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the drawdown stops or a pump rate of 100 mL/min is obtained. If the water level stabilizes (no <br />further drawdown), then purging and sampling may continue at that flow rate. Purging and <br />sampling will not occur until drawdown is found to be at a minimum and/or water levels are <br />stabilized. Water levels in the well will be measured at regular intervals (approximately 3 <br />minutes apart) and recorded on the Water Sampling Field Data sheet (Appendix D) during the <br />purging process to document that drawdown was not occurring during the purge phase (refer <br />to Section B.1, "Standard Practice for Field Documentation Processes" in Appendix B). <br />After the start of the low -flow purging process, temperature, pH, and specific conductance will <br />be measured at regular intervals based on volume purged or time, with measurements <br />recorded at regular intervals approximately 3 minutes apart. Sample collection will begin as <br />soon as a minimum of one pump/tubing volume has been removed and pH, specific <br />conductance, and temperature measurements stabilize. Specific conductance and pH will be <br />considered stable when the three most current consecutive readings are within 10 percent and <br />within 0.1 pH units, respectively. Criteria for purging a well are summarized in Table 1. <br />Parameter <br />Purge Criteria <br />Purge volume <br />>_1 pump/tubing volume <br />Flow rate <br />>100 mL/m and <500 mL/m <br />1 <br />Water level <br />Minimal to no drawdown <br />pH <br />± 0.1 pH units <br />Specific Conductance <br />± 10 percent <br />Table 1. Summary of Groundwater Purge Protocol. <br />High TDS purge water will be collected in a five gallon bucket or other suitable container and <br />discarded into the waste pond or other appropriate receptacle. <br />3.1 Sample Collection <br />Groundwater samples will be collected with an approved method (Appendix B, Sections B.6, <br />"General Considerations for the Sampling of Liquids," and B.8, "Standard Practice for Purging of <br />Monitoring Wells"). Sample collection will be conducted using the same flow rate used during <br />the purging of the well. Refer to Section B.13, "Standard Practice for the Collection and <br />Preservation of Liquid Samples," in Appendix B. <br />Daub & Associates, Inc. 5 NS LLC 2015 S A P Rev. 2 <br />