Water quality - Radium 226 and Radium 228 - Test method using liquid scintillation counting (ISO 22908:2020)

This document specifies the determination of radium-226 (226Ra) and radium-228 (228Ra) activity concentrations in drinking water samples by chemical separation of radium and its measurement using liquid scintillation counting.
Massic activity concentrations of 226Ra and 228Ra which can be measured by this test method utilizing currently available liquid scintillation counters go down to 0,01 Bq/kg for 226Ra and 0,06 Bq/kg for 228Ra for a 0,5 kg sample mass and a 1 h counting time in a low background liquid scintillation counter[8].
The test method can be used for the fast detection of contamination of drinking water by radium in emergency situations.

Wasserbeschaffenheit - Radium-226 und Radium-228 - Verfahren mit dem Flüssigszintillationszähler (ISO 22908:2020)

Dieses Dokument legt ein Verfahren zur Bestimmung der Aktivitätskonzentrationen von Radium-226 (226Ra) und Radium-228 (228Ra) in Trinkwasserproben durch chemische Abtrennung von Radium und seine Messung mit dem Flüssigszintillationszähler fest.
Mit diesem Prüfverfahren können mit derzeit erhältlichen Flüssigszintillationszählern massenbezogene Aktivitätskonzentrationen an 226Ra und 228Ra bis zu einer Untergrenze von 0,01 Bq/kg (226Ra) bzw. 0,06 Bq/kg (228Ra) bestimmt werden, wenn in einem Flüssigszintillationszähler mit niedrigem Nulleffekt 0,5 kg Probenmasse und eine Messdauer von 1 h verwendet werden [8].
Das Prüfverfahren kann für die Schnellerkennung der Kontamination von Trinkwasser mit Radium in Notfallsituationen verwendet werden.

Qualité de l'eau - Radium 226 et radium 228 - Méthode d'essai par comptage des scintillations en milieu liquide (ISO 22908:2020)

Le présent document explicite la détermination des activités volumiques du radium-226 (226Ra) et du radium-228 (228Ra) dans des échantillons d'eau potable par séparation chimique du radium et son mesurage par comptage des scintillations en milieu liquide.
Les activités massiques du 226Ra et du 228Ra, qui peuvent être mesurées par cette méthode d'essai à l'aide de compteurs à scintillations en milieu liquide actuellement disponibles, sont comprises entre 0,01 Bq/kg pour le 226Ra et 0,06 Bq/kg pour le 228Ra, pour une masse d'échantillon de 0,5 kg et un temps de comptage de 1 h dans un compteur à scintillations en milieu liquide faible bruit de fond[8].
La méthode d'essai peut être utilisée pour la détection rapide de la pollution de l'eau potable par le radium en situation d'urgence.

Kakovost vode - Radij Ra-226 in Ra-228 - Preskusna metoda s štetjem s tekočinskim scintilatorjem (ISO 22908:2020)

General Information

Status
Published
Publication Date
04-Feb-2020
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
05-Feb-2020
Completion Date
05-Feb-2020

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SLOVENSKI STANDARD
SIST EN ISO 22908:2020
01-maj-2020
Kakovost vode - Radij Ra-226 in Ra-228 - Preskusna metoda s štetjem s
tekočinskim scintilatorjem (ISO 22908:2020)

Water quality - Radium 226 and Radium 228 - Test method using liquid scintillation

counting (ISO 22908:2020)
Wasserbeschaffenheit - Radium-226 und Radium-228 - Verfahren mit dem
Flüssigszintillationszähler (ISO 22908:2020)
Qualité de l'eau - Radium 226 et radium 228 - Méthode d'essai par comptage des
scintillations en milieu liquide (ISO 22908:2020)
Ta slovenski standard je istoveten z: EN ISO 22908:2020
ICS:
13.060.50 Preiskava vode na kemične Examination of water for
snovi chemical substances
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 22908:2020 en,fr,de

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

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SIST EN ISO 22908:2020
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SIST EN ISO 22908:2020
EN ISO 22908
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 13.060.60; 13.280; 17.240
English Version
Water quality - Radium 226 and Radium 228 - Test
method using liquid scintillation counting (ISO
22908:2020)

Qualité de l'eau - Radium 226 et radium 228 - Méthode Wasserbeschaffenheit - Radium-226 und Radium-228 -

d'essai par comptage des scintillations en milieu Verfahren mit dem Flüssigszintillationszähler (ISO

liquide (ISO 22908:2020) 22908:2020)
This European Standard was approved by CEN on 20 December 2019.

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 22908:2020 E

worldwide for CEN national Members.
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SIST EN ISO 22908:2020
EN ISO 22908:2020 (E)
Contents Page

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

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SIST EN ISO 22908:2020
EN ISO 22908:2020 (E)
European foreword

This document (EN ISO 22908:2020) 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 August 2020, and conflicting national standards shall

be withdrawn at the latest by August 2020.

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.

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 22908:2020 has been approved by CEN as EN ISO 22908:2020 without any modification.

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SIST EN ISO 22908:2020
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SIST EN ISO 22908:2020
INTERNATIONAL ISO
STANDARD 22908
First edition
2020-01
Water quality — Radium 226 and
Radium 228 — Test method using
liquid scintillation counting
Qualité de l'eau — Radium 226 et radium 228 — Méthode d'essai par
comptage des scintillations en milieu liquide
Reference number
ISO 22908:2020(E)
ISO 2020
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SIST EN ISO 22908:2020
ISO 22908:2020(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
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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 2020 – All rights reserved
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SIST EN ISO 22908:2020
ISO 22908:2020(E)
Contents Page

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

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

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

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

3 Terms, definitions, symbols and units ........................................................................................................................................... 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Symbols, definitions and units .................................................................................................................................................. 2

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

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

5.1 Reagents........................................................................................................................................................................................................ 3

5.2 Equipment ................................................................................................................................................................................................... 4

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

7 Instrument set-up and calibration .................................................................................................................................................... 5

7.1 Optimization of counting conditions ................................................................................................................................... 5

7.1.1 Preparation of sources ................................................................................................................................................ 5

7.1.2 Optimization process ................................................................................................................................................... 6

226 228

7.2 Counting efficiencies of Ra and Ra .......................................................................................................................... 6

226 228

7.2.1 Preparation of Ra and Ra standard sources .............................................................................. 6

7.2.2 Determination of counting efficiencies ........................................................................................................ 6

7.3 Blank sample measurement ........................................................................................................................................................ 7

8 Procedure..................................................................................................................................................................................................................... 7

8.1 General ........................................................................................................................................................................................................... 7

8.2 Separation of radium by precipitation ............................................................................................................................... 7

8.3 Purification of radium ....................................................................................................................................................................... 8

8.4 Test sample preparation ................................................................................................................................................................. 8

8.5 Measurement ............................................................................................................................................................................................ 9

8.6 Chemical recovery ................................................................................................................................................................................ 9

8.6.1 General...................................................................................................................................................................................... 9

226 228

8.6.2 Preparation of a QC sample with known Ra and Ra activities ................................... 9

8.6.3 Determination of overall counting efficiencies ...................................................................................... 9

8.6.4 Determination of chemical recovery .............................................................................................................. 9

9 Quality control .....................................................................................................................................................................................................10

10 Expression of results .....................................................................................................................................................................................10

226 228

10.1 Calculation of massic activities of Ra and Ra at the sampling date ..........................................10

10.2 Standard uncertainty ......................................................................................................................................................................10

10.3 Decision threshold ............................................................................................................................................................................12

10.4 Detection limit ......................................................................................................................................................................................12

10.5 Confidence limits................................................................................................................................................................................12

11 Interference control .......................................................................................................................................................................................12

12 Test report ................................................................................................................................................................................................................13

Annex A (informative) Flow chart of the procedure ..........................................................................................................................14

Annex B (informative) Decay series relevant to radium isotopes .......................................................................................15

Annex C (informative) Set-up parameters and procedure ..........................................................................................................16

Annex D (informative) Validation data............................................................................................................................................................22

Bibliography .............................................................................................................................................................................................................................28

© ISO 2020 – All rights reserved iii
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SIST EN ISO 22908:2020
ISO 22908:2020(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 on 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 the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 3,

Radioactivity measurements.

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 22908:2020
ISO 22908:2020(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 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 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 a planned or existing situation, the WHO

226 228

guidelines for guidance level in drinking water are 1 Bq/l and 0,1 Bq/l, for Ra and Ra activity

concentrations, respectively.

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

concentrations might be greater.

NOTE 2 The Codex guidelines levels (GLs) apply to radionuclides contained in food 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 .
© ISO 2020 – All rights reserved v
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SIST EN ISO 22908:2020
ISO 22908:2020(E)

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.

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 support 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 set 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 22908:2020
INTERNATIONAL STANDARD ISO 22908:2020(E)
Water quality — Radium 226 and Radium 228 — Test
method using liquid scintillation counting

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
226 228

This document specifies the determination of radium-226 ( Ra) and radium-228 ( Ra) activity

concentrations in drinking water samples by chemical separation of radium and its measurement using

liquid scintillation counting.
226 228

Massic activity concentrations of Ra and Ra which can be measured by this test method utilizing

226

currently available liquid scintillation counters go down to 0,01 Bq/kg for Ra and 0,06 Bq/kg for

228 [8]

Ra for a 0,5 kg sample mass and a 1 h counting time in a low background liquid scintillation counter .

The test method can be used for the fast detection of contamination of drinking water by radium in

emergency situations.
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 17025:2017, 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, definitions, symbols and units
3.1 Terms and definitions
No terms and definitions are listed in this document.

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/
© ISO 2020 – All rights reserved 1
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SIST EN ISO 22908:2020
ISO 22908:2020(E)
3.2 Symbols, definitions and units

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

ISO/IEC Guide 98-3, and the following apply.
Symbol Unit Definition

A Bq/kg Certified massic activity of the analyte in the certified standard solution at the

reference date

Bq/kg Massic activity of the analyte in the quality control sample at the reference date

a Bq/kg Massic activity of the analyte in the test sample at the sampling date
a* Bq/kg Decision threshold of the analyte
a Bq/kg Detection limit of the analyte
⊲ ⊳
a , a Bq/kg Lower and upper limits of the confidence interval

c Bq/l Activity concentration of the analyte in the test sample at the sampling date

C Bq/kg Target massic activity of the analyte in the quality control sample prepared

for the validation of the procedure

m kg Mass of the certified standard solution taken for the analysis of the analyte

s-x
m kg Mass of the quality control sample taken for the analysis of the analyte
t-x
m kg Mass of the test sample
1/s Net count rate of the analyte in the certified standard solution
1/s Net count rate of the analyte in the quality control sample
n 1/s Net count rate of the analyte in the test sample
PI % Precision index
R Bq/kg Reproducibility limit
r Bq/kg Repeatability limit
r 1/s Gross count rate of the analyte in the test sample
g−x
r 1/s Gross count rate of the analyte in the blank sample
0-x
S Bq/kg Standard deviation of repeatability
S Bq/kg Standard deviation of reproducibility
T s Counting time of the analyte in the test sample
s-x
t s Counting time of the analyte in the blank
0-x
t s Time interval between measurement date and reference date of the analyte
s-x
in the certified standard solution
t s Time interval between measurement date and reference date of the analyte
t-x
in the quality control sample
t s Time interval between measurement date and sampling date of the analyte
in the test sample
u(a) Bq/kg Standard uncertainty associated with the measurement result
u(x) Bq/kg Uncertainty in quantity x
U Bq/kg Expanded uncertainty, calculated using U = ku(a), with k = 1, 2,…
w 1/kg Factor equal to 1/ε m
x s
ε — Counting efficiency of the analyte
— Overall efficiency of the analyte in the quality control sample
λ 1/s Decay constant of the analyte
Bq/kg Mean of all measured values of the analyte in the quality control sample
for the validation of the procedure
δ % Relative bias of the method
ρ kg/l Density
2 © ISO 2020 – All rights reserved
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SIST EN ISO 22908:2020
ISO 22908:2020(E)
4 Principle

Barium co-precipitation is used as a method of separation for radium due to the very similar chemical

properties of barium and radium. The exploitation of the ability of barium to react with an excess

of sulfate ions to produce a precipitate allows the quantitative analysis of environmental activity

210

concentrations of radium in water. The inclusion of a lead hold-back carrier allows the removal of Pb

228 210

from solution, which increases the accuracy of Ra measurement, as Pb can produce a spectral

210

interference. The removal of Pb is achieved by lowering the pH of the solution to re-precipitate

210

barium sulfate using acetic acid in which lead sulfate is soluble. This allows Pb to remain in solution

and therefore be removed.

The source preparation is achieved by suspending the barium sulfate precipitate in the EDTA

solution. Barium sulfate is insoluble in water, alkalis and acids, but EDTA increases the solubility due

to the complexation of barium and the speciation effect. The EDTA molecule inhibits barium sulfate

nucleation. This enables the use of a naphthalene-based scintillation cocktail to gain better spectral

resolution than with the use of a gel-forming cocktail.
The flow chart of the procedure is given in Annex A.
226 228

Massic activities of Ra and Ra in the sample are calculated from net count rates of the sample

source, sample amount and the overall efficiency that can be obtained from spiked sample with known

226 228
activities of Ra and Ra, and tha
...

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