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Monitoring and Sampling Procedures <br />RALPH SQUARE-BUI <br />2122 South Airport Way, Stockton, California <br />STATIC WATER LEVEL MEASUREMENTS <br />Before sampling and during groundwater monitoring, static water levels are measured <br />using an electric water level indicator. Water level data is recorded to the nearest 0.01 - <br />foot from a reference point marked of the top of the PVC well casing. <br />WELL PURGING <br />Subsequent to measurement of depth to water and prior to sampling, each well is purged <br />to ensure samples are representative of the formation, rather than standing water in the <br />well casing. Wells are purged using a dedicated disposable polyethylene bailer. <br />Wells are purged until a minimum of three casing -water volumes is removed from the well <br />and/or the field -measured ground water parameters (pH, temperature, and conductivity) <br />are stabilized. However, if a well is purged dry prior to evacuating three casing volumes, <br />a sample is collected following 80 percent recovery of groundwater within the well or after <br />a minimum of 1 hour, but within 8 hours, of well purging activities. <br />SAMPLE WITHDRAWAL <br />Water samples are collected from each monitoring point using a disposable polyethylene <br />bailer. Bailers are disposed of after a single use (sample) and require no decontaminating; <br />plastic tubing used with the inertia pump is either dedicated to each well point or changed <br />at each sampling event, thereby minimizing cross contamination due to sampling devices. <br />Samples are drawn and collected in such a manner that agitation and exposure of the <br />groundwater to the atmosphere is minimal. <br />SAMPLE HANDLING <br />Groundwater samples are collected into laboratory -supplied 40 -ml volatile organic <br />analysis (VOA) vials with preservative and, if appropriate, one -liter amber glass <br />containers without a preservative. Samples are collected with no visible air bubbles are <br />present in the vials after filling and capping. Following collection, samples are <br />appropriately labeled, placed on ice, and kept in a cooler until delivered to a State of <br />California Environmental Laboratory Accreditation Program (ELAP)-certified analytical <br />laboratory, for analysis. The samples are analyzed for: <br />