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5 . All water retained for chemical analysis will be placed in clean, borosilicate, 40 ml VOA vial with a teflon cap, or clean amber glass one-liter bottles and other sample containers as appropriate for water sampling purpose and test parameters. Each sample vial or bottle is topped-off to avoid air space, and will be inverted to check for air bubbles, and filled to minimum headspace. Samples will be placed on ice, blue ice, or refrigerated at 4 degrees Centigrade at all times. 6 . Water samples blanks of distilled water will be poured through the sampling bailer and placed in clean sample collection bottles or vials. One water sample blank will be taken for each set of water samples collected from each boring or well. The number of blanks will be one per sampling run or 10% depending on the number of wells sampled. 7 . All sampling equipment will be decontaminated following each sampling event, prior to use the next monitoring well. Sample Records and Chain of Custody_ 1 . Sample records for each sample will contain information on sample type and source; project number, sampler name, sampling date, location, Laboratory name, sampling method, and any significant conditions that may affect the sampling. 2 . A signature Chain-of-custody and transference documentation will be strictly maintained at all times. 3 . A copy of the Laboratory sample results and the completed Chain of Custody will be provided with the technical report. Quality Control and Qualitv Assurance Ob'ectives The sampling and analysis procedures employed for groundwater sampling and monitoring follow quality assurance and quality control (QA/QC) guidelines set out to Federal, State and local agencies guidance. Quality assurance objectives have been established to develop and implement procedures for obtaining and evaluating water quality and field data in an accurate, precise and complete manner. In this way, sampling procedures and field measurements provide information that is comparable and representative of actual field conditions. Quality control is maintained by site specific field protocols and requiring the analytical Iaboratory to perform internal and external QC checks. The goal is to provide data that are accurate, precise, complete, comparable and representative. The definitions asdeveloped by overseeing federal, state, and local agency guidance documents for accuracy, precision, completeness, comparability and representativeness are: • Accuracy - the degree of agreement of a measurement with an accepted reference or true value. • Precision - a measure of agreement among individual measurements under similar conditions. Usually expressed in terms of standard deviation. • Completeness - the amount of valid data obtained from a measurement system compared to the amount that was expected to meet the project data goals. Wright Environmental Services, Inc. rev. 6/2/94 Geoscience Protocols Page 4