ISO/TC 61/SC 14/WG 2 - Biodegradability

This document specifies a method, by measuring the amount of carbon dioxide evolved, for the determination of the degree of aerobic biodegradability of plastic materials, including those containing formulation additives. The test material is exposed in a synthetic medium under standardized laboratory conditions to an inoculum from activated sludge under aerobic conditions. The conditions used in this document do not necessarily correspond to the optimum conditions allowing maximum biodegradation to occur, but this test method is designed to measure the biodegradation of plastic materials and give an indication of their potential biodegradability. The method enables the assessment of the biodegradation to be improved by calculating a carbon balance (optional, see Annex C). The method applies to the following materials: —   natural and/or synthetic polymers, copolymers or mixtures thereof; —   plastic materials which contain additives such as plasticizers, colorants or other compounds; —   water-soluble polymers; —   materials which, under the test conditions, do not inhibit the microorganisms present in the inoculum. Inhibitory effects can be determined using an inhibition control or by another appropriate method (see, for example, ISO 8192[1]). If the test material is inhibitory to the inoculum, a lower test concentration, another inoculum or a pre-exposed inoculum can be used.

This document specifies test methods for the measurement of the physical degradation of samples made with plastics materials when exposed to marine environmental matrices under aerobic conditions at laboratory scale. This document is not suitable for the assessment of degradation caused by heat (thermo-degradation) or light exposure (photo-degradation).

This document specifies procedures and requirements for plastics, and products made from plastics, that are suitable for recovery through organic recycling. The four following aspects are addressed: a) disintegration during composting; b) ultimate aerobic biodegradation; c) no adverse effects of compost on terrestrial organisms; d) control of constituents. These four aspects are suitable to assess the effects on the industrial composting process. This document is intended to be used as the basis for systems of labelling and claims for compostable plastics materials and products. This document does not provide information on requirements for the biodegradability of plastics which end up in the environment as litter. It is also not applicable to biological treatment undertaken in small installations by householders. NOTE 1   The recovery of compostable plastics through composting can be carried out under the conditions found in well-managed industrial composting processes, where the temperature, water content, aerobic conditions, carbon/nitrogen ratio and processing conditions are optimized. Such conditions are generally obtained in industrial and municipal composting plants. Under these conditions, compostable plastics disintegrate and biodegrade at rates comparable to yard trimmings, kraft paper bags and food scraps. NOTE 2   “Compostable” or “compostable in municipal and industrial composting facilities” are expressions considered to be equivalent to organically recyclable for the purposes of this document.

This document defines a test method used to determine the degree of disintegration of plastic materials in a pilot-scale aerobic composting test under defined conditions. It forms part of an overall scheme for the evaluation of the industrial compostability of plastics as outlined in ISO 17088. The test method laid down in this document is also used to determine the influence of the test material on the composting process and the quality of the compost obtained. This test method cannot be used to determine the aerobic biodegradability of a test material. NOTE Other methods are available for this test (for example, see ISO 14851, ISO 14852 or ISO 14855-1 and ISO 14855-2).

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.

This document specifies a laboratory test method for determining the degree and rate of the aerobic biodegradation level of plastic materials. Biodegradation of plastic materials is determined by measuring the oxygen demand in a closed respirometer 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.

This document specifies a test method to determine the degree and rate of aerobic biodegradation of plastic materials when settled on marine sandy sediment at the interface between seawater and the seafloor, by measuring the evolved carbon dioxide (CO2). This test method can also be applied to other solid materials. 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 benthic zone where sunlight reaches the ocean floor (photic zone) that, in marine science, is called sublittoral zone The determination of biodegradation of plastic materials and other solid materials buried in marine sediment is outside the scope of this document. NOTE Measurement of aerobic biodegradation can also be obtained by monitoring the oxygen consumption, as described in ISO 18830. The conditions described in this document do not always correspond to the optimum conditions for the maximum degree of biodegradation to occur.

This document specifies test methods and criteria for showing intrinsic biodegradability in marine environments of virgin plastic materials and polymers without any preliminary environmental exposure or pre-treatment. Test methods applied in this document are carried out at temperatures in the mesophilic range under aerobic conditions and are aimed to show ultimate biodegradability, i.e. conversion into carbon dioxide, water and biomass. This document neither assesses the constituents, such as regulated metals or substances hazardous to the environment, nor potential ecotoxic effects but intrinsic biodegradability only. These aspects will be considered in a separate standard covering the overall environmental impact of products intentionally or accidentally released in the marine environment. This document does not cover the performance of products made from biodegradable plastic materials and biodegradable polymers. Lifetime and biodegradation rates in the sea of products made with biodegradable plastic materials are generally affected by the specific environmental conditions and by thickness and shape. Although results might indicate that the tested plastic materials and polymers biodegrade under the specified test conditions at a certain rate, the results of any laboratory exposure cannot be directly extrapolated to marine environments at the actual site of use or leakage. This document is not applicable for "marine biodegradable" claims of biodegradable plastic materials. For such purpose, see relevant product standards, if available. The testing scheme specified in this document does not provide sufficient information for determining the specific biodegradation rate (i.e. the rate per available surface area) of the material under testing. For such purpose, see relevant standards about specific biodegradation rate, if available.

This document specifies test methods for the determination of the degree of disintegration of plastic materials exposed to marine habitats under real field conditions. The marine areas under investigation are the sandy sublittoral and the sandy eulittoral zone where plastic materials can either be placed intentionally (e.g. biodegradable fishing nets) or end up as litter due to irresponsible human behaviour. This depends on their physical characteristics, form and size of the materials, and on water currents and tidal movements. This document specifies the general requirements of the apparatus, and the procedures for using the test methods described. The determination of the level of disintegration of plastic materials exposed to pelagic zones such as the sea surface or the water column above the seafloor are not within the scope of this document. 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.

This document is used to determine the degree of disintegration of plastic materials in a pilot-scale aerobic composting test under defined conditions. It forms part of an overall scheme for the evaluation of the compostability of plastics as outlined in ISO 17088. The test method laid down in this document is also used to determine the influence of the test material on the composting process and the quality of the compost obtained. It cannot be used to determine the aerobic biodegradability of a test material. Other methods are available for this (for example, see ISO 14851, ISO 14852 or ISO 14855-1 and ISO 14855-2).

This document specifies a laboratory test method to determine the degree and rate of aerobic biodegradation level of plastic materials. This test method can also be applied to other materials. Biodegradation is determined by measuring the CO2 evolved by the plastic material when exposed to marine sediments sampled from a sandy tidal zone and kept wet with salt-water under laboratory conditions. This test method is a simulation under laboratory conditions of the habitat found in sandy tidal zone that, in marine science, is called eulittoral zone. The conditions described in this document might not always correspond to the optimum conditions for the maximum degree of biodegradation to occur. Deviations from the test conditions described in this document are justified in the test report.

This document specifies a method for determining the ultimate aerobic biodegradability of plastic materials in soil by measuring the oxygen demand in a closed respirometer or the amount of carbon dioxide evolved. The method is designed to yield an optimum degree of biodegradation by adjusting the humidity of the test soil. If a non-adapted soil is used as an inoculum, the test simulates the biodegradation processes which take place in a natural environment; if a pre-exposed soil is used, the method can be used to investigate the potential biodegradability of a test material. This method applies to the following materials: — natural and/or synthetic polymers, copolymers or mixtures of these; — plastic materials which contain additives such as plasticizers or colorants; — water-soluble polymers. It does not necessarily apply to materials which, under the test conditions, inhibit the activity of the microorganisms present in the soil. Inhibitory effects can be measured using an inhibition control or by another suitable method. If the test material inhibits the microorganisms in the soil, a lower test material concentration, another type of soil or a pre-exposed soil can be used.

This document specifies a method of evaluating the ultimate anaerobic biodegradability of plastic materials in a controlled anaerobic slurry digestion system with a solids concentration not exceeding 15 %, which is often found for the treatment of sewage sludge, livestock faeces or garbage. The test method is designed to yield a percentage and rate of conversion of the organic carbon in the test materials to carbon dioxide and methane produced as biogas. The method applies to the following materials, provided they have a known carbon content: — natural and/or synthetic polymers, copolymers or mixtures; — plastic materials that contain additives such as plasticizers, colorants, or other compounds; — water-soluble polymers. It does not apply to materials which exhibit inhibitory effects on the test microorganisms at the concentration chosen for the test. NOTE Inhibitory effects can be determined by an inhibition test (e.g. ISO 13641-1 or ISO 13641-2).

This document specifies a method, by measuring the oxygen demand in a closed respirometer, for the determination of the degree of aerobic biodegradability of plastic materials, including those containing formulation additives. The test material is exposed in an aqueous medium under laboratory conditions to an inoculum from activated sludge. If an unadapted activated sludge is used as the inoculum, the test simulates the biodegradation processes which occur in a natural aqueous environment; if a mixed or pre-exposed inoculum is used, the method is used to investigate the potential biodegradability of a test material. The conditions used in this document do not necessarily correspond to the optimum conditions allowing maximum biodegradation to occur, but this document is designed to determine the potential biodegradability of plastic materials or give an indication of their biodegradability in natural environments. The method enables the assessment of the biodegradability to be improved by calculating a carbon balance (optional, see Annex E). The method applies to the following materials. — Natural and/or synthetic polymers, copolymers or mixtures thereof. — Plastic materials which contain additives such as plasticizers, colorants or other compounds. — Water-soluble polymers. — Materials which, under the test conditions, do not inhibit the microorganisms present in the inoculum. Inhibitory effects can be determined using an inhibition control or by another appropriate method (see, for example, ISO 8192[2]). If the test material is inhibitory to the inoculum, a lower test concentration, another inoculum or a pre-exposed inoculum can be used.

This document specifies a method, by measuring the amount of carbon dioxide evolved, for the determination of the degree of aerobic biodegradability of plastic materials, including those containing formulation additives. The test material is exposed in a synthetic medium under standardized laboratory conditions to an inoculum from activated sludge, mature compost or soil under aerobic, mesophilic conditions. If an unadapted activated sludge is used as the inoculum, the test result can be used to assess the aerobic biodegradation processes which occur in a waste water treatment plant environment. If a mixed or pre-exposed inoculum is used, the method can be used to investigate the potential biodegradability of a test material. The conditions used in this document do not necessarily correspond to the optimum conditions allowing maximum biodegradation to occur, but this test method is designed to measure the biodegradation of plastic materials and give an indication of their potential biodegradability. The method enables the assessment of the biodegradation to be improved by calculating a carbon balance (optional, see Annex C). The method applies to the following materials: — natural and/or synthetic polymers, copolymers or mixtures thereof; — plastic materials which contain additives such as plasticizers, colorants or other compounds; — water-soluble polymers; — materials which, under the test conditions, do not inhibit the microorganisms present in the inoculum. Inhibitory effects can be determined using an inhibition control or by another appropriate method (see, for example, ISO 8192[1]). If the test material is inhibitory to the inoculum, a lower test concentration, another inoculum or a pre-exposed inoculum can be used.

This document specifies a method for determining the ultimate aerobic biodegradability of plastic materials under controlled composting conditions by gravimetric measurement of the amount of carbon dioxide evolved. The method is designed to yield an optimum rate of biodegradation by adjusting the humidity, aeration and temperature of the composting vessel. The method applies to the following materials: — natural and/or synthetic polymers and copolymers, and mixtures of these; — plastic materials that contain additives such as plasticizers or colorants; — water-soluble polymers; — materials that, under the test conditions, do not inhibit the activity of microorganisms present in the inoculum. If the test material inhibits microorganisms in the inoculum, another type of mature compost or pre-exposure compost can be used.

ISO 18830:2016 specifies a test method to determine the degree and rate of aerobic biodegradation of plastic materials when settled on marine sandy sediment at the interface between seawater and the seafloor, by measuring the oxygen demand in a closed respirometer. Measurement of aerobic biodegradation can also be obtained by monitoring the carbon dioxide evolution. This is not in the scope of this International Standard but of ISO 19679. 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 benthic zone where sunlight reaches the ocean floor (photic zone) that, in marine science, is called sublittoral zone The determination of biodegradation of plastic materials buried in marine sediment is outside the scope of this International Standard. The conditions described in this International Standard may not always correspond to the optimum conditions for the maximum degree of biodegradation to occur.

ISO 14853:2016 specifies a method for the determination of the ultimate anaerobic biodegradability of plastics by anaerobic microorganisms. The conditions described in ISO 14853 do not necessarily correspond to the optimum conditions for the maximum degree of biodegradation to occur. The test calls for exposure of the test material to sludge for a period of up to 90 d, which is longer than the normal sludge retention time (25 to 30 d) in anaerobic digesters, although digesters at industrial sites can have much longer retention times. The method applies to the following materials: - natural and/or synthetic polymers, copolymers or mixtures thereof; - plastic materials which contain additives such as plasticizers, colorants or other compounds; - water-soluble polymers; - materials which, under the test conditions, do not inhibit the microorganisms present in the inoculum. Inhibitory effects can be determined using an inhibition control or by another appropriate method (see e.g. ISO 13641). If the test material is inhibitory to the inoculum, a lower test concentration, another inoculum or a pre-exposed inoculum can be used.

ISO 20200:2015 specifies a method of determining the degree of disintegration of plastic materials when exposed to a laboratory-scale composting environment. The method is not applicable to the determination of the biodegradability of plastic materials under composting conditions. Further testing is necessary to be able to claim compostability.

ISO 15985:2014 specifies a method for the evaluation of the ultimate anaerobic biodegradability of plastics based on organic compounds under high-solids anaerobic-digestion conditions by measurement of evolved biogas at the end of the test. This method is designed to simulate typical anaerobic digestion conditions for the organic fraction of mixed municipal solid waste. The test material is exposed in a laboratory test to a methanogenic inoculum derived from anaerobic digesters operating only on pretreated household waste. The anaerobic decomposition takes place under high-solids (more than 20 % total solids) and static non-mixed conditions. The test method is designed to yield the percentage of carbon in the test material and its rate of conversion to evolved carbon dioxide and methane (biogas).

ISO 14855-1:2012 specifies a method for the determination of the ultimate aerobic biodegradability of plastics, based on organic compounds, under controlled composting conditions by measurement of the amount of carbon dioxide evolved and the degree of disintegration of the plastic at the end of the test. This method is designed to simulate typical aerobic composting conditions for the organic fraction of solid mixed municipal waste. The test material is exposed to an inoculum which is derived from compost. The composting takes place in an environment wherein temperature, aeration and humidity are closely monitored and controlled. The test method is designed to yield the percentage conversion of the carbon in the test material to evolved carbon dioxide as well as the rate of conversion. Also specified is a variant of the method, using a mineral bed (vermiculite) inoculated with thermophilic microorganisms obtained from compost with a specific activation phase, instead of mature compost. This variant is designed to yield the percentage of carbon in the test substance converted to carbon dioxide and the rate of conversion.

ISO 10210:2012 describes methods for the preparation of test samples used in the determination of the ultimate aerobic and anaerobic biodegradability of plastic materials in an aqueous medium, soil, controlled compost or anaerobic digesting sludge. The methods described are designed to provide dimensional consistency of test samples, resulting in improved reproducibility of test results during the determination of the ultimate biodegradability of the product. These methods apply to the following materials: natural and/or synthetic polymers, copolymers or mixtures of these; plastic materials that contain additives, such as plasticizers or colorants; plastic composite materials that contain organic or inorganic fillers; products made from the above materials.

ISO 19679:2016 specifies a test method to determine the degree and rate of aerobic biodegradation 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 benthic zone where sunlight reaches the ocean floor (photic zone) that, in marine science, is called sublittoral zone The determination of biodegradation of plastic materials buried in marine sediment is outside the scope of ISO 19679:2016. Measurement of aerobic biodegradation can also be obtained by monitoring the oxygen consumption, as described in ISO 18830. The conditions described in ISO 19679:2016 may not always correspond to the optimum conditions for the maximum degree of biodegradation to occur.

This International Standard specifies procedures and requirements for the identification and labelling of plastics, and products made from plastics, that are suitable for recovery through aerobic composting. The four following aspects are addressed: a) biodegradation; b) disintegration during composting; c) negative effects on the composting process and facility; d) negative effects on the quality of the resulting compost, including the presence of high levels of regulated metals and other harmful components. This specification is intended to establish the requirements for the labelling of plastic products and materials, including packaging made from plastics, as "compostable" or "compostable in municipal and industrial composting facilities" or "biodegradable during composting" (for the purposes of this International Standard, these three expressions are considered to be equivalent). The labelling will, in addition, have to conform to all international, regional, national or local regulations (e.g. European Directive 94/62/EC). NOTE The recovery of compostable plastics through composting can be carried out under the conditions found in well-managed composting plants, where the temperature, water content, aerobic conditions, carbon/nitrogen ratio and processing conditions are optimized. Such conditions are generally obtained in industrial and municipal composting plants. Under these conditions, compostable plastics will disintegrate and biodegrade at rates comparable to yard trimmings, kraft paper bags and food scraps.