Overview
EN ISO 13164-2:2020 (ISO 13164-2:2013) specifies a laboratory test method for determining radon-222 (Rn-222) activity concentration in water by measuring its short-lived decay products using direct gamma‑ray spectrometry of the water sample. Adopted by CEN as a European standard, this method is applicable to drinking water and other water matrices when validated by the laboratory. Typical measurable activity concentrations for a 1 L test sample range from a few becquerels per litre (Bq·L⁻¹) up to several hundred thousand Bq·L⁻¹.
Key topics and requirements
- Principle: Indirect determination of Rn-222 via gamma spectrometric measurement of short-lived progeny in the water sample.
- Sampling: general and specific sampling requirements, recommended sample volumes, and container characteristics to avoid radon loss.
- Transport & storage: conditions to preserve sample integrity and minimize radon decay or escape before measurement.
- Detection & measurement: use of gamma‑ray spectrometers and recommended counting conditions; an annex provides guidance to meet sensitivity required for drinking water monitoring.
- Quality assurance / quality control (QA/QC): instrument verification, method validation, analyst competency, and influence quantities that may affect results.
- Expression of results: calculation of activity concentration, standard uncertainty, decision threshold, detection limit and confidence limits.
- Reporting: required information for test reports to support traceability and regulatory compliance.
- Laboratory responsibility: laboratories must verify method validity for untested water matrices and ensure qualified personnel perform tests.
Practical applications and users
EN ISO 13164-2:2020 is intended for:
- Water testing laboratories performing radionuclide analyses for regulatory compliance and public-health monitoring.
- Public water suppliers and municipal authorities assessing drinking-water radon levels.
- Environmental and groundwater monitoring programs, especially where radon is geologically elevated.
- Mining, geothermal and industrial facilities where naturally occurring radioactive materials may influence water quality.
- Accreditation bodies and QA managers needing standardized procedures for lab accreditation and inter-laboratory comparability.
The standard supports risk assessment and control measures - for example, WHO guidance suggests considering mitigation when radon in drinking water exceeds about 100 Bq·L⁻¹.
Related standards
- EN ISO 13164-1: General principles for Rn-222 in water
- EN ISO 13164-3: Test method using emanometry
- EN ISO 13164-4 (under preparation): Two-phase liquid scintillation counting
Keywords: EN ISO 13164-2:2020, radon-222, gamma-ray spectrometry, water quality, radon measurement, radon activity concentration, drinking water monitoring, gamma spectrometry test method.
