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1 <br /> April 20, 1990 <br /> GKOUND-VA 4TER SAMP-LING AND ANALYSIS <br /> 1 QuaItt� Assurance/Quality Control Obtecttves <br /> The sampling and analysis procedures emploved by Gettler-Ryan Inc <br /> (G-R) for ground-,tater sampling and monitoring follow specific Qualitv <br /> Assurance/Quality Control (QA/QC) guidelines Qualw, Assurance <br /> objectives have been established b� G-R to develop and implement <br /> 1 procedures for obtaining and evaluating water quality and field data <br /> in an accurate, precise, and complete manner so that sampling <br /> Procedures and field measurements provide t:iformation that is <br /> comparable and representative of actual field conditions Quality <br /> Control (QC) t� maintained by G-R b,, using snectftc field protocols <br /> and requiring the analvtical iaborator, to perform tnt_rnal and <br /> 1 external QC checks It is the goal of G-R to provide data that are <br /> accurate, precise, complete, comparable, and representative The <br /> definitions for accuracy, precision, completeness, comparability, and <br /> representativeness are as follows <br /> Accuracy - the degree of agreement of a <br /> 1 measurement with an accepted referenced or true <br /> value <br /> - Precision - a measure of agreement among <br /> individual measurements under similar <br /> conditions Usually expressed to terms of the <br /> standard deviation <br /> - Completeness - the amount of valid data obtained <br /> from a measurement system compared to the amount <br /> that was expected to meet the project data <br /> goals <br /> - Comparability - expresses the confidence with <br /> which one data set can be compared to another <br /> - Reoresentattveness - a sample or group of <br /> samples that reflects the characteristics of the <br /> media at the sampling point It also includes <br /> how well the sampling point represents the <br /> actual parameter variations which are under <br /> study <br />` As part of the G-R QA/QC program, applicable federal, state, and local <br /> reference guidance documents are followed The procedures outlined in <br /> these regulations, manuals, handbooks, guidance documents, and <br /> ,journals are incorporated into the G-R sampling procedures to assure <br /> that, (1) ground-water samples arc properly collectea, (2) <br /> ground-rater samples are identified, preservea, and transported to a <br /> manner such that they are representauve of field conditions, and (3) <br /> chemical analysis of samples are accurate and reproducible <br /> I <br /> c <br /> �effler — rYan inc (415)7837500 Page 6 <br /> l general and environmental coniraclors <br />