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QUALITY CONTROL REPORT <br /> r <br /> METHOD BLANK RESULTS: A method blank (MB) is a laboratory generated sample free <br /> of any contamination. The method blank assesses the degree to which the <br /> laboratory operations and procedures cause false-positive analytical results for <br /> your samples. The method blank results associated with your samples are <br /> attached. <br /> LABORATORY CONTROL SPIKES <br /> The LCS Program: <br /> The laboratory control spike is a well characterized matrix (organic pure <br /> type II for water samples and contamination free sand for soil samples) <br /> which is spiked with certain target parameters and analyzed in duplicate <br /> at approximately 108 of the sample load in order to assure the accuracy <br /> and precision of the analytical method. The results of the laboratory <br /> control spike associated with your samples are attached. <br /> Accuracy is measured using percent recovery, i.e. : <br /> (measured concentration) <br /> Percent Recovery — ------------------------ x 100 <br /> (actual concentration) <br /> Precision is measured using the relative percent difference (RPD) from <br /> duplicate tests, i.e. : <br /> 8 Recovery of Spike0) - 8 Recovery of Spike (2) <br /> RPD — --------------------------------------------------- <br /> x 100 <br /> (8 Recovery of Spike(l) + 8 Recovery of Spike(,) )/2 <br /> Control limits for accuracy and precision are different for different <br /> methods. They may also vary with the different sample matrices. They are <br /> based on laboratory average historical data and EPA limits which are <br /> approved by the Quality Assurance Department. McLaren Analytical <br /> Laboratory reanalyzes samples if the precision or accuracy is out of <br /> acceptance control limits. <br /> McLaren <br /> (DC3-CN2558) <br />