EN ISO 13165-1:2024

Water quality - Radium-226 - Part 1: Test method using liquid scintillation counting (ISO 13165-1:2022)

This document specifies the determination of radium-226 (226Ra) activity concentration in non-saline
water samples by extraction of its daughter radon-222 (222Rn) and its measurement using liquid
scintillation analysis.
The test method described in this document, using currently available scintillation counters, has a
detection limit of approximately 50 mBq·l−1. This method is not applicable to the measurement of other
radium isotopes.

Wasserbeschaffenheit - Radium-226 - Teil-1: Verfahren mit dem Flüssigszintillationszhler (ISO 13165-1:2022)

Dieses Dokument legt ein Verfahren für die Bestimmung der Aktivitätskonzentration von Radium 226 (226Ra) in nicht salzhaltigem Wasser durch Extraktion des Tochterisotops Radon 222 (222Rn) und dessen Messung mithilfe eines Flüssigszintillationszählers fest.
Das in diesem Dokument beschriebene Verfahren, bei der derzeit verfügbare Szintillationszähler verwendet werden, hat eine Nachweisgrenze von etwa 50 mBq· l−1 Dieses Verfahrens ist nicht für die Messung anderer Radiumisotope anwendbar.

Qualité de l'eau - Radium-226 - Partie 1: Méthode d'essai par comptage des scintillations en milieu liquide (ISO 13165-1:2022)

Kakovost vode - Radij Ra-226 - 1. del: Preskusna metoda s štetjem s tekočinskim scintilatorjem (ISO 13165-1:2022)

Ta dokument določa metodo za določanje koncentracije aktivnosti radija 226 (226Ra) v vzorcih neslane vode s postopkom ekstrakcije njegovega potomca radona 222 (222Rn) in z merjenjem z analizo s tekočinskim scintilatorjem.
Preskusna metoda, opisana v tem dokumentu, s trenutno razpoložljivimi števci s tekočinskim scintilatorjem ima mejo zaznavnosti približno 50 mBq l−1. Ta metoda se ne uporablja za merjenje drugih izotopov radija.

General Information

• Status: Published
• Publication Date: 20-Feb-2024
• ICS: 13.060.60 - Examination of physical properties of water
• ICS: 17.240 - Radiation measurements
• Technical Committee: CEN/TC 230 - Water analysis
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 21-Feb-2024
• Due Date: 20-Dec-2025
• Completion Date: 21-Feb-2024
• Ref Project: SIST EN ISO 13165-1:2024 - Water quality - Radium-226 - Part 1: Test method using liquid scintillation counting (ISO 13165-1:2022)

Relations

• Replaces: EN ISO 13165-1:2020 - Water quality - Radium-226 - Part 1: Test method using liquid scintillation counting (ISO 13165-1:2013)
• Effective Date: 16-Aug-2023

Overview

EN ISO 13165-1:2024 (identical to ISO 13165-1:2022) specifies a standardized test method using liquid scintillation counting (LSC) for determination of Radium-226 (Ra-226) activity concentration in water. Published by CEN and prepared by ISO/TC 147 “Water quality”, this European adoption supersedes EN ISO 13165-1:2020 and is intended for routine and regulatory water quality and radioactivity measurements.

Key topics and technical requirements

The standard covers the principles and practical requirements for LSC-based measurement of Ra‑226, including:

• Principle of measurement using liquid scintillation counting for Ra‑226.
• Reagents and equipment needed for sample preparation and LSC analysis.
• Sampling guidance for surface, groundwater, seawater and drinking water.
• Instrument set-up and calibration, including preparation of calibration sources and optimization of counting conditions.
• Detection efficiency assessment and blank sample preparation/measurement.
• Procedures: direct counting, thermal preconcentration, sample preparation and measurement steps.
• Quality control and validation: calibration, blanks, control samples, and documented validation data.
• Expression of results: calculation of massic activity, estimation of standard uncertainty, decision threshold and detection limit, and reporting of coverage intervals.
• Interference control to identify and mitigate radionuclide or chemical interferences.
• Test report content and reporting requirements. These topics align with ISO/IEC Guide 98-3 principles for uncertainty and reference international guidance (e.g., WHO).

Applications

EN ISO 13165-1:2024 is applicable where accurate measurement of Ra‑226 in water is required:

• Drinking water monitoring to assess compliance with guidance levels (WHO guidance level for Ra in drinking water is cited in the standard).
• Environmental surveillance of surface waters, groundwaters and seawater.
• Effluent control from industrial or mining activities involving naturally occurring radioactive materials (NORM).
• Emergency response monitoring after radiological incidents.
• Laboratory validation and method harmonization for routine radioactivity testing using liquid scintillation counting.

Who should use this standard

• Analytical laboratories performing radioactivity measurements and accreditation bodies.
• Water utilities and public health authorities responsible for drinking water safety.
• Environmental monitoring agencies and consultants.
• Nuclear and industrial facilities managing radioactive effluents.
• Researchers and developers validating LSC methods for radionuclide analysis.

Related standards

• ISO 13165 series (other parts for complementary methods or radionuclides)
• ISO/IEC Guide 98-3 (evaluation of measurement uncertainty)
• Relevant WHO and national drinking water radioactivity guidance documents

Using EN ISO 13165-1:2024 helps ensure consistent, validated, and reportable results for Radium‑226 in water using LSC, supporting regulatory compliance and public health protection.

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2024
Nadomešča:
SIST EN ISO 13165-1:2020
Kakovost vode - Radij Ra-226 - 1. del: Preskusna metoda s štetjem s tekočinskim
scintilatorjem (ISO 13165-1:2022)
Water quality - Radium-226 - Part 1: Test method using liquid scintillation counting (ISO
13165-1:2022)
Wasserbeschaffenheit - Radium-226 - Teil-1: Verfahren mit dem
Flüssigszintillationszhler (ISO 13165-1:2022)
Qualité de l'eau - Radium-226 - Partie 1: Méthode d'essai par comptage des scintillations
en milieu liquide (ISO 13165-1:2022)
Ta slovenski standard je istoveten z: EN ISO 13165-1:2024
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
17.240 Merjenje sevanja Radiation measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 13165-1
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2024
EUROPÄISCHE NORM
ICS 13.060.60; 17.240 Supersedes EN ISO 13165-1:2020
English Version
Water quality - Radium-226 - Part 1: Test method using
liquid scintillation counting (ISO 13165-1:2022)
Qualité de l'eau - Radium-226 - Partie 1: Méthode Wasserbeschaffenheit - Radium-226 - Teil-1: Verfahren
d'essai par comptage des scintillations en milieu mit dem Flüssigszintillationszhler (ISO 13165-1:2022)
liquide (ISO 13165-1:2022)
This European Standard was approved by CEN on 12 February 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13165-1:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 13165-1:2022 has been prepared by Technical Committee ISO/TC 147 "Water quality”
of the International Organization for Standardization (ISO) and has been taken over as EN ISO 13165-
1:2024 by Technical Committee CEN/TC 230 “Water analysis” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2024, and conflicting national standards shall
be withdrawn at the latest by August 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 13165-1:2020.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 13165-1:2022 has been approved by CEN as EN ISO 13165-1:2024 without any
modification.
INTERNATIONAL ISO
STANDARD 13165-1
Second edition
2022-11
Water quality — Radium-226 —
Part 1:
Test method using liquid scintillation
counting
Qualité de l'eau — Radium-226 —
Partie 1: Méthode d'essai par comptage des scintillations en milieu
liquide
Reference number
ISO 13165-1:2022(E)
ISO 13165-1:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 13165-1:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units. 2
5 Principle . 2
6 Reagents and equipment . 3
6.1 Reagents . 3
6.2 Equipment . 3
7 Sampling . 4
8 Instrument set-up and calibration. 4
8.1 Preparation of calibration sources . 4
8.2 Optimization of counting conditions . 4
8.3 Detection efficiency . 4
8.4 Blank sample preparation and measurement. 5
9 Procedure .5
9.1 Direct counting . 5
9.2 Thermal preconcentration . 5
9.3 Sample preparation . 6
9.4 Sample measurement . 6
10 Quality control . 6
11 Expression of results . 7
11.1 Calculation of massic activity . . 7
11.2 Standard uncertainty . 7
11.3 Decision threshold . 8
11.4 Detection limit . 8
11.5 Limits of the coverage intervals . 8
11.5.1 Limits of the probabilistically symmetric coverage interval . 8
11.5.2 Shortest coverage interval . 9
11.6 Calculations using the activity concentration . 9
12 Interference control .9
13 Test report . 9
[13]
Annex A (informative) Set-up parameters and validation data .11
Bibliography .15
iii
ISO 13165-1:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 3,
Radioactivity measurements.
This second edition cancels and replaces the first edition (ISO 13165-1:2013), which has been technically
revised.
The main changes are as follows:
— the introduction has been updated;
— the list of symbols has been updated;
— the expression of results has been updated;
— the test report has been updated;
— the validation data has been updated;
A list of all parts in the ISO 13165 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
ISO 13165-1:2022(E)
Introduction
Radioactivity from several naturally-occurring and anthropogenic sources is present throughout the
environment. Thus, water bodies (such as surface waters, ground waters, sea waters) can contain
radionuclides of natural, human-made, or both origins.
40 3 14
— Natural radionuclides, including K, H, C, and those originating from the thorium and uranium
226 228 234 238 210 210
decay series, in particular Ra, Ra, U, U, Po and Pb can be found in water for
natural reasons (e.g. desorption from the soil and washoff by rain water) or can be released from
technological processes involving naturally occurring radioactive materials (e.g. the mining and
processing of mineral sands or phosphate fertilizers production and use).
— Anthropogenic radionuclides such as transuranium elements (americium, plutonium, neptunium,
3 14 90
curium), H, C, Sr and gamma emitting radionuclides can also be found in natural waters.
Small quantities of these radionuclides are discharged from nuclear fuel cycle facilities into the
environment as a result of authorized routine releases. Some of these radionuclides used for
medical and industrial applications are also released into the environment after use. Anthropogenic
radionuclides are also found in waters as a result of past fallout contaminations resulting from
the explosion in the atmosphere of nuclear devices and accidents such as those that occurred in
Chernobyl and Fukushima.
Radionuclide activity concentration in water bodies can vary according to local geological
characteristics and climatic conditions and can be locally and temporally enhanced by releases from
[1]
nuclear installations during planned, existing and emergency exposure situations. Drinking water
can thus contain radionuclides at activity concentrations which can present a risk to human health.
The radionuclides present in liquid effluents are usually controlled before being discharged into the
[2]
environment and water bodies. Drinking waters are monitored for their radioactivity content as
[3]
recommended by the World Health Organization (WHO) so that proper actions can be taken to ensure
that there is no adverse health effect to the public. Following these international recommendations,
national regulations usually specify radionuclide authorized concentration limits for liquid effluent
discharged to the environment and radionuclide guidance levels for waterbodies and drinking waters
for planned, existing and emergency exposure situations. Compliance with these limits can be assessed
using measurement results with their associated uncertainties as specified by ISO/IEC Guide 98-3 and
[4]
ISO 5667-20 .
Depending on the exposure situation, there are different limits and guidance levels that would result in
an action to reduce health risk. As an example, during planned or existing situation, the WHO guidelines
−1 226
for guidance level in drinking water is 1 Bq·l for Ra activity concentration.
−1
NOTE 1 The guidance level (GL) is the activity concentration with an intake of 2 l·d of drinking water for
−1
one year that results in an effective dose of 0,1 mSv·a for members of the public. This is an effective dose
that represents a very low level of risk and which is not expected to give rise to any detectable adverse health
[7]
effects .
[5]
In the event of a nuclear emergency, the WHO Codex Guideline Levels mentioned that the activity
concentration can be greater.
NOTE 2 The Codex GLs apply to radionuclides contained in foods destined for human consumption and traded
internationally, which have been contaminated following a nuclear or radiological emergency. These GLs apply to
food after reconstitution or as prepared for consumption, i.e. not to dried or concentrated foods and are based on
[5]
an intervention exemption level of 1 mSv in a year for members of the public (infant and adult) .
Thus, the test method can be adapted so that the characteristic limits, decision threshold, detection
limit and uncertainties ensure that the radionuclide activity concentrations test results can be verified
to be below the guidance levels required by a national authority for either planned/existing situations
[6][7]
or for an emergency situation .
Usually, the test methods can be adjusted to measure the activity concentration of the radionuclide(s)
in either wastewaters before storage or in liquid effluents before being discharged to the environment.
v
ISO 13165-1:2022(E)
The test results will enable the plant/installation operator to verify that, before their discharge,
wastewaters/liquid effluent radioactive activity concentrations do not exceed authorized limits.
The test method(s) described in this document may be used during planned, existing and emergency
exposure situations as well as for wastewaters and liquid effluents with specific modifications that can
increase the overall uncertainty, detection limit and threshold.
The test method(s) may be used for water samples after proper sampling, sample handling and test
sample preparation (see the relevant part of the ISO 5667 series).
This document has been developed to answer the need of test laboratories carrying out these
measurements, that are sometimes required by national authorities, as they can be required to obtain a
specific accreditation for radionuclide measurement in drinking water samples.
This document is one of a set of International Standards on test methods dealing with the measurement
of the activity concentration of radionuclides in water samples.
vi
INTERNATIONAL STANDARD ISO 13165-1:2022(E)
Water quality — Radium-226 —
Part 1:
Test method using liquid scintillation counting
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
determine the applicability of any other restrictions.
IMPORTANT — It is absolutely essential that tests conducted according to this document be
carried out by suitably trained staff.
1 Scope
This document specifies the determination of radium-226 ( Ra) activity concentration in non-saline
water samples by extraction of its daughter radon-222 ( Rn) and its measurement using liquid
scintillation analysis.
The test method described in this document, using currently available scintillation counters, has a
−1
detection limit of approximately 50 mBq·l . This method is not applicable to the measurement of other
radium isotopes.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 80000-10, ISO/IEC Guide 98-3
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
ISO 13165-1:2022(E)
4 Symbols and units
For the purposes of this document, the symbols given in Table 1, ISO 80000-10 and ISO/IEC Guide 98-3
apply.
Table 1 — Symbols
Symbol Description Unit
−1
a Massic activity of the sample at the measuring time Bq·g
226 −1
a Massic activity of the Ra standard solution at the measuring time Bq·g
S
−1
a* Decision threshold for the massic alpha-activity Bq·g
# −1
a Detection limit for the massic alpha-activity Bq·g
⊲ ⊳ −1
a , a Lower and upper limits of the probabilistically symmetric coverage interval Bq·g
< > −1
a , a Lower and upper limits of the shortest coverage interval Bq·g
−1
c Concentration mol· l
−1
c Activity concentration Bq·l
A
k Coverage factor —
m Mass of the test sample g
m Mass of initial sample subject to heating or possibly concentration g
m Mass of heated or concentrated sample g
m Mass of heated or concentrated sample transferred in the vial g
m Mass of Ra standard solution used for the preparation of the calibration sample g
S
p Probability (for instance p = 1 − α , 1− β or 1- γ /2) —
q Probability —
−1
r Blank sample count rate in the alpha-window s
−1
r Sample gross count rate in the alpha-window s
g
−1
r Count rate of the calibration sample in the alpha-window s
S
t Blank sample counting time s
t Sample counting time s
g
t Calibration sample counting time s
S
−1
u(a) Standard uncertainty associated with the measurement result Bq·l
ũ(ã) Standard uncertainty of a as a function of its true value —
u Relative standard uncertainty —
rel
u Combined uncertainty —
c
−1
U Expanded uncertainty, calculated using U = ku(a), with k = 1, 2, … Bq·l
w Factor equal to 1/ε m —
ε Alpha-efficiency, relative —
−1
ρ Density g·l
Φ Distribution function of the standardized normal distribution —
ω Auxiliary quantity —
γ Coverage interval probability —
5 Principle
226 222
The massic activity of Ra is indirectly determined by isolating its progeny Rn by liquid scintillation
222 226 222
counting (LSC). Rn is in secular equilibrium with its pare
...