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ADVISORY-ACTIVE SOIL GAS INVESTIGATIONS <br /> i <br /> The regulating agency may inspect the field and/or stationary laboratory QA/QC <br /> procedures. Copies of the QA/QC plan and laboratory calibration data should be <br /> presented upon request. <br /> All calibration and QA/QC standards, traceable to a source, should be documented by <br /> the laboratory. Continuing calibration and QC standards should be from a second <br /> source or a different lot from the same supplier. Vapor phase standards should be used <br /> 1 to calibrate laboratory instruments. <br /> { The following items should be included when using USEPA Methods: <br /> i <br /> • Initial calibration; <br /> • Daily calibration/continuing calibration; <br /> i Laboratory control spike; <br /> • Internal standards; <br /> • Surrogates; <br /> • Method blank; and <br /> • Field blank. <br /> All surrogate recovery data should comply with laboratory-derived control limits. Control <br /> limits should be listed in the laboratory reports for reference. <br /> Surrogate recovery limits should be approximately 70 percent to 130 percent(30 percent <br /> deviation). The laboratory-derived recovery limits may be wider or narrower than the 30 <br /> percent figure depending on sample introduction technique and compound used. If a <br /> compound-specific recovery limit is not selected, an explanation should be provided to <br /> justify the recovery limit used. See Appendix F for surrogate introduction techniques. <br /> 6.3.1 Sample Blanks <br /> • Method Blanks: Method blanks should be used to verify the effectiveness of <br /> decontamination procedures in the laboratory, and to detect any possible <br /> interference from ambient air; <br /> • Trip Blanks for Off-site Shipments: Trip blanks should be included in the shipping <br /> containers when collecting USEPA TO-17 samples; <br /> • Material Blanks: Prior to soil gas sampling, an assembled soil gas probe, tip and <br /> tubing should be blank tested at a frequency of one analysis per new batch of <br /> tubing or material used; and <br /> • Equipment Blanks: Equipment blanks should be collected from decontaminated <br /> equipment before reuse at a frequency specified in the workplan. One equipment <br /> blank should be collected and analyzed for each batch of 20 samples, or at least <br /> one per day, whichever is more often. <br /> April 2012 30 <br />