Handheld X-Ray Fluorescence Spectrometry for Measuring Mercury in Soil
Channel: JMU ISAT
Date: 02/07/2017

Full Title: Validation and Use of Handheld X-Ray Fluorescence Spectrometry for Measuring Mercury in Soil by Joseph Luther and Hunter Wines
Advised by: Dr. Robert Brent
Sponsors: Dupont
Abstract: The purpose of this study was to demonstrate that a handheld x-ray fluorescence spectrometer (XRF) can accurately and efficiently characterize mercury contamination in the soil along the banks of the South River RCRA site in Waynesboro, VA. This study was divided into three parts: Method Validation, Method Interferences/Correction, and Field Characterization. Historically, XRF instruments have not been seen as an alternative to traditional laboratory methods for measuring mercury, because of poor sensitivity. In this study, improved sensitivity was achieved with a site-specific calibration. In the first part of this study the instrument was used in a split study comparing the field XRF method with laboratory EPA Method 7471A. The results of this split study showed that the two methods agreed with an R-squared value of 0.93 and a median coefficient of variation of 15%. The precision estimates from sample duplicates and triplicates showed that precision was influenced more by sample heterogeneity than method capabilities. The Method Interferences/ Correction portion of this study was conducted by spiking field-collected soils with known amounts of mercury and then adjusting the moisture levels of the soils to a range of 0-30% moisture. This study found that moisture creates a systematic bias in the measurements, but this bias is no more significant than the variation associated with sample heterogeneity. Finally, the Field Characterization portion of this project was a 6-day sampling campaign that analyzed 2,000-ft of contaminated banks along the South River near Hopeman Parkway, Waynesboro, VA. This study showed that the handheld XRF can provide fast, in-situ results that allow decision makers to more quickly identify and target high priority contamination areas. In summary, this three-part study demonstrated that the handheld XRF with sitespecific calibration can be used as a quicker and cheaper alternative method for characterizing mercury-contaminated banks with similar accuracy, precision, and sensitivity.