ISO/DIS 23517-1

Plastics -- Biodegradable mulch films for use in agriculture and horticulture

Plastiques -- Films de paillage biodégradables pour utilisation en agriculture et horticulture

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 23517-1
ISO/TC 61/SC 14 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-09-10 2020-12-03
Plastics — Biodegradable mulch films for use in
agriculture and horticulture —
Part 1:
Requirements and test methods regarding biodegradation,
ecotoxicity and control of constituents

Plastiques — Films de paillage biodégradables pour utilisation en agriculture et horticulture —

Partie 1: Exigences et méthodes d'essai concernant la biodégradation, l'écotoxicité et le contrôle des

constituants
ICS: 65.020.20; 83.140.10
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ISO/DIS 23517-1:2020(E)
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ISO/DIS 23517-1:2020(E)
Contents  Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2  Normative references ...................................................................................................................................................................................... 1

3  Terms and definitions ..................................................................................................................................................................................... 2

4  Basic requirements ............................................................................................................................................................................................ 3

4.1 General ........................................................................................................................................................................................................... 3

4.1.1 Control of constituents ............................................................................................................................................... 4

4.1.2 Ultimate aerobic biodegradation ....................................................................................................................... 4

4.1.3 Negative effects on terrestrial organism ..................................................................................................... 4

5  Detailed requirements ................................................................................................................................................................................... 4

5.1 Control of constituents ..................................................................................................................................................................... 4

5.1.1 Regulated metals and other elements ........................................................................................................... 4

5.1.2 Per- and poly-fluorinated compounds (PFCs) ........................................................................................ 4

5.1.3 Other hazardous substances ................................................................................................................................. 4

5.1.4 Volatile solids ...................................................................................................................................................................... 5

5.2 Ultimate aerobic biodegradation ............................................................................................................................................ 5

5.2.1 Test method and evaluation criteria ............................................................................................................... 5

5.2.2 Requirements regarding constituents ........................................................................................................... 5

5.3 Negative effects on terrestrial organism........................................................................................................................... 6

5.3.1 Ecotoxicity testing scheme ...................................................................................................................................... 6

5.3.2 Preparation of soils for ecotoxicity tests ..................................................................................................... 7

5.3.3 Acute toxicity plant growth test .......................................................................................................................... 7

5.3.4 Earthworm test ................................................................................................................................................................. 8

5.3.5 Nitrification inhibition test with soil microorganisms ................................................................... 8

6 Test report ................................................................................................................................................................................................................... 9

Annex A (informative) Examples of maximum concentrations of regulated metals and other

elements .....................................................................................................................................................................................................................10

Annex B (normative) Maximum concentrations of per- and poly-fluorinated compounds

and other hazardous substances ......................................................................................................................................................11

Annex C (normative) Determination of acute effects of materials on the emergence and

growth of higher plants ..............................................................................................................................................................................13

Annex D (normative) Determination of acute effects of materials on earthworms .........................................15

Annex E (normative) Determination of effects on reproduction of earthworms................................................16

Annex F (normative) Determination of nitrification of soil microorganisms ........................................................17

Annex G (normative) Preparation of soils for ecotoxicity testing .......................................................................................18

Annex H (informative) Qualitative evaluation of the disintegration in a slide frame test .........................20

Bibliography .............................................................................................................................................................................................................................24

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ISO/DIS 23517-1:2020(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 23517 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.
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ISO/DIS 23517-1:2020(E)
Introduction

Biodegradable mulch films are used worldwide in agriculture and horticulture for many years. They

enhance growing conditions and contribute to increased yields and improved crop quality by, for

example:
— inhibiting the development of weeds;
— reducing significantly the consumption of water and other resources;
— control of soil temperature;
— reduction in leaching of mineral elements and other fertilizer;
— reduction in soil compaction;
— protecting the crops from soil.

In addition, at the end of the intended service life it is no longer necessary for farmers to retrieve the

biodegradable mulch film from the field for disposal or recycling after the harvest. Farmers can simply

plow it under along with what remains from the plants.

This document defines the standard specification to be met for biodegradable mulch films to be used in

agriculture and horticulture.

ISO 23517 consists of the following parts, under the general title Plastics — Biodegradable mulch films

for use in agriculture and horticulture:

— Part 1: Requirements and test methods regarding biodegradation, ecotoxicity and control of constituents

— Part 2: Requirements and test methods regarding product characteristics of mulch films

Part 1 is suited to characterize both the plastic materials which are used to manufacture mulch films

and the mulch films itself with respect to characteristics such as biodegradation, adverse effects on

terrestrial organisms and control of constituents.

Part 2 is a product standard which can be used to characterize mulch films regarding relevant physical

product characteristics including dimensional, mechanical and optical properties.

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DRAFT INTERNATIONAL STANDARD ISO/DIS 23517-1:2020(E)
Plastics — Biodegradable mulch films for use in
agriculture and horticulture —
Part 1:
Requirements and test methods regarding biodegradation,
ecotoxicity and control of constituents
1 Scope

This document is applicable to biodegradable plastic materials used to produce mulch films or

biodegradable mulch films ready to be used for mulch applications in agriculture and horticulture.

Biodegradable mulch films are not designed to be recovered, but to be incorporated into soil at the end

of the intended service life.

This document specifies test methods and evaluation criteria by addressing the following

characteristics:
a) Control of constituents
b) Biodegradation
c) Negative effects on terrestrial organisms

NOTE This document is construed in a way that it can be used to assess other soil biodegradable plastic

products that do not qualify as mulch films. For example: drip tape, twine, clips, and plant pots.

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 10390, Soil quality — Determination of pH

ISO 11268-1, Soil quality — Effects of pollutants on earthworms — Part 1: Determination of acute toxicity

to Eisenia fetida/Eisenia andrei

ISO 11268-2, Soil quality — Effects of pollutants on earthworms — Part 2: Determination of effects on

reproduction of Eisenia fetida/Eisenia andrei

ISO 11269-2, Soil quality — Determination of the effects of pollutants on soil flora — Part 2: Effects of

contaminated soil on the emergence and early growth of higher plants

ISO 11274, Soil quality — Determination of the water-retention characteristic — Laboratory methods

ISO 12846, Water quality — Determination of mercury — Method using atomic absorption spectrometry

(AAS) with and without enrichment

EN 14582, Characterization of waste — Halogen and sulfur content — Oxygen combustion in closed

systems and determination methods

EN 15408, Solid recovered fuels — Methods for the determination of sulphur (S), chlorine (Cl), fluorine (F)

and bromine (Br) content
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ISO/DIS 23517-1:2020(E)

ISO 15685, Soil quality — Determination of potential nitrification and inhibition of nitrification — Rapid

test by ammonium oxidation

ISO 17294-2, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-MS) —

Part 2: Determination of selected elements including uranium isotopes

ISO 17556, Plastics — Determination of the ultimate aerobic biodegradability of plastic materials in soil by

measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved

OECD, 2006), Test No. 208: Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test, OECD

Guidelines for the Testing of Chemicals, Section 2, OECD Publishing, Paris, https:// doi .org/ 10 .1787/

978 926 4 070 06 6 - en
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
mulch film

film made from thermoplastic material intended to be used in agriculture and horticulture to cover the

ground in order to improve growing conditions of crops and depending on the colour to control weeds

Note 1 to entry: It is assumed that a transparent mulch film does not allow to control weeds.

[SOURCE: EN 17033:2018, 3.1.1]
3.2
material

homogenous preparation of biodegradable polymer and additives, as necessary, such as carbon black

and colour pigments

Note 1 to entry: Additives are usually introduced under the form of masterbatches using as carrier resin a

biodegradable polymer.
[SOURCE: EN 17033:2018, 3.1.2]
3.3
ultimate aerobic biodegradation

breakdown of an organic compound by microorganisms in the presence of oxygen into carbon dioxide,

water and mineral salts of any other elements present (mineralization) plus new biomass

[SOURCE: ISO/DIS 17088:2019, 3.9]
3.4
mineralization

decomposition of organic matter or organic substances into carbon dioxide, water and the hydrides,

oxides or other mineral salts
[SOURCE: ISO 11074:2015, 3.3.19]
3.5
disintegration
physical breakdown of a material into fragments
[SOURCE: ISO 18606:2013, 3.3]
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ISO/DIS 23517-1:2020(E)
3.6
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]
3.7
total dry solids

amount of solids obtained by taking a known volume of test material or compost and drying at about

105 °C to constant mass
[SOURCE: ISO/DIS 17088:2019, 3.8]
3.8
volatile solids

amount of solids obtained by subtracting the residue of a known volume of test material or compost

after incineration at about 550 °C from the total dry solids of the same sample

Note 1 to entry: The volatile-solids content is an indication of the amount of organic matter present.

[SOURCE: ISO/DIS 17088:2019, 3.10]
3.9
organic constituent

chemical constituent that contains carbon covalently linked to other carbon atoms and to other

elements, most commonly hydrogen, oxygen or nitrogen

Note 1 to entry: Inorganic carbonates, carbides, cyanides and simple oxides such as carbon monoxide and carbon

dioxide are not considered as organic constituent.

Note 2 to entry: Allotropes of carbon, such as diamond, graphite, carbon black, fullerenes, and carbon nanotubes

are also not considered as organic constituent.
[SOURCE: ISO/DIS 17088:2019, 3.15]
3.10
natural soil
soil collected from the surface layer of fields and/or forests
[SOURCE: EN 17033:2018, 3.3.1]
3.11
per- and poly-fluorinated compound
PFC

organofluorine compounds containing only carbon-fluorine bonds and carbon-carbon bonds but also

other heteroatoms
4  Basic requirements
4.1  General

In order to be identified as a biodegradable mulch film in accordance with this document, the mulch film

or the material of the mulch film under investigation shall fulfil all requirements specified in Clause 4

and Clause 5, respectively.
If not, all requirements are met, no reference to this document shall be made.
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ISO/DIS 23517-1:2020(E)
4.1.1  Control of constituents

The mulch film or the material of the mulch film shall be identified and characterized prior to testing

including
— determination of the presence of regulated metals and other elements;

— determination of the presence of per- and poly-fluorinated compounds (PFC) (determined as

fluorine);

— evaluation of the presence of other hazardous substance as specified in Annex B;

taking legal compliance into consideration.
In addition, volatile solids shall be determined.
4.1.2  Ultimate aerobic biodegradation

The ultimate level of aerobic biodegradation shall be established by testing under controlled conditions

as laid down in chapter 5.2.1.
4.1.3  Negative effects on terrestrial organism

The mulch film or the material of the mulch film shall have no adverse effects on terrestrial organisms.

5  Detailed requirements
5.1  Control of constituents
5.1.1  Regulated metals and other elements

The concentrations of regulated metals and other elements in a mulch film or material of the mulch film

shall be less than 50 % of those prescribed for sludges, fertilizers and composts in the country where

the final product will be placed on the market or disposed of (see Annex A for examples).

Regulated metals and other elements shall be determined and reported.
5.1.2  Per- and poly-fluorinated compounds (PFCs)

From a precautionary perspective, per- and poly-fluorinated compounds (PFCs) shall not be

intentionally added to a mulch film or to a material of the mulch film.

The concentration of per- and poly-fluorinated compounds (PFCs) in the mulch or material of the mulch

film shall be determined and reported as fluorine.

The concentration of per- and poly-fluorinated compounds (PFCs) shall be less than 100 mg fluorine/kg

material (dry matter) (see Annex B).

NOTE 1 Most of per- and poly-fluorinated compounds (PFCs) are extremely persistent in the environment and

in addition, certain PFCs are suspected to have bioaccumulative properties and adverse effects for environment

and human health.

NOTE 2 Per- and poly-fluorinated compounds (PFCs) have been frequently used as surface-treatment agents

in e.g. tableware in order to enhance grease resistance or to control water permeability.

5.1.3  Other hazardous substances

From a precautionary perspective, hazardous substances as specified in Annex B shall not be

intentionally added to a mulch film or material of the mulch film.
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ISO/DIS 23517-1:2020(E)

Information on the use of hazardous substances shall be recorded and can be based on a self-declaration.

5.1.4 Volatile solids

A mulch film or material of a mulch film shall contain a minimum of 50 % of volatile solids.

Volatile solids shall be determined and reported.
5.2  Ultimate aerobic biodegradation
5.2.1  Test method and evaluation criteria

The ultimate aerobic biodegradability shall be determined for the whole material or for each organic

constituent.

Test samples shall not be subjected to conditions or procedures, such as a pretreatment by heat and or

an exposure to radiation exposure, designed to accelerate biodegradation prior to testing according to

ISO 17556.

The material is considered to have demonstrated a satisfactory rate and level of biodegradation in soil

if, when tested in accordance with ISO 17556, it achieves a minimum biodegradation percentage as

specified hereunder;

a) 90 % of the organic carbon shall have been converted to CO by the end of the test period (relative

to a reference material). Both the reference material and the test item shall be tested for the same

length of time and the results compared at the same point in time;

b) as an alternative, 90 % (in absolute terms) of the organic carbon shall have been converted to

carbon dioxide by the end of the test period.

If the level of biodegradation exceeds 90 % (relative to a reference material or in absolute terms), then

the biodegradation test can be terminated. However, the test period shall be no longer than 2 years.

The biodegradation test shall be performed at a temperature constant to within ±2 °C in the range

between 20 °C and 28 °C, preferably 25 °C.

Use as reference material a well-defined biodegradable polymer [microcrystalline-cellulose powder

or ashless cellulose filters)]. If possible, the physical form and size of the reference material should be

comparable to that of the test material.
The validity criteria as stated in ISO 17556 shall be fulfilled.

NOTE Biodegradability is assessed by measuring the mineralization level i.e. the conversion of the organic

carbon of a product or a material into CO with the consumption of O under aerobic conditions, or into CO

2 2 2

and CH under anaerobic conditions. During biodegradation, part of the organic carbon is also assimilated as

biomass. This biomass yield typically ranges from 10 % to 40 %, depending on the substrate. As a consequence,

the mineralization level will rarely reach 100 % also when the biodegradation is 100 %, because of biomass

formation. Standard test methods for the accurate determination of product´s or material’s carbon assimilated in

biomass during biodegradation are not available yet.
5.2.2  Requirements regarding constituents

Organic constituents which are present at concentrations of less than 1 % (dry mass) do not need to

demonstrate biodegradability. However, the sum of such constituents shall not exceed 5 % (dry mass).

For organic constituents which are present in the material at a concentration between 1 % and 15 %

(by dry mass), the level of biodegradation shall be proven separately according to 5.2.1.

As an alternative, the level of biodegradation of an organic constituent may be determined using an

artificial blend of the same material. This artificial blend shall consist of at least 15 % of the respective

organic constituent (by total organic carbon (TOC) content). The chemical composition and the

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ISO/DIS 23517-1:2020(E)

structure of the material shall remain the same, but the amount of the organic constituent under

consideration shall be increased to a minimum of 15 % (by total organic carbon (TOC) content). The

artificial blend shall be produced following the same processing conditions (e.g. extrusion) as used

for the production of the original material containing less than 15 % (by dry mass) of the respective

constituent.

In case that the artificial blend meets the criteria specified in 5.2.1 (in absolute terms), then the

constituent is considered biodegradable in the context of this document. The constituent can then be

used at the same (15 %) or lower concentration (<15 %; by dry mass) in a material that also contains

the same co-substrate as the tested material.

NOTE 1 The objective of testing an artificial blend is to verify a synergistic effect on biodegradation of a non

or moderately biodegradable constituent in the presence of a biodegradable co-substrate in the same material.

NOTE 2 The concentration of the constituent in the artificial blend was set at a minimum of 15 % in order

to avoid false positive results, as theoretically a material with e.g. 10 % of a non- or moderately biodegradable

constituent may still reach the pass level for biodegradation specified in 5.2.1.

Constituents that turned out to be readily biodegradable in a ready biodegradation test according to an

[25] [27]

OECD test guideline (OECD 301, Methods A to F ; OECD 310 ) are considered as biodegradable in

the context of this document.

Carbon black which is frequently used in mulch film is an inert solid. Therefore, it is not considered as

an organic constituent and shall not be accounted in the calculation of the degree of biodegradation.

5.3  Negative effects on terrestrial organism
5.3.1  Ecotoxicity testing scheme

Ecotoxicity tests shall be performed in order to investigate possible adverse effects caused by

degradation products resulting from the degradation of the material of a mulch film in soil at the end of

the intended service life.
The test scheme takes into account:

— all relevant terrestrial organism groups as plants, earthworms (invertebrates) and microorganisms;

— important ecological processes critical due to their role in maintaining soil functions as breakdown

of organic matter, formulation of soil structure and cycling of materials;

— all relevant exposure pathways as soil pore water, soil pore air and soil material.

The link between soil organism groups of major ecological importance covering all significant soil

exposure pathways and suitable test methods for the evaluation of ecotoxicity of the materials of mulch

films and their degradation products is shown in Table 1.
Table 1 — Test scheme for the assessment of ecotoxicity
Organism group Ecological process Soil exposure pathway Test methods
plant growth test according to
plants: mainly soil pore water
primary production OECD 208 or ISO 11269-2 with the
- higher plants (by root uptake)
modifications specified in Annex C
diverse and multiple up-
take routes: acute earthworm test according to
ISO 11268-1 with the modifications
- soil pore water;
breakdown of organic
invertebrates:
specified in Annex D or alternative-
matter; formation of
- ingestion of soil ly chronic earthworm toxicity test
- earthworms
soil structure
according to ISO 11268-2 with the
material;
modifications laid down in Annex E
- soil air
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Table 1 (continued)
Organism group Ecological process Soil exposure pathway Test methods
nitrification inhibition test with
microorganisms:
soil microorganisms according to
recycling of nutrients mainly soil pore water
ISO 15685 with the modifications
- bacteria
specified in Annex F
Ecotoxic effects
...