prEN ISO 5667-15

SLOVENSKI STANDARD
01-september-2025
Kakovost vode - Vzorčenje - 15. del: Konzerviranje in ravnanje z vzorci blata,
sedimenta in suspendiranih snovi (ISO/DIS 5667-15:2025)
Water quality - Sampling - Part 15: Preservation and handling of samples of sludge,
sediment and suspended matter (ISO/DIS 5667-15:2025)
Wasserbeschaffenheit - Probenahme - Teil 15: Anleitung zur Konservierung und
Handhabung von Schlamm- und Sedimentproben (ISO/DIS 5667-15:2025)
Qualité de l’eau - Échantillonnage - Partie 15: Conservation et traitement des
échantillons de boues, de sédiments et de matières en suspension(ISO/DIS 5667-
15:2025)
Ta slovenski standard je istoveten z: prEN ISO 5667-15
ICS:
13.030.20 Tekoči odpadki. Blato Liquid wastes. Sludge
13.060.45 Preiskava vode na splošno Examination of water in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 5667-15
ISO/TC 147/SC 6
Water quality — Sampling —
Secretariat: BSI
Part 15:
Voting begins on:
Preservation and handling of 2025-07-09
samples of sludge, sediment and
Voting terminates on:
2025-10-01
suspended matter
ICS: 13.060.45; 13.030.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
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BEING ACCEPTABLE FOR INDUSTRIAL,
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USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
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POTENTIAL TO BECOME STANDARDS TO
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PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 5667-15:2025(en)
DRAFT
ISO/DIS 5667-15:2025(en)
International
Standard
ISO/DIS 5667-15
ISO/TC 147/SC 6
Water quality — Sampling —
Secretariat: BSI
Part 15:
Voting begins on:
Preservation and handling of
samples of sludge, sediment and
Voting terminates on:
suspended matter
ICS: 13.060.45; 13.030.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
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Published in Switzerland Reference number
ISO/DIS 5667-15:2025(en)
ii
ISO/DIS 5667-15:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms for plastics . 3
5 Sampling and chain of custody . 3
6 Reagents . 3
7 Sample handling and preservation . 4
7.1 General .4
7.2 Sample handling and preservation for chemical analysis .5
7.3 Sample handling and preservation for physical analysis .5
7.4 Sample handling and preservation for radiochemical analysis .5
7.5 Sample handling and preservation for hydrobiological analysis .5
7.6 Sample handling and preservation for microbiological analysis .5
8 Safety precautions. 6
8.1 Staff protection .6
8.2 Sample protection.6
9 Containers . 6
10 Sample collection . 6
11 Identification of samples . 7
12 Sample transport . 7
13 Sample reception . 8
14 Sample storage . 8
Annex A (informative) Techniques for sample preservation .10
Annex B (informative) Container preparation .25
Annex C (informative) Long term storage of wet sediment samples using nitrogen vapour
freezes .27
Bibliography .29

iii
ISO/DIS 5667-15:2025(en)
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 6,
Sampling (general methods).
This third edition cancels and replaces the second edition (ISO 5667-15:2009), which has been technically
revised.
The main changes are as follows:
— ‘suspended matter’ has been added to the title and ‘guidance’ has been deleted from the title;
— ISO/TS 5667-25 has been added as a reference;
— a flow diagram for preservation and storage of samples of sludge, sediment and suspended matter has
been added (in line with ISO 5667-3:2024);
— terms and definitions have been aligned with ISO 5667-3:2024;
— tables from clause 12 have been moved to Annex A;
— references in the previous Tables 1 to 3 have been added;
— the previous Table 3 has been split into Table A.3 ‘Hydrobiological analysis’ and Table A.4 ‘Microbiological
analysis’.
A list of all parts in the ISO 5667 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.

iv
ISO/DIS 5667-15:2025(en)
Introduction
[1]
This document is intended to be used in conjunction with ISO 5667-1, which deals with the design
of sampling programmes and sampling techniques.
Where possible, this document has been aligned with current standards. Where new research or validation
results have provided new insights, the latest knowledge has been used.
[6]
Guidance on validation protocols can be found in ISO/TS 5667-25 .
Tables A.1 to A.4 provide the validated preservation times or conditions as well as the descriptions of best
practice. Tables A.1 to A.4 also refer, for each parameter, to references available at the time of publication of
this document (i.e. ISO 5667-15:202x). This is however not an exhaustive list. Other preservation methods
may be used when they have been validated. However, it is strongly recommended that, where a method
validation is not available, the preservation times for the analyte listed in Tables A.1 to A.4 for ISO and CEN
test methods be followed. In case more than one storage time is provided in Tables A.1 to A.4, the order of
preferred use is:
— validated method;
— method provided by reference;
— best practice.
The preservation and storage conditions and maximum storage times per parameter as listed in Tables A.1
to A.4 should be regarded as default conditions to be applied in the absence of any other information.
However, if validation of preservation techniques and holding times has been carried out, relative to specific
circumstances and matrices, by a laboratory, then, provided that it can produce evidence of this validation
where they differ from those set out in Tables A.1 to A.4, these validated preservation and storage conditions
and maximum storage times are deemed acceptable for use by the validating laboratories. A national
standard can contain information on preservation.
NOTE Samples of sludge, sediment and suspended matter that are dried or freeze-dried behave similarly to dried
[37]
soils. For guidance on freeze-drying, see ISO 16720 .
This document and the related analytical references can be used as presented in Figure 1.

v
ISO/DIS 5667-15:2025(en)
WARNING — ‘Method provided by reference’ and ‘validated method’ can be based on previous
[6]
standards and methods and therefore not be in line with ISO/TS 5667-25. This information can be
interpreted by a qualified and experienced person.
Figure 1 — Flow diagram for the selection of a method for the preservation
and storage of samples of sludge, sediment and suspended matter
[6]
Attention is drawn to ISO/TS 5667-25, which contains guidelines and the elaboration of the required
techniques of how to validate new storage times or preservative methods and details of the techniques
described.
vi
DRAFT International Standard ISO/DIS 5667-15:2025(en)
Water quality — Sampling —
Part 15:
Preservation and handling of samples of sludge, sediment and
suspended matter
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 in accordance with this document be
carried out by suitably qualified staff.
1 Scope
This part of ISO 5667 specifies the general requirements on procedures for the preservation, handling and
storage of samples of sewage and waterworks sludge, suspended matter, marine sediments and freshwater
sediments for chemical, physical, radiochemical and/or biological examination in the laboratory.
The procedures in this part of ISO 5667 are only applicable to wet samples of sludge, sediment
and suspended matter.
NOTE The storage conditions given do not necessarily apply for derived samples, for example sediment eluates or
extracts.
This document is not applicable to samples intended for biotesting with ecotoxicological or biological assays
[5] [7]
(which is specified in ISO 5667-16 ) nor intended for microplastics (which is specified in ISO 5667-27 ).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
best practice
method based upon consensus or general use and that can be referred to in literature
Note 1 to entry: Given the differences in conditions and circumstances as well as the impossibility to validate
all parameters from a validated method (3.10) or technique or process, a best practice method based upon the
corresponding properties of a validated parameter can be used.
[2]
[SOURCE: ISO 5667-3:2024, 3.1]

ISO/DIS 5667-15:2025(en)
3.2
integrity
property of the parameter(s) of interest, information or content of a sample stored in a container that has
not been altered or lost in an unauthorized manner or that has been subject to loss of representativeness
[2]
[SOURCE: ISO 5667-3:2024, 3.2]
3.3
method provided by reference
procedure or technique for the preservation of samples taken from the reference to which it refers
Note 1 to entry: It is not in all cases clear whether the preservation procedure provided by the reference was validated
method (3.10), a best practice (3.1) or which procedure was used for its determination or validation. Where available,
the information about the matrices is taken over.
[2]
[SOURCE: ISO 5667-3:2024, 3.3]
3.4
sample preservation
procedure used to stabilize a sample in such a way that the properties under examination are maintained
stable from the collection step until preparation for analysis
Note 1 to entry: Different analytes can require several samples from the same source that are stabilized by different
procedures. More subsamples from one location can be needed as some parameters require a different preservation
procedure.
[10]
[SOURCE: ISO 11074:2025, 3.401, modified — Note 1 to entry has been added.]
3.5
sample storage
process and the result of keeping a sample available under predefined conditions, usually for a specified
time interval between collection and further treatment of a sample
Note 1 to entry: The specified time is the maximum time interval.
[10]
[SOURCE: ISO 11074:2025, 3.407, modified — Note 1 to entry has been added; “soil sample” has been
changed to “sample”.]
3.6
sediment
matter which settles to the bottom of a liquid, often transported in water before settlement occurs
Note 1 to entry: Sediment samples in this document are a part of water quality analysis. The liquid in this case
is therefore water.
[8]
[SOURCE: ISO 6107:2021, 3.505, modified — Note 1 to entry has been added.]
3.7
sludge
mixture of water and solids originating from various types of water during natural and artificial treatment
[43]
[SOURCE: ISO 19698:2020, 3.23, modified — The word “wastewater” has been replaced by “water”.]
3.8
storage time
period of time between filling of the sample container and further treatment of the sample in the laboratory,
if stored under predefined conditions
Note 1 to entry: Sampling finishes as soon as the sample container has been filled with the sample. Storage time ends
when the sample is taken by the analyst to start sample preparation prior to analysis.
Note 2 to entry: Further treatment is, for most analytes, a solvent extraction or acid destruction. The initial steps
of sample preparation can be steps complementary to the storage conditions for the maintenance of analyte
concentrations.
ISO/DIS 5667-15:2025(en)
[2]
[SOURCE: ISO 5667-3:2024, 3.6]
3.9
suspended matter
solids remaining in suspension in water which can be removed by sedimentation, filtration or centrifugation
[8]
[SOURCE: ISO 6107:2021, 3.554]
3.10
validated method
method for which the validity of correctness has been checked by verification or qualification against
a number of predefined requirements
Note 1 to entry: A validated method indicates that a preservation method is capable of delivering the intended results
with an acceptable degree of uncertainty for the parameter or group of parameters and sample type.
[2]
[SOURCE: ISO 5667-3:2024, 3.7]
4 Abbreviated terms for plastics
FEP perfluoro(ethylene/propylene)
PE polyethylene
PE-HD high density polyethylene
PET polyethylene terephthalate
PFA perfluoroalkoxy (polymer)
PP polypropylene
PTFE polytetrafluoroethylene
PVC poly(vinyl chloride)
5 Sampling and chain of custody
If there is a need to take samples, this is done according to a sampling programme. The first step is to design
[1]
a sampling programme. Guidance on this topic is given in ISO 5667-1 .
Depending on the sample type and matrix, instructions are given in the relevant part(s) of the ISO 5667 series.
The process of preservation and handling of samples consists of several steps. During this process, the
responsibility for the samples can change. To ensure the integrity of the samples, all steps involving the
sample shall be documented.
6 Reagents
WARNING — Sampling personnel should be warned of potential dangers and appropriate safety
procedures should be available. Beware of formaldehyde vapours. Do not store large numbers of
samples in small working areas.
All reagents and waters used shall be of at least analytical grade.
6.1 Deionized water.
ISO/DIS 5667-15:2025(en)
6.2 Sodium sulfate Na SO .
2 4
Heat the sodium sulfate before use for at least 3 h at 500 °C. Store in an desiccator after heating.
6.3 Zinc acetate solution (CH COO) Zn·2H O (100 g/l).
3 2 2
Dissolve 10,0 g of zinc acetate dihydrate in approximately 90 ml of water. Dilute to 100 ml with water.
6.4 Methanol CH OH.
6.5 Ethanol C H OH (volume fraction of 96 %).
2 5
6.6 Formaldehyde solution (formalin), CH O, φ(CH O) = 37 % (freshly prepared).
2 2
WARNING — Beware of formaldehyde vapours. Do not store large numbers of samples in small
working areas.
6.7 Sodium tetraborate (Na B O ·10H O).
2 4 7 2
6.8 Hexamethylenetetramine [(CH ) N ]
2 6 4
6.9 Neutralized formaldehyde solution formaldehyde solution (6.6) neutralized with sodium
tetraborate (6.7) or hexamethylenetetramine (6.8).
Formalin solution at 100 g/l gives a final solution of φ(CH O) = 3,7 %.
WARNING — Beware of formaldehyde vapours. Do not store large numbers of samples in small
working areas.
7 Sample handling and preservation
7.1 General
Sample handling is specific for each determination to be conducted. Manipulation of samples is often
required to yield consistent material for analysis. Homogenization, by mixing or sieving, dilution to obtain
a suitable concentration and addition of chemical preservatives all complicate interpretations of in situ
comparisons.
Any large individuals of macrofauna should be removed from the samples immediately after collecting
samples taken for the chemical, physical, radiochemical and/or biological examinations.
The purpose of preservation is to retain the integrity of the collected material as it was on site in relation
to the parameters to be analyzed. Analytes might be subject to biotransformation, volatilization and
chemical transformation (e.g. oxidation, reduction, hydrolysis, photolysis) during storage. Therefore, careful
consideration should be given to these processes and the storage conditions needed to avoid such alterations.
The need to preserve sludge, sediment and suspended matter begins immediately after a sample has been
taken. The most critical changes to the sample can occur in the first few hours after sampling. Therefore,
where possible, preservation steps should be taken immediately upon sample collection.
The choice of preservation technique depends mainly on the objective of the sample collection and the
analysis being determined. It is important to understand the effects that preservation and storage can have
on the sample quality and the analysis results.
No other general recommendations can be given for a preservation or storage method. A preservation
method suitable for one group of parameters can interfere with the analysis of other groups of parameters.
To overcome this problem, a number of sub-samples should be collected; each sub-sample should be
preserved using a suitable method such that the specific demands of each analytical parameter are met.

ISO/DIS 5667-15:2025(en)
7.2 Sample handling and preservation for chemical analysis
Chemical analysis can be performed to determine the nature and amounts of the substances that are
contained in the whole sample, dissolved in the aqueous phase and absorbed by sludge, sediment or
suspended matter.
Partition of chemical components between the solid phase and the water phase is influenced by several
factors, such as particle size, amount of organic matter, pH, redox potential and salinity. The study of such
attributes can be a sampling objective. Therefore, the preservation needs for the analytical methods to be
employed should be taken into account (see Table A.1). The guidance given in this part of ISO 5667 is relevant
to the determination of components in the sum of the separate phases of sludge, sediment or suspended
matter, unless otherwise indicated.
Preservation of samples by freezing can cause mobilization of contaminants by cellular disruption, whereas
not stabilizing samples can permit continued microbial transformation of critical parameters of interest. In
addition to biodegradation of organics, volatilization is a principal mechanism of loss of volatile compounds
during sample handling. Microbial activity can be responsible for changes in the nitrate-nitrite-ammonia
content, for decrease in biochemical oxygen demand, or for reducing sulfate to sulfide. Anoxic samples
require appropriate preservation techniques such as oxygen exclusion during sample handling. Drying,
freezing and freeze-drying of anoxic samples alter the binding sites of, for example, heavy metals, making
more differentiated investigation of binding forms virtually impossible.
Details of the sample preservation are given in Table A.1.
7.3 Sample handling and preservation for physical analysis
The structure, texture and, for sediments, the layer formation should be determined.
NOTE Sediment matrix changes are obvious if rapid drainage of pore water occurs.
The importance of sludge, sediment or suspended matter integrity to the investigation objectives should be
evaluated as it can influence the preservation and handling techniques. In general, any disturbance of the
samples should be minimized. Where the physical structure of the material sampled is important for the
measurement of parameters (e.g. resistance to filtration), agitation and vibration during transport should
be reduced to a minimum. Freezing of the sludge, sediments or suspended matter may be appropriate. In
some cases, thermal techniques should be avoided as they strongly modify sludge structure, thus affecting
physical characteristics (e.g. de-waterability, settleability, flowability).
Details of the sample preservation are given in Table A.1.
7.4 Sample handling and preservation for radiochemical analysis
Some sampling sites can have measurable radiochemical activity, e.g. in the soil or air. Some items of domestic
equipment within the laboratory can also be a source of radioactive material. Contamination of the sample
by its environment should therefore be avoided, especially if the sample activity is likely to be very low.
Details of the sample preservation are given in Table A.2.
7.5 Sample handling and preservation for hydrobiological analysis
Hydrobiological analysis generally involves classifying the species and numbers of flora and/or fauna
present on and in fixed sludge or sediments.
Details of the sample preservation are given in Table A.3.
7.6 Sample handling and preservation for microbiological analysis
Microbial activity may also be used to characterize samples and can only be determined without fixation.
Details of the sample preservation are given in Table A.4.

ISO/DIS 5667-15:2025(en)
8 Safety precautions
8.1 Staff protection
Health and safety precautions should be observed at all times when sampling potentially hazardous sludge,
sediments or suspended matter.
Human exposure to pathogenic organisms or pollutants should be avoided by using appropriate protective
equipment such as respiratory protective masks, safety glasses, safety boots and protective gloves.
The hazard due to pathogenic organisms in sludge can be very high. It is vital that all sampling personnel
should receive thorough training and be provided with appropriate medical inoculations.
Degradation of sludge produces methane, which presents a risk of fire and explosion if a source of ignition
is present. Containers should be appropriately packed to minimize the fragmentation of the containers if an
excessive pressure build-up of methane occurs.
If sludge samples are to be taken in locations where there is restricted ventilation, staff should take safety
precautions to protect themselves against sulfide, carbon dioxide and methane.
8.2 Sample protection
When sampling, transporting and utilizing sludge, care should be taken to prevent a build-up of gas pressure
in the sample container. Manual release of pressure during and after transport may be necessary if prolonged
storage is required.
Samples collected for the analysis of volatile organic or sulfide compounds should not be homogenized
because many of these compounds could be lost while compositing.
9 Containers
Sample containers should be made of a material appropriate for preserving the natural properties of both
the sample and the expected range of contaminants. Suitable types of containers for each analyte to be
measured are given in Tables A.1 to A.4.
[1]
The choice of sample container is of major importance and ISO 5667-1 provides guidance on this subject.
Although certain container materials are generally favourable for certain analytes, the use of other materials
might be technically correct.
The applicability of the specific sample containers should be verified for contaminations and analyte loss
before usage with samples to avoid the loss of samples.
If the samples are to be frozen, suitable material such as polyethylene (PE), polypropylene (PP) or
polytetrafluoroethylene (PTFE) should be used to minimize the risk of breakage.
Careful consideration should also be given to the suitability of the container for cleaning/decontamination
or disposal and appropriate action taken. Recommendations for the preparation of containers are given in
Annex B.
[4]
In 11.3 of ISO 5667-14:2014, guidance is given on measuring the contamination impact of the container. The
analyte level in the blank should be negligible compared to the analyte level to be measured in the sample.
NOTE Regular container volumes are 500 g to 1 000 g.
10 Sample collection
Samples should be collected in sufficient volumes to allow:
a) separation of sub-samples to be preserved for each type of analysis or examination to be undertaken;

ISO/DIS 5667-15:2025(en)
b) repetition of the analysis in the event of error checking or the routine quality control requirements
of duplicate analysis;
c) preparation of time-dependent composites; for example, a daily aliquot of sewage works sludge
(preserved as appropriate) may be retained to produce a composite for monthly analysis.
For sludge samples, it is recommended that the container is filled completely as far as possible, especially if
biological activity is expected, in order to reduce the risk of overpressurization and explosion.
If analysis of volatile compounds is required, containers should be completely filled with sample from the
first grab, prior to sample homogenization. No headspace should remain in either container.
If the sample is to be frozen, enough headspace should be allowed for expansion to take place.
Where samples are collected for the purpose of microscopic examination, for example of activated sludges,
it is recommended to fill the container to no more than 5 % of its capacity to ensure an oxygen supply to the
sludge prior to examination.
The temperature of the sample, especially of sludge samples, can influence the properties of the sample.
Therefore, the initial temperature of the sludge samples should be measured on site and recorded.
11 Identification of samples
Container labels should withstand wetting, drying and freezing without detaching or becoming illegible.
The labelling system shall be waterproof to allow use on site.
The exact information given in the sampling report and on the sample labels depends on the objectives of the
particular measurement programme. In all cases, an indelible label shall be secured to the sample container.
For each sample, at least the following information shall be available:
— Identification of sampling personnel;
— A unique identifier, traceable to sample date, location and sample number shall appear on the label of the
sample container.
All other information is supplementary and should be detailed in the sampling report.
12 Sample transport
Cooling or freezing procedures shall be applied to samples to increase the time period available for transport
and storage (and if required, by Tables A.1 to A.4). When transport takes place, the sampling plan (e.g.
[1]
ISO 5667-1 ) shall consider:
— the time between sampling (end of filling the sample container intended for the laboratory) and start of
transport;
— the transport time;
— the time before further treatment in the laboratory.
The sum of these three periods is limited to the maximum storage times according to Tables A.1 to A.4.
If the maximum storage time cannot be met, then the sampling plan shall be reformulated to allow these
requirements to be accommodated.
[6]
In case the requirements cannot be met, instructions given in ISO/TS 5667-25 can be used to validate the
preservation time of specific water samples or sample types.
Containers holding samples shall be protected and sealed during transport in such a way that the samples
do not deteriorate or lose any part of their content. Container packaging shall protect the containers

ISO/DIS 5667-15:2025(en)
from possible external contamination, particularly near the opening, and should not itself be a source of
contamination.
Glass containers shall be protected from potential breakage during transport by appropriate packaging.
Samples shall be transported as soon as possible after sampling and with cooling (if necessary, according to
Tables A.1 to A.4).
Laboratory samples for dispatch or transport by third parties and preserved laboratory samples should be
sealed in such manner that the integrity of the sample can be maintained.
During transportation to the laboratory, samples shall be stored in a cooling device capable of maintaining
a temperature of 5 °C ± 3 °C. Samples intended for radiochemical analysis can be placed under room
temperature. For proper evaluation of the conditions during transport, a device capable of recording the
(maximum) temperature of the air surrounding the sample can be used. The temperature sensor should
then be placed in a small container (e.g. 50 ml to 100 ml) filled with a fluid in order to avoid short time
fluctuations in temperature.
Cooling and freezing procedures applied shall be in line with instructions from the analytical laboratory.
Freezing especially requires detailed control of the freezing and thawing process in order to return
the sample to its initial equilibrium after thawing.
Samples should not be in direct contact with the ice packs.
NOTE 1 Devices capable of logging of the temperature during the transportation are available.
NOTE 2 For the transport of samples from the field to the laboratory, the preferred fluid for measuring
the temperature is glycerol. If samples are transported in the field (e.g. on large locations), the fluid can also be, for
example, water.
13 Sample reception
All relevant information regarding the sample identification in accordance with Clause 11 and the sample
transport in accordance with Clause 12 shall be recorded.
The laboratory shall receive and check information on sample preservation and sample transport conditions.
If at least one of the conditions is not met, a disclaimer should be reported along with the results.
In all cases, and especially when a “chain of custody” process needs to be established, the number of sample
containers received in the laboratory and the integrity shall be verified against the number of sample
containers submitted.
14 Sample storage
The storage time of samples of sludge, sediment and suspended matter within the laboratory is specific to
the analyte(s) to be analyzed. Samples should be stored no longer than the maximum storage times given in
Tables A.1 to A.4, with the exception of wet sediments that may be stored for longer periods when samples
are preserved using a nitrogen vapour freezer.
NOTE 1 For guidance on long-term storage of wet sediment samples using nitrogen vapour freezers, see Annex C.
[41]
NOTE 2 For further information on long- and short-term storage of dried samples, see ISO 18512 .
The refrigeration conditions within the laboratory shall be 3 °C ± 2 °C. Samples for microbiological analysis
shall be stored at 5 °C ± 3 °C. The temperature of samples frozen for preservation shall be maintained below
–18 °C, unless otherwise specified. Exceptions to these refrigeration conditions are listed in Tables A.1 to A.5.
When thawing frozen samples, it is recommended that each sample container be placed in a separate
secondary container to minimize the risk of liquid loss, should a split become apparent during the thawing
process or a rupture occur during initial freezing and storage. A mild impact can cause splitting of some
plastics at low temperatures. With respect to thawing, it is recommended that this be done under ambient
conditions.
ISO/DIS 5667-15:2025(en)
Be aware of the fact that the cooling conditions within the laboratory (1 °C to 5 °C) are different from the
cooling conditions during transport (2 °C to 8 °C).

ISO/DIS 5667-15:2025(en)
Annex A
(informative)
Techniques for sample preservation
A.1 General
This document and the analytical International Standards listed in this annex are complementary.
In some cases, the alternative preservation techniques listed contradict each other. It is intended that
where an existing analytical standard is used, the preservation technique described in that method applies.
However, alternative preservation techniques given in this document can also be appropriate. Where no
preservation method is described in the analytical International Standard, or no analytical International
Standard is used, the technique(s) listed in this document shall be used.
The information presented by line in each table comes from the international reference standard cited in the
first cell of the line and the source column (best practice, validated method, method provided by reference)
applies to the entire line.
[6]
A validation protocol used for validation studies can be found in ISO/TS 5667-25
A.2 Physicochemical and chemical analysis
The following general remarks should be noted in relation to the use of Table A.1.
— A preservation time of 1 d means that if 24 h is exceeded, this should be stated in the report.
— The types of containers are identical to those in the analytical International Standards. In some cases,
the type of container in the standard is very specific, e.g. PTFE. This can be essential when very low
concentrations of inorganic parameters have to be measured. In other cases, when the specific type of
plastic is not important, the term plastics is sufficient. Plastics used for containers in the laboratory are
for instance PE, PTFE, PET, PP, PFA and FEP.
A.3 Radiochemical analysis
The following general remarks should be noted in relation to the use of Table A.2.
WARNING — Radioprotection, such as shielding, can be necessary, depending on the activity
of the sample.
— Acidification is carried out to avoid algal growth, biological spoilage and adsorption of metal ions to the
inner wall of the sample container.
— Contamination of the sample should be avoided, especially if the sample activity is very low. Some
sample sites can have measurable activity in the soil of air, or in waters other than those being sampled.
Laboratories, as well as some items of domestic equipment, can contain radioactive material. When
sampling precipitation, any special requirements in Table A.2 are additional to those given in ISO 5667-8.
[3]
As the collection of sufficient samples can require a period of days, both the starting and finishing
times and dates should be recorded. A record of precipitation collection for the sample station for the
appropriate period should be appended. A stabilizer or carrier may be added if appropriate for the
analytes being measured.
— Plastics used for containers in the laboratory are for instance PE, PTFE, PET, PP, PFA and FEP.

ISO/DIS 5667-15:2025(en)
NOTE Some plastic bottles slowly concentrate samples over a period of many months by being very slightly
permeable to water.
A.4 Hydrobiological analysis
The following general remarks should be noted in relation to the use of Table A.3.
— Plastics used for containers in the laboratory are for instance PE, PTFE, PET, PP, PFA and FEP.
— If a preservation method is not specified, it is generally unimportant. The indication “1 month” represents
preservatio
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