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4.0 QUALITY ASSURANCE OBJECTIVES FOR MEASUREMENT DATA <br /> The overall QA objective is to develop and implement procedures which will provide <br /> accurate data for field sampling, sample preparation and handling, sample Chain of <br /> Custody,laboratory analyses and reporting. <br /> The purpose of this section is to define the goals for the level of QA effort, namely: <br /> accuracy, precision, and sensitivity of analyses; and completeness, representativeness, <br /> and comparability of measurement data from the analytical laboratory. In addition, QA <br /> objectives for field measurements are defined. <br /> 4.1 ACCURACY, PRECISION AND SENSITIVITY OF ANALYSES <br /> The fundamental QA objective with respect to the accuracy, precision and sensitivity of <br /> analytical data is to achieve the QC acceptance criteria of each analytical protocol. The <br /> purpose of the analytical work performed during the investigation is to provide data for <br /> use in characterizing the Site soils. <br /> The analytical methods to be used are summarized in Table 4.1. These methods have <br /> been selected to meet the objectives of the program. The targeted quantitation limits for <br /> this investigation will be in accordance with the analytical methods used and are <br /> summarized in Table 4.2. <br /> Analytical accuracy will be determined by spiking selected samples or blanks with <br /> representative compounds of interest. Accuracy will be reported as the percent recovery <br /> of the spiking compound(s) and will be compared with the laboratory control limits. <br /> Accuracy will also be used to assess analytical efficiency or any possible sample matrix <br /> interference by adding surrogate compounds to each sample analyzed for organic <br /> parameters. <br /> Analytical precision will be assessed based on the duplicate analysis of samples and <br /> matrix spike samples. A minimum of one matrix spike/matrix spike duplicate <br /> (MS/MSD) or matrix spike/sample duplicate (MS/Dup) per ten samples will be <br /> analyzed. Precision will be evaluated based on laboratory control limits for relative <br /> percent differences (RPDs) between the duplicate results. Sampling and analytical <br /> precision will also be assessed based on the comparability of field duplicate sample <br /> results. <br /> 031090-10(4) -5- CON ESTOGA-ROVERS&ASSOCIATES <br />