Water quality - Gross alpha and gross beta activity - Test method using liquid scintillation counting (ISO 11704:2018)

This document specifies a method for the determination of gross alpha and gross beta activity concentration for alpha- and beta-emitting radionuclides using liquid scintillation counting (LSC).
The method is applicable to all types of waters with a dry residue of less than 5 g/l and when no correction for colour quenching is necessary.
Gross alpha and gross beta activity measurement is not intended to give an absolute determination of the activity concentration of all alpha- and beta-emitting radionuclides in a test sample, but is a screening analysis to ensure particular reference levels of specific alpha and beta emitters have not been exceeded. This type of determination is also known as gross alpha and beta index. Gross alpha and beta analysis is not expected to be as accurate nor as precise as specific radionuclide analysis after radiochemical separations.
The method covers non-volatile radionuclides below 80 °C, since some gaseous or volatile radionuclides (e.g. radon and radioiodine) can be lost during the source preparation.
The method is applicable to test samples of drinking water, rain water, surface and ground water as well as cooling water, industrial water, domestic and industrial waste water after proper sampling and test sample preparation (filtration when necessary and taking into account the amount of dissolved material in the water).
The method described in this document is applicable in the event of an emergency situation, because the results can be obtained in less than 4 h by directly measuring water test samples without any treatment.
It is the laboratory's responsibility to ensure the suitability of this test method for the water samples tested.

Wasserbeschaffenheit - Gesamt-Alpha- und Gesamt-Beta-Aktivität - Verfahren mit dem Flüssigszintillationszähler (ISO 11704:2018)

Diese Internationale Norm legt ein Verfahren zur Bestimmung der Gesamt-Alpha- und Gesamt-Beta-Aktivität durch alpha- und beta-emittierende Radionuklide mit dem Flüssigszintillationszähler (en: liquid scintillation counting, LSC) fest.
Das Verfahren ist anwendbar auf alle Wässer mit einem Trockenrückstand von weniger als 5 g/l und wenn keine Korrektur des Farbquench erforderlich ist.
Die Messung der Gesamt-Alpha- und Gesamt-Beta-Aktivität ist nicht dafür vorgesehen, eine absolute Bestimmung aller alpha- und beta-strahlenden Radionuklide in einer zu untersuchenden Probe zu leisten, aber als Screeningverfahren ist es geeignet sicherzustellen, das definierte Referenzniveaus spezifischer Alpha- und Beta-Strahler nicht überschritten werden. Diese Art der Bestimmung ist auch als Gesamt-Alpha- und Beta-Index bekannt. Die Gesamt-Alpha- und Beta-Analyse wird nicht genauso akkurat und präzise sein, wie die Analyse spezifischer Radionuklide nach radiochemischer Trennung.
Das Verfahren deckt nicht-flüchtige Radionuklide unter 80 °C ab, da einige gasförmige oder flüchtige Radionuklide (z. B. Radon und Radioiod) bei der Aufbereitung der Quelle verloren gehen können.
Das Verfahren ist auf Proben von Trinkwasser, Regenwasser, Oberflächen- und Grundwasser, sowie Kühlwasser, Prozesswasser, häusliches und gewerbliches Abwasser, nach geeigneter Probenahme, Probenbehandlung und Aufbereitung der Untersuchungsprobe (Filtration, falls erforderlich, und Berücksichtigung der im Wasser gelösten Bestandteile) anwendbar.
Das in dieser Norm beschriebene Verfahren ist bei Notfall-Situationen anwendbar, da die Ergebnisse in weniger als 4 h durch direktes Messen der Wasserproben ohne jegliche Vorbehandlung erhalten werden können.
Es liegt in der Verantwortung des Labors die Eignung dieses Prüfverfahrens für die zu prüfenden Wasserproben sicherzustellen.

Qualité de l'eau - Activités alpha globale et bêta globale - Méthode d'essai par comptage des scintillations en milieu liquide (ISO 11704:2018)

Le présent document spécifie une méthode de détermination des activités volumiques alpha globale et bêta globale pour des radionucléides émetteurs alpha et bêta par comptage des scintillations en milieu liquide.
La méthode est applicable à tous les types d'eau ayant un résidu sec inférieur à 5 g/l et lorsqu'aucune correction n'est nécessaire pour l'affaiblissement lumineux de couleur.
Le mesurage des activités alpha globale et bêta globale n'est pas destiné à fournir une détermination absolue de l'activité volumique de tous les radionucléides émetteurs alpha et bêta dans un échantillon pour essai; il s'agit plutôt d'une analyse de contrôle visant à s'assurer que des niveaux de référence donnés d'émetteurs alpha et bêta n'ont pas été dépassés. Ce type de déterminations est également connu sous le nom d'indices alpha et bêta. Il ne faut pas s'attendre à ce que l'analyse des activités alpha globale et bêta globale soit aussi précise, ni aussi juste, que l'analyse de radionucléides spécifiques après séparation radiochimique.
Cette méthode couvre les radionucléides non volatils en dessous de 80 °C, étant donné que certains radionucléides gazeux ou volatils (par exemple, le radon et l'iode radioactif) peuvent être perdus lors de la préparation de la solution source.
Cette méthode peut s'appliquer à des échantillons pour essai d'eau potable, d'eau de pluie, d'eau de surface et d'eau souterraine, ainsi que d'eau de refroidissement, d'eaux industrielles, d'eaux usées domestiques et industrielles, après avoir procédé comme il se doit au prélèvement et à la préparation des échantillons pour essai (en les filtrant lorsque cela s'avère nécessaire et en tenant compte de la quantité de matière dissoute dans l'eau).
La méthode décrite dans le présent document est applicable en cas de situation d'urgence, car les résultats peuvent être obtenus en moins de 4 h en mesurant directement les échantillons d'eau pour essai sans aucun traitement.
Il incombe au laboratoire de s'assurer de la pertinence de la présente méthode d'essai pour les échantillons d'eau soumis à essai.

Kakovost vode - Skupna alfa in skupna beta aktivnost - Preskusna metoda s štetjem s tekočinskim scintilatorjem (ISO 11704:2018)

Ta dokument določa metodo za določevanje koncentracije skupne alfa in skupne beta aktivnosti za alfa in beta oddajne radionuklide s štetjem s tekočinskim scintilatorjem (LSC).
Metoda se uporablja za vse vrste vod s suhim ostankom, manjšim od 5 g/l, pri katerih ni potreben
popravek za dušenje fluorescence.
Meritev skupne alfa in skupne beta aktivnosti ni namenjena absolutni določitvi koncentracije aktivnosti vseh alfa in beta oddajnih radionuklidov v preskusnem vzorcu, temveč je presejalna analiza, s katero se zagotovi, da določene referenčne ravni specifičnih alfa in beta oddajnikov
niso bile presežene. Ta vrsta določevanja se imenuje tudi skupni alfa in beta indeks. Ne pričakuje se, da bo skupna alfa
in skupna beta analiza enako točna in natančna kot specifična radionuklidna analiza po radiokemičnih separacijah.
Metoda zajema nehlapne radionuklide s temperaturo, nižjo od 80 °C, saj se lahko nekateri radionuklidi v plinastem stanju oziroma hlapni radionuklidi (npr. radon in radioaktivni jod) med pripravo virov izgubijo.
Metoda se uporablja za preskusne vzorce pitne vode, deževnice, površinske in podtalne vode
ter vode za hlajenje, industrijske vode, gospodinjske in industrijske odpadne vode po ustreznem vzorčenju in pripravi preskusnih vzorcev (filtracija, kadar je to potrebno, in upoštevanje količine raztopljenih snovi v vodi).
Metoda, opisana v tem dokumentu, se uporablja v izrednih razmerah, saj
je mogoče rezultate pridobiti v manj kot štirih urah z neposrednim merjenjem preskusnih vzorcev vode brez obdelave.
Laboratorij mora zagotoviti primernost te preskusne metode za vzorce vode, ki se preskušajo.

General Information

Status
Published
Publication Date
11-Dec-2018
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
12-Dec-2018
Completion Date
12-Dec-2018

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SLOVENSKI STANDARD
SIST EN ISO 11704:2019
01-maj-2019
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SIST EN ISO 11704:2015
SIST ISO 11704:2013
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Water quality - Gross alpha and gross beta activity - Test method using liquid scintillation

counting (ISO 11704:2018)

Wasserbeschaffenheit - Gesamt-Alpha- und Gesamt-Beta-Aktivität - Verfahren mit dem

Flüssigszintillationszähler (ISO 11704:2018)

Qualité de l'eau - Activités alpha globale et bêta globale - Méthode d'essai par comptage

des scintillations en milieu liquide (ISO 11704:2018)
Ta slovenski standard je istoveten z: EN ISO 11704:2018
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 11704:2019 en,fr,de

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

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SIST EN ISO 11704:2019
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SIST EN ISO 11704:2019
EN ISO 11704
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 13.060.60; 17.240 Supersedes EN ISO 11704:2015
English Version
Water quality - Gross alpha and gross beta activity - Test
method using liquid scintillation counting (ISO
11704:2018)

Qualité de l'eau - Activités alpha globale et bêta globale Wasserbeschaffenheit - Gesamt-Alpha- und Gesamt-

- Méthode d'essai par comptage des scintillations en Beta-Aktivität - Verfahren mit dem

milieu liquide (ISO 11704:2018) Flüssigszintillationszähler (ISO 11704:2018)
This European Standard was approved by CEN on 1 November 2018.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11704:2018 E

worldwide for CEN national Members.
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SIST EN ISO 11704:2019
EN ISO 11704:2018 (E)
Contents Page

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

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SIST EN ISO 11704:2019
EN ISO 11704:2018 (E)
European foreword

This document (EN ISO 11704:2018) 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 June 2019, and conflicting national standards shall be

withdrawn at the latest by June 2019.

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 11704:2015.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 11704:2018 has been approved by CEN as EN ISO 11704:2018 without any modification.

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SIST EN ISO 11704:2019
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SIST EN ISO 11704:2019
INTERNATIONAL ISO
STANDARD 11704
Second edition
2018-11
Water quality — Gross alpha and gross
beta activity — Test method using
liquid scintillation counting
Qualité de l'eau — Activités alpha globale et bêta globale — Méthode
d'essai par comptage des scintillations en milieu liquide
Reference number
ISO 11704:2018(E)
ISO 2018
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SIST EN ISO 11704:2019
ISO 11704:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 11704:2019
ISO 11704:2018(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

5 Reagents and equipment ............................................................................................................................................................................. 3

6 Sampling ........................................................................................................................................................................................................................ 5

7 Procedure..................................................................................................................................................................................................................... 5

7.1 Direct counting........................................................................................................................................................................................ 5

7.2 Thermal preconcentration ............................................................................................................................................................ 5

7.3 Sample preparation ............................................................................................................................................................................ 6

7.4 Liquid scintillation measurement .......................................................................................................................................... 6

7.4.1 Preparation of alpha and beta calibration sources ............................................................................ 6

7.4.2 Optimization of counting conditions .............................................................................................................. 6

7.4.3 Blank sample preparation and measurement ........................................................................................ 7

7.4.4 Alpha and beta efficiencies ..................................................................................................................................... 7

7.4.5 Sample measurement .................................................................................................................................................. 8

8 Expression of results ........................................................................................................................................................................................ 8

8.1 Calculation of activity per mass................................................................................................................................................ 8

8.2 Standard uncertainty ......................................................................................................................................................................... 9

8.3 Decision threshold ............................................................................................................................................................................10

8.4 Detection limit ......................................................................................................................................................................................10

8.5 Confidence limits................................................................................................................................................................................10

8.6 Quality control ......................................................................................................................................................................................11

9 Interference control .......................................................................................................................................................................................11

9.1 Contamination ......................................................................................................................................................................................11

9.2 Ingrowth of radon .............................................................................................................................................................................11

9.3 Loss of polonium ................................................................................................................................................................................11

10 Test report ................................................................................................................................................................................................................11

Annex A (informative) Set-up parameters and validation data .............................................................................................13

Annex B (informative) Method performances under different conditions ...............................................................17

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

© ISO 2018 – All rights reserved iii
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SIST EN ISO 11704:2019
ISO 11704:2018(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 11704:2010), which has been technically

revised. The main changes compared to the previous edition are as follows:
— 5.5.1 has been simplified;

— the application field of this document has been extended to emergency situations;

— slightly different counting conditions have been suggested;
— Annexes A and B have been added.

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 2018 – All rights reserved
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SIST EN ISO 11704:2019
ISO 11704:2018(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

226 228 234 238 210 210
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);

— 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 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 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 waters are monitored for their radioactivity 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 water bodies and drinking waters

for planned, existing and emergency exposure situations. Compliance with these limits can be assessed

[4]

using measurement results with their associated uncertainties as specified by ISO/IEC Guide 98-3

[5]
and 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

guidelines for guidance level in drinking water is 0,5 Bq/l for gross alpha activity and 1 Bq/l for gross

beta activity.

NOTE 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 .

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][8]
or for an emergency situation .

Usually, the test methods can be adjusted to measure the activity concentration of the radionuclide(s)

in either waste waters before storage or in liquid effluents before being discharged to the environment.

The test results will enable the plant/installation operator to verify that, before their discharge, waste

waters/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 waste waters and liquid effluents with specific modifications that

could increase the overall uncertainty, detection limit and threshold.
© ISO 2018 – All rights reserved v
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SIST EN ISO 11704:2019
ISO 11704:2018(E)

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).

An International Standard on a test method of gross alpha and gross beta activity concentrations in

water samples is justified for test laboratories carrying out these measurements, required sometimes

by national authorities, as laboratories may have 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 © ISO 2018 – All rights reserved
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SIST EN ISO 11704:2019
INTERNATIONAL STANDARD ISO 11704:2018(E)
Water quality — Gross alpha and gross beta activity — 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.

IMPORTANT — It is absolutely essential that tests conducted according to this document be

carried out by suitably trained staff.
1 Scope

This document specifies a method for the determination of gross alpha and gross beta activity

concentration for alpha- and beta-emitting radionuclides using liquid scintillation counting (LSC).

The method is applicable to all types of waters with a dry residue of less than 5 g/l and when no

correction for colour quenching is necessary.

Gross alpha and gross beta activity measurement is not intended to give an absolute determination

of the activity concentration of all alpha- and beta-emitting radionuclides in a test sample, but is a

screening analysis to ensure particular reference levels of specific alpha and beta emitters have not

been exceeded. This type of determination is also known as gross alpha and beta index. Gross alpha

and beta analysis is not expected to be as accurate nor as precise as specific radionuclide analysis after

radiochemical separations.

The method covers non-volatile radionuclides below 80 °C, since some gaseous or volatile radionuclides

(e.g. radon and radioiodine) can be lost during the source preparation.

The method is applicable to test samples of drinking water, rain water, surface and ground water as

well as cooling water, industrial water, domestic and industrial waste water after proper sampling and

test sample preparation (filtration when necessary and taking into account the amount of dissolved

material in the water).

The method described in this document is applicable in the event of an emergency situation, because

the results can be obtained in less than 4 h by directly measuring water test samples without any

treatment.

It is the laboratory’s responsibility to ensure the suitability 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/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 2018 – All rights reserved 1
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SIST EN ISO 11704:2019
ISO 11704:2018(E)
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 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/
3.2 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 , a Alpha and beta activity per mass Bq g
α β
a* Decision threshold Bq g
Detection limit Bq g
Lower and upper limits of the confidence interval Bq g
aa,

A , A Activity of the alpha and beta emitter certified reference solution used Bq

α β
for the α and β calibration sources
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 , m Mass of alpha and beta emitters certified reference solutions, respectively g

Sα Sβ
r , r Sample gross count rate, from the alpha and beta windows, respectively s
gα gβ

r , r , r Blank count rate, from the alpha, beta and total windows, respectively s

0α 0β 0T

r , r , Count rate of the alpha calibration source in the alpha, beta and total s

Sα,α Sα,β
r window
Sα,T
r , r , Count rate of the beta calibration source in the alpha, beta and total s
Sβ,α Sβ,β
r window
Sβ,T
t Sample counting time s
t Blank counting time s
t , t Counting time of α and β calibration sources s
sα sβ
u (a) Standard uncertainty associated with the measurement result Bq g
U Expanded uncertainty, calculated from U = ku (a), where k = 1, 2 … Bq g
Standard uncertainty of a as a function of its true value Bq g
  α
2 © ISO 2018 – All rights reserved
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SIST EN ISO 11704:2019
ISO 11704:2018(E)
ε , ε Counting efficiency for alpha and beta, respectively —
α β
τ (χ ) Alpha interference — Fraction of counts observed in the beta window —
α α β
with respect to the total number of counts measured by the counter
when an alpha emitter is measured
τ (χ ) Beta interference — Fraction of counts observed in the alpha window —
β β α
with respect to the total number of counts measured by the counter
when a beta emitter is measured
4 Principle

Gross alpha and beta activity concentrations are determined by using liquid scintillation counting of a

water sample mixed with a scintillation cocktail.

Gross alpha and beta determinations are not absolute determinations of the sample radioactive

contents, but relative determinations referred to a specific alpha or beta emitter which constitutes the

standard calibration sources. These types of determinations are also known as the alpha and beta index

and are usually employed as screening parameters for first assessment of total radioactive content.

The aqueous sample is acidified using nitric acid and heated. Subsequently, water with low salt content

can be thermally concentrated by slow evaporation to improve the method sensitivity. An aliquot of

sample is transferred into a liquid scintillation vial with scintillation cocktail; scintillations from the

vial are then counted by equipment with an alpha and beta discrimination device.

The counter is previously optimized with respect to an alpha and beta discriminator setting and then

calibrated against alpha and beta emitter certified reference solutions. In data evaluation, no correction

for chemical quenching is applied, since the procedure is designed to provide samples with a relatively

constant quench level.
222

The method does not account for Rn and its short lived progeny and it is not suitable for

H measurement.

When suspended matter is present in significant quantities, a filtration step is required before

acidification.
5 Reagents and equipment

All reagents shall be of recognized analytical grade, except for the scintillation cocktail, and shall not

contain any detectable alpha and beta activity, except for the radioactive certified reference solutions.

5.1 Nitric acid, c(HNO ) = commercially available acid with mass fraction w(HNO ) = (65 to 70) %.

3 3
5.2 Water, ISO 3696, grade 3.
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Deionized water can contain detectable amounts of Rn and short lived progeny. It is therefore

strongly recommended to boil water under vigorous stirring and let it stand for one day before use.

Alternatively, use nitrogen flushing for about 1 h for a 2 l sample.
5.3 Scintillation cocktail.

Commercially available scintillation cocktails suitable for alpha and beta discrimination

(e.g. diisopropylnaphthalene-based cocktails), water miscible.
5.4 Volatile organic solvents.
Methanol or ethanol.
© ISO 2018 – All rights reserved 3
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SIST EN ISO 11704:2019
ISO 11704:2018(E)
5.5 Certified reference solutions.
5.5.1 General

In general, the experimental parameters (efficiency, alpha and beta optimum discrimination) depend on

alpha and beta energies, thus the choice of alpha and beta emitter certified reference solutions depends

on knowledge of the type of radioactive contaminant likely to be present in the waters b

...

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