&ER* J technical FACT SHEET ~S BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS www.epa.gov/research EPA!s rapid radiochemical methods expedite analytical turnaround time for selected radionuclides whiie providing quantitative results that meet measurement quality objectives. Methods are applicable to samples where contamination is from either known or unknown origins, This fact sheet is intended for radioanalytical laboratory personnel, decision makers within the incident command structure, additional reoccupancy decision makers (e.g., state and local public health), and other field environmental response personnel. Method Summary: The method is based on a sequence of two chromatographic extraction resins used to concentrate, isolate, and purify americium (Am), Am fraction is prepared for counting by alpha spectrometry by removing interfering radionuclides as well as other components of the water matrix. The method uses vacuum-assisted flow to improve the speed of the separations. Prior to the use of the extraction resins, the water sample is filtered as necessary to remove any insoluble fractions, equilibrated with 243Am tracer, and concentrated by evaporation or calcium phosphate [Ca3(P04)2] precipitation. The sample test source is prepared by microprecipitation with neodym(lll)-fluoride. Standard laboratory protocol for the use of an alpha spectrometer is used when the sample is ready for counting, Rapid Radiochemical Method Americium-241 (241Arri) in Water Samples Time to Process: 8.5-10.5 hr Includes radiochemical processing and counting Compare to traditional method (ASTM D3084-05): 14-27 hr Measurement Quality Objectives Required method uncertainty: 1.9 pCi/L Analytical action level (AAL): 15 pCi/L Required relative uncertainty: 13% above AAL Minimum detectable concentration: 1.5 pCi/L Sample quantity: ~ 200 mL Count time: At least 1 hr Sample Preservation Analysis within 3 days of sampling: No preservation required Holding time >3 days: Adjust pH to <2 with concentrated nitric acid Waste Generated per Sample ~ 70 mL acidic waste 1 mL hydrofluoric acid, ~ 8 mL ethanol Resin cartridges; may contain isotopes of uranium, neptunium, thorium, plutonium If Ca3(P04)2 coprecipitation performed: ~ 100-1000 mL decanted solution, pH neutral Method Access: https://www.epa.gov/sites/production/files/2015- 06/documents/am-241 in water rev 0 1 epa 402-r-10- 001a.pdf Method Application The method is specific for the determination of soluble 241Am in drinking water and aqueous samples. Application of this method should be validated by the laboratory using the protocols provided in Method Validation Guide for Qualifying Methods Used by Radiological Laboratories Participating in Incident Response Activities, or the protocols published by a recognized standards organization for method validation. Equipment and Supplies Analytical balance: 104 g readability or better j Cartridge reservoirs: 10 or 20 mL syringe style with locking device, or equivalent | Centrifuge and 250 mL flasks | Filter apparatus with 25 mm diameter polysulfone filtration chimney, stem support, and stainless steel support or a single-use (disposable) filter funnel/filter combination | Filters: 0,45 pm membrane; 25 mm polypropylene with 0,1 pm pore size or equivalent | Laboratory supplies: 250 mL and 350 mL plastic/glass ware; 10 mL plastic culture tubes with caps; 100 pL pipettes and plastic tips; pH paper; stainless steel planchets or other sample mounts able to hold the 25 mm filter; tweezers | Vacuum system: box; pump or laboratory system; white inner tips; yellow outer tips | Vortex mixer Contacts Program: Kathy Hall Technical: John Griggs 513-379-5260 334-270-3450 hall.kathy@epa.gov griggs.john@epa.gov U.S. Environmental Protection Agency Office of Research and Development, Homeland Security Research Program EPA/600/S-17/054 March 2017 ------- |