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Environmental Technology
Verification Report
Field Portable X-ray Fluorescence Analyzer
Metorex X-MET 920-MP
EPA 600/R-97/151
March 1998
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 standard reference methods,
(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 EPA’s National Exposure Research Laboratory,
EPA Regional and Headquarters Superfund technical staff, the EPA’s Office
of Solid Waste–Methods Section, and the technology developers.
Two sites were used for this demonstration: the RV Hopkins site and the
ASARCO Tacoma Smelter site (ASARCO). RV Hopkins is an active steel drum
recycling facility and 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 test samples analyzed during
this demonstration were evenly distributed between three distinct soil
textures: sand, loam, and clay. 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-Atomic
Emission 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 a portion of the demonstration. This environmental technology verification
report (ETVR) presents information relative to the Metorex X-MET 920-MP.
Separate ETVRs have been published for the other analyzers demonstrated.
Approximately three days of operational downtime was experienced by
the analyzer due to computer software and hardware problems. Most of these
problems were due to operator error or inexperience. None of the downtime
or data loss was associated with mechanical or electronic malfunctions
of the analyzer. Quantitative data was provided by the analyzer on a real-time
basis. The X-MET 920-MP Analyzer reported arsenic, chromium, copper, lead,
zinc, nickel, and barium. This analyzer used count times ranging from
30 live-seconds for in situ-unprepared samples at the ASARCO site to 180
live-seconds for intrusive-prepared samples at the RV Hopkins site. These
count times resulted in a sample throughput averaging between 8 and 14
samples per hour. The X-MET 920-MP Analyzer provided definitive data(equivalent
to reference data) for arsenic and lead; and qualitative screening level
data (identifies the presence or absence of a contaminant) for copper,
barium, and zinc. Insufficient precision data precluded an assignment
of data quality levels for nickel or chromium.
This study showed that the analyzer produced data that exhibited a log10
-log10 linear correlation to the reference data. The analyzer generally
exhibited a precision similar to the reference methods. The analyzer exhibited
precision of less than 10 percent relative standard deviation at 5 to
10 times the method detection limit (MDL) for all of the reported analytes
except chromium and nickel. The precision evaluation was confounded by
changing count times. The precision study indicated that count times probably
had no effect on the precision for all target analytes except copper and
lead. For copper and lead, the increasing count times caused a 2- to a
10-fold increase in precision. The analyzer’s quantitative results were
based on an empirical calibration using site-specific calibration samples.
This demonstration found that the X-MET 920-MP Analyzer was generally
simple to operate in the field; however, its physical configuration made
it more practical for use as a benchtop unit. The auxiliary computer and
cumbersome power requirements of commercial laptop computers limited its
utility as an in situ instrument. The operator required no specialized
experience or training for normal operation of the analyzer. However,
ownership and operation of this analyzer may require specific licensing
by a state nuclear regulatory agency. There are specific radiation safety
training requirements and costs associated with this type of license.
The Metorex X-MET 920-MP Analyzer can provide rapid, real-time analysis
of the metals content of soil samples at hazardous waste sites. The analyzer
can quickly identify contaminated areas from noncontaminated areas allowing
investigation and remediation decisions to be made more efficiently on-site
and reduce the number of samples that need to be submitted for confirmatory
analysis.
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Posted October 31, 2001
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