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NOA Drywell Closure and Investigation Page 12 of 26 <br /> May 30, 2014 <br /> 4.7 Quality Control and Quality Assurance (QC/QA) <br /> 4.7.1 Field OC/OA <br /> 1 Field QC/QA consists of the following: <br /> Equipment Blanks <br /> Replicate Samples <br /> One (1) Equipment Blank was obtained during groundwater sampling and one (1) Equipment <br /> Blank was obtained during soil sampling. Quality Control equipment blanks are used to assess <br /> the caliber of field decontamination procedures. After the sampling equipment was <br /> decontaminated by the appropriate procedures, the distilled water was poured into the <br /> sampling equipment and then into sampling containers. This water was analyzed for RCRA <br /> Metals by EPA Method 6010 in the same manner as the waste fluid and soil samples. Analytical <br /> results are summarized in Section 5.3 and included as Appendix D. <br /> 1 One (1) Replicate Sample was obtained during groundwater sampling and one (1) Replicate <br /> Sample was collected during soil sampling. Replicate sampling is generally used to determine <br /> the consistency in sampling procedures and analytical methods. Samples were obtained from a <br /> sampling point and split between two identical containers. Both containers received the same <br /> method of analysis at the laboratory: RCRA Metals by EPA 6010. Analytical results are <br /> summarized in Section 5.3 and included as Appendix D. <br /> 4.7.2 Laboratory OC/OA <br /> Laboratory QC/QA consists of the following: <br /> • Method Blanks <br /> • Lab Control Spikes <br /> • Lab Control Spike Duplicates <br /> • Matrix Control Spikes <br /> • Matrix Control Spike Duplicates <br /> • Surrogate Recoveries <br /> The laboratory analytical reports provide a detailed summary of the QC/QA sample results, a <br /> written statement affirming that QC was met, and a description of any discrepancies that may <br /> have occurred. <br /> 1 Holdino Time Compliance <br /> Sample preparation and analysis were completed within the required method holding times, <br /> including 14 days for Volatile Organics, Total Petroleum Hydrocarbons, and Total Recoverable <br /> Petroleum Hydrocarbons, 7 days for semi-volatile organics, 180 days for most metals, and 28 <br /> days for mercury. In addition, preservatives were added to groundwater samples as described <br /> in Section 4.4.1. <br /> 1 <br /> 902 Industrial Way • Lodi, CA 95240 • 209.367.3701 • Fax 209.333.8303 ©2014 Neil 0. Anderson&Associates, Inc. <br />