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DATA USABILITY SUMMARY The following sections summarize the findings of the data evaluation process. A summary of qualified data with reason codes is provided in Table B-1. Data validation reason codes for all qualified data with the associated reasons for qualification 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 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 surrogate%Rs were within the required laboratory control limits. Field Duplicates Sample MW-7-WD-060810 is afield duplicate of sample MW-7-W-060810. TPHd were the only analytes detected in the sample and field duplicate. However, TPHd were detected in the method blank associated with these samples and the results are likely biased due to contamination. Therefore,RPDs were not calculated and evaluated for this field duplicate pair. LCS/LCSDs A LCS and LCSD were analyzed with each analytical batch of samples. The%Rs and RPDs were within the laboratory control limits,with one exception: the%Rs for benzo(g,h,i)perylene were 120 percent in the LCS and LCSD,which exceeds the control limit of 117 percent. The expected bias in associated sample results is high,but none of the compounds were detected. Therefore,the expected bias was not realized and no data were qualified. 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/MSDs for BTEX and TPHg analyses. The%Rs and RPDs for the MS/MSD samples were within the required control limits. Representativeness Representativeness was assessed through the evaluation of method blank samples,trip and equipment blank samples,chain-of-custody forms,preservation, and holding times. Method Blank Results TPHd were detected at 36 micrograms per liter(gg/L)in the method blank associated with all samples in this data set analyzed for TPHd. TPHd were detected in sample MW-7-W-060810 at 62 µg/L and in its' field duplicate,MW-7-WD-060810, at 52 gg/L. The results were qualified"U"for the method blank contamination because the concentrations detected in the samples are within 5 times the amount detected in the method blank. Therefore,the results in the samples are likely biased from introduced contamination and not representative of field conditions. Field QC Results One equipment rinsate blank and one trip blank were submitted with the samples. No target analytes were detected in either of the field blank samples.