Overview
ISO 9697:2018 - "Water quality - Gross beta activity - Test method using thick source" specifies a laboratory test method for measuring gross beta activity in non-saline waters using a thick-source preparation. The fourth edition (2018) is intended for the analysis of raw and drinking waters and covers measurement of non‑volatile radionuclides whose maximum beta energies are approximately 0.3 MeV or higher. The standard clarifies which low‑energy beta emitters and volatile radionuclides may not be quantified by this method and places responsibility on the laboratory to confirm method suitability for specific samples.
Key topics and requirements
- Scope and applicability: Non-saline waters (raw and drinking); performance depends on total soluble salts and detector characteristics.
- Radionuclide coverage: Intended for non‑volatile beta emitters with maximum beta energy ≳ 0.3 MeV. Low‑energy emitters (e.g., 3H, 14C, 210Pb) and gaseous/volatile radionuclides (e.g., radon, radioiodine) may be excluded from gross beta quantification.
- Measurement principle: Thick‑source preparation followed by beta counting; the method includes source preparation steps and detector measurement.
- Procedure stages (standardized in the document): Sampling and pre‑treatment; concentration; sulfation and ignition; source preparation; measurement and background determination; calibration; optimization.
- Performance metrics and metrology: Guidance on counting efficiency, background count rate, decision threshold, detection limit, uncertainty estimation and expression of results.
- Quality and safety: Requirements for sampling integrity, contamination checks, potential disequilibrium of radionuclides, and qualified personnel following laboratory safety practices.
Practical applications and users
ISO 9697:2018 is used by:
- Environmental and drinking‑water testing laboratories for routine monitoring and compliance testing
- Public health and regulatory authorities assessing radioactivity in water supplies
- Nuclear facilities and effluent monitoring programs for discharge control
- Emergency response teams evaluating radiological impacts on water resources
- Laboratories seeking accreditation for radionuclide analysis (method aligns with ISO/IEC 17025 expectations)
The method supports verifying that gross beta activity concentrations meet guidance levels (for example, WHO guidance level of 1 Bq/l for gross beta) and helps determine whether further radionuclide‑specific analysis is needed.
Related standards
- ISO 5667 series (water sampling and handling)
- ISO 11929 (characteristic limits for ionizing radiation measurements)
- ISO/IEC 17025 (laboratory competence)
- ISO/IEC Guide 98‑3 (GUM - uncertainty of measurement)
- ISO 80000‑10 (quantities and units - atomic and nuclear physics)
Keywords: ISO 9697:2018, gross beta activity, thick source, water quality testing, non-saline water, drinking water monitoring, radionuclide measurement, detection limit, decision threshold.
