Water quality -- Sampling -- Part 6: Guidance on sampling of rivers and streams

This part of ISO 5667 sets out the principles to be applied to the design of sampling programmes, sampling techniques and the handling of water samples from rivers and streams for physical and chemical assessment. It is not applicable to the sampling of estuarine or coastal waters and has limited applicability to microbiological sampling. This part of ISO 5667 is not applicable to the examination of sediment, suspended solids or biota. In cases where naturally occurring or artificially constructed dams result in the retention or storage of water for several days or more, it might be better to consider the stretch of the river or stream as a standing water body for sampling purposes. ISO 5667-4 provides guidance for sampling in these circumstances.

Qualité de l'eau -- Échantillonnage -- Partie 6: Lignes directrices pour l'échantillonnage des rivières et des cours d'eau

Kakovost vode - Vzorčenje - 6. del: Navodilo za vzorčenje rek in vodnih tokov

General Information

Status
Withdrawn
Publication Date
31-Jan-2007
Withdrawal Date
28-Jan-2015
Technical Committee
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
22-Jan-2015
Due Date
14-Feb-2015
Completion Date
29-Jan-2015

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INTERNATIONAL ISO
STANDARD 5667-6
Second edition
2005-07-15
Water quality — Sampling —
Part 6:
Guidance on sampling of rivers and
streams
Qualité de l'eau — Échantillonnage —
Partie 6: Lignes directrices pour l'échantillonnage des rivières et des
cours d'eau
Reference number
ISO 5667-6:2005(E)
ISO 2005
---------------------- Page: 1 ----------------------
ISO 5667-6:2005(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2005

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 5667-6:2005(E)
Contents Page

Foreword............................................................................................................................................................. v

Introduction ...................................................................................................................................................... vii

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

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

3 Terms and definitions........................................................................................................................... 1

4 Design of sampling programme.......................................................................................................... 3

4.1 Sampling point selection ..................................................................................................................... 3

4.2 Frequency and time of sampling......................................................................................................... 5

5 Preparation for sampling ..................................................................................................................... 6

6 Sampling at specific locations ............................................................................................................ 7

6.1 Sampling from bridges......................................................................................................................... 7

6.2 In-stream sampling............................................................................................................................... 7

6.3 Sampling from the bank side............................................................................................................... 7

6.4 Sampling from craft.............................................................................................................................. 7

6.5 Sampling under ice............................................................................................................................... 7

7 Sampling methods................................................................................................................................ 7

7.1 Single, discrete samples...................................................................................................................... 7

7.2 Sampling from specific depths ........................................................................................................... 8

8 Sampling equipment............................................................................................................................. 8

8.1 Single, discrete samples...................................................................................................................... 8

8.2 Sampling of surface layers for LNAPL (e.g. oils) or surface films .................................................. 9

8.3 Devices for sampling from specific depths .......................................................................................9

8.4 Automatic sampling devices ............................................................................................................... 9

8.5 Other sampling equipment ................................................................................................................ 10

8.6 Provision of storage for sampling equipment and of samples prior to delivery to the

analysing laboratory........................................................................................................................... 10

9 Taking the sample............................................................................................................................... 10

9.1 Arrival on site ...................................................................................................................................... 10

9.2 Rinsing the equipment ....................................................................................................................... 10

9.3 Direct sampling ................................................................................................................................... 11

9.4 Indirect sampling using a sampling vessel ..................................................................................... 11

9.5 Sampling through ice ......................................................................................................................... 11

9.6 Sampling of surface layers or films.................................................................................................. 11

9.7 Sampling by increments .................................................................................................................... 12

9.8 Adding preservatives in the field ...................................................................................................... 12

9.9 Labelling .............................................................................................................................................. 12

10 Stabilization, transport and storage of samples ............................................................................. 12

10.1 Stabilization......................................................................................................................................... 12

10.2 Transportation..................................................................................................................................... 12

10.3 Security and traceability of samples during storage and delivery................................................ 13

11 Quality.................................................................................................................................................. 13

11.1 Avoidance of contamination.............................................................................................................. 13

11.2 Sample identification and records.................................................................................................... 14

12 Reports ................................................................................................................................................ 14

12.1 Analytical reports................................................................................................................................ 14

12.2 Sampling protocols ............................................................................................................................ 15

© ISO 2005 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 5667-6:2005(E)

13 Certification/registration/accreditation............................................................................................. 15

14 Quality control..................................................................................................................................... 15

15 Safety precautions .............................................................................................................................. 15

Bibliography ..................................................................................................................................................... 16

iv © ISO 2005 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 5667-6:2005(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 5667-6 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 6, Sampling

(general methods).

This second edition cancels and replaces the first edition (ISO 5667-6:1990), 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
 Part 2: Guidance on sampling techniques
 Part 3: Guidance on the 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 and water used for food and beverage processing

 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

1) ISO 5667-1 and ISO 5667-2 are currently undergoing joint revision, which will be published as ISO 5667-1.

© ISO 2005 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 5667-6:2005(E)
 Part 13: Guidance on sampling of sludges from sewage and water-treatment works

 Part 14: Guidance on quality assurance of environmental water sampling and handling

 Part 15: Guidance on preservation and handling of sludge and sediment samples
 Part 16: Guidance on biotesting of samples
 Part 17: Guidance on sampling of suspended sediments
 Part 18: Guidance on sampling of groundwater at contaminated sites
 Part 19: Guidance on sampling of marine sediments
vi © ISO 2005 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 5667-6:2005(E)
Introduction

An understanding of the purpose of sampling is an essential prerequisite to identifying the principles to be

applied to a particular sampling problem. Examples of the purposes of sampling programmes commonly

devised for rivers and streams are as follows:

a) to determine the suitability of the water quality of a river or stream within a river basin for a particular use,

such as:
1) a source of drinking water,
2) for agricultural use (e.g. all types of irrigation, live-stock watering),
3) for the maintenance and/or development of fisheries,
4) for amenity use (e.g. aquatic sports and swimming);
b) to assess the impact of human activities on the quality of water, such as:

1) to study the effects of waste discharge or accidental spillages on a receiving water,

2) to assess the impact of land use on river or stream quality,

3) to assess the effect of the accumulation and release of substances including contaminants from

bottom deposits on aquatic biota within the water mass, or on bottom deposits,

4) to study the effects of abstraction, river regulation and river-to-river water transfers on the chemical

quality of rivers and their aquatic biota,

5) to study the effects of river engineering works on water quality (e.g. addition/removal of weirs,

changes to channel/bed structure).
© ISO 2005 – All rights reserved vii
---------------------- Page: 7 ----------------------
INTERNATIONAL STANDARD ISO 5667-6:2005(E)
Water quality — Sampling —
Part 6:
Guidance on sampling of rivers and streams
1 Scope

This part of ISO 5667 sets out the principles to be applied to the design of sampling programmes, sampling

techniques and the handling of water samples from rivers and streams for physical and chemical assessment.

It is not applicable to the sampling of estuarine or coastal waters and has limited applicability to

microbiological sampling.
NOTE Procedures for microbiological sampling are given in ISO 19458.

This part of ISO 5667 is not applicable to the examination of sediment, suspended solids or biota.

In cases where naturally occurring or artificially constructed dams result in the retention or storage of water for

several days or more, it might be better to consider the stretch of the river or stream as a standing water body

for sampling purposes. ISO 5667-4 provides guidance for sampling in these circumstances.

WARNING — The focus of this part of ISO 5667 is the collection and integrity of water samples. The

collection of these samples can be hazardous and attention is therefore drawn to the existence in

some countries of legislative requirements for the safety of personnel.
2 Normative references

The following referenced documents are indispensable for the application 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 5667-18:2001, Water quality — Sampling — Part 18: Guidance on sampling of groundwater at

contaminated sites
ISO 6107-2:1997, Water quality — Vocabulary — Part 2
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5667-18 and ISO 6107-2 and the

following apply.
3.1
automatic sampling

process whereby samples are taken either discretely or continuously, independently of human intervention,

and according to a predetermined programme
[ISO 6107-2:1997]
© ISO 2005 – All rights reserved 1
---------------------- Page: 8 ----------------------
ISO 5667-6:2005(E)
3.2
incremental sampling

technique in which small samples are taken because of a low flow rate (with the possibility of contamination by

bottom deposits) or because of restricted access (e.g. where a sample is obtained through a small aperture),

these small samples then being aggregated to form a composite sample

NOTE All the liquid contained in the small samples is used, unlike blending of aliquots used to make a

flow-proportional sample (see 8.4).
3.3
isokinetic sampling

technique in which the sample from a water stream passes into the orifice of a sampling probe with a velocity

equal to that of the stream in the immediate vicinity of the probe
[ISO 6107-2:1997]
3.4
light non-aqueous-phase liquid
LNAPL

organic compounds which have low water solubility and a density less than that of water, e.g. petroleum

products
[ISO 5667-18:2001]
3.5
random sampling

form of sampling whereby the chances of obtaining different concentration values of a determinand are

precisely those defined by the probability distribution of the determinand in question

3.6
river

natural body of water flowing continuously or intermittently along a well-defined course into an ocean, sea,

lake, inland depression, marsh or other watercourse
[ISO 6107-2:1997]
3.7
sampling site
general area within a body of water from which samples are taken
[ISO 6107-2:1997]
3.8
sampling point
precise position within a sampling location from which samples are taken
[ISO 6107-2:1997]
3.9
stream

water flowing continuously or intermittently along a well-defined course, as for a river, but generally on a

smaller scale
[ISO 6107-2:1997]
3.10
sub-sample
portion removed from a sample and intended to be representative of that sample
2 © ISO 2005 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 5667-6:2005(E)
3.11
systematic sampling

sampling whereby the samples are taken at predetermined intervals, often equally spaced in time

4 Design of sampling programme
4.1 Sampling point selection
4.1.1 General

The following factors are usually considered in advance of the sampling event. Practical sampling issues,

such as accessibility, may make the ideal sampling point impractical. Any change to the designated sampling

point on any grounds should be discussed and agreed with the sampling programme originator. The outcome

of the deliberations may be recorded in a sampling point file which contains directions to the sampling site, the

detailed location of the sampling point, the method of sampling and specific details (e.g. keys required and

health and safety issues). It may differentiate between equivalent sampling points that may be used if, for

instance, river conditions change. It may also specify the type of sampling to be carried out, e.g. the depth to

sample.
4.1.2 Choice of sampling site

In choosing the exact point from which samples are required, two aspects are generally involved:

a) the selection of the sampling site (i.e. the location of the sampling cross-section within the river basin,

river or stream);
b) the identification of the precise point at the sampling site.

The purpose of sampling often defines sampling sites (as in the case of the determination of the quality of an

effluent discharge), but sometimes the purpose only leads to a general idea of the sampling site, as in the

characterization of quality in a river basin.

The choice of sampling sites for single sampling stations is usually relatively easy. For example, a monitoring

station for a baseline record of water quality can be chosen to permit the use of a convenient bridge, or to

allow an upstream effluent discharge or tributary to be well mixed laterally before the station. Stations for

monitoring water supply abstraction points might need to be fixed within narrow limits (i.e. in proximity to the

abstractions).

In regions that receive seasonal rainfall only, and that have long periods without rain, river volumes and flows

can vary tremendously, and sampling sites for regular use should be chosen so as to ensure that they remain

appropriate and practical for sampling during periods of both maximum and minimum flow.

Where it is necessary to carry out sampling through ice in winter, the chosen sampling site should be as close

as possible to the sampling site used during other seasons of the year. If sampling is to be carried out near a

bridge, the site should be located far enough upstream to avoid contamination from road salt and sand.

Deviations from the routine sampling point should be detailed as part of the dataset and recorded with the

analytical results.
4.1.3 Importance of mixing

When the effects of a tributary, or an effluent, on the quality in a particular identified stretch of river or the main

stream are of interest, at least two sampling sites should be chosen; one should be just upstream of the

confluence and the other should be sufficiently far downstream to ensure that mixing is complete.

The physical characteristics of the channels of watercourses largely control distances required for the

complete mixing of effluents with stream flow.
© ISO 2005 – All rights reserved 3
---------------------- Page: 10 ----------------------
ISO 5667-6:2005(E)
Effluents mix in three dimensions in a stream, namely:
a) vertically (from top to bottom);
b) laterally (from one side to the other);

c) longitudinally (levelling out of peaks and troughs in the concentration of effluent constituents as water

passes downstream).

The distances over which effluents mix in these three dimensions should be considered in the selection of

sampling sites and points and are affected by, amongst other things, the water velocity. Tracer techniques

using dyes can be useful in studying mixing processes and conductivity measurements can also be helpful.

NOTE The use of tracer techniques might be subject to licensing by the authority responsible for the watercourse, as

there might be concerns over the release of chemicals into the environment. Where this is the case, it might be better to

use determinants already present, such as pH, temperature or conductivity, to study mixing processes.

Effluents discharged into most streams mix vertically completely within a kilometre. Normally a stream need

not be sampled at more than one depth, although stratification can be induced in slow-moving rivers and

streams by thermal and other density effects. In these cases, sampling at several depths might be necessary

and preliminary tests should be carried out to assess the degree of stratification (see 4.2 for guidance).

The distance necessary for complete lateral mixing is generally dependent on the occurrence of relatively

sharp reverse bends, islets or boulders and is measured in kilometres rather than fractions of a kilometre.

Therefore, to obtain representative samples a stream should be sampled at two or more points across its

width at sites downstream from an effluent or tributary discharge.

Consideration of longitudinal mixing distances can be important in deciding on the frequency of sampling. To

give representative results just below an irregular discharge, more frequent sampling will be required than

would be necessary some distance downstream where longitudinal mixing has been completed to a greater

extent.

The distance in metres, l, for complete mixing, to within 1 % of complete homogeneity, should be calculated

approximately using the following formula (originally published in ISO 555-2):
0,13bc(0,72)c + g
l =
where
b is the average width of the reach, in metres;
c is the Chezy coefficient for the reach (15 < c < 50);
g is the acceleration due to gravity, in metres per second squared;
d is the mean depth of the reach, in metres.

The following example gives an illustration of the effect of different Chezy coefficients on the longitudinal

mixing of a stream.

EXAMPLE Consider two streams both 5 m wide and 1 m deep but with extreme values of the Chezy coefficient; one

of 15 (very rough bottom, i.e. the stream is very fast and turbulent) and the other of 50 (very smooth bottom, i.e. a very

tranquil, slow-moving stream). When calculated in accordance with the equation given in this subclause, the former will

have reached complete homogeneity after 83 m while the latter will not be homogeneous until it has travelled 683 m.

It should be noted that some tests have shown that the above expression can underestimate the mixing length

for small streams of about 5 m in width and overestimate the mixing length for rivers of over about 50 m in

width. This is most likely due to the fact that the average width, average depth and Chezy coefficient are

4 © ISO 2005 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 5667-6:2005(E)

usually estimates. Lateral mixing can take place much more slowly than expected and vertical mixing more

quickly. There are many literature sources containing alternative calculations that deal with mixing distances

(see Reference [15]).
4.1.4 Consideration of time-of-travel data

Time-of-travel data can often be of relevance to the choice of sampling location. For example, sampling sites

might have to be arranged to allow certain constituents or pollutants to be traced through a system,

particularly from a discrete source of pollution. This necessitates knowledge of the residence time within the

system under investigation (i.e. the time of travel). Knowledge of the time of travel is also important in

sampling studies to investigate the rate of change of unstable constituents (e.g. in the self-purification of a

water body, the time of travel can provide information on kinetic rate coefficients).

In determining the time of travel, one of the three principal methods should be used, namely the use of surface

floats (see ISO 748), the use of tracers (originally published in ISO 555-1, ISO 555-2 and ISO 555-3) or the

measurement of flow rate with knowledge of cross-sectional areas (see ISO 748 and ISO 1070).

Measurements should be made at a minimum of five different flow rates and the resulting times of travel

plotted against the corresponding flow rates, thereby enabling other travel times to be obtained by

extrapolation or interpolation. However, extrapolation outside 10 % of a measured flow rate value can provide

inaccurate information on time of travel.

It should also be noted that time of travel can vary greatly between seasons in regions that experience

seasonal rainfall only.

ISO 5667-1 should be consulted for general guidance on time of travel and ISO/TR 8363 should be consulted

for guidance on the measurement of liquid flow in open channels.
4.1.5 Non-homogeneous sites

Problems arise in selecting suitable sampling sites whenever the determinands are not homogeneously

distributed throughout the water body of interest. In general, such sampling sites should be avoided, except

when the sites themselves are of direct interest, as they might not yield representative samples of the major

part of the water body. If there is any possibility of a non-homogeneous distribution of the determinands of

interest at the chosen site, experimental tests on the nature and magnitude of any heterogeneity in all three

dimensions should be made. If such tests show that the determinands are distributed homogeneously, any

sampling point will suffice. Otherwise another site should be sought where the determinands are

homogeneously distributed. If it is impossible to find such a sampling site, samples should be taken from

sufficient points at the chosen site to ensure representative results.

These samples can often be combined as sub-samples to form one single composite sample representative of

the quality at the sampling location, so that it is not necessary to analyse individual samples taken from each

of the sampling points. However, this provides no information on the variability in quality between the sampling

points. In addition, the combination of sub-samples in this way cannot be undertaken when sampling for

dissolved gases or other volatile constituents.
4.2 Frequency and time of sampling

It is essential that the sampling programme be properly statistically designed in order that the statistical

summary information produced from the analytical results provides an estimate of the required information to

within the tolerance limits of the programme’s objectives. If the objectives do not include a definition of the

magnitude of the tolerable error, a statistically based sampling programme is impossible. Guidance and

recommendations on the application of statistics to sampling frequency are given in ISO 5667-1.

Where cyclic or other persistent variations are present, better precision should be sought in estimating mean

concentrations by systematic rather than by random sampling (for any given number of samples), provided

that the sampling interval is short enough for consecutive samples to reveal the variations.

© ISO 2005 – All rights reserved 5
---------------------- Page: 12 ----------------------
ISO 5667-6:2005(E)

When using systematic sampling, it is essential to ensure that the frequency of sampling does not coincide

with any natural cycle present in the system, or with some other time-based effect (e.g. a pump just upstream

starting once an hour), a study of the effects of which are not part of the sampling objectives.

In river systems, regular cyclic variations in water quality can occur with, for example, periods of one day, one

week and one year. W
...

SLOVENSKI STANDARD
SIST ISO 5667-6:2007
01-februar-2007
1DGRPHãþD
SIST ISO 5667-6:1996
.DNRYRVWYRGH9]RUþHQMHGHO1DYRGLOR]DY]RUþHQMHUHNLQYRGQLKWRNRY
Water quality -- Sampling -- Part 6: Guidance on sampling of rivers and streams

Qualité de l'eau -- Échantillonnage -- Partie 6: Lignes directrices pour l'échantillonnage

des rivières et des cours d'eau
Ta slovenski standard je istoveten z: ISO 5667-6:2005
ICS:
13.060.10 Voda iz naravnih virov Water of natural resources
13.060.45 Preiskava vode na splošno Examination of water in
general
SIST ISO 5667-6:2007 en

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

---------------------- Page: 1 ----------------------
SIST ISO 5667-6:2007
---------------------- Page: 2 ----------------------
SIST ISO 5667-6:2007
INTERNATIONAL ISO
STANDARD 5667-6
Second edition
2005-07-15
Water quality — Sampling —
Part 6:
Guidance on sampling of rivers and
streams
Qualité de l'eau — Échantillonnage —
Partie 6: Lignes directrices pour l'échantillonnage des rivières et des
cours d'eau
Reference number
ISO 5667-6:2005(E)
ISO 2005
---------------------- Page: 3 ----------------------
SIST ISO 5667-6:2007
ISO 5667-6:2005(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2005

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 5667-6:2007
ISO 5667-6:2005(E)
Contents Page

Foreword............................................................................................................................................................. v

Introduction ...................................................................................................................................................... vii

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

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

3 Terms and definitions........................................................................................................................... 1

4 Design of sampling programme.......................................................................................................... 3

4.1 Sampling point selection ..................................................................................................................... 3

4.2 Frequency and time of sampling......................................................................................................... 5

5 Preparation for sampling ..................................................................................................................... 6

6 Sampling at specific locations ............................................................................................................ 7

6.1 Sampling from bridges......................................................................................................................... 7

6.2 In-stream sampling............................................................................................................................... 7

6.3 Sampling from the bank side............................................................................................................... 7

6.4 Sampling from craft.............................................................................................................................. 7

6.5 Sampling under ice............................................................................................................................... 7

7 Sampling methods................................................................................................................................ 7

7.1 Single, discrete samples...................................................................................................................... 7

7.2 Sampling from specific depths ........................................................................................................... 8

8 Sampling equipment............................................................................................................................. 8

8.1 Single, discrete samples...................................................................................................................... 8

8.2 Sampling of surface layers for LNAPL (e.g. oils) or surface films .................................................. 9

8.3 Devices for sampling from specific depths .......................................................................................9

8.4 Automatic sampling devices ............................................................................................................... 9

8.5 Other sampling equipment ................................................................................................................ 10

8.6 Provision of storage for sampling equipment and of samples prior to delivery to the

analysing laboratory........................................................................................................................... 10

9 Taking the sample............................................................................................................................... 10

9.1 Arrival on site ...................................................................................................................................... 10

9.2 Rinsing the equipment ....................................................................................................................... 10

9.3 Direct sampling ................................................................................................................................... 11

9.4 Indirect sampling using a sampling vessel ..................................................................................... 11

9.5 Sampling through ice ......................................................................................................................... 11

9.6 Sampling of surface layers or films.................................................................................................. 11

9.7 Sampling by increments .................................................................................................................... 12

9.8 Adding preservatives in the field ...................................................................................................... 12

9.9 Labelling .............................................................................................................................................. 12

10 Stabilization, transport and storage of samples ............................................................................. 12

10.1 Stabilization......................................................................................................................................... 12

10.2 Transportation..................................................................................................................................... 12

10.3 Security and traceability of samples during storage and delivery................................................ 13

11 Quality.................................................................................................................................................. 13

11.1 Avoidance of contamination.............................................................................................................. 13

11.2 Sample identification and records.................................................................................................... 14

12 Reports ................................................................................................................................................ 14

12.1 Analytical reports................................................................................................................................ 14

12.2 Sampling protocols ............................................................................................................................ 15

© ISO 2005 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 5667-6:2007
ISO 5667-6:2005(E)

13 Certification/registration/accreditation............................................................................................. 15

14 Quality control..................................................................................................................................... 15

15 Safety precautions .............................................................................................................................. 15

Bibliography ..................................................................................................................................................... 16

iv © ISO 2005 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 5667-6:2007
ISO 5667-6:2005(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 5667-6 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 6, Sampling

(general methods).

This second edition cancels and replaces the first edition (ISO 5667-6:1990), 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
 Part 2: Guidance on sampling techniques
 Part 3: Guidance on the 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 and water used for food and beverage processing

 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

1) ISO 5667-1 and ISO 5667-2 are currently undergoing joint revision, which will be published as ISO 5667-1.

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 Part 13: Guidance on sampling of sludges from sewage and water-treatment works

 Part 14: Guidance on quality assurance of environmental water sampling and handling

 Part 15: Guidance on preservation and handling of sludge and sediment samples
 Part 16: Guidance on biotesting of samples
 Part 17: Guidance on sampling of suspended sediments
 Part 18: Guidance on sampling of groundwater at contaminated sites
 Part 19: Guidance on sampling of marine sediments
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Introduction

An understanding of the purpose of sampling is an essential prerequisite to identifying the principles to be

applied to a particular sampling problem. Examples of the purposes of sampling programmes commonly

devised for rivers and streams are as follows:

a) to determine the suitability of the water quality of a river or stream within a river basin for a particular use,

such as:
1) a source of drinking water,
2) for agricultural use (e.g. all types of irrigation, live-stock watering),
3) for the maintenance and/or development of fisheries,
4) for amenity use (e.g. aquatic sports and swimming);
b) to assess the impact of human activities on the quality of water, such as:

1) to study the effects of waste discharge or accidental spillages on a receiving water,

2) to assess the impact of land use on river or stream quality,

3) to assess the effect of the accumulation and release of substances including contaminants from

bottom deposits on aquatic biota within the water mass, or on bottom deposits,

4) to study the effects of abstraction, river regulation and river-to-river water transfers on the chemical

quality of rivers and their aquatic biota,

5) to study the effects of river engineering works on water quality (e.g. addition/removal of weirs,

changes to channel/bed structure).
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SIST ISO 5667-6:2007
INTERNATIONAL STANDARD ISO 5667-6:2005(E)
Water quality — Sampling —
Part 6:
Guidance on sampling of rivers and streams
1 Scope

This part of ISO 5667 sets out the principles to be applied to the design of sampling programmes, sampling

techniques and the handling of water samples from rivers and streams for physical and chemical assessment.

It is not applicable to the sampling of estuarine or coastal waters and has limited applicability to

microbiological sampling.
NOTE Procedures for microbiological sampling are given in ISO 19458.

This part of ISO 5667 is not applicable to the examination of sediment, suspended solids or biota.

In cases where naturally occurring or artificially constructed dams result in the retention or storage of water for

several days or more, it might be better to consider the stretch of the river or stream as a standing water body

for sampling purposes. ISO 5667-4 provides guidance for sampling in these circumstances.

WARNING — The focus of this part of ISO 5667 is the collection and integrity of water samples. The

collection of these samples can be hazardous and attention is therefore drawn to the existence in

some countries of legislative requirements for the safety of personnel.
2 Normative references

The following referenced documents are indispensable for the application 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 5667-18:2001, Water quality — Sampling — Part 18: Guidance on sampling of groundwater at

contaminated sites
ISO 6107-2:1997, Water quality — Vocabulary — Part 2
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5667-18 and ISO 6107-2 and the

following apply.
3.1
automatic sampling

process whereby samples are taken either discretely or continuously, independently of human intervention,

and according to a predetermined programme
[ISO 6107-2:1997]
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3.2
incremental sampling

technique in which small samples are taken because of a low flow rate (with the possibility of contamination by

bottom deposits) or because of restricted access (e.g. where a sample is obtained through a small aperture),

these small samples then being aggregated to form a composite sample

NOTE All the liquid contained in the small samples is used, unlike blending of aliquots used to make a

flow-proportional sample (see 8.4).
3.3
isokinetic sampling

technique in which the sample from a water stream passes into the orifice of a sampling probe with a velocity

equal to that of the stream in the immediate vicinity of the probe
[ISO 6107-2:1997]
3.4
light non-aqueous-phase liquid
LNAPL

organic compounds which have low water solubility and a density less than that of water, e.g. petroleum

products
[ISO 5667-18:2001]
3.5
random sampling

form of sampling whereby the chances of obtaining different concentration values of a determinand are

precisely those defined by the probability distribution of the determinand in question

3.6
river

natural body of water flowing continuously or intermittently along a well-defined course into an ocean, sea,

lake, inland depression, marsh or other watercourse
[ISO 6107-2:1997]
3.7
sampling site
general area within a body of water from which samples are taken
[ISO 6107-2:1997]
3.8
sampling point
precise position within a sampling location from which samples are taken
[ISO 6107-2:1997]
3.9
stream

water flowing continuously or intermittently along a well-defined course, as for a river, but generally on a

smaller scale
[ISO 6107-2:1997]
3.10
sub-sample
portion removed from a sample and intended to be representative of that sample
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3.11
systematic sampling

sampling whereby the samples are taken at predetermined intervals, often equally spaced in time

4 Design of sampling programme
4.1 Sampling point selection
4.1.1 General

The following factors are usually considered in advance of the sampling event. Practical sampling issues,

such as accessibility, may make the ideal sampling point impractical. Any change to the designated sampling

point on any grounds should be discussed and agreed with the sampling programme originator. The outcome

of the deliberations may be recorded in a sampling point file which contains directions to the sampling site, the

detailed location of the sampling point, the method of sampling and specific details (e.g. keys required and

health and safety issues). It may differentiate between equivalent sampling points that may be used if, for

instance, river conditions change. It may also specify the type of sampling to be carried out, e.g. the depth to

sample.
4.1.2 Choice of sampling site

In choosing the exact point from which samples are required, two aspects are generally involved:

a) the selection of the sampling site (i.e. the location of the sampling cross-section within the river basin,

river or stream);
b) the identification of the precise point at the sampling site.

The purpose of sampling often defines sampling sites (as in the case of the determination of the quality of an

effluent discharge), but sometimes the purpose only leads to a general idea of the sampling site, as in the

characterization of quality in a river basin.

The choice of sampling sites for single sampling stations is usually relatively easy. For example, a monitoring

station for a baseline record of water quality can be chosen to permit the use of a convenient bridge, or to

allow an upstream effluent discharge or tributary to be well mixed laterally before the station. Stations for

monitoring water supply abstraction points might need to be fixed within narrow limits (i.e. in proximity to the

abstractions).

In regions that receive seasonal rainfall only, and that have long periods without rain, river volumes and flows

can vary tremendously, and sampling sites for regular use should be chosen so as to ensure that they remain

appropriate and practical for sampling during periods of both maximum and minimum flow.

Where it is necessary to carry out sampling through ice in winter, the chosen sampling site should be as close

as possible to the sampling site used during other seasons of the year. If sampling is to be carried out near a

bridge, the site should be located far enough upstream to avoid contamination from road salt and sand.

Deviations from the routine sampling point should be detailed as part of the dataset and recorded with the

analytical results.
4.1.3 Importance of mixing

When the effects of a tributary, or an effluent, on the quality in a particular identified stretch of river or the main

stream are of interest, at least two sampling sites should be chosen; one should be just upstream of the

confluence and the other should be sufficiently far downstream to ensure that mixing is complete.

The physical characteristics of the channels of watercourses largely control distances required for the

complete mixing of effluents with stream flow.
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Effluents mix in three dimensions in a stream, namely:
a) vertically (from top to bottom);
b) laterally (from one side to the other);

c) longitudinally (levelling out of peaks and troughs in the concentration of effluent constituents as water

passes downstream).

The distances over which effluents mix in these three dimensions should be considered in the selection of

sampling sites and points and are affected by, amongst other things, the water velocity. Tracer techniques

using dyes can be useful in studying mixing processes and conductivity measurements can also be helpful.

NOTE The use of tracer techniques might be subject to licensing by the authority responsible for the watercourse, as

there might be concerns over the release of chemicals into the environment. Where this is the case, it might be better to

use determinants already present, such as pH, temperature or conductivity, to study mixing processes.

Effluents discharged into most streams mix vertically completely within a kilometre. Normally a stream need

not be sampled at more than one depth, although stratification can be induced in slow-moving rivers and

streams by thermal and other density effects. In these cases, sampling at several depths might be necessary

and preliminary tests should be carried out to assess the degree of stratification (see 4.2 for guidance).

The distance necessary for complete lateral mixing is generally dependent on the occurrence of relatively

sharp reverse bends, islets or boulders and is measured in kilometres rather than fractions of a kilometre.

Therefore, to obtain representative samples a stream should be sampled at two or more points across its

width at sites downstream from an effluent or tributary discharge.

Consideration of longitudinal mixing distances can be important in deciding on the frequency of sampling. To

give representative results just below an irregular discharge, more frequent sampling will be required than

would be necessary some distance downstream where longitudinal mixing has been completed to a greater

extent.

The distance in metres, l, for complete mixing, to within 1 % of complete homogeneity, should be calculated

approximately using the following formula (originally published in ISO 555-2):
0,13bc(0,72)c + g
l =
where
b is the average width of the reach, in metres;
c is the Chezy coefficient for the reach (15 < c < 50);
g is the acceleration due to gravity, in metres per second squared;
d is the mean depth of the reach, in metres.

The following example gives an illustration of the effect of different Chezy coefficients on the longitudinal

mixing of a stream.

EXAMPLE Consider two streams both 5 m wide and 1 m deep but with extreme values of the Chezy coefficient; one

of 15 (very rough bottom, i.e. the stream is very fast and turbulent) and the other of 50 (very smooth bottom, i.e. a very

tranquil, slow-moving stream). When calculated in accordance with the equation given in this subclause, the former will

have reached complete homogeneity after 83 m while the latter will not be homogeneous until it has travelled 683 m.

It should be noted that some tests have shown that the above expression can underestimate the mixing length

for small streams of about 5 m in width and overestimate the mixing length for rivers of over about 50 m in

width. This is most likely due to the fact that the average width, average depth and Chezy coefficient are

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usually estimates. Lateral mixing can take place much more slowly than expected and vertical mixing more

quickly. There are many literature sources containing alternative calculations that deal with mixing distances

(see Reference [15]).
4.1.4 Consideration of time-of-travel data

Time-of-travel data can often be of relevance to the choice of sampling location. For example, sampling sites

might have to be arranged to allow certain constituents or pollutants to be traced through a system,

particularly from a discrete source of pollution. This necessitates knowledge of the residence time within the

system under investigation (i.e. the time of travel). Knowledge of the time of travel is also important in

sampling studies to investigate the rate of change of unstable constituents (e.g. in the self-purification of a

water body, the time of travel can provide information on kinetic rate coefficients).

In determining the time of travel, one of the three principal methods should be used, namely the use of surface

floats (see ISO 748), the use of tracers (originally published in ISO 555-1, ISO 555-2 and ISO 555-3) or the

measurement of flow rate with knowledge of cross-sectional areas (see ISO 748 and ISO 1070).

Measurements should be made at a minimum of five different flow rates and the resulting times of travel

plotted against the corresponding flow rates, thereby enabling other travel times to be obtained by

extrapolation or interpolation. However, extrapolation outside 10 % of a measured flow rate value can provide

inaccurate information on time of travel.

It should also be noted that time of travel can vary greatly between seasons in regions that experience

seasonal rainfall only.

ISO 5667-1 should be consulted for general guidance on time of travel and ISO/TR 8363 should be consulted

for guidance on the measurement of liquid flow in open channels.
4.1.5 Non-homogeneous sites

Problems arise in selecting suitable sampling sites whenever the determinands are not homogeneously

distributed throughout the water body of interest. In general, such sampling sites should be avoided, except

when the sites themselves are of direct interest, as they might not yield representative samples of the major

part of the water body. If there is any possibility of a non-homogeneous distribution of the determinands of

interest at the chosen site, experimental tests on the nature and magnitude of any heterogeneity in all three

dimensions should be made. If such tests show that the determinands are distributed homogeneously, any

sampling point will suffice. Otherwise another site should be sought where the determinands are

homogeneously distributed. If it is impossible to find such a sampling site, samples should be taken from

sufficient points at the chosen site to ensure representative results.

These samples can often be combined as sub-samples to form one single composite sample representative of

the quality at the sampling location, so that it is not necessary to analyse individual samples taken from each

of the sampling points. However, this provides no information on the variability in quality between the sampling

points. In addition, the combination of sub-samples in this way cannot be undertaken when sampling for

dissolved gases or other volatile constituents.
4.2 Frequency and time of sampling

It is essential that the sampling programme be properly statistically designed in order that the statistical

summary information produced from the analytical results provides an estimate of the required information t

...

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