1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationWater quality Examination and determination of colourBS EN ISO 7887:2011National forewordThis British Standard is the UK implementation of EN ISO 7887:2011. It supersedes BS EN I
2、SO 7887:1995 which is withdrawn.The UK participation in its preparation was entrusted by Technical CommitteeEH/3, Water quality, to Subcommittee EH/3/2, Physical chemical and biochemical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 pub
3、lication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. 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
4、 fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 29 February 2012.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN ISO 7887:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7
5、887 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 Bestimmung der Frbung (ISO 7887:2011) This
6、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 referen
7、ces 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 m
8、ember 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, Icela
9、nd, 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 KOMITEE FR NORMUNG Management Centre: Avenue
10、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 7887:2011EN ISO 7887:2011 (E) 3 Foreword This document (EN ISO 7887:2011) has been prepared by Technical Committee ISO/TC 147
11、 “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 confl
12、icting 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
13、 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, Gre
14、ece, 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
15、modification. BS EN ISO 7887:2011ISO 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 of the true colour using optical instruments 3 6 Method C: Determination of true
16、 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 BS EN ISO 78
17、87:2011INTERNATIONAL STANDARD ISO 7887:2011(E) ISO 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 problem
18、s, 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
19、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 h
20、exachloroplatinate scale (Reference 1). Methods C 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
21、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 co
22、lour 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 a
23、nd 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. Howeve
24、r, 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
25、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 3
26、696, 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 BS EN ISO 7887:2011ISO 7887:2011(E) 2 ISO 2011 All rights reserved3 Terms and definitions For the
27、 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 c
28、hanging 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 m pore size, including cyanate and thiocyanate ISO 8245:1999,63.4 NOTE DOC in natura
29、l 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
30、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 conc
31、entration 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 m 4 Method A: Visual examination 4.1 Sampling bottles Colourless bottle, see ISO 5667-3. Maintain all gl
32、assware 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 recommended for laboratory use. Finally rinse with water for washing (5.4.2) and allow to drain. 4.2 Sampling and samples
33、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.
34、4.3 Procedure Shake the sample to solubilize any matter that can dissolve. BS EN ISO 7887:2011ISO 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 suspe
35、nded 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 o
36、f 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
37、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
38、 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
39、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
40、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 sam
41、ple 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 r
42、etained 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 pres
43、ent. 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. BS EN ISO 7887:2011ISO 7887:2011(E) 4 ISO 2011 All rights reserved5.4 Reagents 5.4.1 Optically pure water
44、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 ab
45、sorbance, 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 doubl
46、e 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 filte
47、r assembly, with filters of pore size 0,2 m and 0,45 m. 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 examinat
48、ion, filter the water sample through a membrane filter of pore size 0,45 m (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 t
49、o 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. If the spectral absorption coefficient, , at the wavelength, , is less than 0,1 cm1, the optical pathlength of the cell should be 10 mm or mor
