SIST EN ISO 22908:2020

SLOVENSKI STANDARD
oSIST prEN ISO 22908:2018
01-oktober-2018
.DNRYRVWYRGH5DGLM5DLQ5D3UHVNXVQDPHWRGDãWHWMDVWHNRþLQVNLP
VFLQWLODWRUMHP,62',6
Water quality - Radium 226 and radium 228 - Test method using liquid scintillation
counting (ISO/DIS 22908:2018)
asserbeschaffenheit - Radium 226 und Radium 228 - Verfahren mit dem
Flüssigszintillationszähler (ISO/DIS 22908:2018)
Qualité de l'eau - Radium 226 et radium 228 - Méthode d'essai par comptage des
scintillations en milieu liquide (ISO/DIS 22908:2018)
Ta slovenski standard je istoveten z: prEN ISO 22908
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
oSIST prEN ISO 22908:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 22908:2018

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oSIST prEN ISO 22908:2018
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22908
ISO/TC 147/SC 3 Secretariat: AFNOR
Voting begins on: Voting terminates on:
2018-08-24 2018-11-16
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
ICS: 13.060.60; 13.280; 17.240
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 22908:2018(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2018

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oSIST prEN ISO 22908:2018
ISO/DIS 22908:2018(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
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ii © ISO 2018 – All rights reserved

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oSIST prEN ISO 22908:2018
ISO/DIS 22908:2018(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Symbols, definitions and units . 2
4 Principle . 3
5 Reagents and equipment . 4
5.1 Reagents. 4
5.2 Equipment . 5
6 Sampling . 5
7 Instrument set-up and calibration . 6
7.1 Optimization of counting conditions . 6
7.1.1 Preparation of sources . 6
7.1.2 Optimization process . 6
226 228
7.2 Counting efficiencies of Ra and Ra . 7
226 228
7.2.1 Preparation of Ra and Ra standard sources . 7
7.2.2 Determination of counting efficiencies . 7
7.3 Blank sample measurement . 7
8 Procedure. 7
8.1 General . 7
8.2 Separation of radium by precipitation . 8
8.3 Purification of radium . 8
8.4 Source preparation . 8
8.5 Measurement . 9
226 228
8.6 Overall counting efficiencies of Ra and Ra . 9
8.6.1 General. 9
8.6.2 Preparation of a QC sample with known 226Ra and 228Ra activities . 9
8.6.3 Determination of overall counting efficiencies .10
9 Quality control .10
10 Expression of results .10
10.1 Calculation of massic activities of 226Ra and 228Ra at the sampling date .10
10.2 Standard uncertainty .11
10.3 Decision threshold .12
10.4 Detection limit .12
10.5 Confidence limits.12
11 Interference control .13
12 Test report .13
Annex A (informative) Decay series relevant to radium isotopes .14
Annex B (informative) Flow chart of the procedure .15
Annex C (informative) Set-up parameters and procedure .16
Annex D (informative) Validation data.22
Bibliography .28
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oSIST prEN ISO 22908:2018
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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 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.
The committee responsible for this document is Technical Committee ISO/TC 147, Water quality,
Subcommittee SC 3, radioactivity measurements.
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oSIST prEN ISO 22908:2018
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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 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 of 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 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
[5][6][7].
or for an emergency situation
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oSIST prEN ISO 22908:2018
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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).
226 228
An International Standard on a test method of for Ra and Ra 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.
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oSIST prEN ISO 22908:2018
DRAFT INTERNATIONAL STANDARD ISO/DIS 22908:2018(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
ensure compliance with any national regulatory conditions.
IMPORTANT — It is essential that tests conducted according to this test method be carried out
by suitably trained staff.
1 Scope
226 228
The 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
226 228
liquid scintillation counting. Ra and Ra are present in the environment as radionuclides from the
238 232
U and Th decay series, as shown in Annex A.
/
The test method applies to the analysis of 0,5 kg of drinking water containing less than 100 mg kg
barium. If the barium concentration is higher than 100 mg/kg, it is recommended to reduce the volume
of the test sample to be analysed so that the total content of barium in the sample does not exceed 50 mg.
226 228
Activity concentrations of Ra and Ra can vary widely according to local geological and climatic
226
characteristics. Ra activity concentration range from some mBq/l in surface waters up to several
[8] 226
tens of Bq/l in some natural groundwaters ; the guidance level for Ra in drinking water as
[3][9] 228
recommended by WHO is 1 Bq/l . Ra activity concentration range from a few mBq/l in surface
[8] 228
waters up to several Bq/l in some natural groundwaters ; the guidance level for Ra in drinking
[3][9]
water as recommended by WHO is 0,1 Bq/l .
226 228
Activity concentrations of Ra and Ra which can be measured by this test method utilizing currently
226 228
available liquid scintillation counters goes down to 0,01 Bq/kg for Ra and 0,06 Bq/kg for Ra for a
[10]
0,5 kg sample mass and a 1 h counting time in a low background liquid scintillation counter.
NOTE Adjustment of the test sample mass and counting time can lead to lower detection limits. As an
228
example, a limit of detection of 0,04 Bq/kg can be achieved for Ra using a 0,5 kg test sample and a 2 h counting
228
time; similarly a limit of detection of 0,02 Bq/kg can be achieved for Ra using a 1 kg test sample and a 2 h
counting time.
The test method can be used for the fast detection of contamination of drinking water by radium in
emergency situations or for routine environmental monitoring purposes.
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 8258, Shewhart control charts
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ISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the
confidence interval) for measurements of ionizing radiation — Fundamentals and application
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
measurement (GUM: 1995)
3 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.
u(x) uncertainty in quantity x.
A certified massic activity of the analyte in the certified standard solution at the reference date,
x
in becquerels per kilogram
t
massic activity of the analyte in the quality control sample at the reference date, in becquerels
A
x
per kilogram
a massic activity of the analyte in the test sample at the sampling date, in becquerels per kilogram
x
a* decision threshold of the analyte, in becquerels per kilogram
#
a detection limit of the analyte, in becquerels per kilogram
⊲ ⊳
a , a lower and upper limits of the confidence interval, in becquerels per kilogram
c activity concentration of the analyte in the test sample at the sampling date, in becquerels per litre
a
C target massic activity of the analyte in the quality control sample prepared for the validation
x
of the procedure, in becquerels per kilogram
m mass of the certified standard solution taken for the analysis of the analyte, in kilograms
s-x
mass of the quality control sample taken for the analysis of the analyte, in kilograms
m
tx−
m mass of the test sample, in kilograms
s
s
net count rates of the analyte in the certified standard solution, in reciprocal seconds
n
x
t
net count rates of the analyte in the quality control sample, in reciprocal seconds
n
x
n net count rates of the analyte in the test sample, in reciprocal seconds
x
PI precision index, in per cent
R reproducibility limit, in becquerels per kilogram
L
r repeatability limit, in becquerels per kilogram
L
gross count rate of the analyte in the test sample, in reciprocal seconds
r
gx−
r gross count rate of the analyte in the blank sample, in reciprocal seconds
0-x
S standard deviation of repeatability, in becquerels per kilogram
r
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oSIST prEN ISO 22908:2018
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S standard deviation of reproducibility, in becquerels per kilogram
R
T counting time of the analyte in the test sample, in seconds
s-x
t counting time of the analyte in the blank, in seconds
0-x
t time interval between measurement date and reference date of the analyte in the certified
s-x
standard solution, in seconds
t time interval between measurement date and reference date of the analyte in the quality con-
t-x
trol sample, in seconds
t time interval between measurement date and sampling date of the analyte in the test sample,
x
in seconds
u(a) standard uncertainty associated with the measurement result; in becquerels per kilogram
U expanded uncertainty, calculated using U = ku(a), with k = 1, 2, … in becquerels per kilogram
w factor equal to 1/ε m
x s
counting efficiency of the analyte
ε
x
c
overall efficiency of the analyte in the quality control sample
ε
x
decay constant of the analyte, in reciprocal seconds
λ
x
mean of all measured values of the analyte in the quality control sample for the validation of
Χ
x
the procedure, in becquerels per kilogram
relative bias of the method, in per cent
δ
ρ density, in kilograms per litre
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 carrier allows the removal of Pb from
228 210
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 sulphate 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 B.
226 228
Massic activities of Ra and Ra in the sample are calculated from net count rates of the sample,
sample amount and the overall efficiency that can be obtained from spiked sample with known activities
226 228
of Ra and Ra, and that shows the ability of the method to extract radium (chemical recovery) as
well as the ability (counting efficiency) of the instrument to detect it.
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oSIST prEN ISO 22908:2018
ISO/DIS 22908:2018(E)

5 Reagents and equipment
5.1 Reagents
All reagents shall be of recognized analytical grade and, except for 5.1.12, 5.1.13 and 5.1.14, shall not
contain any detectable alpha- and beta-activity.
5.1.1 Laboratory water, distilled or deionized, complying with ISO 3696, grade 3.
5.1.2 Lead carrier solution prepared using 2,397 g lead nitrate, 0,5 ml nitric acid solution (5.1.4) and
made up to 100 ml with laboratory water (5.1.1).
5.1.3 Barium carrier solution prepared using 2,836 g barium chloride, 0,5 ml nitric acid solution
(5.1.4) and made up to 100 ml laboratory water (5.1.1).
5.1.4 Nitric acid solution, c(HNO ) = 15,8 mol/l, ρ = 1,42 g/ml, mass fraction w(HNO ) = 70 %.
3 3
5.1.5 Hydrochloric acid solution, c(HCl) = 10,2 mol/l, ρ = 1,16 g/ml, mass fraction w(HCl) = 32 %.
5.1.6 Sulfuric acid solution, c(H SO ) =9,2 mol/l, ρ = 1,84 g/ml, mass fraction w(H SO ) = 98 %.
2 4 2 4
5.1.7 Ammonia solution, c(NH ) = 13,4 mol/l, ρ = 0,91 g/ml, mass fraction w(NH ) = 25 %.
3 3
5.1.8 Glacial acetic acid solution, c(CH COOH) = 16,8 mol/l, ρ = 1,05 g/ml, mass fraction
3
w(CH COOH) = 96 %.
3
5.1.9 Ethylenediaminetetraacetic acid (EDTA), M(EDTA) = 292,2 g/mol.
NOTE Within the whole document, an EDTA solution warmed up within the 60-80°C temperature range is
considered as a hot EDTA solution.
5.1.10 Analytical grade ammonium sulphate, M((NH ) SO ) = 132,1 g/mol.
4 2 4
5.1.11 Scintillation cocktail, commercially available scintillation cocktails, water immiscible and
suitable for alpha and beta discrimination (e.g. diisopropylnaphthalene-based cocktails).
226 228
5.1.12 Ra and Ra
...