1、BS ISO 19679:2016Plastics Determination ofaerobic biodegradation of non-floating plastic materials in aseawater/sediment interface Method by analysis of evolvedcarbon dioxideBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 19679:2016 BRITISH STANDARDNational fo
2、rewordThis British Standard is the UK implementation of ISO 19679:2016. The UK participation in its preparation was entrusted to TechnicalCommittee PRI/21, Testing of plastics.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not p
3、urport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 89528 9ICS 83.080.01Compliance with a British Standard cannot confer immunity fromlegal obligati
4、ons.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 September 2016.Amendments/corrigenda issued since publicationDateT e x t a f f e c t e dBS ISO 19679:2016 ISO 2016Plastics Determination of aerobic biodegradation of non-floating plastic m
5、aterials in a seawater/sediment interface Method by analysis of evolved carbon dioxidePlastiques Dtermination de la biodgradation arobie des matires plastiques non-flottantes linterface eau de mer/sdiments Mthode par analyse du dioxyde de carbone librINTERNATIONAL STANDARDISO19679First edition2016-0
6、8-15Reference numberISO 19679:2016(E)BS ISO 19679:2016ISO 19679:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by
7、any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 40
8、1CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19679:2016ISO 19679:2016(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 25 Test environment . 26 Reagents 27 Apparatus . 38 Procedure.
9、 38.1 Test material . 38.2 Reference material . 48.3 Preparation of the sediment 48.4 Test setup . 48.5 Pre-conditioning phase 48.6 Start of the test 58.7 Carbon dioxide measurement 58.8 End of the test 69 Calculation and expression of results . 69.1 Calculation 69.1.1 Amount of CO2produced 69.1.2 P
10、ercentage of biodegradation. 89.2 Visual inspection . 89.3 Expression and interpretation of results . 810 Validity of results . 911 Test report . 9Annex A (informative) Example of respirometric system based on CO2measurement .10Bibliography .11 ISO 2016 All rights reserved iiiContents PageBS ISO 196
11、79:2016ISO 19679:2016(E)ForewordISO (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
12、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 Commissi
13、on (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents shoul
14、d be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for iden
15、tifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the conveni
16、ence of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the
17、 following URL: www.iso.org/iso/foreword.html.The committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemical properties.iv ISO 2016 All rights reservedBS ISO 19679:2016ISO 19679:2016(E)IntroductionProducts made with biodegradable plastics are designed to be
18、recovered by means of organic recycling in composting plants or in anaerobic digesters. The uncontrolled dispersion of biodegradable plastics in natural environments is not desirable. The biodegradability of products cannot be considered as an excuse to spread wastes that should be recovered and rec
19、ycled. However, test methods to measure rate and level of biodegradation in natural environments (such as soil or the marine environment) are of interest in order to better characterize the behaviour of plastics in these very particular environments. As a matter of fact, some plastics are used in pr
20、oducts that are applied in the sea (e.g. fishing gear) and sometimes they can get lost or put willingly in marine environment. The characterization of biodegradable plastic materials can be enlarged by applying specific test methods that enable the quantitative assessment of biodegradation of plasti
21、cs exposed to marine sediment and seawater. Plastic products are directly littered or arrive with fresh waters in the pelagic zone (free water). From there, and depending on density, tides, currents, and marine fouling plastics may sink to the sublittoral, and reach the seafloor surface. Many biodeg
22、radable plastics have a density higher than 1 and therefore tend to sink. The sediment passes from aerobic to anoxic and finally anaerobic conditions going from the surface (the interface with seawater) into deeper layers, displaying a very steep oxygen gradient. ISO 2016 All rights reserved vBS ISO
23、 19679:2016BS ISO 19679:2016Plastics Determination of aerobic biodegradation of non-floating plastic materials in a seawater/sediment interface Method by analysis of evolved carbon dioxide1 ScopeThis International Standard specifies a test method to determine the degree and rate of aerobic biodegrad
24、ation of plastic materials when settled on marine sandy sediment at the interface between seawater and the seafloor, by measuring the evolved carbon dioxide.This test method is a simulation under laboratory conditions of the habitat found in different seawater/sediment-areas in the sea, e.g. in a be
25、nthic zone where sunlight reaches the ocean floor (photic zone) that, in marine science, is called sublittoral zoneThe determination of biodegradation of plastic materials buried in marine sediment is outside the scope of this International Standard.Measurement of aerobic biodegradation can also be
26、obtained by monitoring the oxygen consumption, as described in ISO 18830.The conditions described in this International Standard may not always correspond to the optimum conditions for the maximum degree of biodegradation to occur.2 Normative referencesThe following documents, in whole or in part, a
27、re normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 14852:1999, Determination of the ultimate aerobic b
28、iodegradability of plastic materials in an aqueous medium Method by analysis of evolved carbon dioxideISO 8245, Water quality Guidelines for the determination of total organic carbon (TOC) and dissolved organic carbon (DOC)3 Terms and definitionsFor the purposes of this document the following terms
29、and definitions apply.3.1theoretical amount of evolved carbon dioxideThCO2maximum theoretical amount of carbon dioxide evolved after completely oxidising a chemical compound, calculated from the molecular formula or from determination of total organic carbon (TOC)Note 1 to entry: It is expressed as
30、milligrams of carbon dioxide evolved per milligram or gram of test compound.3.2total organic carbonTOCamount of carbon bound in an organic compoundNote 1 to entry: Total organic carbon is expressed as milligrams of carbon per 100 mg of the compound.INTERNATIONAL STANDARD ISO 19679:2016(E) ISO 2016 A
31、ll rights reserved 1BS ISO 19679:2016ISO 19679:2016(E)3.3dissolved organic carbonDOCthat part of the organic carbon in water which cannot be removed by specified phase separation methods, for example by centrifugation at 40 000 ms-2for 15 min or by membranes with pores of 0,2 m to 0,45 m diameter3.4
32、pre-conditioning phasepre-incubation of an inoculum under the conditions of the subsequent test in the absence of test material, with the aim to consume potential organic matter present in excess that could disturb biodegradation measurement and to improve the acclimatization of the microorganisms t
33、o the test conditions4 PrincipleThis test method is based on the determination of evolved carbon dioxide and derives from ISO 14852. The testing medium is based on a solid phase and a liquid phase. The solid phase is a sandy marine sediment laid in the bottom of a closed flask; the liquid phase is a
34、 column of natural or artificial sea water, poured on the sediment. The test material is preferably in the form of a film to be laid down on top of the sediment, at the interface between the solid phase and the liquid phase. This is a simulation of an object that has sunk and finally reached the sea
35、 floor. The system is contained in a closed flask.The carbon dioxide evolved during the microbial degradation is determined by a suitable analytical method. The level of biodegradation is determined by comparing the amount of carbon dioxide evolved with the theoretical amount (ThCO2) and expressed i
36、n percentage. The test result is the maximum level of biodegradation, determined from the plateau phase of the biodegradation curve. The principle of a system for measuring evolved carbon dioxide is given in ISO 14852:1999, Annex A.The details of interlaboratory testing based on the test method spec
37、ified in this International Standard are available in Reference 5.5 Test environmentIncubation shall take place in the dark or in diffuse light in an enclosure which is free from vapours inhibitory to microorganisms and which is maintained at a constant temperature, preferably between 15 C to 25 C,
38、but not exceeding 28 C, to an accuracy of 2 C. Any change in temperature shall be justified and clearly indicated in the test report.NOTE Test results are obtained for temperature that may be different from real conditions in marine environment.6 Reagents6.1 Distilled or deionized water, free of tox
39、ic substances (copper in particular) and containing less than 2 mg/l of DOC.6.2 Artificial seawaterDissolve:Sodium chloride (NaCl) 22 gMagnesium chloride hexahydrate (MgCl2 6 H2O) 9,7 gSodium sulfate (Na2SO4) 3,7 g2 ISO 2016 All rights reservedBS ISO 19679:2016ISO 19679:2016(E)Calcium chloride (CaCl
40、2) 1 gPotassium chloride (KCl) 0,65 gSodium hydrogen carbonate (NaHCO3) 0,20 gin water (6.1) and make up to 1 000 ml.6.3 Natural seawater/sedimentTake a sample of a sandy sediment and seawater with a shovel beneath the low-water line into a bucket. Transfer the wet sediment together with seawater in
41、to sealed containers for transport and fast deliver it to the laboratory. After delivery, conserve the sediment at low temperature (approximately 4 C) until use. The seawater/sediment sample should be preferably used within 4 weeks after sampling. Record storage time and conditions.NOTE Seawater and
42、 sediment can also be sampled from large, well-running public marine aquaria.Measure the TOC, pH and nitrogen content of the sediment and of the natural seawater if used instead of artificial seawater. The carbon content of sediment should be in the range of 0,1 % to 2 %.A preliminary oxidation can
43、be applied to the sediment in order to decrease the organic matter content and the background respiration. Sediment and seawater are fluxed with air and gently stirred (max. 20 r/min to 30 r/min) in a large container for the desired period of time. Report this pre-treatment process in the test repor
44、t.7 Apparatus7.1 Test flasksBiometer flasks of the volume of about 250 ml are appropriate. The vessels shall be located in a constant-temperature room or in a thermostatic apparatus (e.g. water-bath). Stirring can be applied on seawater on condition that it does not disturb the sediment/seawater int
45、erface.NOTE A suitable apparatus is shown in Figure A.1. An example of a stirred apparatus is given in OECD TG 308, Annex 4.67.2 Container for the CO2absorberA glass beaker to be located in the headspace of the reactor and filled with 10 ml of Ba(OH)20,025 N or with 3 ml of KOH 0,5 N.7.3 Analytical
46、balanceAnalytical balance shall have a sensitivity of at least 0,1 mg.7.4 pH meter8 Procedure8.1 Test materialThe test material should be in film or sheet form. Cut samples of the test material in the shape of a disk. Disks shall have a smaller diameter than the glass flasks, so that the disks can b
47、e easily laid on the bottom of the glass flask.The sample shall be of known mass and contain sufficient carbon to yield CO2that can be adequately measured by the system used. ISO 2016 All rights reserved 3BS ISO 19679:2016ISO 19679:2016(E)Use a test material concentration of at least 100 mg/l of sea
48、water plus sediment. This mass of the sample should correspond to TOC of about 60 mg/l. The maximum mass of sample per flask is limited by the oxygen supply to the glass flask. The use of 150 mg to 300 mg of test material per litre seawater plus sediment is recommended.Calculate the TOC from the che
49、mical formula or determine it by a suitable analytical technique (e.g. elemental analysis or measurement in accordance with ISO 8245) and calculate the ThCO2.The form and shape of the test material may influence its biodegradability. Similar shapes and thicknesses should preferably be used if different kinds of plastic materials are to be compared.NOTE 1 The test material may also be introduced as powder. However, this can be critical, as practical experience has shown that it is difficult to keep a powder settled at
