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Data Usability Summary Page 2 of 3 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. The following data validation qualifier was 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). E Indicates the reported value is estimated due to associated quality control results. 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/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. LCS/LCSDs LCS/LCSDs were analyzed with each analytical batch of samples. The%Rs and RPDs were within the laboratory control limits with the following exceptions: the%Rs for dibenz(a,h)anthracene(49 percent), indeno(1,2,3-cd)pyrene(69 percent), acenaphthylene(68 percent), and anthracene(61 percent)were below QC criteria. In addition,LCS/LCSD RPDs associated with benzo(b)flouranthene(33 percent), benzo(k)flouranthene(33 percent), and benzo(a)pyrene(31 percent)were above upper QC limits. The expected bias in associated sample results is high,but none of the compounds were detected in samples QA-R-070508 and MW-5-W-070508;therefore,the expected bias was not realized and no data were qualified. MS/MSDs Project-specific MS/MSD samples MW-6-W-070501MS and MW-6-W-070501MSD were collected with the field samples evaluated for this report. 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, the equipment rinsate blank sample, chain-of-custody forms,preservation, and holding times. Field QC Results One equipment rinsate blank was collected with the samples extracted on May 1, 2007;rinsate blank sample QA-R-070501 was submitted with this data set. Naphthalene was detected in this sample at 0.012 micrograms per liter(gg/L)and consequently qualified as E. In addition,naphthalene was detected in equipment rinsate blank QA-R-070508 at 0.015 gg/L and also qualified as E. Field Duplicate Samples Field duplicate pair results were within the required control limits. Method Blank Results All laboratory method blanks were free of contamination.