Overview
ISO 13165-1:2022 - Water quality - Radium-226 - Part 1: Test method using liquid scintillation counting specifies a validated laboratory method to determine radium‑226 (226Ra) activity concentration in non‑saline water. The method extracts 226Ra’s daughter, radon‑222 (222Rn), and quantifies it by liquid scintillation counting (LSC). With currently available scintillation counters the method gives a typical detection limit of approximately 50 mBq·L⁻¹. This standard applies to environmental and drinking water monitoring and is not applicable to other radium isotopes.
Key topics and technical requirements
- Principle: Extraction of 222Rn from a water sample and measurement by LSC.
- Scope limitations: Only for non‑saline waters; not suitable for measuring other radium isotopes.
- Detection performance: Practical detection limit ≈ 50 mBq·L⁻¹ (using conventional counters).
- Sampling & sample handling: Guidance to follow ISO 5667 series for sampling, preservation and handling.
- Instrument set‑up & calibration: Preparation of calibration sources, optimization of counting conditions and determination of detection efficiency.
- Sample preparation options: Direct counting, thermal preconcentration and other preparation methods described.
- Quality assurance: Blank measurements, quality control procedures, uncertainty estimation (per ISO/IEC Guide 98‑3), decision threshold and detection limit calculations.
- Reporting: Expression of results, massic activity calculations, and recommended content for test reports.
- Safety & competence: Laboratory safety practices and requirement that tests are performed by suitably trained staff.
Practical applications
- Routine monitoring of drinking water, groundwater and surface water for 226Ra contamination.
- Compliance testing against public‑health guidance (e.g., WHO guidance levels) and national regulatory limits.
- Monitoring liquid effluents and wastewaters from industrial or mining operations (with method adaptations as required).
- Emergency and post‑incident surveillance where radionuclide concentrations need to be assessed rapidly.
- Support for laboratories seeking ISO/IEC 17025 accreditation for radionuclide measurements.
Who should use this standard
- Environmental and public‑health laboratories
- Water utilities and drinking water authorities
- Nuclear facility and industrial discharge monitoring teams
- Accreditation bodies and laboratory quality managers
- Regulators setting or verifying compliance with radionuclide limits
Related standards
- ISO 5667 series (water sampling)
- ISO 3696 (water for analytical use)
- ISO/IEC 17025 (laboratory competence)
- ISO/IEC Guide 98‑3 (uncertainty of measurement)
- ISO 80000‑10 (quantities and units - atomic and nuclear physics)
Keywords: ISO 13165-1:2022, radium‑226, water quality, liquid scintillation counting, radon‑222 extraction, detection limit, radionuclide measurement, drinking water monitoring.