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Quality Assurance Project Plan <br />Red Creek Quarry Monitoring Program Section 4: DQOs and Criteria <br /> <br /> <br />4-2 <br /> <br />The DQOs will be fulfilled by implementing the following QA/QC activities during data collection: <br />• Collection of field data and water quality samples according to the sampling design specified in <br />the SAP and the medium-specific SOPs. <br />• Adherence to the SOPs for field measurements, sampling, sample handling, and sample COCs. <br />• Analysis of samples in accordance with standard method protocols specified in the SOPs. <br />• Adherence to data validation procedures specified in Appendix B of this QAPP. <br />• Implementation of training, quality auditing, and corrective/preventative action processes <br />described in this QAPP. <br />The analytical data support level for the Project is as follows: <br />• Field screening data (i.e., field measurements of pH, water temperature, specific conductance <br />[SC], dissolved oxygen [DO], and turbidity) will be at data quality Level I. Level I refers to field <br />screening using portable instruments that are generally not compound specific or very <br />quantitative. <br />• Laboratory analytical data will be at Level II. Level II refers to standard USEPA-approved methods <br />with data reviewed by standard QA protocols. <br />Data quality indicators, including analytical accuracy, precision, representativeness, comparability, <br />and completeness, are the principal metrics used to assess data quality. Data quality indicators for <br />the Project are described in the following sections. <br />4.1 Accuracy <br />Accuracy is a measure of the agreement between a “true” or reference value and the associated <br />measured value and is based on reported recoveries from the laboratory. The recoveries of lab <br />control samples (LCSs) and matrix spike (MS) samples will be used to evaluate the accuracy of the <br />measurements. Laboratory accuracy for each analysis is determined through statistical analysis of <br />the laboratory equipment by the laboratory; the acceptable accuracy range for the laboratory <br />equipment is typically 70 to 130 percent; however, laboratory method SOPs may deviate slightly <br />from this range. Final recovery ranges are reported on each laboratory report for each parameter. <br />Any outliers from the acceptable range in percent recovery, as determined by the laboratory, will be <br />flagged by the laboratory. <br />4.2 Precision <br />Precision is a measure of agreement between two measurements of the same property under <br />prescribed conditions. Sampling events may include duplicate samples (field replicates or split <br />samples) or may rely on LCS split sample results. The relative percent difference (RPD) of duplicate <br />samples will be used to assess data precision. <br />Precision will be based on field, LCS, and, if used, MS duplicates (MSD). The acceptable RPD range <br />for the laboratory equipment will be indicated in the laboratory sheets. Field duplicate RPD goals are <br />identified in the medium-specific SOPs. Appropriate measurement range is determined by reviewing <br />results in comparison to the laboratory practical quantitation limits or method detection limits. <br />Reporting requirements are determined prior to sampling through a review of historical data for the <br />analytes and region of interest and reflected in the choice of analytical laboratories, analysis <br />methods, and requested reporting levels or method detection limits.