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1 <br />' PROTOCOLS FOR QUARTERLY GROUNDWATER MONITORING <br />' GROUNDWATER GAUGING <br /> Wells are opened prior to gauging to allow the groundwater level in the wells to equilibrate with <br /> atmospheric pressure The depth to groundwater and depth to liquid-phase hydrocarbons,if present, <br /> are then measured to the nearest 0 01 feet using an electronic water level meter or optical interface <br /> probe The measurements are made from a permanent reference point at the top of the well casing <br /> If less than 1 foot of water is measured in a well, the water is bailed from the well and, if the well <br /> does not recover,the well is considered"functionally dry" Wells with a sheen or measurable liquid- <br /> phase hydrocarbons are generally not purged or sampled <br /> WELL PURGING <br /> G G <br /> After the wells are gauged, each well is purged of approximately 3 well casing volumes of water to <br /> provide representative groundwater samples for analysis Field parameters of pH,temperature, and <br /> electrical conductance are measured dunng purging to ensure that these parameters have stabilized <br /> before groundwater in a well is sampled Groundwater in each well is purged using an inertial pump <br /> (WaTerra), an electric submersible pump, or a bailer After the well is purged, the water level is <br /> 1 checked to ensure that the well has recharged to at least 80 percent of its onglnal water level <br /> GROUNDWATER SAMPLING <br /> 10 After purging, groundwater in each well is sampled using dedicated tubing and an inertialum <br /> P P <br /> (WaTerra) or a factory-cleaned disposable bailer Samples from extraction wells are typically <br /> 1 collected from sample ports associated with the groundwater remediation system Samples collected <br /> for volatile organic analysis are placed in Teflon septum-sealed 40-milliliter glass vials Samples <br /> collected for diesel analysis are placed in 1-liter amber glass bottles Each sample bottle is labeled <br /> 1 with the site name,well number,date, sampler's initials,and preservative The samples are placed in <br /> a cooler with ice for delivery to a state-certified laboratory The information for each sample is <br /> entered on a chain-of-custody form prior to transport to the laboratory <br /> 1 <br /> 1 <br /> 1 <br /> i <br /> 1 <br />' G\Projects\ExxonMobil\Master\ExxonMobti QMR templates\QMR protocols purge waterra doc <br />