Development of synthetic environmental radioactivity reference materials.

Area of Science:

• Environmental Science
• Materials Science
• Analytical Chemistry

Background:

• Accurate measurement of environmental radioactivity is crucial for safety and monitoring.
• Standardized reference materials are essential for validating analytical methods and ensuring data comparability.
• Existing reference materials may not cover the full spectrum of radionuclides or matrix types encountered in environmental samples.

Purpose of the Study:

• To describe a novel method for developing synthetic environmental radioactivity reference materials.
• To produce solid reference materials with a silicon dioxide (SiO(2)) matrix incorporating specific radionuclides.
• To validate the developed reference materials through international proficiency testing.

Main Methods:

• Sol-gel process utilizing tetraethyl orthosilicate (TEOS), ethanol, and standardized mixed radionuclide solutions.
• Hydrolysis of liquid precursors to form a solid SiO(2) matrix.
• Determination of certified radionuclide activity concentrations by the National Physical Laboratory (NPL).
• Intercomparison of results from 36 international organizations across 17 countries.

Main Results:

• Two solid reference materials with SiO(2) matrices were successfully synthesized.
• Certified activity concentration values (in Bqg(-1)) were obtained for (60)Co, (133)Ba, (134)Cs, (137)Cs, (152)Eu, (154)Eu, and (241)Am.
• Indicative values were determined for (55)Fe and (90)Sr.
• Results from 36 organizations showed good agreement, validating the reference materials.

Conclusions:

• The sol-gel process is an effective method for producing synthetic environmental radioactivity reference materials.
• The developed reference materials are suitable for interlaboratory comparisons and proficiency testing.
• These materials contribute to improving the accuracy and reliability of environmental radioactivity measurements globally.