Appendix B: Description of Methods and Quality Assurance Procedures 
The quality assurance/quality control (QA/QC) program for this study is defined by the 
“Western Ecology Division Data Quality Management Plan (QMP) (US EPA, 2001). Measurements 
Data Quality Objectives (MQOs) establish the data user’s requirements for precision and accuracy. 
The Measurement Quality Objectives for each parameter in this study are presented in Table B.l. 
Quality control measures were incorporated to assure data reliability and comparability and are 
described in the QMP plan. All contributing research was performed in compliance with an approved 
Quality Assurance Project Plan (QAPP). In addition, Standard Operating Procedures (SOP’s) were 
followed to standardize routine data collection, processing and analysis for specific parameters. All 
procedural documents and QA/QC plans are approved by the WED Quality Assurance Manager. 
Standard QMP protocols include routine instrument calibrations, measures of analytical 
accuracy and precision (e.g., analysis of standard reference materials, spiked samples, and field and 
laboratory replicates), overall data, range checks on the various types of data, cross-checks between 
original data sheets (field or lab) and the various computer-entered data sets, and participation in 
intercalibration exercises. Additionally, QA/QC included ensuring field and laboratory personnel were 
properly trained and experienced. Specific QA procedures are detailed in the following sections 
relative to each data parameter. 
Accuracy and precision are indicators of MQOs and were established from considerations of 
instrument manufacturer’s specifications, scientific experience, and/or historical data. A measure of 
systematic error (measured vs. true or expected): accuracy and the random error (precision) is 
presented. Accuracy is a measure of how close measured values are to true values. In this appendix, 
accuracy is calculated using the following equation: 
Accuracy (%) = (1.0-(£(|^-F„|)/n/F,)*100 
where V t is the true or standard value, V m is the measured values, and n is the number of measured 
values. Precision is an indication of the similarity of repeated analyses or sampling. Precision is 
calculated with the following equation: 
Precision (%) = (1.0 - SD / X) * 100 
where SD is the standard deviation, and X is the mean. 
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