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_ _ <br /> l <br /> cw ' <br /> WaterWork <br /> Groundwater Sampling rotocol <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 delonized water. <br /> ' The sample washing procedure will be carried out onsite before <br /> sampling of other monitoring wells, in such cases where more than <br /> one monitoring well is to be sampled. <br /> w <br /> Immediately prior to sampling, the depth to water (DTW) level in <br /> the well <br /> thewill be recorded. The thickness of product on top of <br /> groundwater, if present, will be measured using an interface <br /> probe. The procedure for conducting these munitorings 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 this 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 /> 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 purgingof each well casing <br /> volume. Once the well is purged and well grater has stabilized, a <br /> sample will be collected after the water level approaches 80 <br /> -- 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 will 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 <br /> Pro,-,--ed <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 /> bottom emptying devices. Duplicate samples will be transferred <br /> to vials or containers that meet -Regional Board spacifications <br /> t =: (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 /> Jy-. <br /> IN <br />