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ATTACHMENT B: DATA USABILITY SUMMARY AND LABORATORY CHEMICAL ANALYTICAL REPORT LABORATORY DATA USABILITY SUMMARY Introduction SAIC evaluated the analytical data for the following groundwater and water-matrix quality control(QC) samples collected on May 4,2006, at Vernalis Pump Station,Vernalis, California: • MW-5-W-060504(field sample); • MW-6-W-060504(field sample); • MW-7-W-060504(field sample); • QA-T-060504 (trip blank); • QA-R-060504(equipment rinsate blank); and • MW-7-WD-060504(field duplicate sample of MW-7-W-060504). Lancaster Laboratories performed all the analyses on the samples. All samples except the trip blank sample were analyzed for the following: • Benzene,toluene, ethylbenzene,and total xylenes (BTEX)by U.S. Environmental Protection Agency(EPA)Method SW8021B; • Total petroleum hydrocarbons as diesel-range organics(TPHd), carbon range C,o-C25,by EPA Method SW8015 modified; • Total petroleum hydrocarbons as gasoline-range organics(TPHg), carbon range C6-C10, by EPA Method SW8015 modified; and • Polynuclear aromatic hydrocarbons (PAHs)by EPA Method SW8270C with selected ion monitoring(SW8270C-SIM). The trip blank sample was only analyzed for BTEX by Method SW8021B. A separate analysis for TPHd was also performed on samples MW-5-W-060504,MW-7-W-060504, QA-R-060504, and MW-7-WD-060504 with a silica-gel procedure (based on EPA Method SW3630)prior to analysis to remove non-target biogenic compounds. The data was evaluated in general conformance to the requirements of project objectives specified in the following documents: • Quality Assurance& Quality Control:Sample Collection, Handling, and Analysis Guidelines; ChevronTexaco Historical Pipeline Portfolio Sites, California,January 2006 (Update); • SAIC Technical Procedure TP-DM-300-7,Data Validation; and • SAIC Technical Procedure TP-DM-300-14,Evaluation of Field and Analytical Data. Intended Uses of the Data Laboratory data are being used for site evaluation and decision making regarding petroleum releases attributed to Chevron's historical crude oil and Bunker C fuel oil pipelines. The data generated will be compared to Regional Water Quality Control Board water quality objectives and may be used for risk assessment purposes.