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Testing, Sampling, and Analysis Plan <br />January 15, 2025 <br />11 <br />Zone 7 Water Agency and <br />City of Pleasanton <br />8.1. Field Quality Control <br />8.1.1. Equipment Blank <br />The equipment blank only applies when decontaminated equipment is used. <br />Purpose:Assess the adequacy of the decontamination process. Assess contamination from the total <br />sampling, sample preparation, and measurement process when decontaminated sampling equipment is <br />used to collect samples. <br />Procedure:A sample of analyte-free water is poured through decontaminated field sampling equipment <br />prior to the collection of test well samples. <br />Frequency:1 blank per 20 samples. <br />8.1.2. Field Blank <br />Purpose:Assess contamination from field conditions during sampling. Assess contamination from the <br />total sampling, sample preparation, and measurement process, minus the decontamination process. <br />Procedure:A sample of analyte-free water is poured into the container in the field, preserved and shipped <br />to the laboratory with the test well samples. <br />Frequency:1 blank per 20 samples. <br />8.1.3. Field Duplicate <br />Purpose:Assess the precision (i.e., repeatability) of sampling results as influenced by the natural <br />variability of concentrations during sampling. <br />Procedure:A duplicate sample is retrieved immediately following retrieval of the test well sample. <br />Frequency:1 duplicate per 20 samples. <br />8.2. Laboratory Quality Control <br />8.2.1. Method Blank <br />Purpose:Assess contamination introduced during sample preparation activities in the laboratory. <br />Procedure: The laboratory is currently certified by ELAP to conduct the requested analyses. A blank is <br />prepared to represent the matrix as closely as possible. The method blank is prepared/extracted/digested <br />and analyzed exactly like the test well samples. <br />Frequency:1 blank per batch.