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