September 2016 Update: EPA has validated and published a rapid method for sodium hydroxide fusion of asphalt roofing material matrices for analysis of americium-241, plutonium-238, plutonium-239, radium- 226, strontium-90, uranium-234, uranium-235, and uranium-238. The method is summarized and accessible through the link provided below. Rapid Method for Sodium Hydroxide Fusion of Asphalt Roofing Material Matrices Prior to Americium, Plutonium, Strontium, Radium, and Uranium Analyses Analyte(s) CAS RN® Americium-241 14596-10-2 Plutonium-238 13981-16-3 Plutonium-239 15117-48-3 Radium-226 13982-63-3 Strontium-90 10098-97-2 Uranium-234 13966-29-5 Uranium-235 15117-96-1 Uranium-238 7440-61-1 Analysis Purpose: Qualitative analysis Technique: Alpha spectrometry Method Developed for: Americium-241 (241Am), plutonium-238 (238Pu), plutonium-239 (239Pu), radium-226 (226Ra), strontium-90 (90Sr), uranium-234 (234U), uranium-235 (235U) and uranium- 238 (238U) in asphalt roofing material samples Method Selected for: SAM will list this method for qualitative analysis of americium-241, plutonium-238, plutonium-239, radium-226, strontium-90, uranium-234, uranium-235 and uranium-238 in asphalt shingle matrices (roofing material). Description of Method: The term "asphalt roofing materials" is used in this procedure to mean asphalt organic shingles or asphalt fiberglass shingles typically used for residential or commercial roofs. This roofing material procedure was validated with asphalt fiberglass shingles. Other roofing types will need to be validated by the laboratory. Asphalt roofing material samples should be cut into very small pieces prior to taking a representative aliquant for furnace heating and fusion. The method is based on ashing a 25 gram (g) subsample of asphalt roofing material sample in a furnace to remove organic components, followed by taking a representative aliquant from the ashed sample. The 1-1.5 g aliquant of ashed sample is fused using sodium hydroxide fusion at 600 °C. Plutonium, uranium, and americium are separated from the alkaline matrix using an iron/titanium hydroxide precipitation (enhanced with calcium phosphate precipitation) followed by a lanthanum fluoride matrix removal step. Strontium is separated from the alkaline matrix using a phosphate precipitation, followed by a calcium fluoride precipitation to remove silicates. Radium is separated from the alkaline matrix using a carbonate precipitation. The method is applicable to the sodium hydroxide fusion of asphalt shingle samples, prior to the chemical separation procedures described in the following procedures: U.S. Environmental Protection Agency Office of Research and Development, Homeland Security Research Program EPA 600/S-16/271 September 2016 ------- • U.S. EPA. Rapid Radiochemical Method for Americium-241 in Building Materials for Environmental Remediation Following Radiological Incidents (EPA 402-R14-007, April 2014) • U.S. EPA. Rapid Radiochemical Method for Plutonium-238 and Plutonium-239/240 in Building Materials for Environmental Remediation Following Radiological Incidents (EPA 402-R14-006, April 2014) • U.S. EPA. Rapid Radiochemical Method for Radium-226 in Building Materials for Environmental Remediation Following Radiological Incidents (EPA 402-R14-002, April 2014) • U.S. EPA. Rapid Radiochemical Method for Total Radiostrontium (Sr-90) in Building Materials for Environmental Remediation Following Radiological Incidents (EPA 402-R14- 00, April 2014) • U.S. EPA. Rapid Radiochemical Method for Isotopic Uranium in Building Materials for Environmental Remediation Following Radiological Incidents (EPA 402-R14-005, April 2014) Special Considerations: The bitumen components, which can have affinity for the radionuclides, are destroyed in this method. Radionuclides deposited on the surface of the asphalt roofing material are effectively digested, including refractory radionuclide particles. A small amount of mineralized granules might remain after the fusion. Information regarding the elemental composition of the sample may be helpful. For example, asphalt roofing materials can have native concentrations of uranium, radium, thorium, stable strontium, or stable barium, all of which could have an effect on the chemical separations used following the fusion of the sample. In those samples where native constituents are present that could interfere with the determination of the chemical yield (e.g., strontium for 90Sr analysis) or with the creation of a sample test source (e.g., barium for 226Radium analysis by alpha spectrometry), it might be necessary to determine the concentration of these native constituents in advance of chemical separation (using a separate aliquant of fused material) and make appropriate adjustments to the yield calculations or amount of carrier added. Matrix blanks for these matrices might not be practical to obtain. Efforts should be made to obtain independent, analyte-free materials that have similar composition as the samples to be analyzed. These blanks will serve as process monitors for the fusion, and as potential monitors for cross contamination during batch processing. Uncontaminated asphalt roofing material may be acceptable blank material for Pu, Am, and Sr analyses, but this material will contain background levels of naturally occurring U and Ra isotopes. Re-used zirconium crucibles should be cleaned very well using soap and water, followed by warm nitric acid, and a final water rinse. Blank measurements should be monitored to ensure effective cleaning. Additional information regarding potential interferences and procedures for addressing the interferences is provided in Section 4 of the method. Source: U.S. EPA, National Air and Radiation Environmental Laboratory. "Rapid Method for Sodium Hydroxide Fusion of Asphalt Matrices Prior to Americium, Plutonium, Strontium, Radium, and Uranium Analyses." EPA 402-R16-003, Revision 0, August 2016. https://www.epa.gov/radiation/rapid-radiochemical-methods-selected-radionuclides U.S. Environmental Protection Agency Office of Research and Development, Homeland Security Research Program EPA 600/S-16/271 September 2016 ------- |