Overview
EN ISO 22908:2020 - "Water quality - Radium 226 and Radium 228 - Test method using liquid scintillation counting" (adopted by CEN) specifies a laboratory method for determining activity concentrations of radium-226 (226Ra) and radium-228 (228Ra) in drinking water. The method uses chemical separation of radium from the water matrix followed by measurement with liquid scintillation counting (LSC). It is suitable for routine monitoring and for rapid detection of radium contamination in emergency situations.
Key performance information included in the standard:
- Typical achievable massic activity quantification down to 0.01 Bq/kg for 226Ra and 0.06 Bq/kg for 228Ra using a 0.5 kg sample and 1 h counting time on a low-background LSC.
- Procedure elements from sampling through test report, including calibration, quality control and uncertainty estimation.
Key Topics and Requirements
- Scope and principle: Chemical separation of radium and measurement by LSC to obtain massic activities in drinking water.
- Sampling: Guidance on representative water sampling for radionuclide analysis.
- Reagents & equipment: Specification of required chemicals and LSC instrumentation.
- Instrument set-up & calibration:
- Optimization of counting conditions and preparation of calibration/standard sources.
- Determination of counting efficiencies for 226Ra and 228Ra.
- Blank measurements to control background.
- Analytical procedure:
- Radium separation (precipitation) and purification steps.
- Sample preparation for LSC and measurement protocols.
- Determination of chemical recoveries and overall counting efficiency.
- Quality control & data treatment:
- QC samples, uncertainty estimation, calculation of massic activities at sampling date.
- Decision threshold, detection limit and confidence limits.
- Interference control and test report content requirements.
Applications and Who Uses It
This standard is intended for:
- Environmental and public health laboratories performing drinking water testing for radionuclides.
- Utilities and water suppliers monitoring water quality and regulatory compliance.
- Regulatory bodies and supervisors implementing radiological protection limits.
- Emergency response teams needing rapid screening for radium contamination after incidents.
- Research and geological survey labs assessing natural radium levels in groundwater.
Practical benefits:
- Provides a validated LSC-based procedure for sensitive radium analysis.
- Enables consistent, comparable results across laboratories for regulatory and health risk assessments.
Related Standards
- ISO 22908:2020 was prepared by ISO/TC 147 (Water quality) and endorsed as EN ISO 22908:2020 by CEN.
- The standard references general guidance on uncertainty and sampling such as ISO/IEC Guide 98-3 (GUM) and ISO 5667-20 for sampling of waters.
Keywords: EN ISO 22908:2020, radium 226, radium 228, liquid scintillation counting, water quality, drinking water testing, radionuclide analysis, detection limit, radiological monitoring.