Multi-Laboratory Study of ICP-MS for Analysis of Selenium and Arsenic in Flue Gas Desulfurization Wastewater

Oral Presentation

Prepared by M. Powell-Hernandez1, N. Goodman2
1 - EcoChem, Inc., 500 Union Street, Suite 1010, Seattle, WA, 98101, United States
2 - EPRI, 3420 Hillview Avenue, Palo Alto, CA, 94304, United States


Contact Information: mhernandez@ecochem.net; 206-508-2111


ABSTRACT

Wet flue gas desulfurization (FGD) scrubbers on coal-fired power plants produce a liquid effluent that poses challenges for accurate measurement of trace metals. The wastewater contains elevated levels of sulfur, salts and other substances originating in the coal, source water, limestone and other additives which can cause extreme biases when analyzed by ICP-MS. This study evaluates the impact on the accuracy and precision of analytical results from sample preservation techniques and procedural variations of EPA Method 200.8, for the analysis of arsenic and selenium by ICP-MS with interference reduction techniques. Large-volume samples were obtained from effluent of biological treatment systems that received wastewater from FGD blowdown or gypsum ponds. The samples were homogenized, fortified to concentrations near U.S. regulatory limits, and distributed to 16 laboratories for analysis. The resulting multi-laboratory study data, variations in sample processing and laboratory practice conducive to good precision and accuracy will be discussed.