Superfund Innovative Technology Evaluation (SITE)
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
|ETV Field Portable X-ray Fluorescence Analyzer Niton XL Spectrum Analyzer
In April 1995, the U.S. Environmental Protection Agency (EPA) conducted a demonstration of field portable X-ray fluorescence (FPXRF) analyzers. The primary objectives of this demonstration were (1) to determine how well FPXRF analyzers perform in comparison to a standard reference method, (2) to identify the effects of sample matrix variations on the performance of FPXRF, (3) to determine the logistical and economic resources needed to operate these analyzers, and (4) to test and validate an SW-846 draft method for FPXRF analysis. The demonstration design was subjected to extensive review and comment by the EPAs National Exposure Research Laboratory, EPA Regional and Headquarters Superfund technical staff, the EPAs Office of Solid WasteMethods Section, and the technology developers.
Two sites were used for this demonstration: RV Hopkins and the ASARCO Tacoma Smelter. RV Hopkins is an active steel drum recycling facility and the site of a former battery recycling operation. It is located in Davenport, Iowa. The ASARCO site is a former copper and lead smelter and is located in Tacoma, Washington. The samples analyzed during this demonstration, were evenly distributed between three distinct soil textures: sand, loam, and clay. In addition, four sample preparation steps were evaluated. The reference methods used to evaluate the comparability of data were EPA SW-846 Methods 3050A and 6010A, Acid Digestion of Sediments, Sludges, and Soils and Inductively Coupled Plasma-AtomicEmission Spectroscopy, respectively.
The FPXRF analyzers tested in this demonstration were designed to provide rapid, real-time analysis of metals concentrations in soil samples. This information will allow investigation and remediation decisions to be made on-site more efficiently and can reduce the number of samples that need to be submitted for confirmatory analysis. Of the seven commercially available analyzers tested, one is manufactured by Niton Corporation (the XL Spectrum Analyzer); two are manufactured by TN Spectrace (the TN 9000 and TN Pb Analyzer); two are manufactured by Metorex Inc. (the X-MET 920-P Analyzer and the X-MET 920- MP Analyzer); one is manufactured by HNU Systems, Inc. (the SEFA-P Analyzer); and one is manufactured by Scitec Corporation (the MAP Spectrum Analyzer). The X-MET 940, a prototype FPXRF analyzer developed by Metorex, was given special consideration and replaced the X-MET 920-P for part of the RV Hopkins sample analyses. This environmental technology verification report (ETVR) presents information relative to the XL Spectrum Analyzer developed by Niton. Separate ETVRs have been published for the other analyzers demonstrated.
No operational downtime was experienced by the Niton analyzer through the 20 days required to conduct this demonstration. Quantitative data was provided by the analyzer on a real-time basis. The XL Spectrum Analyzer was configured to report arsenic, chromium, copper, lead, and zinc. This analyzer used relatively short count times of 60 live-seconds for this demonstration. This relatively short count time resulted in a high sample throughput, averaging between 20 and 25 samples per hour. The XL Spectrum Analyzer provided definitive level data quality (equivalent to reference quality data) for lead, andquantitative screening level data quality (not equivalent to reference data but correctable with the analysisof confirmatory samples) for arsenic, copper, and zinc. No data quality assessment could be made forchromium since the short count time made the precision and method detection limit measurements problematic.
This study showed that the Niton XL Spectrum Analyzer produced data that exhibit a log10 -log10 relationship with the reference data. The analyzer generally exhibited a lower precision compared to the reference methods. The XL Spectrum Analyzer precision RSD was generally between 6 and 14 percent at 5 - 10 times the method detection limit. The analyzers quantitative results were based on a developer-set calibration using the Compton Ratio method which required the use of well defined site specific calibration standards. Sample homogenization was the single most important factor influencing data comparability. The site and soil texture variables did not show a measurable influence on data comparability. This demonstration found that the analyzer was generally simple to operate in the field. The operator required no specialized experience or training. Ownership and operation of this analyzer may require specific licensing by state nuclear regulatory agencies. There are special radiation safety training requirements and costs associated with this type of license.
The Niton XL Spectrum Analyzer is an effective tool for field use and can provide rapid, real-time analysis of the metals content of soil samples at hazardous waste sites. The analyzer can quickly identify contaminated areas allowing investigation or remediation decisions to be made more efficiently on-site, and thus reduce the number of samples that need to be submitted for confirmatory analysis.