XRF Calibration And Quality Control Sample Clauses

XRF Calibration And Quality Control. An Innov-X tube-based XRF analyzer will be used to perform XRF analyses. XRF procedures will be consistent with USEPA Method 6200, the Generic QAPP, and operator manual instructions. XRF standardization will occur according to manufacturer specifications at the beginning and end of each day the XRF instrument is used, and generally following analysis of every 20 samples. Additionally, National Institute of Standards and Technology (NIST), or equivalent, standard samples will be utilized to compare reported concentrations to true values of the beginning and end of each field day. If reported levels are not generally within 20 percent of true values, the XRF instrument will be recalibrated prior to additional use. USEPA Method 6200 and the operator manual further outline XRF start-up and standardization/calibration procedures. Rocks, gravel, and other heterogeneous materials will be removed from XRF samples prior to field analysis to minimize matrix interference. Samples will be homogenized in the field to further reduce interference and provide data representative of the entire sample interval. Samples will be analyzed for a minimum of 30 seconds to reduce detection limits. Duplicate XRF analyses will occur as needed to generate a minimum of 10% duplicate data. Consistent with Method 6200, XRF data quality will be evaluated through a statistical regression analysis of XRF data versus laboratory data. Regression analysis results will be documented and discussed in the final report as basis for acceptance or rejection of data. The regression analysis may result in a correlation coefficient (r2) values less than of 0.7 due to limited statistical observation pool by site, sample heterogeneity, and heterogeneous contaminants (i.e. lead particulates). This will not necessarily result in the rejection of closure data but will result in further evaluation of specific data points and other quality assurance and quality control data to evaluate data usability. Closure samples will be held by Terracon or the laboratory until final data review has been completed and deemed acceptable. XRF field sheets and calibration logs will be included in the final report in order to document field XRF activities.