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WaterWork <br /> Groundwater Sampling Protocol <br /> Prior to arriving at the sampling site, all sampling equipment <br /> will be washed with laboratory grade detergent, and rinsed twice <br /> with tap water, once with acetone, and once with deionized water. <br /> The sample washing procedure will be carried out on-site before <br /> sampling of other monitoring wells, in such cases where more than <br /> one monitoring well is to be sampled. <br /> Immediately prior to sampling, the depth to water (DTW) level in <br /> the well will be recorded. The thickness of product on top of <br /> the groundwater, if present, will be measured using an interface <br /> probe. The procedure for conducting these monitorings are <br /> presented in the Groundwater Monitoring Protocol attachment. <br /> If free product is detected, analysis of groundwater for <br /> dissolved product will be conducted after the free product has <br /> been removed from the well. If all free product cannot be <br /> removed, an interval specific sampling device will be utilized to <br /> u collect a sample from below the zone of free product. Before <br /> collecting at least two groundwater samples from each well, the <br /> wEll will be purged until indicator parameters (temperature; <br /> conductivity and pH) stabilize. This will entail the removal of <br /> at least four or more well casing volumes by bailing or pumping. <br /> The criteria for determining well casing volumes and storage of <br /> purged waste is discussed in the WaterWork Well Development <br /> Protocol Attachment. The indicator parameter measurements will <br /> be taken both before and after purging of each well casing <br /> volume. Once the well is purged and well water has stabilized, a <br /> sample will be collected after the water level approaches 80 <br /> , Y percent of its initial elevation. Where water level recovery is <br /> slow, the sample will be collected after stabilization is <br /> achieved and enough water is present to fill sample containers. <br /> Cross contamination from transferring pumps (or bailers) from <br /> well to well wia-1 be avoided_by'_utilizing _dedicated_ equipment. <br /> Where this is not feasible thorough cleaning of equipment will be <br /> performed between sampling rounds. Sampling will proceed from <br /> the least contaminated to the most contaminated well, if <br /> information is available before sample collection, or if it is <br /> indicated by field evidence. <br /> Groundwater samples will be collected with a Teflon bailer with <br /> - <br /> bottom emptying devices. Duplicate samples will be transferred <br /> to vials or containers that meet Regional Board specifications <br /> (Table 1). Groundwater from the• bailer will be transferred to <br /> the sample container by allowing the fluid to .flow slowly. along <br /> the sides of the vessel. All containers will be filled above the <br /> top of the opening to form a positive meniscus. No head space <br />