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Data Usability Summary Page 2 of 4 DATA QC OBJECTIVES The SAIC evaluated project analytical data according to the following parameters in order to determine their usability: • Precision • Accuracy • Representativeness • Completeness • Comparability DATA USABILITY SUMMARY The following sections summarize the findings of the data evaluation process. The following data validation qualifiers were used in the data evaluation: ualifier Description J Indicates the reported value is an estimated concentration detected between the method detection limit(MDL)and limit of quantitation (LOQ). U Indicates the analyte was analyzed for,but not detected above the level of the associated value. 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 matrix spike/matrix spike duplicate(MS/MSD)pairs provided information on the precision of sampling and analytical procedures. The RPDs for laboratory control sample samples and laboratory control sample duplicates (LCS/LCSDs)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. All LCS/LCSD%Rs,LCS/LCSD RPDs, and surrogate %Rs were within the required laboratory control limits. Field Duplicate Sample WFSMW-I-WD-070123 is a field duplicate of WFSMW-I-W-070123. The field duplicate was analyzed for TPHd and PAHs. TPHd were the only analyte detected in both the parent sample and field duplicate above the LOQ. The RPD for this analyte is 14 percent,which indicates good precision for TPHd analyzed in the field duplicate pair. Several PAHs were detected in the field duplicate pair; however, all the detections were below the laboratory LOQ and are considered estimated values. RPDs were not calculated for estimated concentrations, and the analytes were not assessed for field duplicate precision. MS/MSDs Project-specific MS/MSD samples were not collected with the field samples evaluated for this report. However,the laboratory randomly selected project samples to prepare MS samples for chloride, sulfate, nitrate,nitrite,and phosphate analyses. The%Rs for the MS samples were within the required control limits. The samples in this data set were not evaluated in terms of the recoveries of the non-project MS/MSDs because they are not likely representative of the same sample matrix. From science to Solutions