SIST EN ISO 23977-1:2022

Plastics - Determination of the aerobic biodegradation of plastic materials exposed to seawater - Part 1: Method by analysis of evolved carbon dioxide (ISO 23977-1:2020)

This document specifies a laboratory test method for determining the degree and rate of the aerobic biodegradation level of plastic materials. Biodegradation is determined by measuring the CO2 evolved from plastic materials when exposed to seawater sampled from coastal areas under laboratory conditions.
The conditions described in this document might not always correspond to the optimum conditions for the maximum degree of biodegradation, however this test method is designed to give an indication of the potential biodegradability of plastic materials.
NOTE     This document addresses plastic materials but can also be used for other materials.

Kunststoffe - Bestimmung des aeroben Bioabbaus von Meerwasser ausgesetzten Kunststoff-Materialien - Teil 1: Verfahren mittels Analyse des freigesetzten Kohlenstoffdioxids (ISO 23977 1:2020)

Dieses Dokument legt ein Laborprüfverfahren für die Bestimmung des Grads und der Geschwindigkeit des aeroben Bioabbaus von Kunststoffmaterialien fest. Der Bioabbau wird durch die Messung des CO2, das von Kunststoffmaterialien in Kontakt mit Meerwasser aus Küstenbereichen freigesetzt wird, unter Labor-bedingungen bestimmt.
Die in diesem Dokument beschriebenen Bedingungen entsprechen möglicherweise nicht immer den optima¬len Bedingungen für den maximalen Grad des Bioabbaus, jedoch ist dieses Prüfverfahren dafür ausgelegt, einen Hinweis auf die potentielle Bioabbaubarkeit von Kunststoffmaterialien zu liefern.
ANMERKUNG   Dieses Dokument behandelt Kunststoffmaterialien, kann aber auch für andere Materialien verwendet werden.

Plastiques - Détermination de la biodégradation aérobie des matières plastiques exposées à l'eau de mer - Partie 1: Méthode par analyse du dioxyde de carbone dégagé (ISO 23977-1:2020)

Le présent document spécifie une méthode d’essai en laboratoire permettant de déterminer le taux et le niveau de biodégradation aérobie des matériaux plastiques. La biodégradation est déterminée en mesurant le CO2 libéré par des matériaux plastiques exposés à de l’eau de mer prélevée dans des zones côtières, dans des conditions de laboratoire.
Les conditions décrites dans le présent document ne correspondent pas nécessairement aux conditions optimales permettant d’obtenir le taux maximal de biodégradation; cependant, cette méthode d’essai est conçue pour donner une indication de la biodégradabilité potentielle des matériaux plastiques.
NOTE       Le présent document concerne les matériaux plastiques, mais il peut aussi être utilisé pour d’autres matériaux.

Polimerni materiali - Določanje aerobne biorazgradljivosti polimernih materialov, izpostavljenih morski vodi - 1. del: Metoda z analizo sproščenega ogljikovega dioksida (ISO 23977-1:2020)

Ta dokument določa laboratorijsko preskusno metodo za določevanje stopnje in hitrosti aerobne biorazgradljivosti polimernih materialov. Biorazgradljivost se določi z merjenjem CO2, ki se sprošča iz polimernih materialov ob izpostavljenosti morski vodi, vzorčeni iz obalnih območij pod laboratorijskimi pogoji.
Pogoji, ki so opisani v tem dokumentu, morda niso vedno enaki idealnim pogojem, pri katerih pride do največje stopnje biorazgradljivosti, vendar je ta preskusna metoda zasnovana tako, da podaja oceno potencialne biorazgradljivosti polimernih materialov.
OPOMBA: Ta dokument obravnava polimerne materiale, vendar ga je mogoče uporabiti tudi za druge materiale.

General Information

• Status: Published
• Public Enquiry End Date: 30-Sep-2021
• Publication Date: 24-Nov-2021
• ICS: 13.020.40 - Pollution, pollution control and conservation
• ICS: 83.080.01 - Plastics in general
• Technical Committee: IPMA - Polimer materials and products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 17-Nov-2021
• Due Date: 22-Jan-2022
• Completion Date: 25-Nov-2021
• Ref Project: EN ISO 23977-1:2021 - Plastics - Determination of the aerobic biodegradation of plastic materials exposed to seawater - Part 1: Method by analysis of evolved carbon dioxide (ISO 23977-1:2020)

Overview

EN ISO 23977-1:2021 (ISO 23977-1:2020) specifies a laboratory test method to determine the aerobic biodegradation of plastic materials exposed to seawater. The method quantifies biodegradation by measuring carbon dioxide (CO2) evolved from test specimens when incubated with seawater sampled from coastal areas. The procedure gives an indication of potential biodegradability under controlled laboratory conditions and can also be applied to other materials beyond plastics. Note: the test conditions may not represent optimal or full-scale environmental degradation.

Key topics and technical requirements

• Principle: Biodegradation is followed respirometrically by analysis of evolved CO2 as plastics are metabolized by marine microorganisms.
• Test environments: Uses pelagic seawater (simulating offshore/low-current conditions) or seawater with suspended sediment (simulating coastal/high-current conditions).
• Test components covered in the standard:
  • Selection and preparation of test material and reference materials
  • Sampling and handling of coastal seawater as the microbial inoculum
  • Required reagents, apparatus, and an example respirometric system (informative annex)
  • Test setup and pre-conditioning steps
  • CO2 measurement methods and monitoring during the test
  • Calculation of CO2 produced and expression of biodegradation as a percentage
  • Visual inspection, validity criteria and test report requirements
• Data and interpretation: Procedures for calculating the amount of CO2 evolved, converting to percentage biodegradation, and documenting results.

Applications and who uses it

This standard is intended for:

• Materials scientists and polymer formulators evaluating marine biodegradability of new polymers or additives
• Environmental testing laboratories performing standardized biodegradation assays
• Regulatory agencies and certification bodies assessing environmental claims
• Product designers and manufacturers seeking data for eco-design or sustainability assessments
• Researchers studying plastic persistence and ecological impact in marine environments

Practical uses include screening candidate materials for marine biodegradability, supporting environmental risk assessments, generating comparative data for product development, and informing lifecycle or eco-labeling studies. The standard also cautions that biodegradability is not an excuse to release waste into the environment.

Related standards

EN ISO 23977-1 is part of a family of biodegradation test methods. Related ISO tests address other environments and conditions, for example:

• ISO 14855 (composting aerobic tests), ISO 15985 / ISO 13975 (anaerobic tests)
• ISO 17556 (soil), ISO 14851 / 14852 / 14853 (aquatic systems)
• ISO 23977-2 and other marine sediment/seawater interface methods (see ISO catalogue for details)

Keywords: ISO 23977-1, EN ISO 23977-1:2021, plastics biodegradation, seawater biodegradation, evolved CO2, respirometric test, marine environment, laboratory test method.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2022
Polimerni materiali - Določanje aerobne biorazgradljivosti polimernih materialov,
izpostavljenih morski vodi - 1. del: Metoda z analizo sproščenega ogljikovega
dioksida (ISO 23977-1:2020)
Plastics - Determination of the aerobic biodegradation of plastic materials exposed to
seawater - Part 1: Method by analysis of evolved carbon dioxide (ISO 23977-1:2020)
Kunststoffe - Bestimmung des aeroben Bioabbaus von Meerwasser ausgesetzten
Kunststoff-Materialien - Teil 1: Verfahren mittels Analyse des freigesetzten
Kohlenstoffdioxids (ISO 23977 1:2020)
Plastiques - Détermination de la biodégradation aérobie des matières plastiques
exposées à l'eau de mer - Partie 1: Méthode par analyse du dioxyde de carbone dégagé
(ISO 23977-1:2020)
Ta slovenski standard je istoveten z: EN ISO 23977-1:2021
ICS:
13.020.40 Onesnaževanje, nadzor nad Pollution, pollution control
onesnaževanjem in and conservation
ohranjanje
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 23977-1
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2021
EUROPÄISCHE NORM
ICS 83.080.01
English Version
Plastics - Determination of the aerobic biodegradation of
plastic materials exposed to seawater - Part 1: Method by
analysis of evolved carbon dioxide (ISO 23977-1:2020)
Plastiques - Détermination de la biodégradation Kunststoffe - Bestimmung des aeroben Bioabbaus von
aérobie des matières plastiques exposées à l'eau de Meerwasser ausgesetzten Kunststoff-Materialien - Teil
mer - Partie 1: Méthode par analyse du dioxyde de 1: Verfahren mittels Analyse des freigesetzten
carbone dégagé (ISO 23977-1:2020) Kohlenstoffdioxids (ISO 23977 1:2020)
This European Standard was approved by CEN on 8 November 2021.

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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23977-1:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 23977-1:2020 has been prepared by Technical Committee ISO/TC 61 "Plastics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 23977-1:2021
by Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN.
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 May 2022, and conflicting national standards shall be
withdrawn at the latest by May 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
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, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 23977-1:2020 has been approved by CEN as EN ISO 23977-1:2021 without any
modification.
INTERNATIONAL ISO
STANDARD 23977-1
First edition
2020-11
Plastics — Determination of the
aerobic biodegradation of plastic
materials exposed to seawater —
Part 1:
Method by analysis of evolved carbon
dioxide
Plastiques — Détermination de la biodégradation aérobie des
matières plastiques exposées à l'eau de mer —
Partie 1: Méthode par analyse du dioxyde de carbone dégagé
Reference number
ISO 23977-1:2020(E)
©
ISO 2020
ISO 23977-1:2020(E)
© ISO 2020
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 23977-1:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Test environment . 3
6 Reagents . 3
7 Apparatus . 4
8 Procedure. 5
8.1 Test material . 5
8.2 Reference materials . 5
8.3 Test set up . 6
8.4 Pre-conditioning phase . 6
8.5 Start of the test . 6
8.6 Carbon dioxide measurement . 7
8.7 End of the test . 7
9 Calculation and expression of results . 8
9.1 Calculation . 8
9.1.1 Amount of CO produced . 8
9.1.2 Percentage of biodegradation.10
9.2 Visual inspection .11
9.3 Expression and interpretation of results .11
10 Validity of results .11
11 Test report .12
Annex A (informative) Example of a respirometric system .13
Bibliography .15
ISO 23977-1:2020(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.
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 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).
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. 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 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.
A list of all parts in the ISO 23997 series can be found on the ISO website.
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 © ISO 2020 – All rights reserved

ISO 23977-1:2020(E)
Introduction
According to the United Nations Environment Program (UNEP), one of the most notable properties of
synthetic polymers and plastics is their durability which, combined with their accidental loss, deliberate
release and poor waste management has resulted in the ubiquitous presence of plastic in oceans (UNEP,
[16]
2015 ).
It is well known and documented that marine litter can pose risks and a negative impact on living
marine organisms and on human beings. Degradability of plastic materials exposed to the marine
environment is one of the factors affecting impact and strength of effects. The uncontrolled dispersion
of biodegradables 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 recycled. However,
test methods to measure rate and level of biodegradation in natural environments are of interest in
order to better characterize the behaviour of plastics in these very particular environments. Thus, the
degree and rate of biodegradation is of major interest in order to obtain an indication of the potential
biodegradability of plastic materials when exposed to different marine habitats.
ISO/TC 61/SC 14 has established several test methods for biodegradation testing of plastic materials
under laboratory conditions covering different environmental compartments and test conditions, as
shown in Table 1.
Table 1 — Test methods for biodegradation testing of plastics
Conditions
Test methods
Environmental compartment Presence/absence of oxygen
ISO 14855-1
Controlled composting conditions Aerobic conditions
ISO 14855-2
High-solids anaerobic-digestion
Anaerobic conditions ISO 15985
conditions
Controlled anaerobic slurry system Anaerobic conditions ISO 13975
Soil Aerobic conditions ISO 17556
ISO 14851
Aerobic conditions
Aqueous medium ISO 14852
Anaerobic conditions ISO 14853
a
ISO 18830
Seawater/sandy sediment interface Aerobic conditions
a
ISO 19679
a
Marine sediment Aerobic conditions ISO 22404
a
ISO 23977-1
Seawater Aerobic conditions
a
ISO 23977-2
a
Test method for measuring biodegradation of plastic materials when exposed to marine microbes.
All marine biodegradation test methods are based on exposure of plastic materials to marine samples
(seawater and/or sediment) taken from shoreline areas. By a quantitative viewpoint, these methods
are not equivalent, because, for example, the microbial density in seawater is generally lower compared
to the density determined in sediment. In addition, the microbial composition and diversity can be
different. Moreover, as a rule, the nutrient concentration found in sediment is normally higher compared
to the concentration in seawater.
This document provides a test method for determining the biodegradation level of plastic materials
exposed to the microbial population present in seawater from a pelagic zone under laboratory
conditions. The biodegradation is followed by measuring the evolved CO .
The test is performed with either seawater only (“pelagic seawater test”) or with seawater to which
little sediment was added (“suspended sediment seawater test”).
ISO 23977-1:2020(E)
The pelagic seawater test simulates the conditions found in offshore areas with low water currents and
low tidal movements, whereas the suspended sediment seawater test simulates conditions which might
be found in coastal areas with stronger water currents and tidal movements.
vi © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 23977-1:2020(E)
Plastics — Determination of the aerobic biodegradation of
plastic materials exposed to seawater —
Part 1:
Method by analysis of evolved carbon dioxide
1 Scope
This document specifies a laboratory test method for determining the degree and rate of the aerobic
biodegradation level of plastic materials. Biodegradation is determined by measuring the CO evolved
from plastic materials when exposed to seawater sampled from coastal areas under laboratory
conditions.
The conditions described in this document might not always correspond to the optimum conditions for
the maximum degree of biodegradation, however this test method is designed to give an indication of
the potential biodegradability of plastic materials.
NOTE This document addresses plastic materials but can also be used for other materials.
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 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 8245, Water quality — Guidelines for the determination of total organic carbon (TOC) and dissolved
organic carbon (DOC)
ISO 10210, Plastics — Methods for the preparation of samples for biodegradation testing of plastic
materials
ISO 10523, Water quality — Determination of pH
ISO 11261, Soil quality — Determination of total nitrogen — Modified Kjeldahl method
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 http:// www .electropedia .org/
3.1
pelagic zone
water body above the seafloor
Note 1 to entry: It is also referred to as the open water or the water column.
ISO 23977-1:2020(E)
Note 2 to entry: The surface of the pelagic zone is moved by wind-driven waves, is in contact with the atmosphere
and exposed to sunlight. With increasing depth pressure increases, temperature decreases, and light and surface
wave energy are attenuated.
[SOURCE: ISO 22766:2020, 3.4]
3.2
dissolved inorganic carbon
DIC
part of the inorganic carbon in water which cannot be removed by specified phase separation
−2
Note 1 to entry: Phase separation can be achieved for example by centrifugation at 40 000 m⋅s for 15 min or by
membrane filtration using membranes with pores of 0,2 μm to 0,45 μm diameter.
[SOURCE: ISO 14852:—, 3.4]
3.3
theoretical amount of evolved carbon dioxide
ThCO
maximum theoretical amount of carbon dioxide evolved after completely oxidizing a chemical
compound, calculated from the molecular formula
Note 1 to entry: It is expressed as milligrams of carbon dioxide evolved per milligram or gram of test compound.
[SOURCE: ISO 14852:—, 3.5]
3.4
total organic carbon
TOC
amount of carbon bound in an organic compound
Note 1 to entry: It is expressed as milligrams of carbon per 100 mg of the compound.
[SOURCE: ISO 17556:2019, 3.14]
3.5
dissolved organic carbon
DOC
part of the organic carbon in water which cannot be removed by specified phase separation
−2
Note 1 to entry: Phase separation can be achieved for example by centrifugation at 40 000 m⋅s for 15 min or by
membrane filtration using membranes with pores of 0,2 μm to 0,45 μm diameter.
[SOURCE: ISO 14852:—, 3.7]
3.6
lag phase
time from the start of a test until adaptation and/or selection of the degrading microorganisms is
achieved and the degree of biodegradation of a chemical compound or organic matter has increased to
about 10 % of the maximum level of biodegradation (3.8)
Note 1 to entry: It is measured in days.
[SOURCE: ISO 14852:—, 3.8]
3.7
biodegradation phase
time from the end of the lag phase (3.6) of a test until the plateau phase has been reached
Note 1 to entry: It is measured in days.
[SOURCE: ISO 14852:—, 3.10]
2 © ISO 2020 – All rights reserved

ISO 23977-1:2020(E)
3.8
maximum level of biodegradation
degree of biodegradation of a chemical compound or organic matter in a test, above which no further
biodegradation takes place during the test
Note 1 to entry: It is measured in per cent.
[SOURCE: ISO 14852:—, 3.9]
3.9
plateau phase
time from the end of the biodegradation phase (3.7) until the end of a test
Note 1 to entry: It is measured in days.
[SOURCE: ISO 14852:—, 3.11]
3.10
pre-conditioning
pre-incubation of an inoculum under the conditions of the subsequent test in the absence of the chemical
compound or organic matter under test, with the aim of improving the test by acclimatization of the
microorganisms to the test conditions
[SOURCE: ISO 14852:—, 3.13]
4 Principle
This document describes two variations of a test method for determining the biodegradability of plastic
materials by the indigenous population of microorganisms in natural seawater using a static aqueous
test system. The test is performed under mesophilic test conditions for up to two years by incubating
plastic materials with either seawater only (“pelagic seawater test”) or with seawater to which low
amount of sediment has been added (“suspended sediment seawater test”), coming from the same site
as that from which the seawater was taken.
Biodegradation is followed by measuring the evolution of carbon dioxide using a suitable, analytical
method. The level of biodegradation is determined by comparing the amount of carbon dioxide evolved
with the theoretical amount [theoretical amount of evolved carbon dioxide (ThCO )] and expressed in
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:—, Annex A.
5 Test environment
Incubation shall take place in the dark or in diffused light, in an enclosure which is free from vapours
inhibitory to marine microorganisms and which is maintained at a constant mesophilic temperature.
It should preferably be between 15 °C to 25 °C, but not exceeding 28 °C, to an accuracy of ±1 °C. Any
change in temperature shall be justified and clearly indicated in the test report.
NOTE Test results are obtained for temperatures that can be different from real conditions in marine
environment.
6 Reagents
Use only reagents of recognized analytical grade.
6.1 Water
Distilled or deionized water, free of toxic substances (copper in particular) and containing less than
2 mg/l of TOC.
ISO 23977-1:2020(E)
6.2 Natural seawater/sediment
Sampling, preservation, handling, transport and storage of natural seawater, and, if applicable,
sediment collected from the same site as that from which the seawater is taken, shall be in accordance
with ISO 5667-3.
Prior to use, remove coarse particles from the seawater and, if applicable, from the sediment by
appropriate means. The procedure used shall be reported.
Seawater can be filtered using a paper filter in order to remove coarse particles. It is recommended to
reduce the amount of coarse particles in sediment by means of at least two washing steps using filtered
seawater without coarse particles.
Measure TOC, pH and nitrogen content of seawater and, if applicable, of sediment samples according to
ISO 8245, ISO 10523 and ISO 11261, respectively.
If the TOC content of the seawater sample is found to be high, the seawater should be pre-conditioned
for about a week prior to use. If, for instance, the background concentration of TOC exceeds about 20 %
of the total TOC after addition of the test item, then pre-condition the seawater and, if applicable, the
sediment by stirring under aerobic conditions at the test temperature and in the dark or in diffuse light
in order to reduce the content of easily degradable organic material.
Provide the following information on the seawater, and, if applicable, on the sediment sample itself:
— date of collection;
— depth of collection (m);
— appearance of sample - turbid, clear, etc.;
— temperature at the time of collection (°C);
— salinity (PSU);
— total organic carbo
...