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Monitoring and Sampling Procedures <br /> WELDON CHURCH PROPERTY <br /> 104 West Beverly Place, Tracy, California <br /> STATIC WATER LEVEL MEASUREMENTS <br /> Before sampling and during ground water monitoring, static water levels are measured using an <br /> electric water level indicator. Water level data is recorded to the nearest 0.01-foot from a reference <br /> point marked on the top of the PVC well casing. <br /> WELL PURGING <br /> Subsequent to the measurement of depth to water and prior to sampling, each well is purged to <br /> ensure samples are representative of the formation, rather than standing water in the well casing. <br /> Wells are purged using either a Waterra inertial pump and dedicated %-inch plastic tubing or <br /> dedicated disposable polyethylene bailers. <br /> Wells are purged until a minimum of three casing-water volumes is removed from the well and/or <br /> the field-measured ground water parameters (pH, temperature, and conductivity) are stabilized. <br /> However, if a well is purged dry prior to evacuating three casing volumes, a sample is collected <br /> following 80 percent recovery of ground water within the well,or after a minimum of one hour,but <br /> within eight hours, of well purging activities. <br /> Field data and logs are provided in Appendix C. <br /> SAMPLE WITHDRAWAL <br /> Water samples are collected from each monitoring well using either an inertial pump with dedicated <br /> plastic/Teflon tubing or a disposable polyethylene bailer. Bailers are disposed of after a single use <br /> (sample) and require no decontaminating; plastic tubing used with the inertia pump is either <br /> dedicated to each well point or changed at each sampling event, thereby minimizing cross <br /> contamination due to sampling devices. Samples are drawn and collected in such a manner that <br /> agitation and exposure of the groundwater to the atmosphere is minimal. <br /> SAMPLE HANDLING <br /> Ground water samples are collected into laboratory-supplied 40-m1 volatile organic analysis(VOA) <br /> vials without preservative; the samples are collected with no visible air bubbles present in the vials <br /> after filling and capping.Following collection,samples are appropriately labeled,placed on ice,and <br /> Advanced GeoEnvironmental,Inc. <br />