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1 <br /> the flow rate may be regulated by the 7,5 Filtering <br />' sampler The sample may be discharged <br /> from the pump outlet directly into the For samples requiring filtering, such as total metals <br /> appropriate sample container analysis, the filter must be decontaminated prior to <br /> and between uses Filters work by two methods A <br /> 4 Cap the sample container tightly and place barrel filter such as the "Geotech" filter works with a <br /> prelabeled sample container in a carrier bicycle pump,used to build up positive pressure in the <br /> chamber containing the sample which is then forced <br /> 5 Replace the well cap through the filter paper(minimum size 0 45 lim) into <br /> a jar placed underneath The barrel itself is filled <br /> 6 Log all samples in the site logbook and on manually from the bailer or directly via the hose of the <br /> field data sheets and label all samples sampling pump The pressure must be maintained up <br />' 7 Package samples and complete necessary to 30 lbs/int by periodic pumping <br /> paperwork A vacuum type filter involves two chambers, the <br /> upper chamber contains the sample and a filter <br /> 8 Transport sample to decontamination zone (minimum size 0 45 }Lm)divides the chambers Using <br /> for preparation for transport to the analytical a hand pump or a Gilian type pump,air is withdrawn <br /> laboratory from the lower chamber, creating a vacuum and thus <br />' <br /> 9 Upon completion, remove pump and causing the sample to move through the filter into the <br /> lower chamber where it is drained into a sample jar <br /> decontaminate or discard,as appropriate Repeated pumping may be required to drain all the <br />' sample into the lower chamber If preservation of the <br /> 7 4 6 Sample Retrieval - Syringe sample is necessary, this should be done after <br /> filtering <br /> A limited number of commercial syringe type <br />' samplers are available, (IEA, TIMCO,etc )some are 76 Post Operation <br /> homemade devices These devices are claimed to <br /> provide good quality samples for volatile analysis,but After all samples are collected and preserved, the <br />' are severly limited in sample volume and are specific sampling equipment should be decontaminated prior <br /> to sampling for volatiles Essentially, they operated to sampling another well to prevent <br /> with an evacuated chamber that is lowered down the cross-contamination of equipment and monitor wells <br /> well, and allowed to fill with the pressure of the between locations <br /> t water The entire mechanism is then brought to the <br /> surface with the sample The sample may then be 1 Decontaminate all equipment <br /> transferred to a sample vial,or the entire unit may be <br /> sent as the sample container 2 Replace sampling equipment in storage <br />' 1 Evacuate the syringe if necessary, and lower containers <br /> the sampling device to just below the well 3 Prepare and transport ground water samples <br />' screen to the laboratory Check sample <br /> documentation and make sure samples are <br /> 2 Remove the constriction from the device and properly packed for shipment <br /> allow the sample to fill the syringe, apply <br />' slight suction as necessary 7,7 Special Considerations for VOA <br /> 3 Bring unit to the surface If necessary, Sampling <br />' transfer the sample to vials, as outlined in <br /> steps 2 through 7 above The proper collection of a sample for volatile organics <br /> requires minimal disturbance of the sample to limit <br /> volatilization and therefore a loss of volatiles from the <br />' sample <br /> 11 <br />