Overview
EN ISO 13164-4:2023 - Water quality - Radon-222 - Part 4 describes a validated laboratory method for measuring radon-222 (222Rn / Rn-222) activity concentration in non-saline waters using two-phase liquid scintillation counting. The standard is the CEN-adopted version of ISO 13164-4:2023 and supersedes the 2020 edition. It is intended for routine environmental and drinking-water monitoring where typical measurable activity concentrations are above 0.5 Bq·L−1 (using a 10 ml test sample and ~1 h counting time).
Key topics and technical requirements
- Scope and limitations
- Applicable to non-saline waters; laboratories must verify method validity for untested matrices.
- Typical detection limit: ~0.5 Bq·L−1 for specified sample volume and counting time.
- Principle
- Extraction of 222Rn into a scintillation phase followed by two-phase liquid scintillation counting.
- Sampling and sample handling
- Procedures for sampling with and without on-site source preparation to preserve radon integrity.
- Reagents and apparatus
- Lists of required reagents, consumables and counting equipment suitable for two-phase liquid scintillation.
- Measurement procedure
- Calibration source preparation, optimization of counting conditions, determination of detection efficiency, blank preparation and sample measurement.
- Quality assurance / quality control
- Instrument verification, contamination control, interference checks, method verification and analyst competency requirements.
- Expression of results
- Calculation of count rates, activity concentration per unit mass, combined uncertainty, decision threshold and detection limit reporting.
- Annex A (informative)
- Set-up parameters and validation data (counting conditions and examples to meet detection limits for drinking water monitoring).
Practical applications
- Routine monitoring of drinking water and groundwater for radon-222 compliance and risk assessment.
- Environmental surveillance of surface waters and groundwater near uranium-bearing geology or industrial sites.
- Support for regulatory laboratories, accredited testing bodies and research labs performing radioactivity measurements.
- Baseline studies, exposure assessments and investigations following releases from industrial or natural sources.
Who should use this standard
- Water testing laboratories and environmental monitoring services
- Public health and drinking-water regulators
- Accredited radiation measurement laboratories
- Consultants and researchers in hydrogeology, environmental radiochemistry and public health
Related standards
- Other parts of the ISO 13164 series covering radon measurement in water
- ISO/TC 147 (Water quality) and CEN/TC 230 (Water analysis) publications for broader water-quality testing guidance
Keywords: EN ISO 13164-4:2023, radon-222, Rn-222, water quality, two-phase liquid scintillation counting, drinking water monitoring, detection limit, non-saline waters.
