SIST ISO 5667-4:2018

INTERNATIONAL ISO
STANDARD 5667-4
Second edition
2016-07-01
Water quality — Sampling —
Part 4:
Guidance on sampling from lakes,
natural and man-made
Qualité de l’eau — Échantillonnage —
Partie 4: Lignes directrices pour l’échantillonnage des eaux des lacs
naturels et des lacs artificiels
Reference number
ISO 5667-4:2016(E)
©
ISO 2016

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ISO 5667-4:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

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ISO 5667-4:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling equipment . 2
4.1 Material selection . 2
4.2 Cleaning . 3
4.3 Maintenance . 3
5 Design of the sampling programme . 3
6 Sampling procedure . 4
6.1 General . 4
6.2 Sampling location . 4
6.2.1 General. 4
6.2.2 Horizontal distribution of sampling positions . 4
6.2.3 Vertical distribution of sampling points . 5
6.3 Frequency and timing of sampling . 5
6.4 Choice of sampling method . 5
6.5 Choice of the sampling device . 5
6.6 Aids for recovery of lost sampling equipment . 6
6.7 Blank sample . 6
6.8 Transport, stabilization and keeping of samples . 6
7 Occupational health and safety . 6
8 Sample containers . 6
9 Priority of procedure . 6
10 Sample collection, contamination with environmental materials .8
11 Rinsing the sampling equipment . 9
12 Sampling surface or near-surface water with an open sampling device .9
12.1 General . 9
12.2 Sampling . 9
12.3 Filling multiple containers . 9
13 Sampling with closed samplers.10
14 Sampling for volatile parameters .10
15 Sampling through ice .10
16 Severe freezing conditions .10
17 Sample identification and records .11
18 Quality assurance and quality control .11
18.1 General .11
18.2 Avoidance of contamination .12
Annex A (informative) Examples of sampling devices .14
Annex B (informative) Advantages and disadvantages of sampling equipment .28
Annex C (informative) Sampling from boats — Maintaining station .29
Annex D (informative) Example of a report — Sampling from lakes, natural and man-made .31
Annex E (informative) Continuous measurement of water samples with immersion probes .32
Bibliography .34
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ISO 5667-4:2016(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 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 147, Water quality, Subcommittee SC 6, Sampling
(general methods).
This second edition cancels and replaces the first edition (ISO 5667-4:1987), which has been technically
revised.
ISO 5667 consists of the following parts, under the general title Water quality — Sampling:
— Part 1: Guidance on the design of sampling programmes and sampling techniques
— Part 3: Preservation and handling of water samples
— Part 4: Guidance on sampling from lakes, natural and man-made
— Part 5: Guidance on sampling of drinking water from treatment works and piped distribution systems
— Part 6: Guidance on sampling of rivers and streams
— Part 7: Guidance on sampling of water and steam in boiler plants
— Part 8: Guidance on the sampling of wet deposition
— Part 9: Guidance on sampling from marine waters
— Part 10: Guidance on sampling of waste waters
— Part 11: Guidance on sampling of groundwaters
— Part 12: Guidance on sampling of bottom sediments
— Part 13: Guidance on sampling of sludges
— Part 14: Guidance on quality assurance and quality control of environmental water sampling and
handling
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ISO 5667-4:2016(E)

— Part 15: Guidance on the preservation and handling of sludge and sediment samples
— Part 16: Guidance on biotesting of samples
— Part 17: Guidance on sampling of bulk suspended solids
— Part 19: Guidance on sampling of marine sediments
— Part 20: Guidance on the use of sampling data for decision making — Compliance with thresholds and
classification systems
— Part 21: Guidance on sampling of drinking water distributed by tankers or means other than
distribution pipes
— Part 22: Guidance on the design and installation of groundwater monitoring points
— Part 23: Guidance on passive sampling in surface waters
— Part 24: Guidelines for the auditing of water quality sampling
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INTERNATIONAL STANDARD ISO 5667-4:2016(E)
Water quality — Sampling —
Part 4:
Guidance on sampling from lakes, natural and man-made
1 Scope
This part of ISO 5667 gives guidelines for the design of sampling programmes, techniques and the
handling and preservation of samples of water, from natural and man-made lakes during open-water
and ice-covered conditions. This part of ISO 5667 is applicable to lakes with and without aquatic
vegetation.
Guidance on sampling for microbiological examination is not included.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
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 5667-14, Water quality — Sampling — Part 14: Guidance on quality assurance and quality control of
environmental water sampling and handling
ISO 7027, Water quality — Determination of turbidity
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
grab sample
single discrete sample collected from a body of water at a specific time, location and depth
3.2
depth profile samples
two or more discrete samples collected at two or more depths at a specific time and location on a lake
3.3
area profile samples
two or more discrete samples collected from the same depth at two or more locations on a lake
3.4
composite sample
two or more depth profile (3.2) or area profile samples (3.3) that are combined to form a single sample
prior to measurement of water quality parameters
3.5
integrated sample
single sample collected by a tube or similar sampler that collects a water sample across a range of depths
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ISO 5667-4:2016(E)

3.6
in-situ measurement
measurement of a water quality parameter made within a body of water, not requiring collection of a
water sample
Note 1 to entry: The measurement is generally taken by use of an electronic probe.
3.7
ex-situ measurement
measurement of a water quality parameter made outside a body of water, and requiring collection and
possibly transport of a water sample prior to measurement
3.8
open sampling device
open-mouthed vessel, including beakers, buckets, containers or tubes, used for sampling at or near the
water surface (<1 m depth)
Note 1 to entry: Open sampling devices are not suitable for sampling for volatile parameters or dissolved gases.
3.9
closed sampling device
vertically or horizontally aligned hollow-bodied tube, pipe, box or container fitted with shutters, valves,
stoppers or other devices that prevent entry of air into and/or enclosure of air with the water sample
and the exchange of water between the collected sample and the surrounding water column
Note 1 to entry: Closed sampling devices are used for collecting water samples from deeper waters or for
collection of water samples for the analysis of volatile parameters and dissolved gases.
3.10
sampling pole
pole or rod with a terminal apparatus that accepts an open or closed sampling device (3.9) and that is
used to extend the reach of samplers
3.11
sampling iron
weighted container holder attached to a line and used to extend the reach of samplers or to submerse a
sample container to a specific depth
3.12
pumping device
hand or motor operated suction or submersible pumps, or pneumatic ejection samplers used for
collection of samples from defined depths or a series of depths
3.13
filling device
funnel, ladle, churn sample splitter or other device used to transfer sample water from a sampling
device to a sampling container
3.14
negative control
quality control sample that is used to ensure a negative response
4 Sampling equipment
4.1 Material selection
Sampling probes, devices and other equipment should be chosen, as far as possible, which do not give
rise to any interaction between the water and the material composition. The equipment and devices
to be used should be checked at random for the presence of emission, absorption and adsorption of
substances or influence of properties that are to be determined in the samples to be taken. Examples of
2 © ISO 2016 – All rights reserved

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ISO 5667-4:2016(E)

common sampling equipment are summarized in Annex A. Advantages and disadvantages of sampling
equipment are provided in Annex B. If a boat, marine vessel or any floatation device is used, care
shall be taken so that it does not result in contamination of the samples. Additional details regarding
sampling from a vessel are summarized in Annex C. A winch with steel rope and counter is advisable for
deeper lakes. This ensures the required sinking and resurfacing velocity of the sampling devices. Any
solvents, chemicals or fuels should be stored in sealed non-permeable containers. For example, the use
of electric motors on small boats can be of value in eliminating the risk of contamination by combustion
exhaust and engine lubricants. ISO 5667-14 provides guidance for checking the uptake and emission of
the substances to be measured by equipment and devices that are used for sampling.
4.2 Cleaning
A proper quality assurance and quality control (QA/QC) system should be in place to prevent
contamination and detect any contamination that could affect analytical results. All equipment and
devices should be regularly mechanically and, if appropriate, chemically cleaned, both internally and
externally, to prevent contamination of water samples.
4.3 Maintenance
Where equipment uses mechanical or other triggering devices, these mechanisms should be regularly
tested. Electronic devices and probes should be tested and calibrated according to the manufacturer’s
recommendations. A log of testing and calibration dates and results should be maintained.
5 Design of the sampling programme
Proper sampling is critical to ensure the quality of the investigation and resulting data. Developing
a detailed sampling strategy prior to collecting samples will minimize any sampling errors and will
provide the most representative sample for analysis. General aspects that should be considered in a
sampling programme are summarized in ISO 5667-1. These include, but are not limited to, the following:
a) purpose of the investigation;
b) parameters to be analysed for each sampling point;
c) measurements to be carried out at the sampling point as specified in the analytical method, e.g.
temperature, dissolved oxygen, pH, turbidity, conductivity;
d) frequency and times of sampling and type of sample;
e) sampling site and the number and locations of sampling points;
f) sampling equipment;
g) quality assurance procedures to be followed;
h) transport preservation and storage of samples;
i) hydrodynamic and morphologic characteristics of the water sampled;
j) local circumstances such as water depth, vegetation, accessibility of location and other potential
obstacles such as floating layers or sludge layers present;
k) sampling depth(s);
l) composition and quantity of the water to be sampled;
m) safety considerations.
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ISO 5667-4:2016(E)

6 Sampling procedure
6.1 General
As recommended in ISO 5667-1, an investigation plan should be established before a sampling program
is initiated. The plan should include: the purpose of the investigation; parameters to be analysed
for each sampling site; frequency and times of sampling; the type of collection gear and containers;
the number and locations of sampling points; sample preservation requirements; access and safety
concerns; hydrodynamic, morphological and biological characteristics of the sampling site(s); the
sampling depth(s); and quantity of water to be collected.
Phytoplankton and/or chlorophyll, as well nutrients for water protection issues, should be sampled
in the euphotic zone or mixed layer, respectively. The decision down to which depth an integrated
sample has to be taken should be done according to EN 16698. The decision depends on lake type,
stratification and phytoplankton turbidity. That means before the sampling procedure, the current
probe measurement data and Secchi disk readings have to be available.
6.2 Sampling location
6.2.1 General
General guidance is given in ISO 5667-1.
Samples from surface layers containing floating material should be taken with special surface samplers.
The spatial distribution of sampling locations can be properly decided only after detailed preliminary
work using a large number of sampling locations to provide information to which statistical techniques
may be applied.
6.2.2 Horizontal distribution of sampling positions
6.2.2.1 Sampling point for characterization of water quality
Morphologically complex lakes, those either consisting of several basins or having a complicated
shoreline can show significant heterogeneities in a horizontal direction. In order to evaluate the extent
of such heterogeneities, it is necessary to set up several sampling points to carry out preliminary
investigations. The data gathered then enable the necessary number of sampling points to be fixed
effectively. One sampling point above the deepest part of the lake is generally sufficient for lakes
showing no significant heterogeneities in a horizontal direction. Sampling points should be defined
clearly, and if possible, marked with buoys. Use navigation devices to identify the sampling points if the
surface area is too large to allow the fixing of buoys. If appropriate to the sampling purpose, samples
can be collected from the lake shore, ideally at or near the outflow, or jetty or promontory, using a
device such as a sampling iron or sampling pole.
6.2.2.2 Sampling point for quality control
Negative control samples should be taken such that they are not influenced by potential sources of
contamination. These could include other nearby non-impacted areas or other nearby bodies of water
that are representative of the body of water being sampled.
6.2.2.3 Sampling point for special investigations
Samples should be taken as single or replicate samples where unusual phenomena have been observed.
The sites should be clearly identified in the report, with a map or sketch where possible.
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ISO 5667-4:2016(E)

6.2.3 Vertical distribution of sampling points
The water quality in natural and man-made lakes can show large vertical heterogeneities due to
stratification. The reasons for these are influences from the water surface (changes of the water quality
by photosynthesis in the euphotic zone and changes in water temperature by heating) and influences
arising from the sediment (dissolution or resuspension of substances from the sediment). Furthermore,
vertical heterogeneities can arise from sedimentation of suspended matter. Large differences in water
quality are also frequently observed at the thermocline. For these reasons, the distance between grab
sample depths in heterogeneous zones should be minimized. The exact arrangement of sampling levels
depends on the information required and the local circumstances. It is therefore advisable to carry out
preliminary investigations using measuring probes (for measurement of temperature, if possible, as
well as dissolved oxygen concentration, pH value, conductivity, turbidity and chlorophyll fluorescence),
which allow either continuous monitoring or monitoring at short intervals. In such cases, stagger the
sampling depth to allow the recording of all vertical heterogeneity. Once a sampling programme has
been defined, it should be carried out to completion, since if it is altered during sampling, the data
gathered will be incompatible. In large and deep bodies of water where internal movement of water can
occur, the use of a series of samplers, which all take samples simultaneously, is recommended.
6.3 Frequency and timing of sampling
Detailed guidance, including statistical considerations, is given in ISO 5667-1.
The water quality of natural and man-made lakes varies seasonally. Consequently, the frequency of
sampling will depend on the information required.
In general, for lentic waters, an interval of 1 month or longer between the collection of consecutive
samples is acceptable for water quality characterization over a long period of time. For the purpose of
quality control measurement, a minimum interval of one week is necessary. If rapid changes in water
quality are apparent, daily or even continuous sampling can be necessary.
Lake sampling four times a year will allow an acceptable water quality characterization over a long
period of time. For the purpose of quality control measurement, a higher frequency may be required.
In addition, quality can vary significantly during a day. Samples should be taken at about the same time
of the day. If daily variation is of special interest, sampling every 2 h or 3 h is recommended.
6.4 Choice of sampling method
The choice of sampling method depends on the objective of the sampling programme. Samples taken
for special reasons or for quality control purposes will, in most cases, be grab samples. For monitoring
water quality, a series of grab samples is used, but composite samples can be useful. The analysis of a
series of grab samples can be costly and these are often combined to reduce analytical costs; however,
composite samples will indicate only mean values and will not reveal details of extreme conditions or
the extent of quality variation. Both methods may be combined by taking composite samples at short
intervals and a series of samples at longer intervals.
6.5 Choice of the sampling device
The choice of the sampling device depends on the objective of the sampling program. Samples taken
for special reasons or for quality control purposes will, in most cases, be grab samples (see Annex A
for examples of sampling devices). For monitoring water quality, a series of grab samples is often used,
but composite samples may be useful, especially for the investigation of defined water layers, e.g. the
epilimnion or the euphotic zone. However, composite samples will indicate only mean values and will
not reveal details of extreme conditions or the extent of quality variation.
Immersion probes may used for a continuous measurement of pH or dissolved oxygen in unstable water
samples (Annex E).
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ISO 5667-4:2016(E)

6.6 Aids for recovery of lost sampling equipment
When handing sampling devices in small boats, there is an increased risk of losing equipment overboard.
It is recommended that the trailing end of the tether line comprises of “floating rope” to aid recovery
should the equipment be lost in shallow waters. Floating ropes are designed as safety products that
remain near the surface for easy capture and recovery of objects to which they are attached. They are
readily available for a range of safety applications and load ratings.
6.7 Blank sample
When collecting and processing water samples, it is necessary to include blank samples such as field
blanks, travel blanks and filter blanks to measure the degree of contamination that may have been
introduced into the samples as a result of sampling related activities. Detailed guidance on the use of
blanks and other quality control samples is given in ISO 5667-14.
6.8 Transport, stabilization and keeping of samples
ISO 5667-3 gives general guidance on sample handling and preservation.
Ensure that sample containers are delivered to the laboratory tightly sealed and protected from the
effects of light and excessive heat, because the quality may change rapidly due to gas exchange, chemical
reactions and the metabolism of organisms. Ensure that samples which cannot be analysed quickly
are filtered (if required by specific analytical method) and stabilized or preserved if required. The
method of preservation shall be chosen to avoid interference with the parameters of interest and does
not interfere with the subsequent examination or influence
...

SLOVENSKI STANDARD
oSIST ISO 5667-4:2018
01-junij-2018
.DNRYRVWYRGH9]RUþHQMHGHO1DYRGLOR]DY]RUþHQMHQDUDYQLKLQXPHWQLK
MH]HU
Water quality - Sampling - Part 4: Guidance on sampling from lakes, natural and man-
made
Qualité de l'eau - Échantillonnage - Partie 4: Lignes directrices pour l'échantillonnage
des eaux des lacs naturels et des lacs artificiels
Ta slovenski standard je istoveten z: ISO 5667-4:2016
ICS:
13.060.10 Voda iz naravnih virov Water of natural resources
13.060.45 Preiskava vode na splošno Examination of water in
general
oSIST ISO 5667-4:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST ISO 5667-4:2018

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oSIST ISO 5667-4:2018
INTERNATIONAL ISO
STANDARD 5667-4
Second edition
2016-07-01
Water quality — Sampling —
Part 4:
Guidance on sampling from lakes,
natural and man-made
Qualité de l’eau — Échantillonnage —
Partie 4: Lignes directrices pour l’échantillonnage des eaux des lacs
naturels et des lacs artificiels
Reference number
ISO 5667-4:2016(E)
©
ISO 2016

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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

---------------------- Page: 4 ----------------------
oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling equipment . 2
4.1 Material selection . 2
4.2 Cleaning . 3
4.3 Maintenance . 3
5 Design of the sampling programme . 3
6 Sampling procedure . 4
6.1 General . 4
6.2 Sampling location . 4
6.2.1 General. 4
6.2.2 Horizontal distribution of sampling positions . 4
6.2.3 Vertical distribution of sampling points . 5
6.3 Frequency and timing of sampling . 5
6.4 Choice of sampling method . 5
6.5 Choice of the sampling device . 5
6.6 Aids for recovery of lost sampling equipment . 6
6.7 Blank sample . 6
6.8 Transport, stabilization and keeping of samples . 6
7 Occupational health and safety . 6
8 Sample containers . 6
9 Priority of procedure . 6
10 Sample collection, contamination with environmental materials .8
11 Rinsing the sampling equipment . 9
12 Sampling surface or near-surface water with an open sampling device .9
12.1 General . 9
12.2 Sampling . 9
12.3 Filling multiple containers . 9
13 Sampling with closed samplers.10
14 Sampling for volatile parameters .10
15 Sampling through ice .10
16 Severe freezing conditions .10
17 Sample identification and records .11
18 Quality assurance and quality control .11
18.1 General .11
18.2 Avoidance of contamination .12
Annex A (informative) Examples of sampling devices .14
Annex B (informative) Advantages and disadvantages of sampling equipment .28
Annex C (informative) Sampling from boats — Maintaining station .29
Annex D (informative) Example of a report — Sampling from lakes, natural and man-made .31
Annex E (informative) Continuous measurement of water samples with immersion probes .32
Bibliography .34
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oSIST ISO 5667-4:2018
ISO 5667-4:2016(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 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 147, Water quality, Subcommittee SC 6, Sampling
(general methods).
This second edition cancels and replaces the first edition (ISO 5667-4:1987), which has been technically
revised.
ISO 5667 consists of the following parts, under the general title Water quality — Sampling:
— Part 1: Guidance on the design of sampling programmes and sampling techniques
— Part 3: Preservation and handling of water samples
— Part 4: Guidance on sampling from lakes, natural and man-made
— Part 5: Guidance on sampling of drinking water from treatment works and piped distribution systems
— Part 6: Guidance on sampling of rivers and streams
— Part 7: Guidance on sampling of water and steam in boiler plants
— Part 8: Guidance on the sampling of wet deposition
— Part 9: Guidance on sampling from marine waters
— Part 10: Guidance on sampling of waste waters
— Part 11: Guidance on sampling of groundwaters
— Part 12: Guidance on sampling of bottom sediments
— Part 13: Guidance on sampling of sludges
— Part 14: Guidance on quality assurance and quality control of environmental water sampling and
handling
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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

— Part 15: Guidance on the preservation and handling of sludge and sediment samples
— Part 16: Guidance on biotesting of samples
— Part 17: Guidance on sampling of bulk suspended solids
— Part 19: Guidance on sampling of marine sediments
— Part 20: Guidance on the use of sampling data for decision making — Compliance with thresholds and
classification systems
— Part 21: Guidance on sampling of drinking water distributed by tankers or means other than
distribution pipes
— Part 22: Guidance on the design and installation of groundwater monitoring points
— Part 23: Guidance on passive sampling in surface waters
— Part 24: Guidelines for the auditing of water quality sampling
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oSIST ISO 5667-4:2018

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oSIST ISO 5667-4:2018
INTERNATIONAL STANDARD ISO 5667-4:2016(E)
Water quality — Sampling —
Part 4:
Guidance on sampling from lakes, natural and man-made
1 Scope
This part of ISO 5667 gives guidelines for the design of sampling programmes, techniques and the
handling and preservation of samples of water, from natural and man-made lakes during open-water
and ice-covered conditions. This part of ISO 5667 is applicable to lakes with and without aquatic
vegetation.
Guidance on sampling for microbiological examination is not included.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
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 5667-14, Water quality — Sampling — Part 14: Guidance on quality assurance and quality control of
environmental water sampling and handling
ISO 7027, Water quality — Determination of turbidity
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
grab sample
single discrete sample collected from a body of water at a specific time, location and depth
3.2
depth profile samples
two or more discrete samples collected at two or more depths at a specific time and location on a lake
3.3
area profile samples
two or more discrete samples collected from the same depth at two or more locations on a lake
3.4
composite sample
two or more depth profile (3.2) or area profile samples (3.3) that are combined to form a single sample
prior to measurement of water quality parameters
3.5
integrated sample
single sample collected by a tube or similar sampler that collects a water sample across a range of depths
© ISO 2016 – All rights reserved 1

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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

3.6
in-situ measurement
measurement of a water quality parameter made within a body of water, not requiring collection of a
water sample
Note 1 to entry: The measurement is generally taken by use of an electronic probe.
3.7
ex-situ measurement
measurement of a water quality parameter made outside a body of water, and requiring collection and
possibly transport of a water sample prior to measurement
3.8
open sampling device
open-mouthed vessel, including beakers, buckets, containers or tubes, used for sampling at or near the
water surface (<1 m depth)
Note 1 to entry: Open sampling devices are not suitable for sampling for volatile parameters or dissolved gases.
3.9
closed sampling device
vertically or horizontally aligned hollow-bodied tube, pipe, box or container fitted with shutters, valves,
stoppers or other devices that prevent entry of air into and/or enclosure of air with the water sample
and the exchange of water between the collected sample and the surrounding water column
Note 1 to entry: Closed sampling devices are used for collecting water samples from deeper waters or for
collection of water samples for the analysis of volatile parameters and dissolved gases.
3.10
sampling pole
pole or rod with a terminal apparatus that accepts an open or closed sampling device (3.9) and that is
used to extend the reach of samplers
3.11
sampling iron
weighted container holder attached to a line and used to extend the reach of samplers or to submerse a
sample container to a specific depth
3.12
pumping device
hand or motor operated suction or submersible pumps, or pneumatic ejection samplers used for
collection of samples from defined depths or a series of depths
3.13
filling device
funnel, ladle, churn sample splitter or other device used to transfer sample water from a sampling
device to a sampling container
3.14
negative control
quality control sample that is used to ensure a negative response
4 Sampling equipment
4.1 Material selection
Sampling probes, devices and other equipment should be chosen, as far as possible, which do not give
rise to any interaction between the water and the material composition. The equipment and devices
to be used should be checked at random for the presence of emission, absorption and adsorption of
substances or influence of properties that are to be determined in the samples to be taken. Examples of
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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

common sampling equipment are summarized in Annex A. Advantages and disadvantages of sampling
equipment are provided in Annex B. If a boat, marine vessel or any floatation device is used, care
shall be taken so that it does not result in contamination of the samples. Additional details regarding
sampling from a vessel are summarized in Annex C. A winch with steel rope and counter is advisable for
deeper lakes. This ensures the required sinking and resurfacing velocity of the sampling devices. Any
solvents, chemicals or fuels should be stored in sealed non-permeable containers. For example, the use
of electric motors on small boats can be of value in eliminating the risk of contamination by combustion
exhaust and engine lubricants. ISO 5667-14 provides guidance for checking the uptake and emission of
the substances to be measured by equipment and devices that are used for sampling.
4.2 Cleaning
A proper quality assurance and quality control (QA/QC) system should be in place to prevent
contamination and detect any contamination that could affect analytical results. All equipment and
devices should be regularly mechanically and, if appropriate, chemically cleaned, both internally and
externally, to prevent contamination of water samples.
4.3 Maintenance
Where equipment uses mechanical or other triggering devices, these mechanisms should be regularly
tested. Electronic devices and probes should be tested and calibrated according to the manufacturer’s
recommendations. A log of testing and calibration dates and results should be maintained.
5 Design of the sampling programme
Proper sampling is critical to ensure the quality of the investigation and resulting data. Developing
a detailed sampling strategy prior to collecting samples will minimize any sampling errors and will
provide the most representative sample for analysis. General aspects that should be considered in a
sampling programme are summarized in ISO 5667-1. These include, but are not limited to, the following:
a) purpose of the investigation;
b) parameters to be analysed for each sampling point;
c) measurements to be carried out at the sampling point as specified in the analytical method, e.g.
temperature, dissolved oxygen, pH, turbidity, conductivity;
d) frequency and times of sampling and type of sample;
e) sampling site and the number and locations of sampling points;
f) sampling equipment;
g) quality assurance procedures to be followed;
h) transport preservation and storage of samples;
i) hydrodynamic and morphologic characteristics of the water sampled;
j) local circumstances such as water depth, vegetation, accessibility of location and other potential
obstacles such as floating layers or sludge layers present;
k) sampling depth(s);
l) composition and quantity of the water to be sampled;
m) safety considerations.
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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

6 Sampling procedure
6.1 General
As recommended in ISO 5667-1, an investigation plan should be established before a sampling program
is initiated. The plan should include: the purpose of the investigation; parameters to be analysed
for each sampling site; frequency and times of sampling; the type of collection gear and containers;
the number and locations of sampling points; sample preservation requirements; access and safety
concerns; hydrodynamic, morphological and biological characteristics of the sampling site(s); the
sampling depth(s); and quantity of water to be collected.
Phytoplankton and/or chlorophyll, as well nutrients for water protection issues, should be sampled
in the euphotic zone or mixed layer, respectively. The decision down to which depth an integrated
sample has to be taken should be done according to EN 16698. The decision depends on lake type,
stratification and phytoplankton turbidity. That means before the sampling procedure, the current
probe measurement data and Secchi disk readings have to be available.
6.2 Sampling location
6.2.1 General
General guidance is given in ISO 5667-1.
Samples from surface layers containing floating material should be taken with special surface samplers.
The spatial distribution of sampling locations can be properly decided only after detailed preliminary
work using a large number of sampling locations to provide information to which statistical techniques
may be applied.
6.2.2 Horizontal distribution of sampling positions
6.2.2.1 Sampling point for characterization of water quality
Morphologically complex lakes, those either consisting of several basins or having a complicated
shoreline can show significant heterogeneities in a horizontal direction. In order to evaluate the extent
of such heterogeneities, it is necessary to set up several sampling points to carry out preliminary
investigations. The data gathered then enable the necessary number of sampling points to be fixed
effectively. One sampling point above the deepest part of the lake is generally sufficient for lakes
showing no significant heterogeneities in a horizontal direction. Sampling points should be defined
clearly, and if possible, marked with buoys. Use navigation devices to identify the sampling points if the
surface area is too large to allow the fixing of buoys. If appropriate to the sampling purpose, samples
can be collected from the lake shore, ideally at or near the outflow, or jetty or promontory, using a
device such as a sampling iron or sampling pole.
6.2.2.2 Sampling point for quality control
Negative control samples should be taken such that they are not influenced by potential sources of
contamination. These could include other nearby non-impacted areas or other nearby bodies of water
that are representative of the body of water being sampled.
6.2.2.3 Sampling point for special investigations
Samples should be taken as single or replicate samples where unusual phenomena have been observed.
The sites should be clearly identified in the report, with a map or sketch where possible.
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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

6.2.3 Vertical distribution of sampling points
The water quality in natural and man-made lakes can show large vertical heterogeneities due to
stratification. The reasons for these are influences from the water surface (changes of the water quality
by photosynthesis in the euphotic zone and changes in water temperature by heating) and influences
arising from the sediment (dissolution or resuspension of substances from the sediment). Furthermore,
vertical heterogeneities can arise from sedimentation of suspended matter. Large differences in water
quality are also frequently observed at the thermocline. For these reasons, the distance between grab
sample depths in heterogeneous zones should be minimized. The exact arrangement of sampling levels
depends on the information required and the local circumstances. It is therefore advisable to carry out
preliminary investigations using measuring probes (for measurement of temperature, if possible, as
well as dissolved oxygen concentration, pH value, conductivity, turbidity and chlorophyll fluorescence),
which allow either continuous monitoring or monitoring at short intervals. In such cases, stagger the
sampling depth to allow the recording of all vertical heterogeneity. Once a sampling programme has
been defined, it should be carried out to completion, since if it is altered during sampling, the data
gathered will be incompatible. In large and deep bodies of water where internal movement of water can
occur, the use of a series of samplers, which all take samples simultaneously, is recommended.
6.3 Frequency and timing of sampling
Detailed guidance, including statistical considerations, is given in ISO 5667-1.
The water quality of natural and man-made lakes varies seasonally. Consequently, the frequency of
sampling will depend on the information required.
In general, for lentic waters, an interval of 1 month or longer between the collection of consecutive
samples is acceptable for water quality characterization over a long period of time. For the purpose of
quality control measurement, a minimum interval of one week is necessary. If rapid changes in water
quality are apparent, daily or even continuous sampling can be necessary.
Lake sampling four times a year will allow an acceptable water quality characterization over a long
period of time. For the purpose of quality control measurement, a higher frequency may be required.
In addition, quality can vary significantly during a day. Samples should be taken at about the same time
of the day. If daily variation is of special interest, sampling every 2 h or 3 h is recommended.
6.4 Choice of sampling method
The choice of sampling method depends on the objective of the sampling programme. Samples taken
for special reasons or for quality control purposes will, in most cases, be grab samples. For monitoring
water quality, a series of grab samples is used, but composite samples can be useful. The analysis of a
series of grab samples can be costly and these are often combined to reduce analytical costs; however,
composite samples will indicate only mean values and will not reveal details of extreme conditions or
the extent of quality variation. Both methods may be combined by taking composite samples at short
intervals and a series of samples at longer intervals.
6.5 Choice of the sampling device
The choice of the sampling device depends on the objective of the sampling program. Samples taken
for special reasons or for quality control purposes will, in most cases, be grab samples (see Annex A
for examples of sampling devices). For monitoring water quality, a series of grab samples is often used,
but composite samples may be useful, especially for the investigation of defined water layers, e.g. the
epilimnion or the euphotic zone. However, composite samples will indicate only mean values and will
not reveal details of extreme conditions or the extent of quality variation.
Immersion probes may used for a continuous measurement of pH or dissolved oxygen in unstable water
samples (Annex E).
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oSIST ISO 5667-4:2018
ISO 5667-4:2016(E)

6.6 Aids for recovery of lost sampling equipment
When handing sampling devices in small boats, there is an increased risk of losing equipment overboard.
It is recommended that the trailing end of the tether line comprises of “floating rope” to aid recovery
should the equipment be lost in shallow waters. Floating ropes are designed as safety products that
remain near the surface for easy capture and recovery of objects to which they are attached. They are
...