Superfund Innovative Technology Evaluation (SITE)
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
|Innovative Technology Verification Report,
Field Measurement Technology for Mercury in Soil and Sediment
Metorex's X-MET® 2000 X-Ray Fluorescence Technology
Metorex's X-MET 2000 X-ray fluorescence analyzer was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003, at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN. The purpose of the demonstration was to collect reliable performance and cost data for the X-MET 2000 and four other field measurement devices for mercury in soil and sediment. The key objectives of the demonstration were: 1) determine sensitivity of each instrum ent with respect to a vendor-generated m ethod detection limit (MDL) and practical quantitation limit (PQL); 2) determ ine analytical accuracy associated with vendor field measurements using field samples and standard reference materials (SRMs); 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes.
The demonstration involved analysis of SRMs, field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those of an off-site laboratory using reference method, Test Methods for Evaluating Solid Waste (SW-846) Method 7471B.
The sensitivity, accuracy, and precision measurements were successfully evaluated. The X-MET 2000 was found to have an MDL of between 16.5 and 26.9 m g/kg and a PQL of approximately 64 mg/kg; however, this PQL was difficult to estimate due to poor instrument accuracy. The instrument was found to be very precise (Metorex had an average relative standard deviation on sample replicates of 9.34% compared to the referee laboratory's 20.6%), but have poor accuracy (22 of 32 samples had a percent difference of greater than 50% ). During the demonstration, Metorex required 18 hours (36 man hours) for analysis of 197 samples. The measurement costs were estimated to be $6,556 for Metorex's X-MET 2000 rental option or $33.28 per sample; $16.02 per sample excluding rental costs.
The X-MET 2000 exhibited good ease of use and durability, as well as no major health and safety concerns. The analyzer is lightweight and extremely portable. The demonstration findings collectively indicated that the X-MET 2000 is a rapid and portable field measurement device for mercury in soil.