1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationWater quality Examination and determination of colourBS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo re
2、production or networking permitted without license from IHS-,-,-National forewordThis British Standard is the UK implementation of EN ISO 7887:2011. It supersedes BS EN ISO 7887:1995 which is withdrawn.The UK participation in its preparation was entrusted by Technical CommitteeEH/3, Water quality, t
3、o Subcommittee EH/3/2, Physical chemical and biochemical methods.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.
4、 The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 60665 6ICS 13.060.60Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 29
5、 February 2012.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EUROPEAN STANDARD
6、NORME EUROPENNE EUROPISCHE NORM EN ISO 7887 December 2011 ICS 13.060.60 Supersedes EN ISO 7887:1994English Version Water quality - Examination and determination of colour (ISO 7887:2011) Qualit de leau - Examen et dtermination de la couleur (ISO 7887:2011) Wasserbeschaffenheit - Untersuchung und Bes
7、timmung der Frbung (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-t
8、o-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 transla
9、tion 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,
10、 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 COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMIT
11、EE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7887:2011: EBS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under licen
12、se with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN ISO 7887:2011 (E) 3 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
13、 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 draw
14、n 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 natio
15、nal 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,
16、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. BS EN ISO 7887:2011Copyright European Committee for Standardization Provided
17、 by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 7887:2011(E) ISO 2011 All rights reserved iiiContents Page 1 Scope 1 2 Normative references 1 3 Terms and definitions . 2 4 Method A: Visual examination . 2 5 Method B: Determination
18、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 c
19、ontrol 12 Annex B (informative) Precision data . 13 Bibliography 15 BS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD ISO 7887:2011(E) ISO
20、 2011 All rights reserved 1Water 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 resp
21、onsibility 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 T
22、his 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
23、and D are harmonized with this traditional procedure (References 23). 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 invo
24、lves 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
25、 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
26、 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
27、 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 fo
28、llowing 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 Specifica
29、tion and test methods ISO 5667-3, Water quality Sampling Part 3: Preservation and handling of water samples ISO 10523, Water quality Determination of pH BS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networki
30、ng permitted without license from IHS-,-,-ISO 7887:2011(E) 2 ISO 2011 All rights reserved3 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
31、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 passin
32、g through a membrane filter of 0,45 m pore size, including cyanate and thiocyanate ISO 8245:1999,63.4 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. Th
33、e 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 f
34、or 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
35、 pore size 0,45 m 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 with hydrochloric acid c(HCI) 2 mol l1 or with surfactant cleaning solution which is re
36、commended 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. Pr
37、event 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. BS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under license with CE
38、NNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 7887:2011(E) ISO 2011 All rights reserved 3Put 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 matte
39、r 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
40、 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 yel
41、low-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
42、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 Metho
43、d 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); w
44、avelengths (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 fil
45、tered (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
46、 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
47、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. BS EN ISO 7887:2011Copyright European Committee for Standardization Provided by IHS under license with CENNot for Re
48、saleNo reproduction or networking permitted without license from IHS-,-,-ISO 7887:2011(E) 4 ISO 2011 All rights reserved5.4 Reagents 5.4.1 Optically pure water Soak a membrane filter, of pore size 0,2 m, 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.
