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APPENDIX B <br /> Monitoring and Sampling Procedures <br /> SAVE ON GAS (former Rainwater Car Wash) <br /> 420 West Yosemite Avenue, Manteca, 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 <br /> 0.01-foot from a reference point marked at 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 Waterra inertial pump and dedicated 5/8-inch <br /> plastic/teflon tubing. <br /> Wells are purged until a minimum of three casing-water volumes are removed from the <br /> well and/or the Feld-measured ground water parameters (pH, temperature, and <br /> conductivity) are stabilized. However, if a well is purged dry prior to evacuating three <br /> casing volumes, a sample is collected following 80 percent recovery of ground water <br /> within the well, or after a minimum of one hour, but within eight hours of purging activities. <br /> SAMPLE WITHDRAWAL <br /> Water samples are collected from each monitoring well using either an interia pump with <br /> dedicated plastic/Teflon tubing or a disposable polyethylene bailer. Bailers are disposed <br /> of after a single use (sample) and require no decontaminating; plastic tubing used with <br /> the inertia pump is either dedicated to each well point or changed at each sampling event, <br /> thereby minimizing cross contamination due to sampling devices. Samples are drawn and <br /> collected in such a manner that agitation and exposure of the groundwater to the <br /> atmosphere is minimal. <br /> SAMPLE HANDLING <br /> Ground water samples are collected into laboratory-supplied 40-ml volatile organic <br /> analysis (VOA) vials without preservative and, if appropriate, one-liter amber glass <br /> containers without a preservative; the samples are collected with no visible air bubbles <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 Department of Public Health-certified analytical laboratory, for analysis. The <br /> samples are analyzed for: <br />