Laserfiche WebLink
APPENDIX A <br />Monitoring and Sampling Procedures <br />BOULEVARD AUTOMOTIVE SERVICE <br />2151 Country Club Boulevard, Stockton, California <br />STATIC WATER LEVEL MEASUREMENTS <br />Before sampling and during groundwater monitoring, static water level are measured from <br />wells MW-1 through MW-5 and MW-7 through MW-24 using an electric water level <br />indicator. Water level data is recorded to the nearest 0.01-foot from a reference point <br />marked of the top of the PVC well casing. <br />WELL EVACUATION <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 utilizing disposable polyethylene bailers, a disposable 3/8-inch <br />plastic tubing with an inertial pump or a dedicated 5/8-inch plastic tubing with a Waterra <br />inertial pump. <br />Wells are purged until: 1) a minimum of three casing-water volumes is removed from the <br />well; and/or 2) the field-measured ground water parameters, pH, temperature and <br />conductivity, are stabilized. However, if a well is purged dry prior to evacuating three casing <br />volumes, a sample is collected following 80 percent recovery of ground water within the <br />well, or after a minimum of 1 hour, but within 8 hours, of well evacuation. <br />SAMPLE WITHDRAWAL <br />Water samples are collected from each monitoring well using a disposable polyethylene <br />bailer or a dedicated plastic/Teflon tubing in conjunction with the inertia pump. Bailers are <br />disposed after a single use (sample) and require no decontaminating; plastic tubing used <br />with the inertia pump is either dedicated to each well point or changed at each sampling <br />event, thereby minimizing cross contamination due to sampling devices. Samples are <br />drawn and collected in such a manner that agitation and exposure of the groundwater to <br />the atmosphere is minimal. Ground water sample containers were labeled with the well <br />designation, date, time, and sampler's initials. <br />SAMPLING HANDLING <br />Ground water samples are collected into laboratory-supplied 40-ml volatile organic analysis <br />(VOA) vials with no preservative and, into one-liter amber glass containers without a <br />Advanced GeoEnvironmental, Inc.