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' socj: [NCT� <br /> QUALITY ASSURANCE/QUALITY CONTROL (QA/QC) PROCEDURES <br /> Field Procedures <br /> To prevent contamination of the samples and/or cross-contammation of monitoring wells ATC personnel <br /> adhere to the following procedures in the field <br /> • New, clean pair of appropriate disposable gloves is dawned prior to sampling each well <br /> • Wells are gauged and purged in the expected order of increasing degree of contamination based on <br /> historical analytical results <br /> • All purging equipment will be thoroughly decontaminated between each well using the procedures <br /> previously described at the beginning of this section <br /> • During sample collection for volatile organic analysis,the amount of air passing through the sample <br /> is minimized This helps prevent the air from stripping the volatiles from the groundwater Sample <br /> bottles are filled by slowly running the sample down the side of the bottle until there is a convex <br /> meniscus over the mouth of the bottle The hd is carefully screwed onto the bottle such that no air <br /> bubbles are present within the bottle If a bubble is present,the cap is removed and additional water <br /> is added to the sample container After resealing the sample container, if bubbles stall are present <br /> inside,the sample container is discarded and the procedure is repeated with a new container <br /> . Sample Control <br /> Laboratory and field handling procedures may be monitored, if required by the client or local regulatory <br /> agency, by including quality control (QC) samples for analysis with the groundwater samples Examples of <br /> different types of QC samples are as follows <br />' • Trip blanks are prepared at the analytical laboratory, by laboratory personnel to check handling <br /> procedures while in the field, as required by site conditions and local regulations Trip blanks are <br /> transported to the protect site in the same manner as the laboratory-supplied sample containers to be <br /> filled They are not opened, and are returned to the laboratory with the samples collected Trip <br /> blanks are analyzed for purgable organic compounds <br /> • Equipment blanks are prepared in the field to determine if decontamination of field sampling <br /> equipment has been effective, as required by site conditions and local regulations The sampling <br /> equipment used to collect the groundwater samples is rinsed with distilled water that is then <br /> decanted into laboratory-supplied containers The equipment blanks are transported to the <br /> laboratory, and are analyzed for the same chemical constituents as the samples collected at the site <br />' • Duplicates (split samples) are collected at the same time that the standard groundwater samples are <br /> being collected and are analyzed for the same compounds in order to check the reproducibility of <br />' laboratory data They are typically only collected from one well per sampling event, as required by <br /> site conditions and local regulations 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 determmed by ATC depending on site <br /> conditions and regulatory requirements <br /> M <br />