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:COLORADO LEGACY LAND <br /> Groundwater Sampling SOP:Low Flow <br /> 1. Don the proper PPE: nitrile or latex gloves and eye protection. <br /> 2. Open the well. Unlock well,remove metal well lid and j-plug from monitoring well. <br /> 3. Measure water level: Use water level meter to record the depth to water from the north side of the <br /> PVC casing.Record depth to water(±0.01 ft below top of casing[btoc])on the groundwater sample <br /> field form. <br /> 4. Measure total depth of the well: Use the water level meter to measure the total depth of the well <br /> (±0.01 ft btoc). Record the total depth on the groundwater sample filed form. <br /> 5. As you wind up the static water level,decontaminate the measuring tape with paper towels,alconox <br /> spray bottle,and deionized water spray bottle. <br /> 6. Connect dedicated tubing(stored inside the well casing)to the peristaltic pump on the ground <br /> surface. <br /> 7. Connect the peristaltic pumps to the car. It plugs into the car outlet. <br /> 8. Set up purge bucket near well. Secure the discharge hose from the well in the bucket using a clamp <br /> or zip ties. <br /> 9. Begin purging:Turn on peristaltic pump. Record the purge start time on the sample field form. <br /> 10. Once the flow through cell is full,record the initial field parameters on the sample field form and use <br /> the measuring cup and stop watch to measure the flow rate. The flow rate should be between 100- <br /> 500 mL/minute. If needed adjust the flow rate and remeasure the flow. <br /> 11. Record field parameters,measure depth to water,and flow rate every 3-5 minutes on the sample <br /> field form. <br /> 12. Purge well water until three consecutive measurements of field parameters are within stabilization <br /> criteria. <br /> Field Parameter Stabilization Criteria <br /> Temperature °C ± 1 C <br /> H unitless ±0.1 <br /> Conductivity mS cm) 10% <br /> Dissolved Oxygen m L ± 10%or>0.5 m L <br /> ORP m ± 10mV <br /> Note,if field parameters do not stabilize within 2 hours of purging the field sampler will collect a <br /> sample and note the variance on the field form(e.g."pH did not stabilize during purge,sample <br /> collected after 2 hours"). <br /> 13. Record purge stop time on sample field form. Record total purge volume in purge bucket and close <br /> lid. <br /> 14. To collect a sample,disconnect the discharge tube from the YSI and begin filling bottles provide by <br /> the lab. Put samples on ice for preservation. <br /> 15. After sampling is complete.Disconnect the pump,tubing,and YSI. Store the dedicated tubing in the <br /> monitoring well casing. <br /> 16. Decontaminate equipment:Use spray bottles and paper towels to clean the water level meter and YSI <br /> between monitoring wells. <br /> 17. Record samples on Chain of Custody. Doff PPE and dispose of gloves.Close well lid,secure with lock, <br /> and pack up field supplies. <br /> PAGE 19 OF 22 <br />