perylene below the QC limits. The samples were re-extracted and analyzed outside of the holding times with acceptable QC results and the data was comparable to the