EN ISO 18589-2:2024

SLOVENSKI STANDARD
01-september-2024
Nadomešča:
SIST EN ISO 18589-2:2017
Merjenje radioaktivnosti v okolju - Tla - 2. del: Navodila za izbiro strategije
vzorčenja, vzorčenje in pripravo vzorcev (ISO 18589-2:2022)
Measurement of radioactivity in the environment - Soil - Part 2: Guidance for the
selection of the sampling strategy, sampling and pre-treatment of samples (ISO 18589-
2:2022)
Ermittlung der Radioaktivität in der Umwelt - Erdboden - Teil 2: Leitlinie für die Auswahl
der Probenahmestrategie, Probenahme und Vorbehandlung der Proben (ISO 18589-
2:2022)
Mesurage de la radioactivité dans l'environnement - Sol - Partie 2: Lignes directrices
pour la sélection de la stratégie d'échantillonnage, l'échantillonnage et le prétraitement
des échantillons (ISO 18589-2:2022)
Ta slovenski standard je istoveten z: EN ISO 18589-2:2024
ICS:
13.080.01 Kakovost tal in pedologija na Soil quality and pedology in
splošno general
17.240 Merjenje sevanja Radiation measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 18589-2
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2024
EUROPÄISCHE NORM
ICS 17.240; 13.080.01
English Version
Measurement of radioactivity in the environment - Soil -
Part 2: Guidance for the selection of the sampling strategy,
sampling and pre-treatment of samples (ISO 18589-
2:2022)
Mesurage de la radioactivité dans l'environnement - Ermittlung der Radioaktivität in der Umwelt -
Sol - Partie 2: Lignes directrices pour la sélection de la Erdboden - Teil 2: Leitlinie für die Auswahl der
stratégie d'échantillonnage, l'échantillonnage et le Probenahmestrategie, Probenahme und
prétraitement des échantillons (ISO 18589-2:2022) Vorbehandlung der Proben (ISO 18589-2:2022)
This European Standard was approved by CEN on 7 July 2024.

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

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

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18589-2:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 18589-2:2022 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 18589-2:2024 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
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 January 2025, and conflicting national standards shall
be withdrawn at the latest by January 2025.
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.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 18589-2:2022 has been approved by CEN as EN ISO 18589-2:2024 without any
modification.
INTERNATIONAL ISO
STANDARD 18589-2
Third edition
2022-12
Measurement of radioactivity in the
environment — Soil —
Part 2:
Guidance for the selection of the
sampling strategy, sampling and pre-
treatment of samples
Mesurage de la radioactivité dans l'environnement — Sol —
Partie 2: Lignes directrices pour la sélection de la stratégie
d'échantillonnage, l'échantillonnage et le prétraitement des
échantillons
Reference number
ISO 18589-2:2022(E)
ISO 18589-2:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 18589-2:2022(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
6 Sampling strategy . 4
6.1 General . 4
6.2 Initial investigation . 4
6.3 Types of sampling strategies . 4
6.4 Selection of the sampling strategy. 4
7 Sampling plan . 5
7.1 General . 5
7.2 Selection of sampling areas, units, and points . 6
7.2.1 General . 6
7.2.2 Sampling for use with a probabilistic strategy . 6
7.2.3 Sampling for use with an orientated strategy . 6
7.2.4 Selection criteria of sampling areas and sampling units . 7
7.3 Identification of sampling areas, units, and points . 7
7.4 Selection of field equipment . 8
8 Sampling process . 8
8.1 General . 8
8.2 Collection of samples . 9
8.2.1 Selection of sampling depth versus objectives of the study . 9
8.2.2 Sampling surface soil . 11
8.2.3 Sampling soil profile .12
8.3 Preparation of the sorted sample . 13
8.4 Identification and packaging of samples . 14
8.4.1 General . 14
8.4.2 Sample identification . 14
8.4.3 Sample sheet. 14
8.5 Transport and storage of samples . 15
9 Pre-treatment of samples .15
9.1 Principle . 15
9.2 Laboratory equipment . 15
9.3 Procedure . 16
10 Determination of the activity deposited onto the soil .17
10.1 General . 17
10.2 Determination using surface activity data . 17
10.3 Determination by integration of soil profile activity data . 18
11 Recorded information .18
Annex A (informative) Diagram of the selection of the sampling strategy according to the
objectives and the radiological characterization of the site and sampling areas.19
Annex B (informative) Diagram of the evolution of the sample characteristics from the
sampling site to the laboratory .20
Annex C (informative) Example of sampling plan for a site divided in three sampling areas
(A, B, C) .21
iii
ISO 18589-2:2022(E)
Annex D (informative) Example of a sampling record for a single/composite sample .23
Annex E (informative) Example for a sample record for a soil profile with soil description .25
Bibliography .27
iv
ISO 18589-2:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation 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.
The committee responsible for this document is ISO/TC 85, Nuclear energy, nuclear technologies, and
radiological protection, Subcommittee SC 2, Radiological protection.
This third edition cancels and replaces the second edition (ISO 18589-2:2015), which has been
technically revised.
The main change is as follows:
— the review of the introduction according to the generic introduction adopted for the standards
published on the radioactivity measurement in the environment.
A list of all parts in the ISO 18589 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html
v
ISO 18589-2:2022(E)
Introduction
Everyone is exposed to natural radiation. The natural sources of radiation are cosmic rays and naturally
occurring radioactive substances which exist in the earth, flora and fauna, including the human body.
Human activities involving the use of radiation and radioactive substances add to the radiation exposure
from this natural exposure. Some of those activities, such as the mining and use of ores containing
naturally-occurring radioactive materials (NORM) and the production of energy by burning coal that
contains such substances, simply enhance the exposure from natural radiation sources. Nuclear power
plants and other nuclear installations use radioactive materials and produce radioactive effluent and
waste during operation and decommissioning. The use of radioactive materials in industry, agriculture
and research is expanding around the globe.
All these human activities give rise to radiation exposures that are only a small fraction of the global
average level of natural exposure. The medical use of radiation is the largest and a growing man-made
source of radiation exposure in developed countries. It includes diagnostic radiology, radiotherapy,
nuclear medicine and interventional radiology.
Radiation exposure also occurs as a result of occupational activities. It is incurred by workers in
industry, medicine and research using radiation or radioactive substances, as well as by crew during
air travel. The average level of occupational exposures is generally similar to the global average level of
natural radiation exposure (see Reference [1]).
As uses of radiation increase, so do the potential health risk and the public's concerns. Thus, all these
exposures are regularly assessed in order to
— improve the understanding of global levels and temporal trends of public and worker exposure,
— evaluate the components of exposure so as to provide a measure of their relative importance, and
— identify emerging issues that may warrant more attention and study.
While doses to workers are mostly directly measured, doses to the public are usually assessed
by indirect methods using the results of radioactivity measurements of waste, effluent and/or
environmental samples.
To ensure that the data obtained from radioactivity monitoring programs support their intended use, it
is essential that the stakeholders (for example nuclear site operators, regulatory and local authorities)
agree on appropriate methods and procedures for obtaining representative samples and for handling,
storing, preparing and measuring the test samples. An assessment of the overall measurement
uncertainty also needs to be carried out systematically. As reliable, comparable and ‘fit for purpose’
data are an essential requirement for any public health decision based on radioactivity measurements,
international standards of tested and validated radionuclide test methods are an important tool for
the production of such measurement results. The application of standards serves also to guarantee
comparability of the test results over time and between different testing laboratories. Laboratories
apply them to demonstrate their technical competences and to complete proficiency tests successfully
during interlaboratory comparisons, two prerequisites for obtaining national accreditation.
Today, over a hundred International Standards are available to testing laboratories for measuring
radionuclides in different matrices.
Generic standards help testing laboratories to manage the measurement process by setting out the
general requirements and methods to calibrate equipment and validate techniques. These standards
underpin specific standards which describe the test methods to be performed by staff, for example, for
different types of samples. The specific standards cover test methods for:
40 3 14
— naturally-occurring radionuclides (including K, H, C and those originating from the thorium
226 228 234 238 201
and uranium decay series, in particular Ra, Ra, U, U and Pb) which can be found in
materials from natural sources or can be released from technological processes involving naturally
occurring radioactive materials (e.g. the mining and processing of mineral sands or phosphate
fertilizer production and use);
vi
ISO 18589-2:2022(E)
— human-made radionuclides, such as transuranium elements (americium, plutonium, neptunium,
3 14 90
and curium), H, C, Sr and gamma-ray emitting radionuclides found in waste, liquid and gaseous
effluent, in environmental matrices (water, air, soil and biota), in food and in animal feed as a result
of authorized releases into the environment, fallout from the explosion in the atmosphere of nuclear
devices and fallout from accidents, such as those that occurred in Chernobyl and Fukushima.
The fraction of the background dose rate to man from environmental radiation, mainly gamma
radiation, is very variable and depends on factors such as the radioactivity of the local rock and soil, the
nature of building materials and the construction of buildings in which people live and work.
A reliable determination of the activity concentration of gamma-ray emitting radionuclides in various
matrices is necessary to assess the potential human exposure, to verify conformity with radiation
protection and environmental protection regulations or to provide guidance on reducing health risks.
Gamma-ray emitting radionuclides are also used as tracers in biology, medicine, physics, chemistry, and
engineering. Accurate measurement of the activities of the radionuclides is also needed for homeland
security and in connection with the Non-Proliferation Treaty (NPT).
This document should be used in the context of a quality assurance management system (ISO/IEC 17025).
ISO 18589 is published in several parts for use jointly or separately according to needs. These parts are
complementary and are addressed to those responsible for determining the radioactivity present in
soil, bedrocks and ore (NORM or TENORM). The first two parts are general in nature and describe the
setting up of programmes and sampling techniques, methods of general processing of samples in the
laboratory (ISO 18589-1), the sampling strategy and the soil sampling technique, soil sample handling
and preparation (ISO 18589-2). ISO 18589-3, ISO 18589-4 and ISO 18589-5 deal with nuclide-specific
test methods to quantify the activity concentration of gamma emitters radionuclides (ISO 18589-3
and ISO 20042), plutonium isotopes (ISO 18589-4) and Sr (ISO 18589-5) of soil samples. ISO 18589-6
deals with non-specific measurements to quantify rapidly gross alpha or gross beta activities
and ISO 18589-7 describes in situ measurement of gamma-emitting radionuclides.
The test methods described in ISO 18589-3 to ISO 18589-6 can also be used to measure the radionuclides
in sludge, sediment, construction material and products following proper sampling procedure.
This document is one of a set of International Standards on measurement of radioactivity in the
environment.
vii
INTERNATIONAL STANDARD ISO 18589-2:2022(E)
Measurement of radioactivity in the environment — Soil —
Part 2:
Guidance for the selection of the sampling strategy,
sampling and pre-treatment of samples
1 Scope
This document specifies the general requirements, based on ISO 11074 and ISO/IEC 17025, for all
steps in the planning (desk study and area reconnaissance) of the sampling and the preparation of
samples for testing. It includes the selection of the sampling strategy, the outline of the sampling plan,
the presentation of general sampling methods and equipment, as well as the methodology of the pre-
treatment of samples adapted to the measurements of the activity of radionuclides in soil including
granular materials of mineral origin which contain NORM or artificial radionuclides, such as sludge,
sediment, construction debris, solid waste of different type and materials from technologically
enhanced naturally occurring radioactive materials (mining, coal combustion, phosphate fertilizer
production etc.).
For simplification, the term “soil” used in this document covers the set of elements mentioned above.
This document is addressed to the people responsible for determining the radioactivity present in
soil for the purpose of radiation protection. It is applicable to soil from gardens, farmland, urban, or
industrial sites, as well as soil not affected by human activities.
This document is applicable to all laboratories regardless of the number of personnel or the range of
the testing performed. When a laboratory does not undertake one or more of the activities covered by
this document, such as planning, sampling, test or calibration, the corresponding requirements do not
apply.
NOTE The term “laboratory” is applicable to all identified entities (individuals, organizations, etc.)
performing planning, sampling, test and calibration.
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 11074, Soil quality — Vocabulary
ISO 18589-1, Measurement of radioactivity in the environment — Soil — Part 1: General guidelines and
definitions
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
3 Terms and definitions
For the purposes of this document, the terms, definitions, and symbols given in ISO 80000-10,
ISO 18589-1, ISO 11074, and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
ISO 18589-2:2022(E)
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols
e thickness of the layer sampled
m wet mass of the sorted sample
ss
m′ wet mass of a subsample of the sorted sample
ss
m dry mass of the test sample
ts
a activity per unit of mass of the test sample
A activity per unit area
S
S surface area sampled
5 Principle
The purpose of the measurement of soil radioactivity is to monitor the environmental impact of
[2] [3][4][5][6]
radioactive substances and/or to assess the radiological impact on the population .
The main objectives of the measurement of radionuclides in soil (see ISO 18589-1) are the following:
— characterization of radioactivity in the environment;
— routine surveillance of the impact of radioactivity released from nuclear installations or of the
general evolution of the radioactivity in a region;
— investigations of accidents and incidents;
— planning and surveillance of remedial action;
— decommissioning of installations or the disposal of materials.
Consequently, measurements of soil radioactivity are performed in a variety of situations, but a generic
approach can be described, with the following steps as outlined in this document:
a) Planning process — Selection of the sampling strategy
The selection of the sampling strategy depends on the main objectives and on the results of the
initial investigation of the area. The sampling strategy shall lead to the knowledge of the nature,
activity concentrations, spatial distribution of the radionuclides, as well as their temporal evolution,
taking into account changes caused by migration, atmospheric conditions, and land/soil use.
An initial investigation of the area shall be carried out to determine the sampling strategy.
ISO 18400-104 gives general guidance on sampling strategies and ISO 18400-202 on preliminary
investigations. ISO 18400-205 gives specific guidance for the investigation of natural, near-natural,
and cultivated areas; and ISO 18400-203 deals with the investigation of potentially contaminated
sites.
Details are given in Clause 6 and a scheme for the selection of the sampling strategy is given in
Annex A.
b) Planning process — Sampling plan
The sampling plan shall be developed according to the sampling strategy selected. It shall specify
the selection of sampling areas and units, the sampling pattern, the sampling points, the types
ISO 18589-2:2022(E)
of samples, the sampling procedures and equipment, as well as the safety requirements for the
personnel.
ISO 18400-107 gives general guidance on the framework for the preparation and application of a
sampling plan.
Details, such as the selection of sampling areas and the sampling units that result from the type
of grid applied to these areas, are given in Clause 7. Definitions of the types of samples are given
in ISO 18589-1. The relationship between samples types is given in Annex B.
c) Sampling process — Collection of samples
The collection of any soil samples in the field shall conform to the established sampling plan.
— For sampling of the top layer, a single sample or n increments of a defined thickness are taken from
each of the selected sampling units.
— For vertical sampling of several soil layers, samples are taken at increasing depth vertically below
the surface sampling point. A single sample or n increments are collected from the various soil layers
with different thicknesses according to the sampling depth. Special care should be exercised in
order not to mix samples from different soil layers.
Reference [12] gives guidance on recording and reporting of the samples.
Details are given in Clauses 7 and 8.
d) Sampling process — Preparation of the sorted sample
The preparation of sorted samples is carried out by the reduction of single or composite
samples. A sorted sample should be representative of the average value of one or more given
soil characteristics. The identification, labelling, packaging, and transport procedures of sorted
samples to the laboratory shall guarantee the preservation of their characteristics.
Details are given in 8.3, 8.4, and 8.5.
e) Laboratory process — Handling of the laboratory sample
After arrival at the laboratory, the sorted samples are considered as laboratory samples for storage
and further pre-treatment before their analysis.
Details are given in Clause 9.
f) Laboratory process — Preparation of the test sample
Before any testing, the laboratory samples are pre-treated by drying, crushing, sieving, and
homogenizing to produce test samples in the form of a fine, homogeneous powder. Pre-treatment
shall guarantee that the physical and chemical characteristics of the test sample are constant
over time, thus rendering the results easier to interpret. Representative subsamples with masses
determined by the specifications of the different radioactivity measurements shall be isolated from
the test sample as test portions.
Details are given in Clause 9.
If some material is stored for future investigations or for the purpose of settling a potential dispute,
subsamples shall be taken from the laboratory sample or the test sample in an acceptable and
documented manner.
ISO 18589-2:2022(E)
6 Sampling strategy
6.1 General
During the planning process, the sampling strategy for the site under investigation is determined
[2]
according to the objectives described in Clause 5 item a), resulting in the definition of a sampling plan
[3][5][7][8][9]
.
6.2 Initial investigation
Whatever the objective of the work being carried out is, certain preliminaries shall be undertaken
during the initial investigation phase to help define the sampling strategy, such as the following:
— analysis of historical and administrative data, company archives, previous studies, and interviews
with former employees, which help identify potential sources of radioactive contamination;
— collection of information on geological, hydrological, and pedological characteristics and on the
main climatic parameters, in order to characterize the spatial and temporal development of the
characteristics of the radioactivity of an area;
— survey of the site under investigation to identify its topography, the nature of the vegetation cover,
and any peculiarities that can affect the techniques and the sampling plan;
— for farmland, collection of information from the farmers on the nature and depth of works (sub-
soiling or drainage, ploughing and harrowing ditches, etc.) and on chemical fertilizers and additives
that can lead to excessive natural radioactivity (nature and quantity of products applied).
When data on radioactive soil contamination are not available or in case of suspicion of contamination,
in situ analytical investigation using portable detectors or some preliminary sampling and subsequent
laboratory analysis can be necessary in order to select the sampling areas and strategy.
6.3 Types of sampling strategies
Sampling strategies are either orientated or probabilistic depending upon the objectives and the initial
knowledge of radioactivity distribution over the area under investigation.
Orientated strategies are based on a priori constraints that lead to a selection of sampling units in a
specific area under special scrutiny because of particular interest or level of contamination.
Probabilistic strategies are based on a selection of sampling units without any a priori constraints.
The selection of sampling units and points is described in 7.2.
6.4 Selection of the sampling strategy
The approach or sampling strategy shall be selected depending on the objective pursued and the
relevant end points, for example the protection of humans and the environment, taking into account
social and economic constraints. The sampling strategy selected should ensure that the radioactivity
of the samples is representative of the distribution of radionuclides in the soil of the area under
investigation (see ISO 18400-101 and References [2][3][5][7]).
Although the strategy can only be defined on a case-by-case basis, the selection of the sampling strategy
should follow these stages:
— analysis of the records, which enables an historic study of the sampling site, in particular of its
previous use (identification of the source);
— evaluation of preferential migration pathways and/or accumulation areas;
— site reconnaissance with respect to the boundaries of the sampling areas and sampling undertaken;
ISO 18589-2:2022(E)
— site reconnaissance: a rapid analytical investigation using portable radioactivity detectors can be
used to characterize the distribution of the radioactivity of the areas to be studied.
This step in the planning process determines a large number of choices and can generate important
and costly activities. It also includes the definition of the objectives of the data quality according to the
parameters to be analysed.
Annex A gives a flow diagram that helps in the selection of a sampling strategy according to the
objectives of the investigation.
The choice of the strategy determines the sampling density, the temporal and spatial distribution of
the units from which samples are collected and the timing of the sampling, taking into account the
following:
— potential distribution of radionuclide: homogeneous or heterogeneous (“hot” spots);
— characteristics of the environment;
— minimum mass of soil necessary to carry out all the laboratory tests;
— maximum number of tests that can be performed by the laboratory for the study.
In many cases, a prediction of the possible presence of soil contamination and its distribution
(homogeneous or heterogeneous) can be drawn up. It is then necessary to verify these hypotheses
by an orientated sampling strategy. One variant of this strategy, which is systematic with selected
representative sampling points, is adapted for the routine monitoring of sites whose radioactive origins
and distribution patterns are known. This allows a more accurate definition of the number and location
of the sampling points than a purely probabilistic sampling strategy. This subjective selection of the
sampling points can be combined with a statistical approach to meet the quality requirements for the
interpretation. When the spatial radioactivity distribution is unknown, it is necessary to adopt an
orientated spatially random strategy.
Probabilistic strategies with random sampling (random distribution of sampling points) are suitable
only if the distribution of the radioactivity on the site is considered homogeneous. For a site with
occasional heterogeneities (point sources), the implementation of a systematic sampling strategy that
is dependent upon the degree of knowledge of the distribution of these heterogeneities in the different
sampling areas is recommended.
When the objective of the investigation is the characterization of a recent deposit on the soil surface,
such as in the case of fallout following a routine, authorized gaseous release, or an accident, the
collection of the top layer is recommended.
When the objective is the study of a polluted site, where it is necessary to know the vertical migration of
radionuclides with depth (in order to predict the potential contamination of the groundwater), samples
from layers at various depths shall be collected. Layers can be defined either with the same thickness
or as representative of the different soil horizons.
The sampling strategy leads to a set of technical options that are detailed in Clause 7.
7 Sampling plan
7.1 General
The sampling plan is a precise procedure that, depending on the application of the principles of the
strategy adopted, defines all actions to be realized in the field. The plan also defines the human
resources needed for the sampling operation. The plan is directly linked to the purposes of the study,
the characteristics of the environment of the site, the capacity of the laboratory testing facilities, and
the objectives for the data quality requisite for the interpretation of the results of the measurements.
ISO 18589-2:2022(E)
The sampling plan shall be set up on a case-by-case basis. The plan shall contain all information
needed to perform the sampling, e.g. sampling areas, sampling units, location of sampling points in the
sampling units, types of samples, single or composite, number of increments for composite samples,
periodicity, required mass of a sample considering the planned tests, requirement for archiving the
material, vertical distribution, etc.
7.2 Selection of sampling areas, units, and points
7.2.1 General
After deciding on the sampling strategy, sampling areas and units are defined based on the results of
the initial investigation. In some cases, the boundaries of sampling areas and the location of sampling
units for routine surveillance/monitoring can be fixed by legal requirements, for example as in the
operation of a new nuclear installation. They are defined as a result of the reference radiological
study performed for the project. For accident investigations, the size of the sampling area and location
of the sampling units can also be determined by the environmental conditions (wind strength and
direction, topography, etc.) at the time of accident, as well as the variation of the source characteristics
(radionuclides, activity, release duration, etc.).
For a probabilistic strategy, the sampling units can be selected either by systematic or random
approaches whereas it cannot be done by a random approach for an orientated strategy.
For both strategies, the sampling points can be selected either by a systematic or a random approach.
On the same site, depending on the heterogeneity of the radioactivity distribution, a combination of
these strategies can be applied to the different sampling areas.
7.2.2 Sampling for use with a probabilistic strategy
For a probabilistic strategy, the sampling areas, following their identification, are covered with a grid
that defines the sampling units. The size of the grid mesh should take into account the surface area of
the site and is also governed by the analytical capacity of the laboratory and the financial constraints
that restrict the number of samples that can be analysed. The surface area of the grid units can range
from a few square metres to several square kilometres depending on the site under investigation.
If a radioactivity map is available as a result of a preliminary in situ radiological inspection
(see Reference [10]), the grid mesh imposed on the sampling area can correspond to the grid adopted
for the radioactive cartography. The radioactivity map can be denser where contaminated areas are
suspected, or less dense in the presumed absence of contamination.
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