Development of energy-dispersive X-ray fluorescence as a mobile analysis method for hazardous metals in transuranic waste

Energy-dispersive X-ray fluorescence (EDXRF) is a widely applied technique for both laboratory and field-based characterization of metals in complex matrices. Here an EDXRF method is described for analysis of 13 hazardous (RCRA) metals in Portland cement, a typical matrix for transuranic (TRU) waste from US Department of Energy (DOE) sites. Samples are analyzed as homogeneous powders prepared by simple drying, mixing, and milling. Analyses are performed using a commercial EDXRF spectrometer equipped with an X-ray tube, a high-resolution Si(Li) detector, and fundamental parameters software for data reduction. The spectrometer is rugged and suitable for use in either mobile or fixed-based laboratories. Standardization is accomplished using fundamental parameters techniques for several prepared standards which bracket the expected range in metal concentrations, and typical standardization uncertainties are < 10%. Detection limits range from 2--20 ppm and meet required action levels with a few exceptions including Be, Hg and V. Accuracy is evaluated from a series of unknown quality control samples and ranges from 85--102%, whereas the total method uncertainty is typically < 10%. Consequently, this simple, rapid, and inexpensive technique can provide quantitative characterization of virtually all of the RCRA metals in TRU waste cement samples