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Appendix D.1:Data Usability Summary <br /> • Quality Assurance and Quality Control: Sample Collection, Handling, and Analysis Guidelines; <br /> ChevronTexaco Historical Pipeline Portfolio Sites, California,April 2007; <br /> • SAIC Technical Procedure TP-DM-300-7,Data Validation; and <br /> • SAIC Technical Procedure TP-DM-300-14,Evaluation of Field and Analytical Data. <br /> INTENDED USES OF THE DATA <br /> Laboratory data are being used for site evaluation and decision making for petroleum releases attributed <br /> to Chevron's historical crude-oil and Bunker C fuel-oil pipelines. For contaminant delineation decision <br /> making, soil and groundwater laboratory analytical results were compared to"action levels,"or levels <br /> above which further evaluation to define the extent of contamination is appropriate. <br /> DATA QC OBJECTIVES <br /> SAIC evaluated project analytical data according to the following parameters to determine their usability: <br /> • Precision <br /> • Accuracy <br /> • Representativeness <br /> • Completeness <br /> • Comparability <br /> DATA USABILITY SUMMARY <br /> The following sections summarize the findings of the data evaluation process. Immediately following is a <br /> summary of the data verification and validation qualifiers used in the data evaluation: <br /> ualifier Description <br /> E Indicates the reported value is estimated due to associated quality control <br /> (QC)results. <br /> J Indicates the reported value is an estimated concentration detected <br /> between the method detection limit(MDL)and limit of quantitation <br /> (LOQ). <br /> A summary of qualified data is provided in Table D-1. Data validation reason codes for all qualified data <br /> are also presented and defined on Table D-1. <br /> Precision and Accuracy <br /> The precision and accuracy of field and laboratory QC samples were evaluated. The calculated relative <br /> percent differences(RPDs)for field duplicate and matrix spike/matrix spike duplicate(MS/MSD)pairs <br /> provided information on the precision of sampling and analytical procedures, and the RPDs for laboratory <br /> control sample/laboratory control sample duplicate(LCS/LCSD)pairs provided information on the <br /> precision of the analytical procedures. Evaluation of the percent recoveries (%Rs)of MS/MSDs, <br /> LCS/LCSDs, and surrogates provided information on accuracy. <br /> MS/MSDs <br /> Project-specific MS/MSDs were collected with the groundwater samples. All MS/MSD samples were <br /> within QC range with the following exceptions: (1)MW-6-W-080129MS and MW-6-W-080129MSD <br /> had benzo(a)pyrene, indeno(1,2,3-cd)pyrene, and benzo(g,h,i)perylene recoveries below the QC criteria <br /> and were flagged E for associated samples MW-2-W-080129,MW-3-W-080129,MW-5-W-080129, <br /> MW-6-W-080129, and MW-7-W-080130; (2) SB-29-W-080226MS and SB-29-W-080226MSD had <br /> nitrate,nitrite, anthracene,benzo(A)pyrene, indeno(1,2,3-cd)pyrene, and benzo(g,h,i)perylene below the <br /> D.1-2 =— =— <br /> W ff a:; <br /> a=Ar11`& <br /> From Science to Solutions <br />