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ATTACHMENT B: <br /> DATA USABILITY SUMMARY AND LABORATORY ANALYTICAL RESULTS <br /> (OCTOBER 2007) <br /> INTRODUCTION <br /> SAIC evaluated the analytical data for groundwater samples collected at the Vernalis Pump Station site in <br /> Vernalis, California. This data usability summary presents the results of the data validation process. <br /> SAIC collected environmental samples on behalf of Chevron Environmental Management Company to <br /> delineate the lateral and vertical extent of petroleum-affected groundwater. Samples were collected on <br /> October 29, 2007: <br /> • QA-R-071029 <br /> • MW-7-W-071029 <br /> • MW-6-W-071029 <br /> • MW-6-W-071029MS <br /> • MW-6-W-071029 MSD <br /> Groundwater samples were analyzed for one or more of the following analyses: <br /> • Polynuclear aromatic hydrocarbons(PAHs)by EPA Method SW8270C with selective ion <br /> monitoring(SW8270C-SIM). <br /> • TPH quantified as diesel(TPHd), carbon range CIO-C25,by EPA Method SW8015B modified; a <br /> silica gel-cleanup procedure based on EPA Method SW3630 was also performed on samples with <br /> TPHd detections to remove non-target biogenic compounds. <br /> The data was evaluated in general conformance to the requirements of project objectives specified in the <br /> following documents: <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 in order to determine their <br /> 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. The following is a <br /> summary of the data verification and validation qualifiers used in the data evaluation: <br />