ISO 16636:2025

International
Standard
ISO 16636
First edition
Plastics — Disintegration field
2025-04
test of plastics under water
environmental conditions
Plastiques — Essai sur site de désintégration des plastiques dans
les conditions d'un environnement aquatique
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by 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 ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 1
4 Principle . 2
5  Test procedure . 3
5.1 Test material .3
5.2 Reference material .3
5.3 Preparation of test and reference materials .3
5.4 Number of replicates .4
5.5 Immersion in water .5
5.6 Water conditions .6
5.6.1 General .6
5.6.2 Determination of number of microorganisms in water .6
5.6.3 Analysis of microbial community composition in seawater (optional) .6
5.6.4 Properties of water .6
5.7 Termination of the field test and sampling interval .6
6  Analysis and monitoring of the field test . 7
6.1 Photographic documentation .7
6.2 Determination of disintegration .7
6.2.1 General .7
6.2.2 Calculating degree of disintegration of test material based on weight
determination .7
6.2.3 Calculating degree of disintegration rate (film thickness decrease rate) of film
sample .8
6.2.4 Calculating degree of disintegration rate (weight loss rate) of the sample other
than film .8
6.3 Analysing characteristics of plastic materials (optional) .9
6.4 Monitoring environmental parameters (recommended) .9
7 Test report .10
Annex A (informative)  Example of results for disintegrated plastic materials in real sea .11
Annex B (informative)  Microbial counts in sea water .15
Bibliography .16

iii
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.
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 document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 14, Environmental
aspects.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Marine plastic litter has been continuously increasing. Plastic waste released in the environment eventually
reaches the rivers, the lakes and the sea, floats on the water surface, and some of them sink to the riverbed,
lakebed and seabed. Floating plastic litter has a significant negative impact on aquatic life due to accidental
ingestion or entangling. To minimize the risk of plastic waste, it is recommended that plastics become low
molecular weight by microbial action, lose strength, and disintegrate. Biodegradable plastics are designed to
disintegrate in this way. The biodegradation of plastics in the marine environment is defined in laboratory
tests, such as ISO 18830, ISO 19679, ISO 22404, ISO 23977-1 and ISO 23977-2. ISO 23832 describes a test
method for the determination of the degradation rate and disintegration degree. However, these test
methods do not measure disintegration under environmental conditions. ISO 22766 applies to disintegration
only in the sandy sublittoral and the sandy eulittoral zone.
This document provides a test method for determining the disintegration degree of biodegradable plastic
materials floating on the water surface. It can only apply if the biodegradation test according to the ISO
standard, for example ISO 18830, ISO 19679, ISO 23977-1 and ISO 23977-2, has been carried out and has
given a positive result. This test method is simplified so that it can be conducted in various coastal area.
The disintegration is thought to be due to combination of bio-action, non-biochemical action, and physical
degradation, but it is not specified by this method.

v
International Standard ISO 16636:2025(en)
Plastics — Disintegration field test of plastics under water
environmental conditions
1 Scope
This document specifies test methods for the determination of the degree of disintegration of plastic
materials floating in water.
NOTE The disintegration test is a field test performed under natural environmental conditions in a part of the
sublittoral zone, the shores of lakes or rivers, and the test samples are immersed to a depth between 1,5 m to 3 m from
water surface.
This document specifies the general requirements of the apparatus and the procedures for using the test
methods described.
This document is not suitable for the assessment of disintegration caused by heat or light exposure.
The described field test is a disintegration test and not a biodegradation test. Therefore, it cannot be used
for demonstrating biodegradation or for making unqualified claims such as “biodegradable in marine
environment” and similar.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 4591, Plastics — Film and sheeting — Determination of average thickness of a sample, and average thickness
and yield of a roll, by gravimetric techniques (gravimetric thickness)
ISO 4593, Plastics — Film and sheeting — Determination of thickness by mechanical scanning
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
biodegradation
degradation (3.2) caused by biological activity, especially by enzymatic action, leading to a significant change
in the chemical structure of a material
[SOURCE: ISO 472:2013, 2.1680]

3.2
degradation
irreversible process leading to a significant change in the structure of a material, typically characterized
by a change of properties (e.g. integrity, molecular mass or structure, mechanical strength) and/or by
fragmentation, affected by environmental conditions, proceeding over a period of time and comprising one
or more steps
[SOURCE: ISO 472:2013, 2.262]
3.3
disintegration
physical breakdown of a material into small fragments
[SOURCE: ISO 472:2013, 2.1757]
3.4
sublittoral zone
coastal seafloor that is permanently immersed and extends from the low-water line to the continental shelf
edge at 200 m water depth
Not
...