Water quality - Polonium 210 - Test method using alpha spectrometry (ISO 13161:2020)

This document specifies a method for the measurement of 210Po in all types of waters by alpha
spectrometry.
The method is applicable to test samples of supply/drinking water, rainwater, surface and ground
water, marine water, as well as cooling water, industrial water, domestic, and industrial wastewater
after proper sampling and handling, and test sample preparation. Filtration of the test sample may be
required.
The detection limit depends on the sample volume, the instrument used, the counting time, the
background count rate, the detection efficiency and the chemical yield. The method described in
this document, using currently available alpha spectrometry apparatus, has a detection limit of
approximately 5 mBq l−1, which is lower than the WHO criteria for safe consumption of drinking water
(100 mBq l−1). This value can be achieved with a counting time of 24 h for a sample volume of 500 ml.
The method described in this document is also applicable in an emergency situation.
The analysis of 210Po adsorbed to suspended matter in the sample is not covered by this method.
If suspended material has to be removed or analysed, filtration using a 0,45 μm filter is recommended.
The analysis of the insoluble fraction requires a mineralization step that is not covered by this document
[13]. In this case, the measurement is made on the different phases obtained. The final activity is the
sum of all the measured activity concentrations.
It is the user’s responsibility to ensure the validity of this test method for the water samples tested.

Wasserbeschaffenheit - Polonium-210 - Verfahren mittels Alphaspektrometrie (ISO 13161:2020)

Dieses Dokument legt ein Verfahren zur Messung von 210Po mittels Alphaspektrometrie in allen Wasserarten fest.
Das Verfahren ist auf Messproben von Versorgungs /Trinkwasser, Regenwasser, Oberflächen  und Grundwasser, Meerwasser sowie Kühlwasser, Prozesswasser, häusliches und gewerbliches Abwasser nach geeigneter Probenahme, Probenbehandlung und Vorbereitung der Messprobe anwendbar. Eine Filtration der Messprobe kann erforderlich sein.
Die Nachweisgrenze hängt von folgenden Parametern ab: Probenvolumen, verwendetes Messinstrument, Zähldauer, Zählrate des Nulleffekts, Zählausbeute und chemische Ausbeute. Das in diesem Dokument beschriebene Verfahren hat, bei Verwendung derzeit verfügbarer Alphaspektrometer, eine Nachweisgrenze von etwa 5 mBq . l−1; diese liegt damit unter den WHO Kriterien für den sicheren Verzehr von Trinkwasser (100 mBq  l−1). Dieser Wert kann mit einer Messdauer von 24 h bei einem Probenvolumen von 500 ml erreicht werden.
Das in diesem Dokument beschriebene Verfahren ist auch in Notfallsituationen anwendbar.
Die Analyse von 210Po, das an Schwebstoffen der Probe adsorbiert ist, wird durch dieses Verfahren nicht abgedeckt.
Für den Fall, dass Schwebstoffe entfernt oder analysiert werden müssen, wird eine Filtration einem Filter der Porengröße 0,45 µm empfohlen. Die Analyse unlöslicher Bestandteile erfordert einen Mineralisierungsschritt, der in diesem Dokument nicht behandelt wird [13]. In diesem Fall wird die Bestimmung mit den unterschiedlichen erhaltenen Phasen durchgeführt. Die endgültige Aktivität ist dann die Summe aller gemessenen Aktivitätskonzentrationen.
Es liegt in der Verantwortung des Anwenders, die Validität dieses Prüfverfahrens für die zu prüfenden Wasserproben sicherzustellen.

Qualité de l'eau - Polonium 210 - Méthode d'essai par spectrométrie alpha (ISO 13161:2020)

Le présent document décrit une méthode pour le mesurage par spectrométrie alpha du 210Po dans tous les types d'eaux.
Cette méthode s'applique aux échantillons pour essai d'eau courante et d'eau potable, d'eau de pluie, d'eau de surface et d'eau souterraine, d'eau de mer, ainsi que d'eau de refroidissement, d'eau industrielle, ou encore d'eaux usées domestiques et industrielles, après échantillonnage et manipulation puis préparation des échantillons pour essai dans des conditions appropriées. Une filtration de l'échantillon peut être nécessaire.
La limite de détection dépend du volume de l'échantillon, de l'instrument utilisé, du temps de comptage, du taux de comptage du bruit de fond, du rendement de détection et du rendement chimique. La méthode décrite dans le présent document, qui recourt à l'utilisation d'un appareil de spectrométrie alpha usuel, présente une limite de détection d'environ 5 mBq l−1, ce qui est inférieur aux critères de l'OMS pour une consommation sûre d'eau potable (100 mBq l−1). Cette valeur peut être obtenue avec un temps de comptage de 24 h pour un volume d'échantillon de 500 ml.
La méthode décrite dans le présent document est également applicable dans les situations d'urgence.
L'analyse du 210Po adsorbé sur les matières en suspension dans l'échantillon n'est pas couverte par la présente méthode.
S'il est nécessaire de séparer les matières en suspension ou de les analyser, une filtration à l'aide d'un filtre à porosité de 0,45 µm est recommandée. L'analyse de la fraction insoluble nécessite une étape de minéralisation qui n'est pas couverte par le présent document[13]. Dans ce cas, le mesurage est effectué sur les différentes phases obtenues. L'activité finale est la somme de toutes les activités volumiques mesurées.
Il incombe à l'utilisateur de s'assurer de la validité de la présente méthode d'essai pour les échantillons d'eau soumis à essai.

Kakovost vode - Polonij Po-210 - Preskusna metoda z alfa spektrometrijo (ISO 13161:2020)

General Information

Status
Published
Public Enquiry End Date
03-Apr-2019
Publication Date
07-Dec-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
15-Sep-2020
Due Date
20-Nov-2020
Completion Date
08-Dec-2020

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SLOVENSKI STANDARD
SIST EN ISO 13161:2021
01-januar-2021
Nadomešča:
SIST EN ISO 13161:2016
SIST ISO 13161:2013
Kakovost vode - Polonij Po-210 - Preskusna metoda z alfa spektrometrijo (ISO
13161:2020)

Water quality - Polonium 210 - Test method using alpha spectrometry (ISO 13161:2020)

Wasserbeschaffenheit - Polonium-210 - Verfahren mittels Alphaspektrometrie (ISO
13161:2020)
Qualité de l'eau - Polonium 210 - Méthode d'essai par spectrométrie alpha (ISO
13161:2020)
Ta slovenski standard je istoveten z: EN ISO 13161:2020
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 13161:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 13161:2021
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SIST EN ISO 13161:2021
EN ISO 13161
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2020
EUROPÄISCHE NORM
ICS 13.060.60; 17.240 Supersedes EN ISO 13161:2015
English Version
Water quality - Polonium 210 - Test method using alpha
spectrometry (ISO 13161:2020)

Qualité de l'eau - Polonium 210 - Méthode d'essai par Wasserbeschaffenheit - Polonium-210 - Verfahren

spectrométrie alpha (ISO 13161:2020) mittels Alphaspektrometrie (ISO 13161:2020)
This European Standard was approved by CEN on 16 June 2020.

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, Turkey 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

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13161:2020 E

worldwide for CEN national Members.
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SIST EN ISO 13161:2021
EN ISO 13161:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 13161:2021
EN ISO 13161:2020 (E)
European foreword

This document (EN ISO 13161:2020) has been prepared by Technical Committee ISO/TC 147 "Water

quality" in collaboration with 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 March 2021, and conflicting national standards shall

be withdrawn at the latest by March 2021.

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 13161:2015.

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, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 13161:2020 has been approved by CEN as EN ISO 13161:2020 without any modification.

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SIST EN ISO 13161:2021
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SIST EN ISO 13161:2021
INTERNATIONAL ISO
STANDARD 13161
Second edition
2020-07
Water quality — Polonium 210 — Test
method using alpha spectrometry
Qualité de l'eau — Polonium 210 — Méthode d'essai par
spectrométrie alpha
Reference number
ISO 13161:2020(E)
ISO 2020
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SIST EN ISO 13161:2021
ISO 13161:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 13161:2021
ISO 13161:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions, symbols and abbreviated terms ....................................................................................................... 2

3.1 Terms and definitions ....................................................................................................................................................................... 2

3.2 Symbols and abbreviated terms............................................................................................................................................... 2

4 Principle ........................................................................................................................................................................................................................ 3

4.1 General ........................................................................................................................................................................................................... 3

4.2 Treatment .................................................................................................................................................................................................... 4

4.2.1 Treatment for a deposition on a disc .............................................................................................................. 4

4.2.2 Treatment for a precipitation on a filter...................................................................................................... 4

4.3 Principle of alpha spectrometry .............................................................................................................................................. 5

5 Reagents and equipment ............................................................................................................................................................................. 5

5.1 Reagents........................................................................................................................................................................................................ 5

5.2 Equipment ................................................................................................................................................................................................... 6

5.3 Alpha spectrometry measuring equipment ................................................................................................................... 6

6 Sampling and samples .................................................................................................................................................................................... 6

7 Chemical treatment and deposit process ................................................................................................................................... 7

7.1 General ........................................................................................................................................................................................................... 7

7.2 Chemical treatment ............................................................................................................................................................................. 7

7.2.1 Autodeposition of polonium on a disc........................................................................................................... 7

7.2.2 Microprecipitation on a filter ................................................................................................................................ 8

8 Measurement by alpha spectrometry ............................................................................................................................................ 9

8.1 General ........................................................................................................................................................................................................... 9

8.2 Quality control ......................................................................................................................................................................................... 9

8.3 Measurement ............................................................................................................................................................................................ 9

9 Expression of results ........................................................................................................................................................................................ 9

9.1 General ........................................................................................................................................................................................................... 9

9.2 Total yield .................................................................................................................................................................................................10

210

9.3 Activity concentration of Po in the sample ...........................................................................................................10

9.4 Combined uncertainties ...............................................................................................................................................................11

9.5 Decision threshold ............................................................................................................................................................................11

9.6 Detection limit ......................................................................................................................................................................................11

9.7 Limits of the coverage interval ...............................................................................................................................................12

9.7.1 Limits of the probabilistically symmetric coverage interval...................................................12

9.7.2 The shortest coverage interval .........................................................................................................................12

10 Test report ................................................................................................................................................................................................................13

Annex A (informative) Cell deposit examples ..........................................................................................................................................14

Annex B (informative) Spectrum examples ................................................................................................................................................16

Bibliography .............................................................................................................................................................................................................................18

© ISO 2020 – All rights reserved iii
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SIST EN ISO 13161:2021
ISO 13161:2020(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,

Radiological methods.

This second edition cancels and replaces the first edition (ISO 13161:2011), which has been technically

revised. The main changes compared to the previous edition are as follows:
— addition of a common introduction;

— addition of a new option for the chemical preparation using precipitation on a filter.

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 2020 – All rights reserved
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SIST EN ISO 13161:2021
ISO 13161:2020(E)
Introduction

Radioactivity from several naturally-occurring and anthropogenic sources is present throughout

the environment. Thus, water bodies (e.g. 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

decay series, in particular Ra, Ra, U, U, and Pb, can be found in water for natural reasons

(e.g. desorption from the soil and wash off 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 fertilizer production and use);

— Human-made 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 the 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 installation during planned, existing and emergency exposure situations . Drinking-water

may thus contain radionuclides at activity concentrations which could present a risk to human health.

The radionuclides present in liquid effluents are usually controlled before being discharged into

[2]

the environment and water bodies. Drinking water is monitored for its 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 effects to the public. Following these international recommendations,

national regulation usually specify radionuclide authorized concentration limits for liquid effluent

discharged to the environment and radionuclide guidance levels for water bodies and drinking waters

for planned, existing and emergency exposure situations. Conformance 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 a planned or existing situation, the WHO

guidance level in drinking water is 0,1 Bq l for polonium-210 activity concentration.

NOTE 1 The guidance level is the activity concentration with an intake of 2 l/d of drinking water for 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

[3]

very low level of risk and which is not expected to give rise to any detectable adverse health effects .

[5]

In the event of a nuclear emergency, the WHO Codex Guideline Levels mentioned that the activity

concentration might be greater.

NOTE 2 The Codex guidelines levels (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 an intervention exemption level of 1 mSv in a year for members of the

[5]
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.

© ISO 2020 – All rights reserved v
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SIST EN ISO 13161:2021
ISO 13161:2020(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

could 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 may have to obtain a

specific accreditation for radionuclide measurement in drinking water samples.

This document is one of a family of International Standards on test methods dealing with the

measurement of the activity concentration of radionuclides in water samples.
vi © ISO 2020 – All rights reserved
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SIST EN ISO 13161:2021
INTERNATIONAL STANDARD ISO 13161:2020(E)
Water quality — Polonium 210 — Test method using alpha
spectrometry

WARNING — Persons using this document should be familiar with normal laboratory practices.

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
210

This document specifies a method for the measurement of Po in all types of waters by alpha

spectrometry.

The method is applicable to test samples of supply/drinking water, rainwater, surface and ground

water, marine water, as well as cooling water, industrial water, domestic, and industrial wastewater

after proper sampling and handling, and test sample preparation. Filtration of the test sample may be

required.

The detection limit depends on the sample volume, the instrument used, the counting time, the

background count rate, the detection efficiency and the chemical yield. The method described in

this document, using currently available alpha spectrometry apparatus, has a detection limit of

approximately 5 mBq l , which is lower than the WHO criteria for safe consumption of drinking water

(100 mBq l ). This value can be achieved with a counting time of 24 h for a sample volume of 500 ml.

The method described in this document is also applicable in an emergency situation.

210

The analysis of Po adsorbed to suspended matter in the sample is not covered by this method.

If suspended material has to be removed or analysed, filtration using a 0,45 μm filter is recommended.

The analysis of the insoluble fraction requires a mineralization step that is not covered by this document

[13]

. In this case, the measurement is made on the different phases obtained. The final activity is the

sum of all the measured activity concentrations.

It is the user’s responsibility to ensure the validity of this test method for the water samples tested.

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 5667-10, Water quality — Sampling — Part 10: Guidance on sampling of waste waters

ISO 11929-1, Determination of the characteristic limits (decision threshold, detection limit and limits of

the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 1:

Elementary applications
© ISO 2020 – All rights reserved 1
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SIST EN ISO 13161:2021
ISO 13161:2020(E)

ISO 11929-3, Determination of the characteristic limits (decision threshold, detection limit and limits of

the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 3:

Applications to unfolding methods
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics

ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

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, definitions, symbols and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 80000-10 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1.1
certified standard solution

solution of known concentration traceable to primary or secondary certified radioactivity standard

solution
3.1.2
tracer solution
208 209

usually a secondary standard or reference material, such as Po or Po, employed to determine the

chemical yield of the analysis
3.1.3
quality control standard

radioactive source used to demonstrate that the measurement equipment employed performs within

defined limits

Note 1 to entry: Quality control is usually carried out by the regular measurement of a suitable radioactive source

[14] [15] [16]
in accordance with ISO 7870-1 , ISO 7870-2 , and ISO 7870-4 .
3.2 Symbols and abbreviated terms

For the purposes of this document, the symbols and abbreviated terms defined in ISO 80000-10 and the

following apply.
A activity of the tracer added Bq
210 −1
c activity concentration of Po Bq l
Bq l
decision threshold
Bq l
detection limit
Bq l
lower and upper limits of the shortest coverage interval
cc,
Bq l
lower and upper limits of the probabilistically symmetric coverage interval
cc,
2 © ISO 2020 – All rights reserved
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SIST EN ISO 13161:2021
ISO 13161:2020(E)
R chemical yield /
R total yield /
210 −1
r background count rate in the Po region of interest s
r background count rate in the tracer region of interest s
210 −1
r gross count rate of the sample in the Po region of interest s
r gross count rate in the tracer region of interest s
t background counting time s
t sample counting time s
U expanded uncertainty calculated by U = k ⋅u(c ) with k = 1, 2 ... Bq l
u(c ) standard uncertainty associated with the initial measurement result Bq l
V volume of the test sample aliquot l
ε counting efficiency 1
4 Principle
4.1 General
[17]

Polonium-210 is a natural alpha-emitting radionuclide with a half-life of (138,376 ± 0,002) days . It

238 222

appears in the natural chain of U (see Figure 1). It is a long-life decay product of Rn (Figure 1)

210 [8][12]
through Pb .
210

There are different techniques to measure Po activity concentration in water: alpha spectrometry,

liquid scintillation counting, and alpha proportional counting. This document describes the alpha

spectrometry technique.

After sampling, the test sample undergoes treatment to produce an extremely thin deposit of the

polonium on a metal disc or on a filter for measurement by alpha spectrometry.

The sample shall be analysed as soon as possible in order to evaluate the activity concentration

at the sampling date. If the time elapsed between sampling and measurement is long, the activity

210 210

concentration measured requires correction. It is then necessary to know the Pb and Bi activity

210

concentrations in the sample in order to adjust the Po activity concentration to the sampling date.

© ISO 2020 – All rights reserved 3
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SIST EN ISO 13161:2021
ISO 13161:2020(E)
206
NOTE Pb is stable.
Figure 1 — Uranium-238 and its decay products
4.2 Treatment
4.2.1 Treatment for a deposition on a disc
The main steps of the sample treatment are:
— filtration if nece
...

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