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. All purging eclwpment Will be thoroughly deoantanunated between each Well,using the procedures previously <br /> described at the beginning of this section_ <br /> • During sample collection for volatile organic analysis, the amount of air passing through the sample is <br /> minimized. This helps prevent the air firom stripping the volatiles from the water Sample bottles are filled by <br /> slowly running the sample down the side of the bottle until there is a convex meniscus over the mouth of the <br /> bottle The lid is carefully screwed onto the bottle such that no air bubbles are present within the bottle If a <br /> bubble is present, the cap is removed and additional water is added to the sample container After resealmg <br /> the sample container, if bubbles still are present inside,the sample container is discarded and the procedure is <br /> repeated with a new container <br /> Laboratory and field handling procedures may be monitored, if required by the client or regulators, by including <br /> quality control (QC) samples for analysis with the groundwater samples Examples of different types of QC <br /> samples are as follows <br /> • Trip blanks are preparW at the analytical laboratory by laboratory personnel to check field handling <br /> procedures Trip blanks are transported to the prolett site in the same manner as the laboratory-supplied <br /> sample containers to be filled They are not opened, and are returned to the laboratory with tlr, samples <br /> collected. Trip blanks are analyzed for purgeable organic compounds <br /> • Equipment blanks are prepared in the field to determine A decontamination of field sampling equipment <br /> has <br /> r <br /> been effective The sampling equipment used to collect the ground samples is rinsed with distilled <br /> water <br /> which is then decanted into laboratory-supplied containers The equipment blanks are transported to the <br /> laboratory,and are analyzed for the same chemical constituegts as the samples collected at the site <br /> • Duplicates are collected at the same time that the standard groundwater samples are being collected and are <br /> analyzed for the same compounds in order to check the reproducibility of laboratory data- They are typically <br /> only collected from one well per sampling event The duplicate is assigned an identification number that will <br /> not associate it with the source Well <br /> Generally, trip blanks and field blanks check field handling and transportation procedures Duplicates check <br /> laboratory procedures The configuration of QC samples is determined by Clearwater depending on site conditions <br /> and regulatory requirements <br /> CLEARWATSR GROUP(GWS) 2 revised April 4,2002 <br />