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Focused Groundwater Investigation Work Plan <br /> Deuel Vocational Institution(DVI), Tracy, California Data Acquisition and Quality Assurance/Quality Control <br /> 5.0 Data Acquisition and Quality Assurance/Quality Control <br /> This section discusses the procedures, objectives, functional activities, and specific QA/QC activities <br /> designed to achieve established data quality goals, for all quality-related field sampling and laboratory <br /> analysis activities to be implemented during investigation activities. The measures will be implemented to <br /> produce data that are scientifically valid,be of known and acceptable quality,meet established objectives, <br /> and be legally defensible through the assessment of precision, accuracy,representativeness, <br /> comparability,and completeness (PARCC). <br /> 5.1 Project Design and Rationale <br /> CVWB has initiated this investigation to assess the nature and extent of VOC contamination in the project <br /> vicinity. All samples will be analyzed for select VOCs, specifically PCE and TCE products, at a <br /> minimum. <br /> 5.2 Statistical Parameter Indicators <br /> Specific QA indicators will be established for each of the PARCC data assessment parameters. These <br /> acceptance limits will be expressed as quantitative and qualitative statements concerning the type of data <br /> needed to support a decision,based on a specified level of uncertainty. <br /> 5.2.1 Precision <br /> Precision is a measure of mutual agreement among replicate(duplicate) or co-located sample <br /> measurements of the same analyte within the same method and matrix. The closer that the numerical <br /> values of the measurements are to each other,the more precise the measurement. Precision for a single <br /> analyte will be expressed as the relative percent difference(RPD)between the results of any duplicates. <br /> Field duplicate(FD) samples will be collected and analyzed at a frequency of approximately 10 percent. <br /> Precision also will be assessed for laboratory control samples (LCSs) and sample duplicates(LCSDs). <br /> 5.2.2 Accuracy <br /> Accuracy is a measure of bias in a measurement system. The closer that the value of the measurement <br /> agrees with the true value,the more accurate the measurement. This value will be expressed as the <br /> percent recovery for any spikes (LCSs and surrogates)as well as calibration recoveries. <br /> 5.2.3 Representativeness for Standard Reference Material <br /> Representativeness is a qualitative parameter that expresses the degree to which sample data accurately <br /> and precisely represent a characteristic of a population,variations at a sampling point, or an <br /> environmental condition. The purpose for sampling, selection of the sampling locations,number of <br /> samples to be collected, ambient conditions, frequencies and times for sample collection, and sampling <br /> techniques have been designed to ensure that the environmental conditions will be sufficiently <br /> represented. <br /> 5-1 <br />