SIST EN ISO 7887:2012

Water quality - Examination and determination of colour (ISO 7887:2011)

ISO 7887:2011 specifies four different methods, designated A to D, for the examination of colour.
The previously most employed method for assessment of water colour in water treatment plants, limnological surveys, etc. was based on the hexachloroplatinate scale. Methods C and D are harmonized with this traditional procedure.
Method A involves examination of apparent colour by visually observing a water sample in a bottle. This gives only preliminary information, for example for use in field work. Only the apparent colour can be reported.
Method B involves determination of the true colour of a water sample using optical apparatus and is applicable to raw and potable water and to industrial water of low colour. A subclause on interferences is included.
Method C involves determination of the true colour of a water sample using optical apparatus for comparison with hexachloroplatinate concentration at wavelength, λ = 410 nm. A subclause on interferences is included.
Method D involves determination of colour by visual comparison with hexachloroplatinate standard solutions and can be applied to raw and drinking water. A subclause on interferences is included.
Methods A and B are appropriate if the colour hue of the sample differs from the hue of the matching solution.
When stating the result, the procedure used (methods A to D) is also recorded.

Wasserbeschaffenheit - Untersuchung und Bestimmung der Färbung (ISO 7887:2011)

Diese Internationale Norm legt vier verschiedene Verfahren, als A bis D benannt, zur Bestimmung der Färbung fest.
Das bisher bei der Beurteilung der Färbung von Wasser in Wasseraufbereitungsanlagen, bei limnologischen Untersuchungen usw. am häufigsten angewendete Verfahren beruht auf der Hexachloroplatinat Skala [1]. Die Verfahren C und D sind mit diesem herkömmlichen Verfahren [2] und [3] abgestimmt.
Verfahren A beinhaltet ein Verfahren zur Untersuchung der scheinbaren Färbung durch Betrachtung einer Wasser¬probe in einer Flasche. Damit wird nur eine vorläufige Information erhalten, beispielsweise bei Untersuchungen vor Ort. Das Ergebnis kann nur als scheinbare Färbung angegeben werden.
Verfahren B beinhaltet ein Verfahren zur Bestimmung der wahren Färbung einer Wasserprobe mit Hilfe eines optischen Gerätes. Es ist auf Roh  und Trinkwasser und auf schwach gefärbtes Industrieabwasser anwendbar. Zu Störungen siehe entsprechender Abschnitt.
Verfahren C beinhaltet ein Verfahren zur Bestimmung der wahren Färbung einer Wasserprobe mit Hilfe eines optischen Gerätes zum Vergleich mit einer Hexachloroplatinat Konzentration bei einer Wellenlänge von λ = 410 nm. Zu Störungen siehe entsprechender Abschnitt.
Verfahren D beinhaltet ein Verfahren zur Bestimmung der Färbung durch visuellen Vergleich mit Hexachloroplatinat Standardlösungen. Es kann auf Roh  und Trinkwasser angewendet werden. Zu Störungen siehe entsprechender Abschnitt.
Die Verfahren C und D werden empfohlen, wenn sich der Farbton der Probe vom Farbton der Vergleichslösung unterscheidet.
ANMERKUNG 1   Unter Umständen ist es erforderlich, stark gefärbte Wässer vor der Untersuchung oder Bestimmung zu verdünnen. Das kann jedoch die physikalisch chemischen Bedingungen verändern und zu einer Farbänderung führen.
ANMERKUNG 2   In dieser Internationalen Norm beschreibt Anhang A eine interne Qualitätskontrolle für alle Verfahren.
Bei der Angabe des Ergebnisses ist das angewendete Verfahren (Verfahren A bis D) unbedingt mit anzu-geben.

Qualité de l'eau - Examen et détermination de la couleur (ISO 7887:2011)

L'ISO 7887:2011 spécifie quatre méthodes différentes, désignées A à D, d'examen de la couleur.
La méthode qui était la plus couramment utilisée pour l'évaluation de la couleur de l'eau dans les installations de traitement de l'eau, les études limnologiques, etc. était basée sur l'échelle de couleur à l'hexachloroplatinate. Les méthodes C et D sont harmonisées avec cette méthode traditionnelle.
La méthode A implique l'examen de la couleur apparente par observation visuelle d'un échantillon d'eau dans une bouteille. Cette méthode donne uniquement une première indication, pour une application sur le terrain, par exemple. Seule la couleur apparente peut être déterminée.
La méthode B implique la détermination de la couleur vraie d'un échantillon d'eau au moyen d'un appareillage optique, et peut être appliquée aux eaux brutes et potables, ainsi qu'aux eaux industrielles faiblement colorées. Un paragraphe concernant les interférences est inclus.
La méthode C implique la détermination de la couleur vraie d'un échantillon d'eau au moyen d'un appareillage optique par comparaison avec la concentration d'hexachloroplatinate à une longueur d'onde λ = 410 nm. Un paragraphe concernant les interférences est inclus.
La méthode D implique la détermination de la couleur par comparaison visuelle avec des solutions étalons d'hexachloroplatinate et peut être appliquée aux eaux brutes et potables. Un paragraphe concernant les interférences est inclus.
Les méthodes A et B sont appropriées si la teinte de l'échantillon diffère de celle de la solution étalon.
Dans le rapport d'essai, le mode opératoire utilisé (méthodes A à D) est également consigné.

Kakovost vode - Pregled in določevanje barve (ISO 7887:2011)

Ta mednarodni standard določa štiri različne metode, označene od A do D, za pregled barve. V preteklosti najpogosteje uporabljana metoda za presojo barve vode v čistilnih napravah, pri limnoloških raziskavah itd. je temeljila na lestvici heksakloroplatinata. Metodi C in D sta usklajeni s tem tradicionalnim postopkom. Metoda A vključuje presojo dejanske barve z vizualnim opazovanjem vodnega vzorca v steklenici. To daje samo predhodne informacije, na primer pri uporabi na terenu. Poročati je mogoče samo o dejanski barvi. Metoda B vključuje določevanje realne barve vodnega vzorca z optično napravo in se uporablja za neobdelano in pitno vodo ter industrijsko vodo, ki ni močno obarvana. Vključena je podtočka o motnjah. Metoda C vključuje določevanje realne barve vodnega vzorca z optično napravo za primerjavo s koncentracijo heksakloroplatinata pri valovni dolžini – 410 nm. Vključena je podtočka o motnjah. Metoda D vključuje določevanje barve z vizualno primerjavo s standardnimi raztopinami heksakloroplatinata in se lahko uporablja za neobdelano in pitno vodo. Vključena je podtočka o motnjah. Metodi A in B sta ustrezni, če se barvni odtenek vzorca razlikuje od odtenka ujemajoče se raztopine. Pri navajanju rezultata se zabeleži tudi uporabljeni postopek (metode od A do D).

General Information

• Status: Published
• Public Enquiry End Date: 19-Jul-2009
• Publication Date: 10-May-2012
• ICS: 13.060.60 - Examination of physical properties of water
• Technical Committee: KAV - Water quality
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 19-Apr-2012
• Due Date: 24-Jun-2012
• Completion Date: 11-May-2012
• Directive: TP018 - Pravilnik o monitoringu kakovosti površinske vode za življenje in rast morskih školjk in morskih polžev
• Directive: TP128 - Pravilnik o prvih meritvah in obratovalnem monitoringu odpadnih voda
• Directive: TRRTP064 - Rules on initial measurements and operational monitoring of wastewater
• Ref Project: EN ISO 7887:2011 - Water quality - Examination and determination of colour (ISO 7887:2011)

Relations

• Replaces: dSIST ISO/DIS 7887:2009 - Water quality - Examination and determination of colour
• Effective Date: 01-Jun-2012
• Replaces: SIST EN ISO 7887:1996 - Water quality - Examination and determination of colour (ISO 7887:1994)
• Effective Date: 01-Jun-2012

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 7887:2012
01-junij-2012
1DGRPHãþD
dSIST ISO/DIS 7887:2009
SIST EN ISO 7887:1996
.DNRYRVWYRGH3UHJOHGLQGRORþHYDQMHEDUYH,62
Water quality - Examination and determination of colour (ISO 7887:2011)
Wasserbeschaffenheit - Untersuchung und Bestimmung der Färbung (ISO 7887:2011)
Qualité de l'eau - Examen et détermination de la couleur (ISO 7887:2011)
Ta slovenski standard je istoveten z: EN ISO 7887:2011
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
SIST EN ISO 7887:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 7887:2012

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SIST EN ISO 7887:2012


EUROPEAN STANDARD
EN ISO 7887

NORME EUROPÉENNE

EUROPÄISCHE NORM
December 2011
ICS 13.060.60 Supersedes EN ISO 7887:1994
English Version
Water quality - Examination and determination of colour (ISO
7887:2011)
Qualité de l'eau - Examen et détermination de la couleur Wasserbeschaffenheit - Untersuchung und Bestimmung
(ISO 7887:2011) der Färbung (ISO 7887:2011)
This European Standard was approved by CEN on 14 December 2011.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.




EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7887:2011: E
worldwide for CEN national Members.

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SIST EN ISO 7887:2012
EN ISO 7887:2011 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 7887:2012
EN ISO 7887:2011 (E)
Foreword
This document (EN ISO 7887:2011) has been prepared by Technical Committee ISO/TC 147 "Water quality"
in collaboration with Technical Committee CEN/TC 230 “Water analysis” the secretariat of which is held by
DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2012, and conflicting national standards shall be withdrawn at
the latest by June 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 7887:1994.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 7887:2011 has been approved by CEN as a EN ISO 7887:2011 without any modification.

3

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SIST EN ISO 7887:2012

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SIST EN ISO 7887:2012

INTERNATIONAL ISO
STANDARD 7887
Third edition
2011-12-15

Water quality — Examination and
determination of colour
Qualité de l'eau — Examen et détermination de la couleur





Reference number
ISO 7887:2011(E)
©
ISO 2011

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SIST EN ISO 7887:2012
ISO 7887:2011(E)

COPYRIGHT PROTECTED DOCUMENT


©  ISO 2011
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 [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2011 – All rights reserved

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SIST EN ISO 7887:2012
ISO 7887:2011(E)
Contents Page
Foreword . iv
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 2
4  Method A: Visual examination . 2
5  Method B: Determination of the true colour using optical instruments . 3
6  Method C: Determination of true colour using optical instruments for determination of
absorbance at wavelength   410 nm . 5
7  Method D: Visual method for the determination of the colour in natural water . 9
8  Test report . 10
Annex A (informative) Quality control . 12
Annex B (informative) Precision data . 13
Bibliography . 15

© ISO 2011 – All rights reserved iii

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SIST EN ISO 7887:2012
ISO 7887:2011(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 7887 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This third edition cancels and replaces the second edition (ISO 7887:1994), which has been technically
revised.

iv © ISO 2011 – All rights reserved

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SIST EN ISO 7887:2012
INTERNATIONAL STANDARD ISO 7887:2011(E)

Water quality — Examination and determination of colour
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this International
Standard be carried out by suitably qualified staff.
1 Scope
This International Standard specifies four different methods, designated A to D, for the examination of colour.
The previously most employed method for assessment of water colour in water treatment plants, limnological
surveys, etc. was based on the hexachloroplatinate scale (Reference [1]). Methods C and D are harmonized
with this traditional procedure (References [2][3]).
Method A involves examination of apparent colour by visually observing a water sample in a bottle. This gives
only preliminary information, for example for use in field work. Only the apparent colour can be reported.
Method B involves determination of the true colour of a water sample using optical apparatus and is applicable
to raw and potable water and to industrial water of low colour. A subclause on interferences is included.
Method C involves determination of the true colour of a water sample using optical apparatus for comparison
with hexachloroplatinate concentration at wavelength,   410 nm. A subclause on interferences is included.
Method D involves determination of colour by visual comparison with hexachloroplatinate standard solutions
and can be applied to raw and drinking water. A subclause on interferences is included.
Methods A and B are appropriate if the colour hue of the sample differs from the hue of the matching solution.
NOTE 1 Under certain circumstances, strongly coloured water samples require dilution before examination or
determination. However, this can alter the physical-chemical conditions leading to a change in colour.
NOTE 2 An internal quality control procedure for all methods specified in this International Standard is given in
Annex A. Precision data are given in Annex B.
When stating the result, the procedure used (methods A to D) is also recorded.
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 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 10523, Water quality — Determination of pH
© ISO 2011 – All rights reserved 1

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SIST EN ISO 7887:2012
ISO 7887:2011(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
apparent colour of water
colour due to dissolved substances and undissolved suspended matter, determined in the original water
sample without filtration or centrifugation
3.2
colour of water
optical property that causes the changing of the spectral composition of transmitted visible light
3.3
dissolved organic carbon
DOC
sum of organically bound carbon present in water originating from compounds passing through a membrane filter of
0,45 µm pore size, including cyanate and thiocyanate
[6]
[ISO 8245:1999, 3.4]
NOTE DOC in natural waters often originates from natgural organic matter (NOM), a complex mixture of compounds
formed as a result of the breakdown of animal and plant material in the environment. The composition of the mixture is
strongly dependent on the environmental source. Spectroscopic methods are often used to characterize the dissolved
organic matter in natural waters (Reference [4]). The ratio of UV absorbance and DOC concentration (specific UV-
absorption, SUVA) has proved to be useful for optimization of water treatment processes.
3.4
specific colour
ratio between the true colour of a sample and its concentration of dissolved organic carbon
3.5
true colour of water
colour due only to dissolved substances, determined after filtration of the water sample through a membrane
filter of pore size 0,45 μm
4 Method A: Visual examination
4.1 Sampling bottles
Colourless bottle, see ISO 5667-3.
Maintain all glassware that comes into contact with the sample in a scrupulously clean condition by washing
1
with hydrochloric acid [c(HCI)  2 mol l ] or with surfactant cleaning solution which is recommended for
laboratory use. Finally rinse with water for washing (5.4.2) and allow to drain.
4.2 Sampling and samples
Collect samples in bottles (4.1) and carry out the colour test as soon as possible. If storage is unavoidable, the
samples can be stored for up to 5 days in the dark at 4 °C  2 °C. Prevent extensive aeration during storage,
especially in cases where colour-changing redox reactions are likely to occur.
4.3 Procedure
Shake the sample to solubilize any matter that can dissolve.
2 © ISO 2011 – All rights reserved

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SIST EN ISO 7887:2012
ISO 7887:2011(E)
Put the unfiltered sample into a bottle (4.1) and examine the sample in diffused light against a white
background for colour intensity and hue. Allow any suspended matter that settles to do so before examination.
4.4 Qualitative description
State the intensity of the colour (nil, pale, light or dark) and the hue (e.g. yellow, yellowish brown).
EXAMPLE Apparent colour in accordance with ISO 7887, method A: pale, yellowish brown.
5 Method B: Determination of the true colour using optical instruments
5.1 General
The intensity of the colour of a water sample is characterized by its light absorption at the wavelength of
maximum absorption and quantified by measuring the absorption coefficient with a filter photometer or
spectrophotometer. Normally, most of the yellow-brown coloured natural waters, and the coloured waste water
samples of discharges of domestic treatment plants can be measured at 436 nm. Waste water from industrial
waste water treatment plants does not show sufficiently sharp and distinguished absorption maxima. Those
waters shall be examined using the wavelengths specified in 5.2.
5.2 Principle
Characterization of the intensity of colour of a water sample is performed by measuring the attenuation
(absorption) of light. Different colours cause maximum absorption at different wavelengths of the incident
radiation. In accordance with Method B of this International Standard, the colour of the water is determined
using a photometer or a spectrometer at a minimum of three different wavelengths, distributed over the range
of the visible spectrum:
a) (1)  436 nm;
b) (2)  525 nm;
c) (3)  620 nm.
Always use the wavelength   436 nm (Hg 436 nm); wavelengths (2) and (3) can differ slightly from those
specified above, depending on the type of optical filter employed. For a better characterization, measurements
at additional wavelengths near the absorption maximum can be performed.
5.3 Interferences
Prior to measurement, the water sample is filtered (5.7) to avoid interferences by undissolved matter. This
filtration can, however, lead to further interferences (e.g. due to oxidation reactions caused by contact with air
or due to precipitations initiated by the filtration step). As an example, iron and manganese compounds can be
retained on the filter or transferred to a coloured oxidation state. In some cases, particularly in the presence of
colloidal solids, e.g. clay or other finely dispersed matter, it can prove impossible to obtain a clear filtrate. In
this case, mention in the test report that colloidal solids are present.
NOTE Colours often depend on pH. Therefore, the pH of the water sample is regularly determined in parallel with
optical measurements and these results are reported with the other findings.
© ISO 2011 – All rights reserved 3

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SIST EN ISO 7887:2012
ISO 7887:2011(E)
5.4 Reagents
5.4.1 Optically pure water
Soak a membrane filter, of pore size 0,2 μm, in distilled or deionized water for approximately 1 h. Pass
approximately 1 l of water, grade 1, as specified in ISO 3696 through the prepared filter, discarding the first
50 ml of filtrate.
NOTE If freshly distilled or deionized water has no measurable absorbance, it can be used.
5.4.2 Water for washing
Water, grade 3, as specified in ISO 3696.
5.5 Apparatus
5.5.1 Spectrophotometer (option 1), for continuous or discontinuous measurement, suitable for the visible
range of the spectrum (approximately from 330 nm to 780 nm), preferably a scanning double beam instrument
with bandwidth 10 nm.
5.5.2 Filter photometer (option 2), for discontinuous measurements, equipped with spectral line filters
having a bandwidth which is as small as possible (about 20 nm), allowing measurements to include
wavelengths 436 nm, 525 nm and 620 nm.
5.5.3 Membrane filter assembly, with filters of pore size 0,2 μm and 0,45 μm.
5.5.4 pH-meter.
5.6 Sampling and samples
See 4.2.
5.7 Procedure
Set up either the spectrophotometer (5.5.1) or filter photometer (5.5.2) and strictly observe the operating
manual supplied by the manufacturer of the instrument. Prior to examination, filter the water sample through a
membrane filter of pore size 0,45 μm (5.5.3). In parallel with each colour determination, measure the pH of the
filtered sample in accordance with ISO 10523. In the case of strong colours, it can be necessary to use optical
cells with suitable pathlengths down to 1 mm. The water sample can also be diluted with a measured volume
of optically pure water (5.4.1), as appropriate, after filtration. The pH shall be measured before and after
dilution.
Transfer the sample to the optical cell of the spectrophotometer or filter photometer and place optically pure
water (5.4.1) in the reference cell.
1
If the spectral absorption coefficient, , at the wavelength, , is less than 0,1 cm , the optical pathlength of
the cell should be 10 mm or more.
NOTE 1 A cell of optical pathlength down to 1 mm can be used to avoid diluting the sample.
Measure natural waters at 436 nm against optically pure water (5.4.1). Perform further measurements at
525 nm and 620 nm.
NOTE 2 In order to determine the absorption maximum, the entire absorption spectrum between 350 nm and 780 nm
can be taken, using a scanning spectrophotometer (5.5.1).
4 © ISO 2011 – All rights reserved

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SIST EN ISO 7887:2012
ISO 7887:2011(E)
5.8 Calculation
Calculate the spectral absorption coefficient,  (), absorbance per metre, using Equation (1):
A
  f (1)

d
where
A is the absorbance of the water sample at wavelength ;
d is the optical pathlength, in millimetres, of the cell;
f is a factor to give the spectral absorption coefficient, in reciprocal metres (f  1 000).
The volume of water used for dilution should be taken into account when stating the result.
NOTE Most
...

SLOVENSKI STANDARD
oSIST prEN ISO 7887:2009
01-junij-2009
.DNRYRVWYRGH3UHJOHGLQGRORþHYDQMHEDUYH,62',6
Water quality - Examination and determination of colour (ISO/DIS 7887:2009)
Wasserbeschaffenheit - Untersuchung und Bestimmung der Färbung (ISO/DIS
7887:2009)
Qualité de l'eau - Examen et détermination de la couleur (ISO/DIS 7887:2009)
Ta slovenski standard je istoveten z: prEN ISO 7887
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
oSIST prEN ISO 7887:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 7887:2009

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oSIST prEN ISO 7887:2009
EUROPEAN STANDARD
DRAFT
prEN ISO 7887
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2009
ICS 13.060.60 Will supersede EN ISO 7887:1994
English Version
Water quality - Examination and determination of colour
(ISO/DIS 7887:2009)
Qualité de l'eau - Examen et détermination de la couleur Wasserbeschaffenheit - Untersuchung und Bestimmung
(ISO/DIS 7887:2009) der Färbung (ISO/DIS 7887:2009)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 230.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 7887:2009: E
worldwide for CEN national Members.

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oSIST prEN ISO 7887:2009
prEN ISO 7887:2009 (E)
Contents Page
Foreword .3

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oSIST prEN ISO 7887:2009
prEN ISO 7887:2009 (E)
Foreword
This document (prEN ISO 7887:2009) has been prepared by Technical Committee ISO/TC 147 "Water
quality" in collaboration with Technical Committee CEN/TC 230 “Water analysis”, the secretariat of which is
held by DIN.
This document is currently submitted to the parallel Enquiry.
This document will supersede EN ISO 7887:1994.
Endorsement notice
The text of ISO/DIS 7887:2009 has been approved by CEN as a prEN ISO 7887:2009 without any
modification.

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oSIST prEN ISO 7887:2009
DRAFT INTERNATIONAL STANDARD ISO/DIS 7887
ISO/TC 147/SC 2 Secretariat: DIN
Voting begins on: Voting terminates on:
2009-04-02 2009-09-02
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Water quality — Examination and determination of colour
Qualité de l'eau — Examen et détermination de la couleur
[Revision of second edition (ISO 7887:1994)]
ICS 13.060.60

ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for Standardization (ISO), and
processed under the ISO-lead mode of collaboration as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member bodies for a parallel
five-month enquiry.
Should this draft be accepted, a final draft, established on the basis of comments received, will be
submitted to a parallel two-month approval vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©
International Organization for Standardization, 2009

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oSIST prEN ISO 7887:2009
ISO/DIS 7887
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©
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Contents Page
Foreword .iv
1 Scope.1
2 Normative references.2
3 Terms and definitions .2
4 Visual examination.2
5 Determination of the true colour using optical instruments.3
6 Determination of true colour using optical instruments for determination of absorbance
at wavelength λ = 410 nm .5
7 Visual method for the determination of the colour in natural water .9
8 Statistical data and test report.11
Annex A (informative) Use of specific colour for characterisation of NOM.13
Annex B (informative) Statistics.14
Bibliography.15

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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
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 7887 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This third edition cancels and replaces the second edition (ISO 7887:1994), which has been technically
revised.

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oSIST prEN ISO 7887:2009
DRAFT INTERNATIONAL STANDARD ISO/DIS 7887

Water quality — Examination and determination of colour

WARNING – Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT – It is absolutely essential that tests conducted in accordance with this International
Standard be carried out by suitably qualified staff.
1 Scope
This International Standard specifies four methods for the examination of colour.
The previously most employed for assessment of water colour in water treatment plants, limnological surveys
etc. was based on the hexachloroplatinate scale [1]. The procedures in Clauses 6 and 7 are harmonised with
this traditional procedure [2] and [4].
Clause 4 specifies a method for the examination of apparent colour by visually observing a water sample in a
bottle. This gives only preliminary information, for example for use in field work. Only the apparent colour can
be reported.
Clause 5 specifies a method for the determination of the true colour of a water sample using optical apparatus
and is applicable to raw and potable water and to industrial water of low colour. For interferences see 5.3.
Clause 6 specifies a method for the determination of the true colour of a water sample using optical apparatus
for comparison with hexachloroplatinate concentration at wavelength λ = 410 nm. For interferences see 6.2.
Clause 7 specifies a method for the determination of the colour by visual comparison with hexachloroplatinate
standard solutions and may be applied to raw and drinking water. For interferences see 7.2.
The procedures in Clauses 4 and 5 are recommended if the colour hue of the sample differs from the hue of
the matching solution.
Under certain circumstances, strongly coloured water samples need to be diluted before examination or
determination. However, this may alter the physical-chemical conditions leading to a change in colour.
One purpose of the present revision is to forward the use of colour units (CU) instead of the traditional unit
-1
mg Pt l which is often a cause of confusion, since the element Pt is hardly present in the sample
When stating the result, it is absolutely necessary to refer to the applied procedure (Clauses 4 to 7).
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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 3696, Water for analytical use — Specification and test methods
ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water
samples
ISO 10523, Water quality — Determination of pH
CIE Publication No. 17.4:1987, International lighting vocabulary
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
apparent colour of water
colour due to dissolved substances and undissolved suspended matter; determined in the original water
sample without filtration or centrifugation
3.2
colour of water
optical property that causes the changing of the spectral composition of transmitted visible light
3.3
natural organic matter
(NOM)
matter found in varying concentrations in all natural water sources
NOTE It is a complex mixture of compounds formed as a result of the breakdown of animal and plant material in the
environment. The composition of the mixture is strongly dependent on the environmental source, and generalisations
regarding chemical character can be prone to misinterpretation as the character of the compounds present in the mixture
is extremely diverse [3]
3.4
specific colour
rate between the true colour of a sample and its concentration of dissolved organic carbon (see Annex A)
3.5
true colour of water
colour due only to dissolved substances; determined after filtration of the water sample through a membrane
filter of pore size 0,45 µm
4 Visual examination
4.1 Sampling bottles
Colourless bottle, see ISO 5667-3.
Maintain all glassware that will come into contact with the sample in a scrupulously clean condition by washing
-1
with hydrochloric acid [c(HCI) ≈ 2 mol l ] or with surfactant cleaning solution which is recommended for
laboratory use. Finally rinse with water for wash (5.4.2) and allow to drain.
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4.2 Sampling and samples
Collect samples in bottles (4.1) and carry out the colour test as soon as possible after collection. If storage is
unavoidable, the samples can be stored up to five days in the dark at 4 °C ± 2 °C. Prevent extensive aeration
during storage, especially in cases where colour-changing redox reactions are likely to occur.
4.3 Procedure
Shake the sample to solubilise any matter that can dissolve.
Put the unfiltered sample into a bottle (4.1) and examine the sample in diffused light against a white
background for colour intensity and hue. If the sample contains suspended matter, allow suspended matter
that will settle, to do this before examination.
4.4 Expression of results
State the intensity of the colour (nil, pale, light or dark) and the hue (e.g. yellow, yellowish brown).
EXAMPLE Apparent colour according to Clause 4: pale, yellowish brown.
5 Determination of the true colour using optical instruments
5.1 General
The intensity of the colour of a water sample is characterized by its light absorption at the wavelength of
maximum absorption and quantified by measuring the absorption coefficient with a filter photometer or
spectrometer. Normally, most of the yellow-brown coloured natural waters, and the coloured waste water
samples of discharges of domestic treatment plants can be measured at 436 nm. Waste water from industrial
waste water treatment plants does not show sufficiently sharp and distinguished absorption maxima. Those
waters shall be examined using the wavelengths specified in 5.2.
5.2 Principle
Characterization of the intensity of colour of a water sample is performed by measuring the attenuation
(absorption) of light. Different colours cause maximum absorption at different wavelengths of the incident
radiation. According to Clause 5 of this International Standard, the colour of the water is determined using a
photometer or a spectrometer at least three different wavelengths, distributed over the range of the visible
spectrum:
λ(1) = 436 nm
λ(2) = 525 nm
λ(3) = 620 nm
Always use the wavelength λ = 436 nm (Hg 436 nm), whereas λ(2) and λ(3) may differ slightly from the values
specified above, depending on the type of optical filter employed. For a better characterization, measurements
at additional wavelengths near the absorption maximum can be performed.
5.3 Interferences
Prior to measurement, the water sample is filtered (5.7) to avoid interferences by undissolved matter. This
filtration can, however, lead to further interferences (for example, due to oxidation reactions caused by contact
with air or due to precipitations initiated by the filtration step). As an example, iron and manganese
compounds can be retained on the filter or transferred to a coloured oxidation state. In some cases,
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particularly in the presence of colloidal solids, for example clay or other finely dispersed matter, it may not be
possible to obtain a clear filtrate. In this case, mention in the test results that colloidal solids are present.
NOTE Colours often depend on pH. Therefore, the pH of the water sample is regularly determined in parallel with
optical measurements and these results are reported with the other findings.
5.4 Reagent
5.4.1 Optically pure water
Soak a membrane filter, of pore size 0,2 µm, in distilled or deionised water for approximately 1 h. Pass
approximately 1 l of water, grade 1, as specified in ISO 3696 through the prepared filter, discarding the first
50 ml of filtrate.
NOTE If freshly distilled or deionised water has no measurable absorbance it can be used.
5.4.2 Water for wash
Water, grade 3, as specified in ISO 3696.
5.5 Apparatus
5.5.1 Spectrophotometer, for continuous or discontinuous measurement, suitable for the v
...